draft-ietf-manet-olsrv2-multipath-10.txt   draft-ietf-manet-olsrv2-multipath-11.txt 
Network Working Group J. Yi Network Working Group J. Yi
Internet-Draft Ecole Polytechnique Internet-Draft Ecole Polytechnique
Intended status: Experimental B. Parrein Intended status: Experimental B. Parrein
Expires: January 6, 2017 University of Nantes Expires: January 26, 2017 University of Nantes
July 5, 2016 July 25, 2016
Multi-path Extension for the Optimized Link State Routing Protocol Multi-path Extension for the Optimized Link State Routing Protocol
version 2 (OLSRv2) version 2 (OLSRv2)
draft-ietf-manet-olsrv2-multipath-10 draft-ietf-manet-olsrv2-multipath-11
Abstract Abstract
This document specifies a multi-path extension for the Optimized Link This document specifies a multi-path extension for the Optimized Link
State Routing Protocol version 2 (OLSRv2) to discover multiple State Routing Protocol version 2 (OLSRv2) to discover multiple
disjoint paths, so as to improve reliability of the OLSRv2 protocol. disjoint paths, so as to improve reliability of the OLSRv2 protocol.
The interoperability with OLSRv2 is retained. The interoperability with OLSRv2 is retained.
Status of this Memo Status of this Memo
skipping to change at page 1, line 35 skipping to change at page 1, line 35
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 6, 2017. This Internet-Draft will expire on January 26, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 17 skipping to change at page 2, line 17
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Motivation and Experiments to Be Conducted . . . . . . . . 3 1.1. Motivation and Experiments to Be Conducted . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5
4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6
5. Parameters and Constants . . . . . . . . . . . . . . . . . . . 7 5. Parameters and Constants . . . . . . . . . . . . . . . . . . . 7
5.1. Router Parameters . . . . . . . . . . . . . . . . . . . . 7 5.1. Router Parameters . . . . . . . . . . . . . . . . . . . . 7
6. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 8 6. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 8
6.1. HELLO and TC messages . . . . . . . . . . . . . . . . . . 8 6.1. HELLO and TC messages . . . . . . . . . . . . . . . . . . 8
6.1.1. SOURCE_ROUTE TLV . . . . . . . . . . . . . . . . . . . 8 6.1.1. SOURCE_ROUTE TLV . . . . . . . . . . . . . . . . . . . 9
6.2. Datagram . . . . . . . . . . . . . . . . . . . . . . . . . 9 6.2. Datagram . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2.1. Source Routing Header in IPv4 . . . . . . . . . . . . 9 6.2.1. Source Routing Header in IPv4 . . . . . . . . . . . . 9
6.2.2. Source Routing Header in IPv6 . . . . . . . . . . . . 9 6.2.2. Source Routing Header in IPv6 . . . . . . . . . . . . 9
7. Information Bases . . . . . . . . . . . . . . . . . . . . . . 9 7. Information Bases . . . . . . . . . . . . . . . . . . . . . . 10
7.1. SR-OLSRv2 Router Set . . . . . . . . . . . . . . . . . . . 9 7.1. SR-OLSRv2 Router Set . . . . . . . . . . . . . . . . . . . 10
7.2. Multi-path Routing Set . . . . . . . . . . . . . . . . . . 10 7.2. Multi-path Routing Set . . . . . . . . . . . . . . . . . . 10
8. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 10 8. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. HELLO and TC Message Generation . . . . . . . . . . . . . 11 8.1. HELLO and TC Message Generation . . . . . . . . . . . . . 11
8.2. HELLO and TC Message Processing . . . . . . . . . . . . . 11 8.2. HELLO and TC Message Processing . . . . . . . . . . . . . 11
8.3. MPR Selection . . . . . . . . . . . . . . . . . . . . . . 11 8.3. MPR Selection . . . . . . . . . . . . . . . . . . . . . . 12
8.4. Datagram Processing at the MP-OLSRv2 Originator . . . . . 12 8.4. Datagram Processing at the MP-OLSRv2 Originator . . . . . 12
8.5. Multi-path Calculation . . . . . . . . . . . . . . . . . . 13 8.5. Multi-path Calculation . . . . . . . . . . . . . . . . . . 13
8.5.1. Requirements of Multi-path Calculation . . . . . . . . 13 8.5.1. Requirements of Multi-path Calculation . . . . . . . . 13
8.5.2. Multi-path Dijkstra Algorithm . . . . . . . . . . . . 14 8.5.2. Multi-path Dijkstra Algorithm . . . . . . . . . . . . 14
8.6. Multi-path Routing Set Updates . . . . . . . . . . . . . . 15 8.6. Multi-path Routing Set Updates . . . . . . . . . . . . . . 15
8.7. Datagram Forwarding . . . . . . . . . . . . . . . . . . . 15 8.7. Datagram Forwarding . . . . . . . . . . . . . . . . . . . 16
9. Configuration Parameters . . . . . . . . . . . . . . . . . . . 15 9. Configuration Parameters . . . . . . . . . . . . . . . . . . . 16
10. Implementation Status . . . . . . . . . . . . . . . . . . . . 16 10. Implementation Status . . . . . . . . . . . . . . . . . . . . 17
10.1. Multi-path extension based on nOLSRv2 . . . . . . . . . . 17 10.1. Multi-path extension based on nOLSRv2 . . . . . . . . . . 18
10.2. Multi-path extension based on olsrd . . . . . . . . . . . 17 10.2. Multi-path extension based on olsrd . . . . . . . . . . . 18
10.3. Multi-path extension based on umOLSR . . . . . . . . . . . 18 10.3. Multi-path extension based on umOLSR . . . . . . . . . . . 18
11. Security Considerations . . . . . . . . . . . . . . . . . . . 18 11. Security Considerations . . . . . . . . . . . . . . . . . . . 18
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
12.1. Expert Review: Evaluation Guidelines . . . . . . . . . . . 19 12.1. Expert Review: Evaluation Guidelines . . . . . . . . . . . 19
12.2. Message TLV Types . . . . . . . . . . . . . . . . . . . . 19 12.2. Message TLV Types . . . . . . . . . . . . . . . . . . . . 19
12.3. Routing Type . . . . . . . . . . . . . . . . . . . . . . . 19 12.3. Routing Type . . . . . . . . . . . . . . . . . . . . . . . 20
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
14.1. Normative References . . . . . . . . . . . . . . . . . . . 20 14.1. Normative References . . . . . . . . . . . . . . . . . . . 20
14.2. Informative References . . . . . . . . . . . . . . . . . . 20 14.2. Informative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Examples of Multi-path Dijkstra Algorithm . . . . . . 22 Appendix A. Examples of Multi-path Dijkstra Algorithm . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
The Optimized Link State Routing Protocol version 2 (OLSRv2) The Optimized Link State Routing Protocol version 2 (OLSRv2)
[RFC7181] is a proactive link state protocol designed for use in [RFC7181] is a proactive link state protocol designed for use in
mobile ad hoc networks (MANETs). It generates routing messages mobile ad hoc networks (MANETs). It generates routing messages
periodically to create and maintain a Routing Set, which contains periodically to create and maintain a Routing Set, which contains
routing information to all the possible destinations in the routing routing information to all the possible destinations in the routing
domain. For each destination, there exists a unique Routing Tuple, domain. For each destination, there exists a unique Routing Tuple,
which indicates the next hop to reach the destination. which indicates the next hop to reach the destination.
skipping to change at page 3, line 39 skipping to change at page 3, line 39
1.1. Motivation and Experiments to Be Conducted 1.1. Motivation and Experiments to Be Conducted
This document is an experimental extension of OLSRv2 that can This document is an experimental extension of OLSRv2 that can
increase the data forwarding reliability in dynamic and high-load increase the data forwarding reliability in dynamic and high-load
MANET scenarios by transmitting datagrams over multiple disjoint MANET scenarios by transmitting datagrams over multiple disjoint
paths using source routing. This mechanism is used because: paths using source routing. This mechanism is used because:
o Disjoint paths can avoid single route failures. o Disjoint paths can avoid single route failures.
o Transmitting datagrams through parallel paths can increase o Transmitting datagrams through parallel paths can increase
aggregated throughput and provide load balancing. aggregated throughput.
o Certain scenarios require some routers must (or must not) be used. o Some scenarios may require some routers must (or must not) be
used.
o By having control of the paths at the source, the delay can be o Having control of the paths at the source benefits the load
provisioned. balancing and traffic engineering.
o An application of this extension is in combination with Forward o An application of this extension is in combination with Forward
Error Correction (FEC) coding applied across packets (erasure Error Correction (FEC) coding applied across packets (erasure
coding). Because the packet drop is normally bursty in a path coding). Because the packet drop is normally bursty in a path
(for example, due to route failure), erasure coding is less (for example, due to route failure), erasure coding is less
effective in single path routing protocols. By providing multiple effective in single path routing protocols. By providing multiple
disjoint paths, the application of erasure coding with multi-path disjoint paths, the application of erasure coding with multi-path
protocol is more resilient to routing failures. protocol is more resilient to routing failures.
While in existing deployments, running code and simulations have While in existing deployments, running code and simulations have
proven the interest of multi-path extension for OLSRv2 in certain proven the interest of multi-path extension for OLSRv2 in certain
networks, more experiments and experiences are still needed to networks, more experiments and experiences are still needed to
understand the effects of the protocol. The multi-path extension for understand the effects of the protocol. The multi-path extension for
OLSRv2 is expected to be revised and improved to the Standard Track, OLSRv2 is expected to be revised and improved to the Standard Track,
once sufficient operational experience is obtained. Other than once sufficient operational experience is obtained. Other than
general experiences including the protocol specification, general experiences including the protocol specification and
interoperability with original OLSRv2 implementations, the interoperability with original OLSRv2 implementations, the
experiences in the following aspects are highly appreciated: experiences in the following aspects are highly appreciated:
o Optimal values for the number of multiple paths (NUMBER_OF_PATHS) o Optimal values for the number of multiple paths (NUMBER_OF_PATHS)
to be used. This depends on the network topology and router to be used. This depends on the network topology and router
density. density.
o Optimal values used in the metric functions. Metric functions are o Optimal values used in the metric functions. Metric functions are
applied to increase the metric of used links and nodes so as to applied to increase the metric of used links and nodes so as to
obtain disjoint paths. What kind of disjointness is desired obtain disjoint paths. What kind of disjointness is desired
(node-disjoint or link-disjoint) may depend on the layer 2 (node-disjoint or link-disjoint) may depend on the layer 2
protocol used, and can be achieved by setting different sets of protocol used, and can be achieved by setting different sets of
metric functions. metric functions.
o Use of different metric types. This multi-path extension can be o Use of different metric types. This multi-path extension can be
used with metric types that meet the requirement of OLSRv2, such used with metric types that meet the requirement of OLSRv2, such
as [RFC7779]. The metric type used has also co-relation with the as [RFC7779]. The metric type used has also impact to the choice
choice of metric functions as indicated in the previous bullet of metric functions as indicated in the previous bullet point.
point.
o The impact of partial topology information to the multi-path o The impact of partial topology information to the multi-path
calculation. OLSRv2 maintains a partial topology information base calculation. OLSRv2 maintains a partial topology information base
to reduce protocol overhead. Although with existing experience, to reduce protocol overhead. Although with existing experience,
multiple paths can be obtained even with such partial information, multiple paths can be obtained even with such partial information,
the calculation might be impacted, depending on the MPR selection the calculation might be impacted, depending on the MPR selection
algorithm used. algorithm used.
o Optimal choice of "key" routers for loose source routing. In some o Optimal choice of "key" routers for IPv4 loose source routing. In
cases, loose source routing is used to reduce overhead or for some cases, loose source routing is used to reduce overhead or for
interoperability with OLSRv2 routers. Other than the basic rules interoperability with OLSRv2 routers. Other than the basic rules
defined in the following of this document, optimal choices of defined in the following of this document, optimal choices of
routers to put in the loose source routing header can be further routers to put in the loose source routing header can be further
studied. studied.
o Different path-selection schedulers. By default, Round-Robin o Different path-selection schedulers. By default, Round-Robin
scheduling is used to select a path to be used for datagrams. In scheduling is used to select a path to be used for datagrams. In
some scenarios, weighted scheduling can be considered: for some scenarios, weighted scheduling can be considered: for
example, the paths with lower metrics (i.e., higher quality) can example, the paths with lower metrics (i.e., higher quality) can
transfer more datagrams compared to paths with higher metrics. transfer more datagrams compared to paths with higher metrics.
o The impacts of the delay variation due to multi-path routing. o The impacts of the delay variation due to multi-path routing.
[RFC2991] brings out some concerns of multi-path routing, [RFC2991] brings out some concerns of multi-path routing,
especially variable latencies. Although current experiment especially variable latencies. Although current experiment
results show that multi-path routing can reduce the jitter in results show that multi-path routing can reduce the jitter in
dynamic scenarios, some transport protocols or applications may be dynamic scenarios, some transport protocols or applications may be
sensitive to the datagram re-ordering. sensitive to the datagram re-ordering.
o The disjoint multi-path protocol has interesting application with o The disjoint multi-path protocol has interesting application with
erasure coding, especially for services like video/audio erasure coding, especially for services like video/audio
streaming. By definition, erasure coding is insensitive to the streaming. The combination of erasure coding mechanisms and this
packet misordering. The combination of erasure coding mechanisms extension is thus encouraged.
and this extension is thus encouraged.
o Different algorithms to obtain multiple paths, other than the o Different algorithms to obtain multiple paths, other than the
default Multi-path Dijkstra algorithm introduced in this default Multi-path Dijkstra algorithm introduced in this
specification. specification.
o The use of multi-topology information. By using [RFC7722], o The use of multi-topology information. By using [RFC7722],
multiple topologies using different metric types can be obtained. multiple topologies using different metric types can be obtained.
It is also encouraged to experiment with the use of multiple Although there is no work defining how this extension can make use
metrics for building multiple paths. of the multi-topology information base yet, it is encouraged to
experiment with the use of multiple metrics for building multiple
paths.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
This document uses the terminology and notation defined in [RFC5444], This document uses the terminology and notation defined in [RFC5444],
[RFC6130], [RFC7181]. Additionally, it defines the following [RFC6130], [RFC7181]. Additionally, it defines the following
skipping to change at page 6, line 4 skipping to change at page 6, line 5
MP-OLSRv2 Routing Process - The multi-path routing process based on MP-OLSRv2 Routing Process - The multi-path routing process based on
this specification as an extension to [RFC7181]. this specification as an extension to [RFC7181].
3. Applicability Statement 3. Applicability Statement
As an extension of OLSRv2, this specification is applicable to MANETs As an extension of OLSRv2, this specification is applicable to MANETs
for which OLSRv2 is applicable (see [RFC7181]). It can operate on for which OLSRv2 is applicable (see [RFC7181]). It can operate on
single, or multiple interfaces, to discover multiple disjoint paths single, or multiple interfaces, to discover multiple disjoint paths
from a source router to a destination router. MP-OLSRv2 is designed from a source router to a destination router. MP-OLSRv2 is designed
for networks with dynamic topology by avoiding single route failure. for networks with dynamic topology by avoiding single route failure.
It can also provide higher aggregated throughput and load balancing. It can also provide higher aggregated throughput and load balancing.
In a router supporting MP-OLSRv2, MP-OLSRv2 does not necessarily In a router supporting MP-OLSRv2, MP-OLSRv2 does not necessarily
replace OLSRv2 completely. The extension can be applied for certain replace OLSRv2 completely. The extension can be applied for certain
applications that are suitable for multi-path routing (mainly video applications that are suitable for multi-path routing (mainly video
or audio streams), based on the information such as DiffServ Code or audio streams), based on the information such as DiffServ Code
Point [RFC2474]. Point [RFC2474].
Compared to OLSRv2, this extension does not introduce new message Compared to OLSRv2, this extension does not introduce new message
type in the air. A new Message TLV type is introduced to identify type. A new Message TLV Type is introduced to identify the routers
the routers that support forwarding based on source route header. It that support forwarding based on source route header. It is
is interoperable with OLSRv2 implementations that do not have this interoperable with OLSRv2 implementations that do not have this
extension. extension.
MP-OLSRv2 supports two different, but interoperable multi-path MP-OLSRv2 supports two different, but interoperable multi-path
calculation approaches: proactive and reactive. In the proactive calculation approaches: proactive and reactive. In the proactive
calculation, the paths to all the destinations are calculated before calculation, the paths to all the destinations are calculated before
needed. In the reactive calculation, only the paths to desired needed. In the reactive calculation, only the paths to desired
destination(s) are calculated on demand. The proactive approach destination(s) are calculated on demand. The proactive approach
requires more computational resources than the reactive one. The requires more computational resources than the reactive one. The
reactive approach requires the IP forwarding plane to trigger the reactive approach requires the IP forwarding plane to trigger the
multi-path calculation. multi-path calculation.
skipping to change at page 7, line 21 skipping to change at page 7, line 22
o In the proactive approach, multiple paths to all possible o In the proactive approach, multiple paths to all possible
destinations are calculated and updated based on control message destinations are calculated and updated based on control message
exchange. The routes are thus available before they are actually exchange. The routes are thus available before they are actually
needed. needed.
o In the reactive approach, a multi-path algorithm is invoked on o In the reactive approach, a multi-path algorithm is invoked on
demand, i.e., only when there is a datagram to be sent from the demand, i.e., only when there is a datagram to be sent from the
source to the destination, and there is no available Routing Tuple source to the destination, and there is no available Routing Tuple
in the Multi-path Routing Set. This requires the IP forwarding in the Multi-path Routing Set. This requires the IP forwarding
information base to trigger the multi-path calculation specified information base to trigger the multi-path calculation specified
in Section 8.5 when no Multi-path Routing Tuple is available. in Section 8.5 when no Multi-path Routing Tuple is available. The
reactive operation is local in the router and no message
transmission delay is introduced.
Routers in the same network may choose either proactive or reactive Routers in the same network may choose either proactive or reactive
multi-path calculation independently according to their computation multi-path calculation independently according to their computation
resources. The Multi-path Dijkstra algorithm (defined in resources. The Multi-path Dijkstra algorithm (defined in
Section 8.5) is introduced as the default algorithm to generate Section 8.5) is introduced as the default algorithm to generate
multiple disjoint paths from a source to a destination, and such multiple disjoint paths from a source to a destination, and such
information is kept in the Multi-path Routing Set. information is kept in the Multi-path Routing Set.
The datagram is forwarded based on source routing. When there is a The datagram is forwarded based on source routing. When there is a
datagram to be sent to a destination, the source router acquires a datagram to be sent to a destination, the source router acquires a
skipping to change at page 7, line 43 skipping to change at page 8, line 4
scheduling algorithms). The path information is stored in the scheduling algorithms). The path information is stored in the
datagram header as source routing header. datagram header as source routing header.
5. Parameters and Constants 5. Parameters and Constants
In addition to the parameters and constants defined in [RFC7181], In addition to the parameters and constants defined in [RFC7181],
this specification uses the parameters and constants described in this specification uses the parameters and constants described in
this section. this section.
5.1. Router Parameters 5.1. Router Parameters
NUMBER_OF_PATHS The number of paths desired by the router. NUMBER_OF_PATHS The number of paths desired by the router.
MAX_SRC_HOPS The maximum number of hops allowed to be put in the MAX_SRC_HOPS The maximum number of hops allowed to be put in the
source routing header. A value set zero means there is no source routing header. A value set zero means there is no
limitation on the maximum number of hops. In an IPv6 network, it limitation on the maximum number of hops. In an IPv6 network, it
MUST be set to 0. In an IPv4 network, it MUST be strictly less MUST be set to 0 because [RFC6554] supports only strict source
than 11 due to the limit of the IPv4 header. routing. All the intermediate routers MUST be included in the
source routing header, which makes the number of hops to be kept a
variable. In an IPv4 network, it MUST be strictly less than 11
and greater than 0 due to the limit of the IPv4 header.
CUTOFF_RATIO The ratio that defines the maximum metric of a path CUTOFF_RATIO The ratio that defines the maximum metric of a path
compared to the shortest path kept in the OLSRv2 Routing Set. For compared to the shortest path kept in the OLSRv2 Routing Set. For
example, the metric to a destination is R_metric based on the example, the metric to a destination is R_metric based on the
Routing Set. Then the maximum metric allowed for a path is Routing Set. Then the maximum metric allowed for a path is
CUTOFF_RATIO * R_metric. CUTOFF_RATIO MUST be equal to or greater CUTOFF_RATIO * R_metric. CUTOFF_RATIO MUST be greater than or
than 1. Note that setting the value to 1 means looking for equal equal to 1. Note that setting the value to 1 means looking for
length paths, which may not be possible in some networks. equal length paths, which may not be possible in some networks.
SR_TC_INTERVAL The maximum time between the transmission of two SR_TC_INTERVAL The maximum time between the transmission of two
successive TC messages by a MP-OLSRv2 Routing Process. successive TC messages by a MP-OLSRv2 Routing Process.
SR_HOLD_TIME The minimal time that a SR-OLSRv2 Router Tuple SHOULD SR_HOLD_TIME_MULTIPLIER The multiplier to calculate the minimal time
be kept in the SR-OLSRv2 Router Set. that a SR-OLSRv2 Router Tuple SHOULD be kept in the SR-OLSRv2
Router Set.
6. Packets and Messages 6. Packets and Messages
This extension employs the routing control messages HELLO and TC This extension employs the routing control messages HELLO and TC
(Topology Control) as defined in OLSRv2 [RFC7181]. To support source (Topology Control) as defined in OLSRv2 [RFC7181] to obtain network
routing, a source routing header is added to each datagram routed by topology information. For the datagram, to support source routing, a
this extension. Depending on the IP version used, the source routing source routing header is added to each datagram routed by this
extension. Depending on the IP version used, the source routing
header is defined in this section. header is defined in this section.
6.1. HELLO and TC messages 6.1. HELLO and TC messages
HELLO and TC messages used by MP-OLSRv2 Routing Process share the HELLO and TC messages used by MP-OLSRv2 Routing Process use the same
same format as defined in [RFC7181]. In addition, a new Message TLV format as defined in [RFC7181]. In addition, a new Message TLV type
type is defined, to identify the originator of the HELLO or TC is defined, to identify the originator of the HELLO or TC message
message that supports source route forwarding. The new Message TLV that supports source route forwarding. The new Message TLV type is
type is introduced for enabling MP-OLSRv2 as an extension of OLSRv2: introduced for enabling MP-OLSRv2 as an extension of OLSRv2: only the
only the routers supporting source-route forwarding can be used in routers supporting source-route forwarding can be used in the source
the source routing header of a datagram, because adding a router that routing header of a datagram, because adding a router that does not
does not understand the source routing header will cause routing understand the source routing header will cause routing failure.
failure.
6.1.1. SOURCE_ROUTE TLV 6.1.1. SOURCE_ROUTE TLV
SOURCE_ROUTE TLV is a Message TLV signalling that the message is SOURCE_ROUTE TLV is a Message TLV signalling that the message is
generated by a router that supports source-route forwarding. It can generated by a router that supports source-route forwarding. It can
be an MP-OLSRv2 Routing Process, or an OLSRv2 Routing Process that be an MP-OLSRv2 Routing Process, or an OLSRv2 Routing Process that
supports source-route forwarding. The SOURCE_ROUTE TLV does not supports source-route forwarding.
include any value.
Every HELLO or TC message generated by a MP-OLSRv2 Routing Process Every HELLO or TC message generated by a MP-OLSRv2 Routing Process
MUST have exactly one SOURCE_ROUTE TLV. MUST have exactly one SOURCE_ROUTE TLV.
+--------------+-----------+----------------------------------------+
| Type | Value | Value |
| | Length | |
+--------------+-----------+----------------------------------------+
| SOURCE_ROUTE | 1 octet | The parameter SR_HOLD_TIME_MULTIPLIER |
| | | (unsigned integer) |
+--------------+-----------+----------------------------------------+
Table 1: SOURCE_ROUTE TLV Definition
Every HELLO or TC message generated by an OLSRv2 Routing Process MAY Every HELLO or TC message generated by an OLSRv2 Routing Process MAY
have one SOURCE_ROUTE TLV, if the OLSRv2 Routing Process supports have one SOURCE_ROUTE TLV, if the OLSRv2 Routing Process supports
source-route forwarding, and is willing to join the source route source-route forwarding, and is willing to join the source route
generated by other MP-OLSRv2 Routing Processes. The existence of generated by other MP-OLSRv2 Routing Processes. The existence of
SOURCE_ROUTE TLV MUST be consistent for a specific OLSRv2 Routing SOURCE_ROUTE TLV MUST be consistent for a specific OLSRv2 Routing
Process, i.e., either it adds SOURCE_ROUTE TLV to all its HELLO/TC Process, i.e., either it adds SOURCE_ROUTE TLV to all its HELLO/TC
messages, or it does not add SOURCE_ROUTE TLV to any HELLO/TC messages, or it does not add SOURCE_ROUTE TLV to any HELLO/TC
messages. messages.
6.2. Datagram 6.2. Datagram
skipping to change at page 10, line 8 skipping to change at page 10, line 26
Process, or OLSRv2 Routing Process with source-route forwarding Process, or OLSRv2 Routing Process with source-route forwarding
support. The set consists of SR-OLSRv2 Router Tuples: support. The set consists of SR-OLSRv2 Router Tuples:
(SR_addr, SR_time) (SR_addr, SR_time)
where: where:
SR_addr - is the network address of the router that supports SR_addr - is the network address of the router that supports
source-route forwarding; source-route forwarding;
SR_time - is the time until which the SR-OLSRv2 Router Tuples is SR_time - is the time until which the SR-OLSRv2 Router Tuple is
considered valid. considered valid.
7.2. Multi-path Routing Set 7.2. Multi-path Routing Set
The Multi-path Routing Set records the full path information of The Multi-path Routing Set records the full path information of
different paths to the destination. It consists of Multi-path different paths to the destination. It consists of Multi-path
Routing Tuples: Routing Tuples:
(MR_dest_addr, MR_path_set) (MR_dest_addr, MR_path_set)
skipping to change at page 10, line 37 skipping to change at page 11, line 8
Each Path Tuple is defined as: Each Path Tuple is defined as:
(PT_metric, PT_address[1], PT_address[2], ..., PT_address[n]) (PT_metric, PT_address[1], PT_address[2], ..., PT_address[n])
where: where:
PT_metric - is the metric of the path to the destination, measured PT_metric - is the metric of the path to the destination, measured
in LINK_METRIC_TYPE defined in [RFC7181]; in LINK_METRIC_TYPE defined in [RFC7181];
PT_address[1...n] - are the addresses of intermediate routers to be PT_address[1, ..., n-1] - are the addresses of intermediate routers
visited numbered from 1 to n, where n is the number of routers in to be visited numbered from 1 to n-1, where n is the number of
the path, i.e., the hop count. routers in the path, i.e., the hop count.
8. Protocol Details 8. Protocol Details
This protocol is based on OLSRv2, and extended to discover multiple This protocol is based on OLSRv2, and extended to discover multiple
disjoint paths from a source router to a destination router. It disjoint paths from a source router to a destination router. It
retains the basic routing control packets formats and processing of retains the basic routing control packets formats and processing of
OLSRv2 to obtain topology information of the network. The main OLSRv2 to obtain topology information of the network. The main
differences between OLSRv2 routing process are the datagram differences between OLSRv2 routing process are the datagram
processing at the source router and datagram forwarding. processing at the source router and datagram forwarding.
8.1. HELLO and TC Message Generation 8.1. HELLO and TC Message Generation
HELLO messages are generated according to Section 15.1 of [RFC7181]. HELLO messages are generated according to Section 15.1 of [RFC7181].
TC message are generated according to Section 16.1 of [RFC7181]. As TC message are generated according to Section 16.1 of [RFC7181]. As
least one TC message MUST be generated by an MP-OLSRv2 Routing least one TC message MUST be generated by an MP-OLSRv2 Routing
Process during SR_TC_INTERVAL. Please note that the TC message Process during SR_TC_INTERVAL. The TC message generation based on
generation based on SR_TC_INTERVAL does not replace the ordinary TC SR_TC_INTERVAL does not replace the ordinary TC message generation
message generation specified in [RFC7181] and does not carry any specified in [RFC7181] and MUST not carry any advertised neighbor
advertised neighbor addresses. This is due to the fact that not all addresses. This is due to the fact that not all routers will
routers will generate TC messages based on OLSRv2. The TC generation generate TC messages based on OLSRv2. The TC generation based on
based on SR_TC_INTERVAL serves for those routers to advertise SR_TC_INTERVAL serves for those routers to advertise SOURCE_ROUTE TLV
SOURCE_ROUTE TLV so that the other routers can be aware of the so that the other routers can be aware of the source-route enabled
source-route enabled routers so as to be used as destinations of routers so as to be used as destinations of multipath routing. The
multipath routing. The SR_TC_INTERVAL is set to a longer value than SR_TC_INTERVAL is set to a longer value than TC_INTERVAL.
TC_INTERVAL.
For both TC and HELLO messages, a single Message TLV with Type := For both TC and HELLO messages, a single Message TLV with Type :=
SOURCE_ROUTE MUST be added to the message. SOURCE_ROUTE MUST be included.
8.2. HELLO and TC Message Processing 8.2. HELLO and TC Message Processing
HELLO and TC messages are processed according to section 15.3 and HELLO and TC messages are processed according to section 15.3 and
16.3 of [RFC7181]. 16.3 of [RFC7181].
For the purpose of this section, the following definitions are used:
o "validity time" is calculated from the Message TLV with Type =
VALIDITY_TIME of the HELLO message or TC message.
o "source route hold time multiplier" is defined as being the value
of a Message TLV with Type = SOURCE_ROUTE.
For every HELLO or TC message received, if there is a Message TLV For every HELLO or TC message received, if there is a Message TLV
with Type := SOURCE_ROUTE, create or update (if the Tuple exists with Type := SOURCE_ROUTE, create or update (if the Tuple exists
already) the SR-OLSR Router Tuple with already) the SR-OLSR Router Tuple with
o SR_addr := originator address of the HELLO or TC message o SR_addr := originator address of the HELLO or TC message
o SR_time := current_time + SR_HOLD_TIME. o SR_time := current_time + source route hold time multiplier *
validity time, unless the existed SR_time is greater than the
newly calculated the SR_time.
8.3. MPR Selection 8.3. MPR Selection
Each MP-OLSRv2 Routing Process selects routing MPRs and flooding MPRs Each MP-OLSRv2 Routing Process selects routing MPRs and flooding MPRs
following Section 18 of [RFC7181]. In a mixed network with OLSRv2- following Section 18 of [RFC7181]. In a mixed network with OLSRv2-
only routers, the following considerations apply when calculating only routers, the following considerations apply when calculating
MPRs: MPRs:
o MP-OLSR routers SHOULD be preferred as routing MPRs. o MP-OLSR routers SHOULD be preferred as routing MPRs.
skipping to change at page 12, line 35 skipping to change at page 13, line 10
If a matching Multi-path Routing Tuple is obtained, the Path Tuples If a matching Multi-path Routing Tuple is obtained, the Path Tuples
of the Multi-path Routing Tuple are applied to the datagrams using of the Multi-path Routing Tuple are applied to the datagrams using
Round-robin scheduling. For example, they are 2 path Tuples (Path-1, Round-robin scheduling. For example, they are 2 path Tuples (Path-1,
Path-2) for destination router D. A series of datagrams (Packet-1, Path-2) for destination router D. A series of datagrams (Packet-1,
Packet-2, Packet-3, ... etc.) are to be sent router D. Path-1 is then Packet-2, Packet-3, ... etc.) are to be sent router D. Path-1 is then
chosen for Packet-1, Path-2 for Packet-2, Path-1 for Packet 3, etc. chosen for Packet-1, Path-2 for Packet-2, Path-1 for Packet 3, etc.
Other path scheduling mechanisms are also possible and will not Other path scheduling mechanisms are also possible and will not
impact the interoperability of different implementations. impact the interoperability of different implementations.
The addresses in PT_address[1...n] of the chosen Path Tuple are thus The addresses in PT_address[1, ..., n-1] of the chosen Path Tuple are
added to the datagram header as the source routing header. For IPv6 thus added to the datagram header as the source routing header. For
networks, strict source routing is used, thus all the intermediate IPv6 networks, strict source routing is used, thus all the
routers in the path are stored in the source routing header following intermediate routers in the path are stored in the source routing
format defined in section 3 of [RFC6554], except the Routing Type header following format defined in section 3 of [RFC6554], except the
field is set to 254 (experimental). Routing Type field is set to 254 (experimental).
For IPv4 networks, loose source routing is used, with following For IPv4 networks, loose source routing is used, with following
rules: rules:
o Only the addresses that exist in SR-OLSR Router Set can be added o Only the addresses that exist in SR-OLSR Router Set can be added
to the source routing header. to the source routing header.
o If the length of the path (n) is greater than MAX_SRC_HOPS, only o If the length of the path (n) is greater than MAX_SRC_HOPS, only
the "key" routers in the path are kept. By default, the key the "key" routers in the path are kept. By default, the key
routers are uniformly chosen in the path. If further information routers are uniformly chosen in the path. If further information
skipping to change at page 13, line 46 skipping to change at page 14, line 23
and requiring multipath routing may result in inferior paths. and requiring multipath routing may result in inferior paths.
By invoking the multi-path algorithm, NUMBER_OF_PATHS paths are By invoking the multi-path algorithm, NUMBER_OF_PATHS paths are
obtained and added to the Multi-path Routing Set, by creating a obtained and added to the Multi-path Routing Set, by creating a
Multi-path Routing Tuple with: Multi-path Routing Tuple with:
o MR_dest_addr := destination of the datagram o MR_dest_addr := destination of the datagram
o A MP_path_set with calculated Path Tuples. Each Path Tuple o A MP_path_set with calculated Path Tuples. Each Path Tuple
corresponds to a path obtained in Multi-path Dijkstra algorithm, corresponds to a path obtained in Multi-path Dijkstra algorithm,
with PT_metric := metric of the calculated path and with PT_metric := metric of the calculated path and PT_address[1,
PT_address[1...n] := list of intermediate routers. ..., n-1] := list of intermediate routers.
8.5.2. Multi-path Dijkstra Algorithm 8.5.2. Multi-path Dijkstra Algorithm
This section introduces Multi-path Dijkstra Algorithm as a default This section introduces Multi-path Dijkstra Algorithm as a default
algorithm. It tries to obtain disjoint paths when appropriate, but algorithm. It tries to obtain disjoint paths when appropriate, but
does not guarantee strict disjoint paths. The use of other does not guarantee strict disjoint paths. The use of other
algorithms is not prohibited, as long as the requirements described algorithms is not prohibited, as long as the requirements described
in Section 8.5.1 are met. Using different multi-path algorithms will in Section 8.5.1 are met. Using different multi-path algorithms will
not impact the interoperability. not impact the interoperability.
skipping to change at page 16, line 24 skipping to change at page 16, line 46
o MAX_SRC_HOPS := 10, for IPv4 networks. For IPv6 networks, it MUST o MAX_SRC_HOPS := 10, for IPv4 networks. For IPv6 networks, it MUST
be set to 0, i.e., no constraint on maximum number of hops. be set to 0, i.e., no constraint on maximum number of hops.
o CUTOFF_RATIO := 1.5. It MUST be strictly greater than 1. o CUTOFF_RATIO := 1.5. It MUST be strictly greater than 1.
o SR_TC_INTERVAL := 10 x TC_INTERVAL. It SHOULD be significantly o SR_TC_INTERVAL := 10 x TC_INTERVAL. It SHOULD be significantly
greater than TC_INTERVAL to reduce unnecessary TC message greater than TC_INTERVAL to reduce unnecessary TC message
generations. generations.
o SR_HOLD_TIME := 3 x SR_TC_INTERVAL. It MUST be greater than o SR_HOLD_TIME_MULTIPLIER := 32. It MUST be greater than 1 and less
SR_TC_INTERVAL. than 255. It SHOULD be greater than 30.
If Multi-path Dijkstra Algorithm is applied: If Multi-path Dijkstra Algorithm is applied:
o fp(c) := 4*c, where c is the original metric of the link. o fp(c) := 4*c, where c is the original metric of the link.
o fe(c) := 2*c, where c is the original metric of the link. o fe(c) := 2*c, where c is the original metric of the link.
The setting of metric functions fp and fc defines the preference of The setting of metric functions fp and fc defines the preference of
obtained multiple disjoint paths. If id is the identity function, obtained multiple disjoint paths. If id is the identity function,
i.e., fp(c)=c, 3 cases are possible: i.e., fp(c)=c, 3 cases are possible:
skipping to change at page 19, line 19 skipping to change at page 19, line 43
12.1. Expert Review: Evaluation Guidelines 12.1. Expert Review: Evaluation Guidelines
For the registry where an Expert Review is required, the designated For the registry where an Expert Review is required, the designated
expert SHOULD take the same general recommendations into expert SHOULD take the same general recommendations into
consideration as are specified by [RFC5444]. consideration as are specified by [RFC5444].
12.2. Message TLV Types 12.2. Message TLV Types
This specification updates the Message Type 7 by adding the new Type This specification updates the Message Type 7 by adding the new Type
Extension SOURCE_ROUTE, as illustrated in Table 1. Extension SOURCE_ROUTE, as illustrated in Table 2.
+-----------+--------------+------------------------+---------------+ +-----------+--------------+------------------------+---------------+
| Type | Name | Description | Reference | | Type | Name | Description | Reference |
| Extension | | | | | Extension | | | |
+-----------+--------------+------------------------+---------------+ +-----------+--------------+------------------------+---------------+
| TBD | SOURCE_ROUTE | Indicates the | This | | TBD | SOURCE_ROUTE | Indicates that the | This |
| | | originator of the | specification | | | | originator of the | specification |
| | | message supports | | | | | message supports | |
| | | source route | | | | | source route | |
| | | forwarding. No value. | | | | | forwarding. The value | |
| | | is a multiplier for | |
| | | calculating the hold | |
| | | time of SR-OLSRv2 | |
| | | Router Tuples. | |
+-----------+--------------+------------------------+---------------+ +-----------+--------------+------------------------+---------------+
Table 1: SOURCE_ROUTE type for RFC 5444 Type 7 Message TLV Type Table 2: SOURCE_ROUTE type for RFC 5444 Type 7 Message TLV Type
Extensions Extensions
12.3. Routing Type 12.3. Routing Type
This specification uses the experimental value 254 of the IPv6 This specification uses the experimental value 254 of the IPv6
Routing Type as specified in [RFC5871] for IPv6 source routing. Routing Type as specified in [RFC5871] for IPv6 source routing.
13. Acknowledgments 13. Acknowledgments
The authors would like to thank Sylvain David, Asmaa Adnane, Eddy The authors would like to thank Sylvain David, Asmaa Adnane, Eddy
Cizeron, Salima Hamma, Pascal Lesage and Xavier Lecourtier for their Cizeron, Salima Hamma, Pascal Lesage and Xavier Lecourtier for their
efforts in developing, implementing and testing the specification. efforts in developing, implementing and testing the specification.
The authors also appreciate valuable discussions with Thomas Clausen, The authors also appreciate valuable discussions with Thomas Clausen,
Ulrich Herberg, Justin Dean, Geoff Ladwig, Henning Rogge , Marcus Ulrich Herberg, Justin Dean, Geoff Ladwig, Henning Rogge , Marcus
Barkowsky and Christopher Dearlove. Barkowsky and especially Christopher Dearlove for his multiple rounds
of reviews during the working group last calls.
14. References 14. References
14.1. Normative References 14.1. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981, DOI 10.17487/RFC0791, September 1981,
<http://www.rfc-editor.org/info/rfc791>. <http://www.rfc-editor.org/info/rfc791>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997, RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
 End of changes. 44 change blocks. 
92 lines changed or deleted 121 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/