draft-ietf-manet-insignia-00.txt   draft-ietf-manet-insignia-01.txt 
INTERNET-DRAFT G-S. Ahn, A. T. Cambell, S-B Lee, X. Zhang
INTERNET-DRAFT Seoung-Bum Lee and Andrew T. Campbell
Columbia University Columbia University
<draft-ietf-manet-insignia-00.txt> November 1998 October 1999
Expires May 1999
<draft-ietf-manet-insignia-01.txt>
Expires May 2000
INSIGNIA INSIGNIA
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are working all provisions of Section 10 of RFC2026. Internet-Drafts are working
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Abstract Abstract
This document specifies INSIGNIA, an in-band signaling system for This document specifies INSIGNIA, an in-band signaling system for
supporting quality of service (QOS) in mobile ad hoc networks. The supporting quality of service (QOS) in mobile ad hoc networks. The
term `in-band signaling` refers to the fact that control information term `in-band signaling` refers to the fact that control information
is carried along with data in IP packets. We argue that in-band is carried along with data in IP packets. We argue that in-band
signaling is more suitable than explicit out-of-band approaches signaling is more suitable than explicit out-of-band approaches
(e.g., RSVP) when supporting end-to-end quality of service in highly (e.g., RSVP) when supporting end-to-end quality of service in highly
dynamic environments such as mobile ad hoc networks where network dynamic environments such as mobile ad hoc networks where network
topology, node connectivity and end-to-end quality of service are topology, node connectivity and end-to-end quality of service are
strongly time-varying. INSIGNIA is designed to support the delivery strongly time-varying. INSIGNIA is designed to support the delivery
of adaptive real-time services and includes fast session/flow/ of adaptive real-time services and includes fast
microflow reservation, restoration and adaptation algorithms session/flow/microflow reservation, restoration and adaptation
between source/destination pairs. In this memo we discuss how algorithms between source/destination pairs. In this memo we discuss
INSIGNIA fits into our broader vision of a wireless flow management how INSIGNIA fits into our broader vision of a wireless flow
model for mobile ad hoc networks and how it interfaces to the management model for mobile ad hoc networks and how it interfaces to
proposed MANET Working Group routing algorithms and IMEP the proposed MANET Working Group routing algorithm.
specification.
Table of Contents Table of Contents
1. INTRODUCTION .................................................. 2 0. WHAT'S CHANGED .............................................. 2
1.1 TERMINOLOGY .............................................. 3
1.2 ASSUMPTIONS .............................................. 5
2. A WIRELESS FOW MANAGEMENT MODEL FOR MOBILE AD HOC NETWORKING .. 5 1. INTRODUCTION ................................................ 3
2.1 PACKET FORWARDING MODULE ................................. 7 1.1 TERMINOLOGY ............................................ 4
2.2 ROUTING MODULE ........................................... 7 1.2 ASSUMPTIONS ............................................ 6
2.3 INSIGNIA MODULE .......................................... 7
2.4 ADMISSION CONTROL MODULE ................................. 7
2.5 PACKET SCHEDULING MODULE ................................. 8
2.6 MEDIUM ACCESS CONTROLLER MODULE .......................... 8
3. INSIGNIA PROTOCOL ............................................. 8 2. A WIRELESS FLOW MANAGEMENT MODEL FOR MOBILE AD HOC NETWORKING 6
3.1 INSIGNIA IP OPTIONS ...................................... 8 2.1 PACKET FORWARDING MODULE ............................... 7
3.2 RESERVATION MODE ......................................... 9 2.2 ROUTING MODULE ......................................... 7
3.3 SERVICE TYPE ............................................. 10 2.3 INSIGNIA MODULE ........................................ 7
3.4 PAYLOAD INDICATOR ........................................ 10 2.4 ADMISSION CONTROL MODULE ............................... 7
3.5 BANDWIDTH INDICATOR ...................................... 10 2.5 PACKET SCHEDULING MODULE ............................... 8
3.6 BANDWIDTH REQUEST ........................................ 11 2.6 MEDIUM ACCESS CONTROLLER MODULE ........................ 8
4. INSIGNIA OPERATIONS ........................................... 12 3. INSIGNIA PROTOCOL ........................................... 8
4.1 FLOW SETUP ............................................... 12 3.1 INSIGNIA IP OPTIONS .................................... 8
4.2 QOS REPORTING ............................................ 14 3.2 RESERVATION MODE ....................................... 9
4.3 SOFT-STATE MANAGEMENT .................................... 15 3.3 SERVICE TYPE ........................................... 10
4.4 FLOW RESTROATION ......................................... 16 3.4 PAYLOAD INDICATOR ...................................... 10
4.5 ADAPTATION ............................................... 17 3.5 BANDWIDTH INDICATOR .................................... 10
3.6 BANDWIDTH REQUEST ...................................... 11
5. INTEROPERABILITY WITH IMEP .................................... 21 4. INSIGNIA OPERATIONS ......................................... 11
4.1 FLOW SETUP ............................................. 12
4.2 QOS REPORTING .......................................... 13
4.3 SOFT-STATE MANAGEMENT .................................. 14
4.4 FLOW RESTROATION ....................................... 15
4.5 ADAPTATION ............................................. 16
6. SECURITY ISSUES ............................................... 21 5. SECURITY ISSUES ............................................. 20
7. APPLICATION ................................................... 22 6. APPLICATION ................................................. 20
8. ACKNOWLEDGMENT ................................................ 22 7. ACKNOWLEDGMENT .............................................. 20
9. REFERENCE ..................................................... 22 8. REFERENCE ................................................... 20
10. AUTHOR'S ADDRESSES ............................................ 24 9. AUTHOR'S ADDRESSES .......................................... 22
0. WHAT'S CHANGED
This memo has minor modifications from the previous draft, the
operation of protocol remains the same. For full detail on the
evaluation of INSIGNIA see [26].
1. INTRODUCTION 1. INTRODUCTION
The introduction of real-time audio, video and data services into The introduction of real-time audio, video and data services into
mobile ad hoc networks presents number of technical barriers that mobile ad hoc networks presents number of technical barriers that are
are due to the time-varying nature of the network topology, node due to the time-varying nature of the network topology, node
connectivity and end-to-end quality of service (QOS). In such connectivity and end-to-end quality of service (QOS). In such
networks, mobile nodes function as hosts and routers. As hosts they networks, mobile nodes function as hosts and routers. As hosts they
represent source and destination nodes in the network while as represent source and destination nodes in the network while as
routers they represent intermediate nodes between a source and routers they represent intermediate nodes between a source and
destination providing store-and-forward services to neighboring destination providing store-and-forward services to neighboring
nodes. The wireless topology that interconnects mobile hosts/routers nodes. The wireless topology that interconnects mobile hosts/routers
can change rapidly in unpredictable ways or remain relatively static can change rapidly in unpredictable ways or remain relatively static
over long periods of time. Another technical issue that needs to be over long periods of time. Another technical issue that needs to be
addressed is associated with the wireless link level performance. addressed is associated with the wireless link level performance.
Mobile ad hoc networks are bandwidth constrained and time-varying Mobile ad hoc networks are bandwidth constrained and time-varying due
due to radio link characteristics and impairments. to radio link characteristics and impairments.
The end-to-end communications abstraction between two communicating The end-to-end communications abstraction between two communicating
mobile hosts can be viewed as a complex channel. Due to node mobile hosts can be viewed as a complex channel. Due to node mobility
mobility and wireless link impairments, user-to-user sessions may and wireless link impairments, user-to-user sessions may need to be
need to be rerouted in the network while preserving the session rerouted in the network while preserving the session connectivity and
connectivity and quality. Network algorithms need to be strongly quality. Network algorithms need to be strongly adaptive and
adaptive and responsive to the time-varying and location dependent responsive to the time-varying and location dependent topological
topological changes, resource availability, quality of service changes, resource availability, quality of service degradation and
degradation and session connectivity. session connectivity.
In order to provide adaptive quality of service support for real- In order to provide adaptive quality of service support for real-time
time service in mobile ad hoc networks, 'flow-states' (i.e., service in mobile ad hoc networks, 'flow-states' (i.e., reservation
reservation states at nodes associated with flows or microflows) states at nodes associated with flows or microflows) need to be
need to be managed. A flow needs to be established, restored, managed. A flow needs to be established, restored, adapted and
adapted and removed over the course of a user-to-user session in removed over the course of a user-to-user session in response to
response to time-varying topology, connectivity and end-to-end time-varying topology, connectivity and end-to-end quality of service
quality of service conditions. conditions.
Since wireless and computational resources are limited in mobile ad Since wireless and computational resources are limited in mobile ad
hoc networks, any signaling overhead needed for wireless flow hoc networks, any signaling overhead needed for wireless flow
management must be kept to a bare minimum. Future signaling systems management must be kept to a bare minimum. Future signaling systems
should be capable of restoring reservations and associated flow- should be capable of restoring reservations and associated flow-
states along a new path in response to topological changes with states along a new path in response to topological changes with
minimum noticeable degradation at the user session level. minimum noticeable degradation at the user session level.
This memo provides an overview of wireless flow management model This memo provides an overview of wireless flow management model that
that supports the delivery of adaptive real-time services in dynamic supports the delivery of adaptive real-time services in dynamic
mobile ad hoc networks. A key component of wireless flow management mobile ad hoc networks. A key component of wireless flow management
is INSIGNIA, an in-band signaling system that supports fast flow is INSIGNIA, an in-band signaling system that supports fast flow
reservation, restoration and adaptation algorithms that are reservation, restoration and adaptation algorithms that are
specifically designed to deliver adaptive real-time services in specifically designed to deliver adaptive real-time services in
mobile ad hoc networking environments. INSIGNIA is designed to be mobile ad hoc networking environments. INSIGNIA is designed to be
lightweight and highly responsive to changes in network topology, lightweight and highly responsive to changes in network topology,
node connectivity and end-to-end quality of service conditions. node connectivity and end-to-end quality of service conditions. For
full detail on the evaluation of INSIGNIA, see [26].
1.1 TERMINOLOGY 1.1 TERMINOLOGY
Mobile Ad Hoc Networks: Mobile Ad Hoc Networks:
Represent autonomous distributed systems that comprise a Represent autonomous distributed systems that comprise a
number of mobile nodes connected by wireless links forming number of mobile nodes connected by wireless links forming
arbitrary time-varying wireless network topologies [20]. arbitrary time-varying wireless network topologies [20].
Adaptive real-time flows: Adaptive real-time flows:
This type of flow represents delay sensitive traffic, e.g., voice This type of flow represents delay sensitive traffic,
and video which can sustain some loss. Real time data flows are e.g., voice and video which can sustain some loss. Real time
assumed to be somewhat loss tolerant and delay sensitive. data flows are assumed to be somewhat loss tolerant and delay
These types of flows typically require flow setup procedures, sensitive. These types of flows typically require flow setup
resource reservation provided by INSIGNIA. procedures, resource reservation provided by INSIGNIA.
Microflows: Microflows:
Micro flows represent short-lived flows, e.g. web style Micro flows represent short-lived flows, e.g. web style
client/server interactions that comprises a limited train of data client/server interactions that comprises a limited train of
packets. These types of flows may require resource assurances in data packets. These types of flows may require resource
the network and, therefore, typically require some form of in- assurances in the network and, therefore, typically require
band support for fast resource allocation. We use the terms some form of in-band support for fast resource allocation. We
session/flow and microflow interchangeably. INSIGNIA has been use the terms session/flow and microflow interchangeably.
designed to transparently support the requirements of both flows INSIGNIA has been designed to transparently support the
and microflows in mobile ad hoc networks. requirements of both flowsand microflows in mobile ad hoc
networks.
Flow Setup: Flow Setup:
A Source initiates a flow set up by transmitting a request packet A Source initiates a flow set up by transmitting a request
with its minimum and maximum bandwidth requirements. Intermediate packet with its minimum and maximum bandwidth requirements.
mobiles receiving request packets, processes the requests and Intermediate mobiles receiving request packets, processes the
forward them to the next appropriate mobile host. A flow setup is requests and forward them to the next appropriate mobile host.
complete when a source receives a QOS report from its peer A flow setup is complete when a source receives a QOS report
destination. from its peer destination.
Restoration: Restoration:
When a reserved flow is rerouted and its associated states When a reserved flow is rerouted and its associated states
(e.g., reservation) are successfully created along the new route. (e.g., reservation) are successfully created along the new
Three types of restoration (viz. `max to max`, `max to min` and route. Three types of restoration (viz. `max to max`,
`min to max`) may be observed along the new path. `max to min` and `min to max`) may be observed along the new
path.
Enhancement Layer (EL) Degradation: Enhancement Layer (EL) Degradation:
When a reserved flow is rerouted and its EL restoration fails, When a reserved flow is rerouted and its EL restoration fails,
then a flow/sessions enhancement layer packets are degraded then a flow/sessions enhancement layer packets are degraded
to best effort service. In a such case, only base layer (BL) to best effort service. In a such case, only base layer (BL)
packets are forwarded/received as reserved packets. packets are forwarded/received as reserved packets.
Flow Degradation: Flow Degradation:
When a reserved flow is rerouted and both EL and BL restoration When a reserved flow is rerouted and both EL and BL restoration
fails. No resource allocation or associated states are created fails. No resource allocation or associated states are created
and all packets are treated as best effort after re-routing. and all packets are treated as best effort after re-routing.
Adaptation: Adaptation:
When EL degradation persists for an unacceptable period, a When EL degradation persists for an unacceptable period, a
destination mobile notifies its source to drop the EL packets destination mobile notifies its source to drop the EL packets
at the source host (scaling down). The destination can also at the source host (scaling down). The destination can also
initiates an EL resource recovery (scaling up) procedure when a initiates an EL resource recovery (scaling up) procedure when a
monitored flow state at the destination indicate that sufficient monitored flow state at the destination indicate that
resources exist along the path to support a better quality level. sufficient resources exist along the path to support a better
quality level.
Adaptation Policy: Adaptation Policy:
Describes the bandwidth adaptation characteristics of a flow and Describes the bandwidth adaptation characteristics of a flow
the actions to be taken based on the observed network conditions and the actions to be taken based on the observed network
experienced by a flow and its ability to adapt to those conditions experienced by a flow and its ability to adapt to
conditions. The decision to trigger adaptation mechanisms (i.e., those conditions. The decision to trigger adaptation mechanisms
scaling flows up/down)is based on application-specific adaptation (i.e., scaling flows up/down)is based on application-specific
policy. adaptation policy.
Adaptation Handler: Adaptation Handler:
A module that stores the adaptation policy that interacts with A module that stores the adaptation policy that interacts with
flow monitoring and QOS report modules. flow monitoring and QOS report modules.
Monitoring Module: Monitoring Module:
A module that keeps track of the incoming INSIGNIA flow state. A module that keeps track of the incoming INSIGNIA flow state.
Typically the packet type, resource availability and QOS Typically the packet type, resource availability and QOS
are periodically monitored. are periodically monitored.
QOS reports: QOS reports:
These are periodic messages that are generated by destinations These are periodic messages that are generated by destinations
to inform peer sources of reception state/status of adaptive to inform peer sources of reception state/status of adaptive
real-time flows. The periodicity depends on the sensitivity of a real-time flows. The periodicity depends on the sensitivity of
flow. Best effort flows do not, typically, generate QOS reports. a flow. Best effort flows do not, typically, generate QOS
reports.
Soft-state management: Soft-state management:
Each mobile host creates, stores and updates the state Each mobile host creates, stores and updates the state
information for each adaptive real-time flow and its reservation information for each adaptive real-time flow and its
status. This state information requires subsequent packets to reservation status. This state information requires subsequent
refresh the flow state otherwise the flow state is considered old packets to refresh the flow state otherwise the flow state is
and automatically removed after a soft-state interval. considered old and automatically removed after a soft-state
interval.
Soft-state timer: Soft-state timer:
The soft-state timer value defines the holding time for real-time The soft-state timer value defines the holding time for real-
reservation state for adaptive real-time flows/flows. If the time reservation state for adaptive real-time flows/flows. If
mobile soft-state is not refreshed within the soft-state timer the mobile soft-state is not refreshed within the soft-state
interval then the state is automatically removed. (Note that the timer interval then the state is automatically removed. (Note
treatment of flows and microflows may differ in terms of the that the treatment of flows and microflows may differ in terms
setting of this state variable. Typically, flows would call for of the setting of this state variable. Typically, flows would
extremely fast reservation and release that may be more aggressive call for extremely fast reservation and release that may be
than the dynamics and timescales associated with longer lived more aggressive than the dynamics and timescales associated
flows. This issue is under experimentation and for further study.) with longer lived flows. This issue is under experimentation
and for further study.)
1.2 ASSUMPTIONS 1.2 ASSUMPTIONS
INSIGNIA assumes that link status sensing and access schemes are INSIGNIA assumes that link status sensing and access schemes are
provided by lower layer entities/protocols. provided by lower layer entities/protocols.
2. A WIRELESS FLOW MANAGEMENT MODEL FOR MOBILE AD HOC NETWORKING 2. A WIRELESS FLOW MANAGEMENT MODEL FOR MOBILE AD HOC NETWORKING
The goal of wireless flow management is to support the delivery of The goal of wireless flow management is to support the delivery of
adaptive real-time services in mobile ad hoc hosts under time- adaptive real-time services in mobile ad hoc hosts under time-
varying conditions. An adaptive service model allows packet audio, varying conditions. An adaptive service model allows packet audio,
video and real-time data applications to specify their maximum and video and real-time data applications to specify their maximum and
minimum bandwidth needs. INSIGNIA plays a central role in the minimum bandwidth needs. INSIGNIA plays a central role in the
resources allocation and management between source and destination resources allocation and management between source and destination
mobiles. Based on availability of end-to-end resources, wireless mobiles. Based on availability of end-to-end resources, wireless
flow management attempts to provide assurances for the minimum or flow management attempts to provide assurances for the minimum or
maximum bandwidth needs depending of resource availability. In maximum bandwidth needs depending of resource availability. In
addition to supporting adaptive real-time services the service model addition to supporting adaptive real-time services the service
also supports IP best-effort packet delivery. model also supports IP best-effort packet delivery.
adaptive mobile adaptive mobile
applications applications
^ ^
+--------------------------------------------------------------+ +--------------------------------------------------------------+
| | | | | |
| +---------------+ | +-----------------+ +-----------+ | | +---------------+ | +-----------------+ +-----------+ |
| | MANET routing | | | INSIGNIA |<---> | admission | | | | MANET routing | | | INSIGNIA |<---> | admission | |
| | protocol | | | | | control | | | | protocol | | | | | control | |
| +---------------+ | +-----------------+ +-----------+ | | +---------------+ | +-----------------+ +-----------+ |
skipping to change at page 6, line 40 skipping to change at page 6, line 50
| \ \ v -ing / \ | drop / \ | | \ \ v -ing / \ | drop / \ |
| \ +------------+ +-----------+ \ | | \ +------------+ +-----------+ \ |
| +-----+ \| packet | | packet | +-----+ | | +-----+ \| packet | | packet | +-----+ |
===>| MAC |===>| forwarding |======>| scheduling|====>| MAC |===> ===>| MAC |===>| forwarding |======>| scheduling|====>| MAC |===>
| +-----+ +------------+ +-----------+ +-----+ | | +-----+ +------------+ +-----------+ +-----+ |
|IP packet in data packets IP packet out| |IP packet in data packets IP packet out|
+--------------------------------------------------------------+ +--------------------------------------------------------------+
Figure 1. Wireless Flow Management Model at a Mobile Host/Router Figure 1. Wireless Flow Management Model at a Mobile Host/Router
Realizing wireless flow management in mobile ad hoc networks Realizing wireless flow management in mobile ad hoc networks presents
presents a number of technical challenges. First, flows and a number of technical challenges. First, flows and microflows should
microflows should be rapidly established without the penalty of a be rapidly established without the penalty of a round trip delay and
round trip delay and with minimal overhead due to signaling. Second, with minimal overhead due to signaling. Second, active flows should
active flows should be maintained and restored in case of routing be maintained and restored in case of routing changes or link
changes or link failure. Wireless flow management should be capable failure. Wireless flow management should be capable of rapidly
of rapidly responding to dynamic topology changes by adapting and responding to dynamic topology changes by adapting and re-
re-establishing affected flows with minimal service disruption. establishing affected flows with minimal service disruption. Third,
Third, flow-state set up during flow establishment should be flow-state set up during flow establishment should be automatically
automatically removed when an application session terminates. Flow- removed when an application session terminates. Flow-state should
state should also be automatically removed at routers no longer on also be automatically removed at routers no longer on the new path
the new path after re-routing has occurred due to topological after re-routing has occurred due to topological changes. The main
changes. modules of the wireless flow management model are illustrated in
Figure 1).
The main modules of the wireless flow management model are
illustrated in Figure 1).
2.1 PACKET FORWARDING MODULE 2.1 PACKET FORWARDING MODULE
The packet forwarding module [15] classifies incoming packets The packet forwarding module [15] classifies incoming packets and
and forwards them to the appropriate module (viz. MANET routing, forwards them to the appropriate module (viz. MANET routing,
INSIGNIA, local applications, wireless packet scheduling modules). INSIGNIA, local applications, wireless packet scheduling modules).
Signaling messages are processed by INSIGNIA and data packets Signaling messages are processed by INSIGNIA and data packets
delivered locally or forwarded to the packet scheduling module. delivered locally or forwarded to the packet scheduling module.
2.2 ROUTING MODULE 2.2 ROUTING MODULE
The routing module dynamically tracks changes in ad hoc network The routing module dynamically tracks changes in ad hoc network
topology making the routing table visible (via APIs) to all topology making the routing table visible (via APIs) to all
intermediate packet forwarding module (e.g., INSIGNIA, packet intermediate packet forwarding module (e.g., INSIGNIA, packet
forwarding). Wireless flow management assumes the availability of forwarding). Wireless flow management assumes the availability of
MANET routing protocol [2] (e.g. Temporally Ordered Routing MANET routing protocol [2] (e.g. Temporally Ordered Routing Algorithm
Algorithm (TORA) [1], Dynamic Source Routing [7], Zone Routing (TORA) [1], Dynamic Source Routing [7], Zone Routing Protocol [5], Ad
Protocol [5], Ad Hoc On demand Distance Vector Routing Protocol Hoc On demand Distance Vector Routing Protocol [6]).
[6]).
2.3 INSIGNIA MODULE 2.3 INSIGNIA MODULE
The INSIGNIA module establishes, restores, adapts and tears down The INSIGNIA module establishes, restores, adapts and tears down
real-time flows. Flow restoration algorithms respond to dynamic real-time flows. Flow restoration algorithms respond to dynamic route
route changes due to mobility. Adaptation algorithms respond to changes due to mobility. Adaptation algorithms respond to changes in
changes in available bandwidth. Based on an in-band signaling available bandwidth. Based on an in-band signaling approach that
approach that explicitly carries control information in the IP explicitly carries control information in the IP packet header, flows
packet header, flows can be rapidly established, restored, adapted can be rapidly established, restored, adapted and released in
and released in response wireless impairments and topology changes. response wireless impairments and topology changes. Because of this
Because of this dynamic environment, network state management is dynamic environment, network state management is based on soft-state
based on soft-state [3], which is well suited to managing [3], which is well suited to managing reservation flow-state in
reservation flow-state in mobile ad hoc networks. mobile ad hoc networks.
2.4 ADMISSION CONTROL MODULE 2.4 ADMISSION CONTROL MODULE
The admission control module is responsible for allocating bandwidth The admission control module is responsible for allocating bandwidth
to flows based on the maximum/minimum bandwidth requested. Once to flows based on the maximum/minimum bandwidth requested. Once
resources have been allocated they are periodically refreshed by a resources have been allocated they are periodically refreshed by a
mobile soft-state mechanism through the reception of data packets. mobile soft-state mechanism through the reception of data packets.
Admission control testing is based on the measured channel Admission control testing is based on the measured channel
capacity/utilization and requested bandwidth. To keep the protocol capacity/utilization and requested bandwidth. To keep the protocol
simple and lightweight, new reservation requests do not affect simple and lightweight, new reservation requests do not affect
existing flow reservations. Rerouted or new flows may be degraded if existing flow reservations. Rerouted or new flows may be degraded
resources are unavailable. ifresources are unavailable.
2.5 PACKET SCHEDULING MODULE 2.5 PACKET SCHEDULING MODULE
The packet scheduling module responds to location dependent channel The packet scheduling module responds to location dependent channel
conditions experienced in wireless networks [22]. The scheduling conditions experienced in wireless networks [22]. The scheduling
mechanism is implementation and QOS model dependent. Currently, we mechanism is implementation and QOS model dependent. Currently, we
have implemented a simple Weighted Round-Robin (WRR) service have implemented a simple Weighted Round-Robin (WRR) service
discipline which takes location dependent channel conditions into discipline which takes location dependent channel conditions into
account. It should be noted that a wide variety of scheduling account. It should be noted that a wide variety of scheduling
disciplines can be used to realize the packet scheduling module. disciplines can be used to realize the packet scheduling module.
2.6 MEDIUM ACCESS CONTROLLER MODULE 2.6 MEDIUM ACCESS CONTROLLER MODULE
The medium access controller module (possibly) provides quality of The medium access controller module (possibly) provides quality of
service driven access to the shared wireless media for adaptive service driven access to the shared wireless media for adaptive
real-time services and best-effort services. The wireless flow real-time services and best-effort services. The wireless flow
management is designed to be transparent to any underlying media management is designed to be transparent to any underlying media
access control protocols. However, the performance of the MANET is access control protocols. However, the performance of the MANET is
strongly coupled to the provisioning of QOS support at the MAC strongly coupled to the provisioning of QOS support at the MAC layer.
layer. Nevertheless, our approach is to investigate the performance Nevertheless, our approach is to investigate the performance of
of INSIGNIA using both non QOS-capable and QOS-capable MACs. INSIGNIA using both non QOS-capable and QOS-capable MACs.
3. INSIGNIA PROTOCOL 3. INSIGNIA PROTOCOL
Mobile ad hoc signaling systems should be lightweight in terms of Mobile ad hoc signaling systems should be lightweight in terms of the
the amount of bandwidth they consume and be capable of reacting to amount of bandwidth they consume and be capable of reacting to fast
fast network dynamics close to call/session and packet transmission network dynamics close to call/session and packet transmission time
time scales. Future signaling systems should be highly responsive to scales. Future signaling systems should be highly responsive to flow
flow re-routing and be capable of re-establishing active re-routing and be capable of re-establishing active reservations
reservations along the new path with minimum disruption to on-going along the new path with minimum disruption to on-going services.
services.
In-band signaling systems are capable of operating close to packet In-band signaling systems are capable of operating close to packet
transmission time scales and are therefore well suited toward transmission time scales and are therefore well suited toward
managing fast time-scale dynamics found in mobile ad hoc managing fast time-scale dynamics found in mobile ad hoc
environments. In contrast, out-of-band signaling systems (e.g. environments. In contrast, out-of-band signaling systems (e.g.
Internet's RSVP, ATM's UNI, etc.) are incapable of responding to Internet's RSVP, ATM's UNI, etc.) are incapable of responding to such
such fast time-scale dynamics. Based on an in-band approach, fast time-scale dynamics. Based on an in-band approach, INSIGNIA is
INSIGNIA is designed to restore 'flow-state' (i.e., a reservation) designed to restore 'flow-state' (i.e., a reservation) in response to
in response to topology changes within the interval of two topology changes within the interval of two consecutive IP packets
consecutive IP packets under ideal conditions. under ideal conditions.
3.1 IP OPTIONS 3.1 IP OPTIONS
To establish an adaptive real-time flows, INSIGNIA uses a new IP To establish an adaptive real-time flows, INSIGNIA uses a new IP
option to setup, restore and adapt resources between source- option to setup, restore and adapt resources between source-
destination pairs. When intermediate nodes receive packets with the destination pairs. When intermediate nodes receive packets with the
these IP options set they attempt to reserve, restore or adapt these IP options set they attempt to reserve, restore or adapt
resources forwarding date packets toward the destination. resources forwarding date packets toward the destination.
By coding control information in the INSIGNIA IP option (in each IP By coding control information in the INSIGNIA IP option (in each IP
header), we support the notion of in-band control which we believe header), we support the notion of in-band control which we believe is
is called for to support QOS in ad-hoc mobile networks. The INSIGNIA called for to support QOS in ad-hoc mobile networks. The INSIGNIA IP
IP option supports flow reservation, restoration and adaptation option supports flow reservation, restoration and adaptation control.
control. Best effort and adaptive real-time services are supported Best effort and adaptive real-time services are supported by INSIGNIA
by INSIGNIA and are indicated by the reservation mode and service and are indicated by the reservation mode and service type fields in
type fields in the IP options as illustrated in Figure 2. Flows are the IP options as illustrated in Figure 2. Flows are represented as
represented as having a discrete base layer (BL) with a minimum having a discrete base layer (BL) with a minimum bandwidth and an
bandwidth and an enhancement layer, which requires the maximum enhancement layer, which requires the maximum bandwidth. This
bandwidth. This characterization is commonly used for multi- characterization is commonly used for multi-resolution traffic (e.g.,
resolution traffic (e.g., MPEG audio and video) and more generally MPEG audio and video) and more generally for real-time data that has
for real-time data that has discrete max-min requirements. discrete max-min requirements.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| IHL |Type of Service| Total Length | |Version| IHL |Type of Service| Total Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |Flags| Fragment Offset | | Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time to Live | Protocol | Header Checksum | | Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address | | Source Address |
skipping to change at page 9, line 36 skipping to change at page 9, line 32
| Destination Address | | Destination Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options (Used for INSIGNIA IP Options) | Padding | | Options (Used for INSIGNIA IP Options) | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2a. IP Header Figure 2a. IP Header
reservation payload bandwidth request reservation payload bandwidth request
mode indicator mode indicator
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
+-------+-----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-------+-----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|REQ/RES|RT/BE|BL/EL|max/min| max_bandwidth | min_bandwidth | |REQ/RES|AS/BE|BL/EL|max/min| max_bandwidth | min_bandwidth |
+-------+-----+-----+-------+---------------+---------------+ +-------+-----+-----+-------+---------------+---------------+
service bandwidth service bandwidth
type indicator type indicator
|<----->|<--->|<--->|<----->|<----------------------------->| |<----->|<--->|<--->|<----->|<----------------------------->|
1 bit 1 bit 1 bit 1 bit 16 bits 1 bit 1 bit 1 bit 1 bit 16 bits
Figure 2b. INSIGNIA IP Options Figure 2b. INSIGNIA IP Options
3.2 RERSERVATION MODE 3.2 RERSERVATION MODE
To establish an adaptive real-time flow, a source node sets the To establish an adaptive real-time flow, a source node sets the
request (REQ) bit in the IP option of a data packet to initiate a request (REQ) bit in the IP option of a data packet to initiate a
reservation request. On reception of a REQ packet, the intermediate reservation request. On reception of a REQ packet, the intermediate
nodes execute admission control and accept or deny the request. If nodes execute admission control and accept or deny the request. If
the request is accepted, resources are committed and subsequent the request is accepted, resources are committed and subsequent
packets are scheduled accordingly. Otherwise, packets are treated as packets are scheduled accordingly. Otherwise, packets are treated as
best effort packets if resources are unavailable. best effort packets if resources are unavailable.
Packets that are received by nodes with their reservation mode set Packets that are received by nodes with their reservation mode set to
to reserved (RES) indicate that the session has previously passed reserved (RES) indicate that the session has previously passed
admission control and resources have been reserved. In the case admission control and resources have been reserved. In the case where
where a RES packet is received and no resources have been allocated a RES packet is received and no resources have been allocated the
the admission controller immediately attempts to make a reservation. admission controller immediately attempts to make a reservation. This
This condition commonly occurs when reserved flows are rerouted condition commonly occurs when reserved flows are rerouted during the
during the lifetime of an active session due to mobility of sources, lifetime of an active session due to mobility of sources,
intermediate router nodes or destinations. intermediate router nodes or destinations.
3.3 SERVICE TYPE 3.3 SERVICE TYPE
The interpretation of the service type, which indicates either a The interpretation of the service type, which indicates either a
real-time (RT) or best-effort (BE) packet, is dependent on the adaptice service (AS) or best-effort (BE) packet, is dependent on the
reservation mode. A packet with the reservation mode set to REQ and reservation mode. A packet with the reservation mode set to REQ and
service type to RT is attempting to setup a real-time flow with the service type to AS is attempting to setup a real-time flow with the
bandwidth requirements of the flow specified in the bandwidth bandwidth requirements of the flow specified in the bandwidth request
request field. A packet with RES/RT set indicates that an end-to-end field. A packet with RES/AS set indicates that an end-to-end
reservation has previously been established. A RES/RT packet service reservation has previously been established. A RES/AS packet service
may be degraded to RES/BE service if the flow is rerouted along a may be degraded to RES/BE service if the flow is rerouted along a new
new path when insufficient resources were available on the new path. path when insufficient resources were available on the new path.
A best effort packet sets the reservation mode to REQ as default and A best effort packet sets the reservation mode to REQ as default and
the service type to BE requiring no resource reservation to be made the service type to BE requiring no resource reservation to be made
in the network. Reception of a RES/BE by a destination node in the network. Reception of a RES/BE by a destination node indicates
indicates an active adaptive real-time flow was degraded to BE due an active adaptive real-time flow was degraded to BE due to
to insufficient resource availability after rerouting to a new path. insufficient resource availability after rerouting to a new path.
3.4 PAYLOAD INDICATOR 3.4 PAYLOAD INDICATOR
The payload field indicates the type of packet being transported. The payload field indicates the type of packet being transported.
INSIGNIA supports two types of payload, i.e., base (BL) and INSIGNIA supports two types of payload, i.e., base (BL) and
enhancement layers (EL). The semantics of the adaptive real-time enhancement layers (EL). The semantics of the adaptive real-time
services are related to the payload type and resource availability. services are related to the payload type and resource availability.
Base and enhancement layers can be assured via distributed end-to- Base and enhancement layers can be assured via distributed end-to-end
end admission control and resource reservation. Maximum bandwidth admission control and resource reservation. Maximum bandwidth
reservation is required to support both base and enhancement layers reservation is required to support both base and enhancement layers
of a flow whereas only minimum bandwidth reservation is required to of a flow whereas only minimum bandwidth reservation is required to
support the base layer. When a flow with minimum reservation support the base layer. When a flow with minimum reservation receives
receives a EL packet in reserved mode (RES/RT) set, it indicates a EL packet in reserved mode (RES/AS) set, it indicates either the
either the reservations for EL has been restored at the bottleneck reservations for EL has been restored at the bottleneck node or an
node or an adaptation (scale-up) has been occurred. adaptation (scale-up) has been occurred.
3.5 BANDWIDTH INDICATOR 3.5 BANDWIDTH INDICATOR
The bandwidth indicator represents the potential resource The bandwidth indicator represents the potential resource
availability for a flow/session along its current path between a availability for a flow/session along its current path between a
source and destination pair. In this respect the bandwidth indicator source and destination pair. In this respect the bandwidth indicator
represents the prospective resource availability to an application represents the prospective resource availability to an application
which will change over time. This does not, however, represent an which will change over time. This does not, however, represent an
actual resource reservation but the potential for one to succeed actual resource reservation but the potential for one to succeed give
give the current indication. The bandwidth indicator is carried in the current indication. The bandwidth indicator is carried in each
each packet and can be therefore viewed as a dynamic state variable packet and can be therefore viewed as a dynamic state variable that
that can be updated by any mobile host on the current path. Based on can be updated by any mobile host on the current path. Based on its
its value it represents a good bandwidth hint that resources are value it represents a good bandwidth hint that resources are
available along the current path to meet the flows minimum or available along the current path to meet the flows minimum or maximum
maximum needs. In this capacity the bandwidth indicator plays an needs. In this capacity the bandwidth indicator plays an important
important role during the flow setup phase and, more importantly, role during the flow setup phase and, more importantly, during the
during the adaptation phase. adaptation phase.
During flow setup the bandwidth indicator represents the resource During flow setup the bandwidth indicator represents the resource
availability along the chosen setup route. Reception of setup availability along the chosen setup route. Reception of setup request
request packets with the bandwidth indicator bit set to MAX packets with the bandwidth indicator bit set to MAX indicates that
indicates that all nodes en-route have sufficient resources to all nodes en-route have sufficient resources to support the maximum
support the maximum bandwidth requested. In contrast, a packet with bandwidth requested. In contrast, a packet with the bandwidth
the bandwidth indicator set to MIN implies that at least one of the indicator set to MIN implies that at least one of the intermediate
intermediate nodes (known as the bottlenecked mobile host) between nodes (known as the bottlenecked mobile host) between the source and
the source and destination has insufficient bandwidth resources to destination has insufficient bandwidth resources to meet the maximum
meet the maximum needs (if specified); however, reception of a needs (if specified); however, reception of a packet with the
packet with the bandwidth indicator set to MIN does indicate that bandwidth indicator set to MIN does indicate that all nodes can
all nodes can support the minimum bandwidth requirement. In this support the minimum bandwidth requirement. In this case, only the
case, only the base layer reservation is acknowledged as having base layer reservation is acknowledged as having been successful
been successful established via QOS reporting (see Section 4.2). QOS established via QOS reporting (see Section 4.2). QOS reporting
reporting between the destination and source can be used to force between the destination and source can be used to force the source to
the source to 'drop' enhancement layers. In this case the source 'drop' enhancement layers. In this case the source would only forward
would only forward the BL packets toward the destination in reserved the BL packets toward the destination in reserved mode. Any
mode. Any enhancement layer packets would be forwarded as best- enhancement layer packets would be forwarded as best-effort packets.
effort packets. This action has the benefit of releasing an 'partial This action has the benefit of releasing an 'partial reservations'
reservations' for the enhancement layer that may exist between a for the enhancement layer that may exist between a bottlenecked
bottlenecked mobile host and the destination. We will discuss the mobile host and the destination. We will discuss the issue of
issue of 'partial reservations' (which may occur in all phases of 'partial reservations' (which may occur in all phases of INSIGNIA
INSIGNIA operation)in the sections of flow setup, restoration and operation)in the sections of flow setup, restoration and adaptation.
adaptation.
The bandwidth indicator is also utilized for restoring the The bandwidth indicator is also utilized for restoring the
reservation for EL if previously degraded to best effort service. reservation for EL if previously degraded to best effort service. In
In order to accomplish scaling up adaptation, the adaptation order to accomplish scaling up adaptation, the adaptation handler
handler resident at destination should monitors a flow's resource resident at destination should monitors a flow's resource
availability (by monitoring the bandwidth indicator) availability (by monitoring the bandwidth indicator) and, based on
and, based on the adaptation policy, initiate a 'scale up' operation the adaptation policy, initiate a 'scale up' operation using a QOS
using a QOS report. report.
3.6 BANDWIDTH REQUEST 3.6 BANDWIDTH REQUEST
The bandwidth request allows a source to specify its maximum (MAX) The bandwidth request allows a source to specify its maximum (MAX)
and minimum (MIN) bandwidth requirements for adaptive real-time and minimum (MIN) bandwidth requirements for adaptive real-time
service support. This assumes that the source has selected the RT service support. This assumes that the source has selected the AS
service type. A source may also simply specify a minimum or a service type. A source may also simply specify a minimum or a maximum
maximum bandwidth requirement. For adaptive real-time services the bandwidth requirement. For adaptive real-time services the base layer
base layer is supported by the MIN bandwidth whereas the MAX is supported by the MIN bandwidth whereas the MAX bandwidth supports
bandwidth supports the delivery of the base and enhancement layers the delivery of the base and enhancement layers between a source and
between a source and destination pair. destination pair.
4. INSIGNIA OPERATIONS 4. INSIGNIA OPERATIONS
The IP option and operations support the delivery of adaptive real- The IP option and operations support the delivery of adaptive real-
time services to mobile hosts. These operations collectively define time services to mobile hosts. These operations collectively define
the foundation of the INSIGNIA system and include flow setup, flow the foundation of the INSIGNIA system and include flow setup, flow
restoration, soft-state management, adaptation and QOS reporting. restoration, soft-state management, adaptation and QOS reporting.
Once a flow has been established between a source-destination pair, Once a flow has been established between a source-destination pair,
QOS reports are used to inform the source of the progress of the QOS reports are used to inform the source of the progress of the
delivered packet quality at the destination. Node mobility may delivered packet quality at the destination. Node mobility may
trigger topology changes. In this case the MANET routing protocol trigger topology changes. In this case the MANET routing protocol may
may provide alternative or new path information to destination, provide alternative or new path information to destination, in which
in which case, INSIGNIA would attempt to restore reservations at all case, INSIGNIA would attempt to restore reservations at all nodes on
nodes on the new path through the restoration operation. Moreover, the new path through the restoration operation. Moreover, adaptation
adaptation may be triggered to adjust a flow to match resources may be triggered to adjust a flow to match resources availability
availability found on the new path. Managing the network state, found on the new path. Managing the network state,while responding to
while responding to these network dynamics, is handled by a soft- these network dynamics, is handleby a soft-state management mechanism
state management mechanism in INSIGNIA. In the following sections, in INSIGNIA. In the following sections,each of the INSIGNIA
each of the INSIGNIA operations are outlined. operations are outlined.
4.1 FLOW SETUP 4.1 FLOW SETUP
To establish adaptive real-time flows, source nodes set the To establish adaptive real-time flows, source nodes set the
appropriate fields in the IP option before forwarding 'reservation appropriate fields in the IP option before forwarding 'reservation
request' packets toward destination mobile hosts. A reservation request' packets toward destination mobile hosts. A reservation
request packet is characterized as having its reservation mode set request packet is characterized as having its reservation mode set to
to REQ, service type set to RT, a valid payload (viz. BL or EL) and REQ, service type set to AS, a valid payload (viz. BL or EL) and a
a MAX/MIN bandwidth requirement. MAX/MIN bandwidth requirement.
Reservation packets traverse intermediate nodes executing admission Reservation packets traverse intermediate nodes executing admission
control modules, allocating resources and establishing flow-state at control modules, allocating resources and establishing flow-state at
all nodes between source-destination pairs. If any intermediate all nodes between source-destination pairs. If any intermediate
mobile node lacks resources to support the requested flow setup, the mobile node lacks resources to support the requested flow setup, the
appropriate IP option field is changed to indicate this condition appropriate IP option field is changed to indicate this condition (or
(or state). state).
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
+---+----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|REQ| RT |BL/EL|max/min| max_bandwidth | min_bandwidth | |REQ| AS |BL/EL|max/min| max_bandwidth | min_bandwidth |
+---+----+-----+-------+---------------+---------------+ +---+----+-----+-------+---------------+---------------+
Figure 3. INSIGNIA Packet Requesting MAX/MIN reservation Figure 3. INSIGNIA Packet Requesting MAX/MIN reservation
If an intermediate mobile receives a request packet and can only If an intermediate mobile receives a request packet and can only
support the minimum requirement then the flow request is degraded to support the minimum requirement then the flow request is degraded to
the minimum request at the bottleneck mobile node by resetting the the minimum request at the bottleneck mobile node by resetting the
bandwidth indicator to MIN. Meanwhile the source continues to send bandwidth indicator to MIN. Meanwhile the source continues to send
reservation requests packets until the destination informs it of the reservation requests packets until the destination informs it of the
status of flow establishment phase via QOS report (discussed in status of flow establishment phase via QOS report (discussed in
Section 4.2). Subsequent reservation request packets do not execute Section 4.2). Subsequent reservation request packets do not execute
admission control but simply refresh existing soft-state admission control but simply refresh existing soft-state reservation.
reservation.
The establishment of an adaptive real-time flow is illustrated in The establishment of an adaptive real-time flow is illustrated in
Figure 4. A source mobile host (M1) issues a flow setup by Figure 4. A source mobile host (M1) issues a flow setup by requesting
requesting resource reservation. M2 performs admission control upon resource reservation. M2 performs admission control upon reception of
reception of the request packet. Resources are allocated if the request packet. Resources are allocated if available and the
available and the request packet is forwarded to the next mobile request packet is forwarded to the next mobile (M3). This process is
(M3). This process is repeated hop by hop until the request packet repeated hop by hop until the request packet reaches the destination
reaches the destination mobile host (M6). The destination mobile mobile host (M6). The destination mobile node determines the resource
node determines the resource allocation status by checking the allocation status by checking the service type and current level of
service type and current level of service. service.
When a reservation request is received at the destination node, the When a reservation request is received at the destination node, the
INSIGNIA module checks the reservation status. The status of the INSIGNIA module checks the reservation status. The status of the flow
flow setup is determined by inspecting the bandwidth indication setup is determined by inspecting the bandwidth indication field. If
field. If the bandwidth indicator is set to MAX then this implies the bandwidth indicator is set to MAX then this implies that all
that all mobile hosts between the source destination have mobile hosts between the source destination have successfully
successfully allocated resources to meet the base and enhancement allocated resources to meet the base and enhancement layers bandwidth
layers bandwidth requirements. On the other hand, a bandwidth requirements. On the other hand, a bandwidth indication set to MIN
indication set to MIN indicates that only the base layer can be indicates that only the base layer can be currently supported. In
currently supported. In this case, all reserved packets with a this case, all reserved packets with a payload of EL received at the
payload of EL received at the destination have their service level destination have their service level flipped from AS to BE by the
flipped from RT to BE by the bottleneck node. In such case, a bottleneck node. In such case, a partial reservation may exist
partial reservation may exist between the source and bottleneck between the source and bottleneck mobile node. This partial
mobile node. This partial reservation can be viewed as a waste of reservation can be viewed as a waste of resources between the source
resources between the source and bottlenecked node (since they go and bottlenecked node (since they go unused) or, as a 'near
unused) or, as a 'near reservation' where all but the remaining reservation' where all but the remaining nodes (between the
nodes (between the bottlenecked node and the destination) hold bottlenecked node and the destination) hold reservations. Holding on
reservations. Holding on to these reservations - in effect locking to these reservations - in effect locking them in - is a 'hedge'
them in - is a 'hedge' against completing the setup phase in the against completing the setup phase in the near future. The treatment
near future. The treatment of 'partial reservations' is still under of 'partial reservations' is still under consideration. Currently,
consideration. Currently, the adaptation process allows the mobile the adaptation process allows the mobile host to clear partial
host to clear partial reservations using the adaptation process or reservations using the adaptation process or leave them in place.
leave them in place.
+----+ +----+ +----+ +----+
QOS_REPORT(2)| M9 |---| M8 |\QOS_REPORT(2) QOS_REPORT(2)| M9 |---| M8 |\QOS_REPORT(2)
+----+ /+----+ +----+ \ +----+ +----+ /+----+ +----+ \ +----+
| M2 |/ / \| M7 |\QOS_REPORT(2) | M2 |/ / \| M7 |\QOS_REPORT(2)
REQ(1)/+----+\ / +----+ \+----+ REQ(1)/+----+\ / +----+ \+----+
+----+/ \ +----+/ +----+ | M6 | +----+/ \ +----+/ +----+ | M6 |
| M1 | REQ(1)\| M3 |---| M4 |REQ(1) /+----+ | M1 | REQ(1)\| M3 |---| M4 |REQ(1) /+----+
+----+ +----+ +----+\ +----+/ +----+ +----+ +----+\ +----+/
REQ(1) \| M5 | REQ(1) REQ(1) \| M5 | REQ(1)
+----+ +----+
Figure 4. INSIGNIA Request Packet and QOS report Figure 4. INSIGNIA Request Packet and QOS report
4.2 QOS REPORTING 4.2 QOS REPORTING
QOS reports are used to inform the source of the status of received QOS reports are used to inform the source of the status of received adaptive
adaptive real-time flows. Destination nodes actively monitor on- real-time flows. Destination nodes actively monitor on-going flows inspecting
going flows inspecting status information (e.g., bandwidth status information (e.g., bandwidth indication) and calculating QOS statistics
indication) and calculating QOS statistics (viz. packet loss, delay, (viz. packet loss, delay, out-of-sequence delivery and throughput). QOS
out-of-sequence delivery and throughput). QOS reports are reports are periodically sent to source host for the purpose of completing
periodically sent to source host for the purpose of completing flow flow establishment and managing adaptations. QOS reporting is application
establishment and managing adaptations. QOS reporting is application dependent where the periodicity of reports is determined by the application's
dependent where the periodicity of reports is determined by the sensitivity to the delivered QOS. Note that QOS reports do not have to travel
application's sensitivity to the delivered QOS. Note that QOS on the reverse path toward the source. Typically they will take an alternate
reports do not have to travel on the reverse path toward the source. route through the ad hoc network as illustrated in Figure 4.
Typically they will take an alternate route through the ad hoc
network as illustrated in Figure 4.
In the case of flow establishment, reception of a reservation In the case of flow establishment, reception of a reservation request packet
request packet with the bandwidth indicator set to MAX (or MIN) with the bandwidth indicator set to MAX (or MIN) indicates that the source's
indicates that the source's maximum (minimum) reservation has been maximum (minimum) reservation has been successfully made en-route. The
successfully made en-route. The destination informs the source of destination informs the source of this reservation status by setting the
this reservation status by setting the bandwidth indicator field bandwidth indicator field with MAX (MIN) in the QOS report, accordingly. The
with MAX (MIN) in the QOS report, accordingly. The QOS report is a QOS report is a best effort data packet with a payload that comprises of a
best effort data packet with a payload that comprises of a 'mirror
copy' of the INSIGNIA IP option received by the destination,
adaptation commands and measured QOS information. adaptation commands and measured QOS information.
QOS reports are also used as part of on-going adaptation process QOS reports are also used as part of on-going adaptation process that responds
that responds to mobility and resources changes in the mobile ad hoc to mobility and resources changes in the mobile ad hoc network. Periodic QOS
network. Periodic QOS reports can be used to inform the source to reports can be used to inform the source to 'drop' (e.g., drop all EL packets)
'drop' (e.g., drop all EL packets) or 'scale-up' (i.e., transmit EL or 'scale-up' (i.e., transmit EL packets) based on available resources and the
packets) based on available resources and the adaptation policy of adaptation policy of the application. These are the 'adaptation commands'.
the application. These are the 'adaptation commands'.
4.2.1 QOS REPORT INTERVAL 4.2.1 QOS REPORT INTERVAL
Since each flow has different sensitivity to QOS, the periodicity of Since each flow has different sensitivity to QOS, the periodicity of QOS
QOS report for each flow should reflect this sensitivity. A flow report for each flow should reflect this sensitivity. A flow that is sensitive
that is sensitive to service quality requires more frequent QOS to service quality requires more frequent QOS report than one that is less
report than one that is less sensitive (i.e., more QOS control). A sensitive (i.e., more QOS control). A source relates the sensitivity of a flow
source relates the sensitivity of a flow via setting the TTL value via setting the TTL value with relatively small value. The destination
with relatively small value. The destination utilizes the TTL value, utilizes the TTL value, requested bandwidth and the adaptation policy to
requested bandwidth and the adaptation policy to determine the determine the flow's sensitivity to service quality. We are currently
flow's sensitivity to service quality. We are currently investigating the migration of this function to the INSIGNIA IP options field.
investigating the migration of this function to the INSIGNIA IP
options field.
4.2.2 QOS PACKET FORMAT 4.2.2 QOS PACKET FORMAT
The role of the QOS report is to serve as a simple notification of The role of the QOS report is to serve as a simple notification of the
the satisfaction level perceived by the destination. The QOS report satisfaction level perceived by the destination. The QOS report includes a
includes a 'mirror copy' of the INSIGNIA IP option, adaptation QOS. In fact, the QOS report of INSIGNIA has the same format as a best effort
commands and measured QOS. In fact, the QOS report of INSIGNIA has INSIGNIA data packet. A QOS report has the reservation mode set to RES and
the same format as a best effort INSIGNIA data packet. A QOS report service type set to BE. The minimum bandwidth field is set to zeros and
has the reservation mode set to RES and service type set to BE. The maximum bandwidth is set to ones. By doing so, the QOS report can be
minimum bandwidth field is set to zeros and maximum bandwidth is set distinguished from the degraded RES packet. The various packet formats are
to ones. By doing so, the QOS report can be distinguished from the illustrated in Figure 8.
degraded RES packet. The various packet formats are illustrated in
Figure 8.
4.2.3 QOS REPORT DELIVERY 4.2.3 QOS REPORT DELIVERY
QOS reports should be delivered in a timely fashion. We propose to QOS reports should be delivered in a timely fashion. We propose to schedule
schedule QOS reports before the transmission of best effort packets QOS reports before the transmission of best effort packets but without
but without affecting the performance of reserved flows. The IP affecting the performance of reserved flows. The IP option codepoint for QOS
option codepoint for QOS reports, even though best effort in reports, even though best effort in service type, set it a side from all
service type, set it a side from all other best effort traffic for a other best effort traffic for a 'better than best effort treatment' at
'better than best effort treatment' at intermediate nodes. intermediate nodes.
4.3 SOFT-STATE MANAGEMENT 4.3 SOFT-STATE MANAGEMENT
Maintaining the quality of service of real time flows in mobile ad Maintaining the quality of service of real time flows in mobile ad hoc network
hoc network is one of the most challenging aspects that INSIGNIA is one of the most challenging aspects that INSIGNIA addresses. Typically,
addresses. Typically, wireline networks requires little QOS or wireline networks requires little QOS or state management where the routes and
state management where the routes and the reservations remain fixed the reservations remain fixed for the duration of the session/flows. This
for the duration of the session/flows. This style of 'hard-state' style of 'hard-state' connection oriented communications guarantees quality of
connection oriented communications guarantees quality of service for service for the duration of the holding time. However, these techniques are
the duration of the holding time. However, these techniques are not not applicable/valid in mobile ad hoc networks where paths and reservations
applicable/valid in mobile ad hoc networks where paths and need to dynamically respond to topology changes in a timely manner over
reservations need to dynamically respond to topology changes in a multiple time scales and network dynamics.
timely manner over multiple time scales and network dynamics.
Based on the work by Clark [3], 'mobile soft-state' relies on the Based on the work by Clark [3], 'mobile soft-state' relies on the fact that
fact that sources periodically send data messages along the existing sources periodically send data messages along the existing path. If a data
path. If a data packet arrives at a mobile router and no reservation packet arrives at a mobile router and no reservation exists then admission
exists then admission control and resource reservations are needed control and resource reservations are needed to establish soft-state
to establish soft-state reservations. Subsequent reception of a data reservations. Subsequent reception of a data packet at a router is used to
packet at a router is used to refresh the soft-state reservation. refresh the soft-state reservation. Thus a mobile host receiving a data packet
Thus a mobile host receiving a data packet for an existing for an existing reservation reconfirms the reservation over the next time
reservation reconfirms the reservation over the next time interval. interval. The holding-time for a reservation is based on a soft-state timer
The holding-time for a reservation is based on a soft-state timer interval and not, as in the case of call setup, based on the session duration
interval and not, as in the case of call setup, based on the session holding time. If a new packet is not received within a soft-state timer
duration holding time. If a new packet is not received within a interval, resources are released and flow-states removed automatically without
soft-state timer interval, resources are released and flow-states any explicit tear-down messaging.
removed automatically without any explicit tear-down messaging.
The soft-state approach is well suited for management of resources The soft-state approach is well suited for management of resources in dynamic
in dynamic environment where the path and reservation associated environment where the path and reservation associated with a flow may change
with a flow may change rapidly. The transmission of data packets is rapidly. The transmission of data packets is strongly coupled to maintenance
strongly coupled to maintenance of flow-states, i.e., reservations. of flow-states, i.e., reservations. As the route changes in the network, new
As the route changes in the network, new reservations will be reservations will be automatically restored by the restoration mechanism
automatically restored by the restoration mechanism provided that provided that resources are available along the new path.
resources are available along the new path.
Another benefit of mobile soft-state is that resources allocated Another benefit of mobile soft-state is that resources allocated during flow
during flow establishment are automatically removed when the path establishment are automatically removed when the path changes without any
changes without any explicit signaling interactions. In-band explicit signaling interactions. In-band approaches are flexible and scalable
approaches are flexible and scalable in dealing with a number of in dealing with a number of difficult mobile ad hoc network issues whereas
difficult mobile ad hoc network issues whereas out-of-band signaling out-of-band signaling systems need to maintain source route information and
systems need to maintain source route information and respond to respond to topology changes by directly signaling 'affected mobiles' to
topology changes by directly signaling 'affected mobiles' to allocate or free radio resources. In some case, this is impossible to do when
allocate or free radio resources. In some case, this is impossible using out-of-band signaling techniques if the 'affected router' is out of
to do when using out-of-band signaling techniques if the 'affected radio contact from the signaling entity that is attempting to de-allocate
router' is out of radio contact from the signaling entity that is resources over the old path.
attempting to de-allocate resources over the old path.
4.4 FLOW RESTORATION 4.4 FLOW RESTORATION
Flows are often rerouted during the lifetime of sessions due to Flows are often rerouted during the lifetime of sessions due to mobility in
mobility in mobile ad hoc networks. The goal of flow restoration is mobile ad hoc networks. The goal of flow restoration is to re-establish
to re-establish reservation as fast and efficiently as possible. reservation as fast and efficiently as possible. Rerouting of an active flow
Rerouting of an active flow involves new admission control and involves new admission control and resource reservations for nodes on the new
resource reservations for nodes on the new path. Restoration path. Restoration procedures also call for the removal of flow-state at nodes
procedures also call for the removal of flow-state at nodes along along the old path. In an ideal case, the restoration of flows can be
the old path. In an ideal case, the restoration of flows can be accomplished within the duration of a few consecutive packets because of the
accomplished within the duration of a few consecutive packets in-band nature of INSIGNIA's control.
because of the in-band nature of INSIGNIA's control.
When a mobile moves out of radio contact and loses connectivity, When a mobile moves out of radio contact and loses connectivity, the
the forwarding router mobile interacts with the routing module and forwarding router mobile interacts with the routing module and forwards
forwards subsequent packets via the new route. (Note that if the subsequent packets via the new route. (Note that if the routing table does not
routing table does not have an alternative route toward the have an alternative route toward the destination then the performance of the
destination then the performance of the restoration process is restoration process is tightly coupled to the performance of the
tightly coupled to the performance of the proactive/reactive MANET proactive/reactive MANET routing protocol that is operational. This issue is
routing protocol that is operational. This issue is for further for further study. In [25], however, we implemented INSIGNIA in a mid size ad
study. In [25], however, we implemented INSIGNIA in a mid size ad hoc network using TORA [1] as the routing protocol and discuss performance
hoc network using TORA [1] as the routing protocol and discuss issues there).
performance issues there).
The mobile hosts on a new path receive rerouted packets and inspect The mobile hosts on a new path receive rerouted packets and inspect their flow
their flow state tables. If a reservation does not exist for the state tables. If a reservation does not exist for the rerouted flow then the
rerouted flow then the INSIGNIA module invokes admission control and INSIGNIA module invokes admission control and tries to allocate
tries to allocate resources. Note that, if the reserved packets are resources. Note that, if the reserved packets are routed back on to the
routed back on to the existing path then the old states are likely existing path then the old states are likely to be still valid; hence, the
to be still valid; hence, the states and reservations are simply states and reservations are simply refreshed, minimizing any service
refreshed, minimizing any service disruption due to re-rerouting. disruption due to re-rerouting.
Network dynamics may also trigger rerouting with service Network dynamics may also trigger rerouting with service degradation. When a
degradation. When a reserved flow is rerouted to a node where reserved flow is rerouted to a node where resources are unavailable, the flow
resources are unavailable, the flow is degraded to best effort is degraded to best effort service. Subsequent downstream nodes receiving
service. Subsequent downstream nodes receiving these degraded these degraded packets make no attempt to attempt to allocate resources or
packets make no attempt to attempt to allocate resources or refresh refresh existing soft-state associated with the flow. This results in the
existing soft-state associated with the flow. This results in the automatic removal of any reservation state. In time the reservation may be
automatic removal of any reservation state. In time the reservation restored if resources free up at the bottleneck mobile node or because of the
may be restored if resources free up at the bottleneck mobile node subsequent rerouting allowing the complete restoration of the flow
or because of the subsequent rerouting allowing the complete quality. The worst case scenario is that the flow will remain degraded for the
restoration of the flow quality. The worst case scenario is that the duration of the session holding time.
flow will remain degraded for the duration of the session holding
time.
The enhancement layer of a reserved flow with maximum reservation The enhancement layer of a reserved flow with maximum reservation may get
may get degraded during flow restoration if the nodes along the new degraded during flow restoration if the nodes along the new path can only
path can only support the minimum bandwidth requirement. If the support the minimum bandwidth requirement. If the degradation of enhancement
degradation of enhancement layer packets persist, it may cause layer packets persist, it may cause service disruptions and may trigger the
service disruptions and may trigger the destination mobile to invoke destination mobile to invoke an adaptation procedure that force the source
an adaptation procedure that force the source node to drop the EL node to drop the EL packets. Adaptation details are provided in the following
packets. Adaptation details are provided in the following section. section.
4.5 ADAPTATION 4.5 ADAPTATION
Reception quality of a flow is monitored and based on an Reception quality of a flow is monitored and based on an application-specific
application-specific adaptation policy, actions may be taken to adaptation policy, actions may be taken to adapt the flow to observed network
adapt the flow to observed network conditions. Actions taken are conditions. Actions taken are conditional on the adaptation-policy resident at
conditional on the adaptation-policy resident at the destination the destination node, e.g., adaptation policy may chose to maintain the
node, e.g., adaptation policy may chose to maintain the service service level under degraded conditions or scale-down flows to their base
level under degraded conditions or scale-down flows to their base layers in respond to degraded conditions. Other policy could scale-up flows
layers in respond to degraded conditions. Other policy could scale- whenever resources become available. The application is free to program its
up flows whenever resources become available. The application is own adaptation policy that is executed by INSIGNIA through interaction between
free to program its own adaptation policy that is executed by the destination and source nodes. Details about the adaptation policy API are
INSIGNIA through interaction between the destination and described in [19].
source nodes. Details about the adaptation policy API are described
in [19].
The adaptation process includes the following adaptation actions: The adaptation process includes the following adaptation actions:
(1) 'EL degradation' is a network driven action that forwards the (1) 'EL degradation' is a network driven action that forwards the
EL packets as best effort packets due to lack of resources; EL packets as best effort packets due to lack of resources;
(2) 'Drop enhancement layer' is a destination mobile driven action (2) 'Drop enhancement layer' is a destination mobile driven action
which requests a source to drop its enhancement layers. This which requests a source to drop its enhancement layers. This
happens when the EL degradation persists beyond an acceptable happens when the EL degradation persists beyond an acceptable
period; and period; and
(3) 'Scale-up', which requests a source to send its base and/or (3) 'Scale-up', which requests a source to send its base and/or
enhancement layers in reserved mode. This event occurs when enhancement layers in reserved mode. This event occurs when
a flow has only minimum reservation and the destination a flow has only minimum reservation and the destination
learns (through the bandwidth indicator) that the route learns (through the bandwidth indicator) that the route
can accommodate the maximum resource requirement. can accommodate the maximum resource requirement.
The EL degradation is a network driven action whereas the others two The EL degradation is a network driven action whereas the others two actions
actions are driven by an adaptation handler resident at the are driven by an adaptation handler resident at the destination mobile
destination mobile host. Typically, the EL degradation can be host. Typically, the EL degradation can be observed after rerouting of an
observed after rerouting of an adaptive real-time flow. In such an adaptive real-time flow. In such an event the EL packets are degraded and
event the EL packets are degraded and forwarded as best effort forwarded as best effort packets whereas BL packets are forwarded in reserved
packets whereas BL packets are forwarded in reserved mode. Note that mode. Note that preference is given to base layers over enhancement layers in
preference is given to base layers over enhancement layers in the the event that reserved packets have to be degraded to best effort. If the EL
event that reserved packets have to be degraded to best effort. degradation persists, a `drop` command may be issued by the adaptation handler
at the destination mobile host according to the adaptation policy. The
If the EL degradation persists, a `drop` command may be issued by decision to drop the EL packets is facilitated by monitoring the incoming
the adaptation handler at the destination mobile host according to packets. The destination mobile can readily detect the degraded RES packets by
the adaptation policy. The decision to drop the EL packets is reading the IP option fields (where the degraded packets have the format of
facilitated by monitoring the incoming packets. The destination Figure 5d). Figure 5 illustrates the different modes of INSIGNIA packets.
mobile can readily detect the degraded RES packets by reading the IP
option fields (where the degraded packets have the format of Figure
5d). Figure 5 illustrates the different modes of INSIGNIA packets.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
+---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|REQ| BE |BL/EL| max | max_bandwidth | min_bandwidth | |REQ| BE |BL/EL| max | max_bandwidth | min_bandwidth |
+---+----+-----+-----+---------------+---------------+ +---+----+-----+-----+---------------+---------------+
Figure 5a. A Best Effort Packet Figure 5a. A Best Effort Packet
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
+---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|REQ| RT |BL/EL| max | max_bandwidth | min_bandwidth | |REQ| AS |BL/EL| max | max_bandwidth | min_bandwidth |
+---+----+-----+-----+---------------+---------------+ +---+----+-----+-----+---------------+---------------+
Figure 5b. A Request Packet (EL or BL) Figure 5b. A Request Packet (EL or BL)
+---+----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+-----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT |BL/EL|max/min| max_bandwidth | min_bandwidth | |RES| AS |BL/EL|max/min| max_bandwidth | min_bandwidth |
+---+----+-----+-------+---------------+---------------+ +---+----+-----+-------+---------------+---------------+
Figure 5c. Typical Reserved (RES) Packet (EL or BL) Figure 5c. Typical Reserved (RES) Packet (EL or BL)
+---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+-----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| BE |BL/EL| max | max_bandwidth | min_bandwidth | |RES| BE |BL/EL| max | max_bandwidth | min_bandwidth |
+---+----+-----+-----+---------------+---------------+ +---+----+-----+-----+---------------+---------------+
Figure 5d. A Degraded RES Packet (EL or BL) Figure 5d. A Degraded RES Packet (EL or BL)
+---+----+----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| BE | BL |max/min|1 1 1 1 1 1 1 1|0 0 0 0 0 0 0 0| |RES| BE | BL |max/min|1 1 1 1 1 1 1 1|0 0 0 0 0 0 0 0|
+---+----+----+-------+---------------+---------------+ +---+----+----+-------+---------------+---------------+
|<----------->| |<----- unique format --------->| |<----------->| |<----- unique format --------->|
a QOS report a QOS report
* max/min indicates the accepted service level * max/min indicates the accepted service level
Figure 5e. Format of a QOS report Figure 5e. Format of a QOS report
'Dropping' the EL packet at the source removes partial reservations exist between a source and bottleneck mobile freeing up resources for other
that may exist between a source and bottleneck mobile freeing up adaptive real-time flows to utilize. It also removes degraded enhancement
resources for other adaptive real-time flows to utilize. It also layer packets from the network which in turn benefits the normal best effort
removes degraded enhancement layer packets from the network which in service flows.
turn benefits the normal best effort service flows.
INSIGNIA is also equipped with capability to restore the reservation INSIGNIA is also equipped with capability to restore the reservation needed
needed for enhancement layers. This process takes advantage of for enhancement layers.This process takes advantage of network and session
network and session dynamics allowing existing sessions to take dynamics allowing existing sessions to take advantages of resources released
advantages of resources released due to re-routing (e.g., resources due to re-routing (e.g., resources released along an old path) or session
released along an old path) or session termination. These events may termination. These events may allow other mobile nodes to take advantage of
allow other mobile nodes to take advantage of released resources by released resources by scaling up. The bandwidth indicator plays a key role in
scaling up. The bandwidth indicator plays a key role in 'reading'
the channels resource availability state in relation to the
bandwidth needs of the particular session/flow. bandwidth needs of the particular session/flow.
Typically, the scale-up process is invoked when the destination Typically, the scale-up process is invoked when the destination observes
observes sufficient resource have become available along the sufficient resource have become available along the existing path restore the
existing path restore the reservation of an enhancement layer. The reservation of an enhancement layer. The decision to scale up is determined by
decision to scale up is determined by the adaptation policy. the adaptation policy.
The following example scenario shows an example of a set of The following example scenario shows an example of a set of states (marked
states (marked [1] through [7]) observed at the destination [1] through [7]) observed at the destination illustrating a flow adaptation
illustrating a flow adaptation scenario: scenario:
Adaptation Procedures : Adaptation Procedures :
[1] Incoming Packets at time t1 with maximum resource allocation [1] Incoming Packets at time t1 with maximum resource allocation
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | max | max_bandwidth | min_bandwidth | |RES| AS | BL | max | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | EL | max | max_bandwidth | min_bandwidth | |RES| AS | EL | max | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
. .
. .
. .
[2] EL packets are degraded due to lack of resources at an [2] EL packets are degraded due to lack of resources at an
intermediate mobile node at time t2 and now packet formats become intermediate mobile node at time t2 and now packet formats become
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | min | max_bandwidth | min_bandwidth | |RES| AS | BL | min | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| BE | EL | min | max_bandwidth | min_bandwidth | |RES| BE | EL | min | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
* Note that EL packet is degraded to a best effort packet * Note that EL packet is degraded to a best effort packet
. .
. .
. .
[3] If the degraded EL packets are determined to be not useful for [3] If the degraded EL packets are determined to be not useful for
destination mobile host, an EL drop command is issued via QOS destination mobile host, an EL drop command is issued via QOS
report. Upon reception of the QOS report the source transmits only report. Upon reception of the QOS report the source transmits only
BL packets in reserved mode and do not transmit any EL packets. BL packets in reserved mode and do not transmit any EL packets.
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | min | max_bandwidth | min_bandwidth | |RES| AS | BL | min | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
* EL packets are not transmitted/received * EL packets are not transmitted/received
. .
. .
. .
[4] Constant resource availability is detected through the bandwidth [4] Constant resource availability is detected through the bandwidth
indicator at t4 where the received packets indicating the resource indicator at t4 where the received packets indicating the resource
availability have the following format. availability have the following format.
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | max | max_bandwidth | min_bandwidth | |RES| AS | BL | max | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
* Currently no EL packets are received. * Currently no EL packets are received.
* Destination learns from the bandwidth indicator bit (set to max) * Destination learns from the bandwidth indicator bit (set to max)
that the current route has the resources available to restore the that the current route has the resources available to restore the
EL packet flow. EL packet flow.
. .
. .
. .
[5] Through the next QOS report destination informs the source to [5] Through the next QOS report destination informs the source to
reinitiate the transmission on EL in RES mode. If the recovery reinitiate the transmission on EL in RES mode. If the recovery
(scale up) is successful, destination receives the following (scale up) is successful, destination receives the following
packets. packets.
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | max | max_bandwidth | min_bandwidth | |RES| AS | BL | max | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| BE | EL | max | max_bandwidth | min_bandwidth | |RES| BE | EL | max | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
. .
. .
. .
[6] If scale up attempt fails at any mobile node on the route, [6] If scale up attempt fails at any mobile node on the route,
destination receives degraded EL packets. destination receives degraded EL packets.
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| RT | BL | min | max_bandwidth | min_bandwidth | |RES| AS | BL | min | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
+---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +---+----+----+-----+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES| BE | EL | min | max_bandwidth | min_bandwidth | |RES| BE | EL | min | max_bandwidth | min_bandwidth |
+---+----+----+-----+---------------+---------------+ +---+----+----+-----+---------------+---------------+
[7] If the EL degradation persist after step [6], another drop EL [7] If the EL degradation persist after step [6], another drop EL
command is issued via following QOS report. command is issued via following QOS report.
The decision to drop/scale up is entirely up to the application- The decision to drop/scale up is entirely up to the application-specific
specific adaptation policy residing at destination mobile. For adaptation policy residing at destination mobile. For example a video flow may
example a video flow may be sensitive to delays and delivery of be sensitive to delays and delivery of constantly changing bandwidth so once
constantly changing bandwidth so once enhancement layer packets are enhancement layer packets are dropped, it requires stable resource
dropped, it requires stable resource availability of resources availability of resources before a scale up decision is made. In the case of
before a scale up decision is made. In the case of real-time data, real-time data, there may not be any drop command and the application may want
there may not be any drop command and the application may want to to closely follow the dynamics of resource availability. In such case the
closely follow the dynamics of resource availability. In such case adaptation policy is quite different from that of a video flow example.
the adaptation policy is quite different from that of a video flow
example.
5. NETWORK LAYER FUNCTIONALITY - INTEROPERABILITY WITH IMEP
Since Internet MANET Encapsulation Protocol is a network layer
protocol designed to support the operation of many routing
algorithms and any other higher layer protocols intended for use in
mobile ad hoc networks, INSIGNIA can be fully incorporated with IMEP
mechanisms. IMEP will provide mechanisms for supporting link status
and neighbor connectivity sensing, lower layer control packet
aggregation and encapsulation, one-hop neighbor broadcast (or
multicast) reliability, multi-point relaying, network-layer address
resolution and provides hooks for inter-router authentication
procedures.
IMEP [18] improves overall network performance by reducing the
number of network control message broadcasts through encapsulation
and aggregation of multiple MANET control messages (e.g. routing
protocol packets, acknowledgements, link status sensing messages,
network-level address resolution, etc.) into larger IMEP messages.
Usage of the IMEP is desirable because per-message, multiple access
delay in contention-based schemes such as CSMA/CA, IEEE 802.11, FAMA
etc. is significant, and thus favors the use of fewer, larger
messages. It would also be useful in reservation-based, time-slotted
access schemes where smaller packets must be aggregated into
appropriately-sized IP packets for transmission in a given time
slot. Upper layer protocols other than routing may make use of this
encapsulation functionality for the same purpose.
Moreover, IMEP will provide the commonality among many network-level
routing algorithms. Many algorithms intended for use in a MANET will
require common functionality such as link status sensing, security
authentication with adjacent mobiles, broadcast reliability of
network control messages, etc. This common functionality can be
extracted from various protocols and can become generic protocol
useful to all. The routing algorithms would also benefit from the
common approach to mobile and interface identification and
addressing. The IMEP will run at the network layer and will be an
adjunct to whichever network routing protocol is using it. Routing
control packets will be encapsulated in IMEP messages, which will be
further encapsulated into IP packets.
6. SECURITY ISSUES
The MANET computing environment is very different from the ordinary
computing environment. In many cases, mobile computers will be
connected to the network via wireless links. Such links are
particularly vulnerable to passive eavesdropping, active replay
attacks, and other active attacks. A stringent authentication and
registration processes are required to avoid any malicious users.
Authentication : 5. SECURITY ISSUES
The IMEP Authentication object [18] is used to authenticate all
IMEP objects. The types of authentication to be supported and
specified in a proposed MANET Authentication Architecture under
development.
Registration : The MANET computing environment is very different from the ordinary computing
Upper layer protocols, i.e., INSIGNIA must register with IMEP environment. In many cases, mobile computers will be connected to the network
prior to use. via wireless links. Such links are particularly vulnerable to passive
eavesdropping, active replay attacks, and other active attacks. A stringent
authentication and registration processes are required to avoid any malicious
users. Currently, INSIGNIA does not specify any special security measures.
7. APPLICATIONS 6. APPLICATIONS
INSIGNIA can be used as signaling support for small (pico-cell) and INSIGNIA can be used as signaling support for small (pico-cell) and large
large scale mobile networks. Flows and microflows can be supported. scale mobile networks. Flows and microflows can be supported. Voice, video and
Voice, video and real-time data applications can be supported using real-time data applications can be supported using the INSIGNIA adaptive
the INSIGNIA adaptive real-time service. In addition, INSIGNIA real-time service. In addition, INSIGNIA networks support traditional best
networks support traditional best effort services. effort services.
8. ACKNOWLEDGMENT 7. ACKNOWLEDGMENT
We would like to thank Mischa Schwartz and Javier Gomez Castellanos The work is supported in part by the Army Research Office (ARO) under award
for comments on this work. DAAD19-99-1-0287 and with support from COMET Group industrial sponsors.
9. REFERENCE 8. REFERENCE
[1] V. Park, and S. Corson, "Temporally Ordered Routing Algorithm [1] V. Park, and S. Corson, "Temporally Ordered Routing Algorithm
(TORA) Version 1 Functional Specification", draft-ietf-manet- (TORA) Version 1 Functional Specification", draft-ietf-manet-
tora-spec-00.txt, November 1997. tora-spec-00.txt, November 1997.
[2] J. Macker, and M. S. Corson, "Mobile Ad hoc Networking (MANET): [2] J. Macker, and M. S. Corson, "Mobile Ad hoc Networking (MANET):
Routing Protocol Performance Issues and Evaluation Routing Protocol Performance Issues and Evaluation
Considerations", draft-ietf-manet-issues-01.txt, April 1998. Considerations", draft-ietf-manet-issues-01.txt, April 1998.
[3] D. D. Clark and D.L. Tennenhouse, "Architectural Consideration [3] D. D. Clark and D.L. Tennenhouse, "Architectural Consideration
for a New Generation of Protocols", Proc. ACM SIGCOMM'90, August for a New Generation of Protocols", Proc. ACM SIGCOMM'90, August
1990. 1990.
skipping to change at page 24, line 4 skipping to change at page 21, line 50
wireless packet networks". In Proceedings of ACM SIGCOMM, San wireless packet networks". In Proceedings of ACM SIGCOMM, San
Francisco, California, 1997 Francisco, California, 1997
[23] OPNET, http://www.mil3.com [23] OPNET, http://www.mil3.com
[24] A. S. Acampora and M. Naghshineh, "QOS provisioning in micro- [24] A. S. Acampora and M. Naghshineh, "QOS provisioning in micro-
cellular networks supporting multiple classes of traffic", cellular networks supporting multiple classes of traffic",
Wireless Networks, 2(3), 1996. Wireless Networks, 2(3), 1996.
[25] Lee, S-B. and A.T. Campbell, "INSIGNIA: In-band Signaling [25] Lee, S-B. and A.T. Campbell, "INSIGNIA: In-band Signaling
Support for QOS in Mobile Ad Hoc Networks" Proc of 5th Support for QOS in Mobile Ad Hoc Networks" Proc of 5th
International Workshop on Mobile Multimedia Communications International Workshop on Mobile Multimedia Communications
(MoMuC,98), Berlin, Germany, October 1998. (MoMuC,98), Berlin, Germany, October 1998.
[26] S-B. Lee, G-S. Ahn, X. Zhang and Andrew T. Campbell,
"INSIGNIA: A QoS Framework for Mobile Ad Hoc Networks", Journal of
Parallel and Distributed Computing - Special Issues on Wireless and
Mobile Computing, Jan 2000 (to be published).
10. AUTHORS' ADDRESSES 9. AUTHORS' ADDRESSES
Seoung-Bum Lee, Andrew T. Campbell
COMET Group Seoung-Bum Lee (Managing Author), Gahng-Seop Ahn, Andrew T. Campbell,
Columbia University Xiawei Zhang
530 w 120th street
Schapiro Research Building
New York, NY 10027
phone (212) 854 - 0871
[sbl,campbell]@comet.columbia.edu
See comet.columbia.edu/insignia for more information Department of Electrical Engineering, Columbia University
Rm. 801 Schapiro Research Building
530 W. 120th Street, New York, N.Y. 10027
phone: (212) 854 3109
fax : (212) 316 9068 (COMET Group)
email: [sbl, ahngang, campbell, xzhang]@comet.columbia.edu
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