draft-ietf-manet-olsrv2-multipath-01.txt   draft-ietf-manet-olsrv2-multipath-02.txt 
Network Working Group J. Yi Network Working Group J. Yi
Internet-Draft LIX, Ecole Polytechnique Internet-Draft LIX, Ecole Polytechnique
Intended status: Experimental B. Parrein Intended status: Experimental B. Parrein
Expires: March 19, 2015 University of Nantes Expires: April 29, 2015 University of Nantes
September 15, 2014 October 26, 2014
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-01 draft-ietf-manet-olsrv2-multipath-02
Abstract Abstract
This document specifies a multi-path extension to the Optimized Link This document specifies a multi-path extension to 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
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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 March 19, 2015. This Internet-Draft will expire on April 29, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 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
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
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 . . . . . . . . . . . . . . . . . . . 6 5. Parameters and Constants . . . . . . . . . . . . . . . . . . . 7
5.1. Router Parameters . . . . . . . . . . . . . . . . . . . . 6 5.1. Router Parameters . . . . . . . . . . . . . . . . . . . . 7
6. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 7 6. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 7
6.1. HELLO and TC messages . . . . . . . . . . . . . . . . . . 7 6.1. HELLO and TC messages . . . . . . . . . . . . . . . . . . 7
6.1.1. MP_OLSRv2 TLV . . . . . . . . . . . . . . . . . . . . 7 6.1.1. MP_OLSRv2 TLV . . . . . . . . . . . . . . . . . . . . 7
6.2. Datagram . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.2. Datagram . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.2.1. Source Routing Header in IPv4 . . . . . . . . . . . . 8 6.2.1. Source Routing Header in IPv4 . . . . . . . . . . . . 8
6.2.2. Source Routing Header in IPv6 . . . . . . . . . . . . 8 6.2.2. Source Routing Header in IPv6 . . . . . . . . . . . . 8
7. Information Bases . . . . . . . . . . . . . . . . . . . . . . 8 7. Information Bases . . . . . . . . . . . . . . . . . . . . . . 8
7.1. MP-OLSRv2 Router Set . . . . . . . . . . . . . . . . . . . 8 7.1. MP-OLSRv2 Router Set . . . . . . . . . . . . . . . . . . . 8
7.2. Multi-path Routing Set . . . . . . . . . . . . . . . . . . 8 7.2. Multi-path Routing Set . . . . . . . . . . . . . . . . . . 9
8. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 9 8. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. HELLO and TC Message Generation . . . . . . . . . . . . . 9 8.1. HELLO and TC Message Generation . . . . . . . . . . . . . 9
8.2. HELLO and TC Message Processing . . . . . . . . . . . . . 9 8.2. HELLO and TC Message Processing . . . . . . . . . . . . . 10
8.3. Datagram Processing at the MP-OLSRv2 Originator . . . . . 10 8.3. Datagram Processing at the MP-OLSRv2 Originator . . . . . 10
8.4. Multi-path Dijkstra Algorithm . . . . . . . . . . . . . . 10 8.4. Multi-path Dijkstra Algorithm . . . . . . . . . . . . . . 11
8.5. Datagram Forwarding . . . . . . . . . . . . . . . . . . . 11 8.5. Datagram Forwarding . . . . . . . . . . . . . . . . . . . 11
9. Configuration Parameters . . . . . . . . . . . . . . . . . . . 12 9. Configuration Parameters . . . . . . . . . . . . . . . . . . . 12
10. Implementation Status . . . . . . . . . . . . . . . . . . . . 13 10. Implementation Status . . . . . . . . . . . . . . . . . . . . 13
10.1. Multi-path extension based on nOLSRv2 . . . . . . . . . . 13 10.1. Multi-path extension based on nOLSRv2 . . . . . . . . . . 13
10.2. Multi-path extension based on olsrd . . . . . . . . . . . 13 10.2. Multi-path extension based on olsrd . . . . . . . . . . . 14
10.3. Multi-path extension based on umOLSR . . . . . . . . . . . 14 10.3. Multi-path extension based on umOLSR . . . . . . . . . . . 14
11. Security Considerations . . . . . . . . . . . . . . . . . . . 14 11. Security Considerations . . . . . . . . . . . . . . . . . . . 14
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
12.1. HELLO Message-Type-Specific TLV Type Registries . . . . . 15 12.1. HELLO Message-Type-Specific TLV Type Registries . . . . . 15
12.2. TC Message-Type-Specific TLV Type Registries . . . . . . . 15 12.2. TC Message-Type-Specific TLV Type Registries . . . . . . . 15
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
14.1. Normative References . . . . . . . . . . . . . . . . . . . 15 14.1. Normative References . . . . . . . . . . . . . . . . . . . 16
14.2. Informative References . . . . . . . . . . . . . . . . . . 16 14.2. Informative References . . . . . . . . . . . . . . . . . . 16
Appendix A. An example of Multi-path Dijkstra Algorithm . . . . . 17 Appendix A. An example of Multi-path Dijkstra Algorithm . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
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
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using source routing. MP-OLSRv2 is designed to be interoperable with using source routing. MP-OLSRv2 is designed to be interoperable with
OLSRv2. OLSRv2.
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 packet over multiple disjoint paths MANET scenarios by transmitting packet over multiple disjoint paths
using source routing. This mechanism is used because: using source routing. This mechanism is used because:
o Disjoint paths can avoid single route failure. o Disjoint paths can avoid single route failures.
o By having control of the paths at the source, the delay can be o Transmitting datagrams through parallel paths can increase
provisioned. aggregated throughput and provide load-balancing.
o Certain scenarios require some routers must (or must not) be used. o Certain scenarios require some routers must (or must not) be used.
o By having control of the paths at the source, the delay can be
provisioned.
o An very important application of this extension is combination o An very important application of this extension is combination
with Forward Error Correction coding. This requires disjoint with Forward Error Correction coding. This requires disjoint
paths. The single path routing is not adapted because the packet paths. The single path routing is not adapted because the packet
drop is normally continuous, in which forward correction coding is drop is normally continuous, in which forward correction coding is
not helpful. not helpful.
While existed deployments, running code and simulations have proven While existed deployments, running code and simulations have proven
the interest of multi-path extension for OLSRv2 in certain networks, the interest of multi-path extension for OLSRv2 in certain networks,
more experiments and experiences are still needed to understand the more experiments and experiences are still needed to understand the
mechanisms of the protocol. The multipath extension for OLSRv2 is mechanisms of the protocol. The multipath extension for OLSRv2 is
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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 for the cost functions. Cost functions are applied o Optimal values for the cost functions. Cost functions are applied
to punish the costs of used links and nodes so as to obtain to punish the costs of used links and nodes so as to obtain
disjoint paths. What kind of disjointness is desired (node- disjoint paths. What kind of disjointness is desired (node-
disjoint or link-disjoint) may depends on the layer 2 protocol disjoint or link-disjoint) may depends on the layer 2 protocol
used, and can be achieved by setting different sets of cost used, and can be achieved by setting different sets of cost
functions. functions.
o Optimal choice of "key" routers for loose source routing. In some
cases, loose source routing is use to reduce overhead or for
interoperability with OLSRv2. Other than the basic rules defined
in the following of this document, optimal choices of routers to
put in the source routing header can be further studied.
o Use of other metric other than hop-count. This multipath o Use of other metric other than hop-count. This multipath
extension can be used not only for hop-count metric type, but extension can be used not only for hop-count metric type, but
other metric types that meet the requirement of OLSRv2, such as other metric types that meet the requirement of OLSRv2, such as
[I-D.ietf-manet-olsrv2-dat-metric]. The metric type used has also [I-D.ietf-manet-olsrv2-dat-metric]. The metric type used has also
co-relation with the choice of cost functions as indicated in the co-relation with the choice of cost functions as indicated in the
previous bullet. previous bullet.
o Optimal choice of "key" routers for loose source routing. In some
cases, loose source routing is used to reduce overhead or for
interoperability with OLSRv2 routers. Other than the basic rules
defined in the following of this document, optimal choices of
routers to put in the loose source routing header can be further
studied.
o Different path-selection schedulers. By default, Round-Robin
scheduling is used to select a path to be used for a datagram. In
some scenarios, weighted scheduling can be considered: for
example, the paths with low costs (higher path quality) can
transfer more datagrams compared to paths with higher costs.
o The impacts to the delay variation due to multi-path routing. o The impacts to 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 experiments especially variable latencies. Although current experiments
result show that multi-path routing can reduce the jitter in result 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 packet re-ordering. sensitive to the packet re-ordering.
o The disjoint multiple path protocol has interesting application o The disjoint multiple path protocol has interesting application
with Forward Error Correction (FEC) Coding, especially for with Forward Error Correction (FEC) Coding, especially for
services like video/audio streaming. The combination of FEC services like video/audio streaming. The combination of FEC
coding mechanisms and this extension is thus encouraged. coding mechanisms and this extension is thus encouraged. By
applying FEC coding, the issue of packet re-ordering can be
alleviated.
o In addition to IP source routing based approach, it can be o In addition to IP source routing based approach, it can be
interesting to try multi-path routing in MANET using label- interesting to try multi-path routing in MANET using label-
switched flow in the future. switched flow in the future.
o The usage of multi-topology information. By using o The usage of multi-topology information. By using
[I-D.ietf-manet-olsrv2-multitopology], multiple topologies using [I-D.ietf-manet-olsrv2-multitopology], multiple topologies using
different metric types can be obtained. It is encouraged to different metric types can be obtained. It is encouraged to
experiment the use of multiple metrics for building multiple paths experiment the use of multiple metrics for building multiple paths
also. also.
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o Identify all the reachable routers in the network. o Identify all the reachable routers in the network.
o Identify a sufficient subset of links in the networks, so that o Identify a sufficient subset of links in the networks, so that
routes can be calculated to all reachable destinations. routes can be calculated to all reachable destinations.
o Provide a Routing Set containing shortest routes from this router o Provide a Routing Set containing shortest routes from this router
to all destinations. to all destinations.
Based on the above information acquired by OLSRv2, the MP-OLSRv2 Based on the above information acquired by OLSRv2, the MP-OLSRv2
Routing Process is able to calculate multiple paths to certain Routing Process is able to calculate multiple paths to desired
destinations based on multi-path Dijkstra algorithm: the Dijkstra destinations based on multi-path Dijkstra algorithm: the Dijkstra
algorithm is performed multiple times . In each iteration, the cost algorithm is performed multiple times . In each iteration, the cost
of used links are increased (i.e., punished), so that they can be of used links are increased (i.e., punished), so that they can be
avoided to be chosen in the next iteration. The multi-path Dijkstra avoided to be chosen in the next iteration. The multi-path Dijkstra
algorithm can generate multiple disjoint paths from a source to a algorithm can generate multiple disjoint paths from a source to a
destination , and such information is kept in Multi-path Routing Set. destination , and such information is kept in Multi-path Routing Set.
The algorithm is invoked on demand, i.e., only when there is data The algorithm is invoked on demand, i.e., only when there is data
traffic to be sent from the source to the destination, and there is traffic to be sent from the source to the destination, and there is
no available routing tuples in the Multi-path Routing Set. no available routing tuples 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
path from the Multi-path Routing Set (in Round-Robin fashion here) . path from the Multi-path Routing Set (MAY be Round-Robin, or other
The path information is stored in the datagram header as source scheduling algorithms). The path information is stored in the
routing header. datagram header as source routing header.
All the intermediate routers are listed in the source routing header All the intermediate routers are listed in the source routing header
(SRH), unless there are routers that do not support MP-OLSRv2 in the (SRH), unless there are routers that do not support MP-OLSRv2 in the
paths, or the paths are too long to be fully stored in the SRH -- in paths, or the paths are too long to be fully stored in the SRH -- in
which case, loose source routing is used. The intermediate routers which case, loose source routing is used. The intermediate routers
listed in the SRH read the SRH and forward the datagram to the next listed in the SRH read the SRH and forward the datagram to the next
hop indicated in the SRH. hop as indicated in the SRH.
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 put in the MAX_SRC_HOPS The maximum number of hops allowed to be put in the
source routing header. source routing header.
fp Incremental function of multi-path Dijkstra algorithm. It is fp Incremental function of multi-path Dijkstra algorithm. It is
used to increase costs of links belonging to the previously used to increase costs of links belonging to the previously
computed path. computed path.
fe Incremental function of multi-path Dijkstra algorithm. It is fe Incremental function of multi-path Dijkstra algorithm. It is
used to increase costs of links who lead to routers of the used to increase costs of links that lead to routers of the
previous computed path. previous computed path.
MR_HOLD_TIME It is the minimal time that a Multi-path Routing Tuple MR_HOLD_TIME It is the minimal time that a Multi-path Routing Tuple
SHOULD be kept in the Multi-path Routing Set. SHOULD be kept in the Multi-path Routing Set.
MP_OLSR_HOLD_TIME It is the minimal time that a MP-OLSRv2 Router MP_OLSR_HOLD_TIME It is the minimal time that a MP-OLSRv2 Router
Tuple SHOULD be kept in the MP-OLSRv2 Router Set. Tuple SHOULD be kept in the MP-OLSRv2 Router Set.
6. Packets and Messages 6. Packets and Messages
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defined, to identify the originator of the HELLO or TC message is defined, to identify the originator of the HELLO or TC message is
running MP-OLSRv2. running MP-OLSRv2.
6.1.1. MP_OLSRv2 TLV 6.1.1. MP_OLSRv2 TLV
An MP_OLSRv2 TLV is a Message TLV that signals the message is An MP_OLSRv2 TLV is a Message TLV that signals the message is
generated by an MP-OLSRv2 Routing Process. It does not include any generated by an MP-OLSRv2 Routing Process. It does not include any
value. value.
Every HELLO or TC message generated by MP-OLSRv2 Routing Process MUST Every HELLO or TC message generated by MP-OLSRv2 Routing Process MUST
has one MP_OLSRv2 TLV. have one MP_OLSRv2 TLV.
6.2. Datagram 6.2. Datagram
6.2.1. Source Routing Header in IPv4 6.2.1. Source Routing Header in IPv4
In IPv4 [RFC0791] networks, the MP-OLSRv2 routing process employs In IPv4 [RFC0791] networks, the MP-OLSRv2 routing process employs
loose source routing, as defined in [RFC0791]. It exists as an loose source routing header, as defined in [RFC0791]. It exists as
option header, with option class 0, and option number 3. an option header, with option class 0, and option number 3.
The source route information is kept in the "route data" field of the The source route information is kept in the "route data" field of the
loss source route header. loss source route header.
6.2.2. Source Routing Header in IPv6 6.2.2. Source Routing Header in IPv6
In IPv6 [RFC2460] networks, the MP-OLSRv2 routing process employs the In IPv6 [RFC2460] networks, the MP-OLSRv2 routing process employs the
source routing header as defined in [RFC6554], with IPv6 Routing Type source routing header as defined in [RFC6554], with IPv6 Routing Type
3. 3.
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It consists of Path Tuples. It consists of Path Tuples.
Each Path Tuple is defined as: Each Path Tuple is defined as:
(PT_cost, PT_address[1], PT_address[2], ..., PT_address[n]) (PT_cost, PT_address[1], PT_address[2], ..., PT_address[n])
where: where:
PT_cost - the cost of the path to the destination; PT_cost - the cost of the path to the destination;
PT_address[1...n] - the addresses of intermediate router to be PT_address[1...n] - the addresses of intermediate routers to be
visited numbered from 1 to n. visited numbered from 1 to n.
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 the source to the destination router. It retains disjoint paths from the source to the destination router. It retains
the basic routing control packets formats and processing of OLSRv2 to the basic routing control packets formats and processing of OLSRv2 to
obtain topology information of the network. The main differences obtain topology information of the network. The main differences
between OLSRv2 routing process is the datagram processing at the between OLSRv2 routing process are the datagram processing at the
source router and datagram forwarding. source router and datagram forwarding.
8.1. HELLO and TC Message Generation 8.1. HELLO and TC Message Generation
HELLO and TC messages are generated according to the section 15.1 or HELLO and TC messages are generated according to the section 15.1 or
section 16.1 of [RFC7181]. section 16.1 of [RFC7181].
A single Message-Type-Specific TLV with Type := MP_OLSRv2 is added to A single Message-Type-Specific TLV with Type := MP_OLSRv2 is added to
the message. the message.
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o Each Path Tuple in the MP_path_set corresponds to a path obtained o Each Path Tuple in the MP_path_set corresponds to a path obtained
in multi-path Dijkstra algorithm, with PT_cost := cost of the path in multi-path Dijkstra algorithm, with PT_cost := cost of the path
to the destination d. to the destination d.
8.5. Datagram Forwarding 8.5. Datagram Forwarding
On receiving a datagram with source routing header, the Destination On receiving a datagram with source routing header, the Destination
Address field of the IP header is first compared to the addresses of Address field of the IP header is first compared to the addresses of
the local interfaces. If a matching local address if found, the the local interfaces. If a matching local address if found, the
datagram is processed as follows: datagram is processed from Step 1 to Step 4 as follows. Or else, the
datagram is processed from Step 3 to Step 4.
1. Obtain the next source address Address[i] in the source route 1. Obtain the next source address Address[i] in the source route
header. How to obtain the next source address depends on the IP header. How to obtain the next source address depends on the IP
version used. In IPv4, the position of the next source address version used. In IPv4, the position of the next source address
is indicated by the "pointer" field of the source routing header is indicated by the "pointer" field of the source routing header
[RFC0791]. In IPv6, the position is indicated by "Segments Left" [RFC0791]. In IPv6, the position is indicated by "Segments Left"
field of the source routing header. If no next source address is field of the source routing header. If no next source address is
found, the forwarding process is finished. found, the forwarding process is finished.
2. Swap Address[i] and destination address in the IP header. 2. Swap Address[i] and destination address in the IP header.
3. Forward the datagram to the destination address according to the 3. If the Destination Address of the IP header belongs to one of the
router's 1-hop symmetric neighbors, the datagram is forwarded to
the neighbor router. Or else:
4. Forward the datagram to the destination address according to the
OLSRv2 Routing Tuple information through R_local_iface_addr where OLSRv2 Routing Tuple information through R_local_iface_addr where
* R_dest_addr = destination address in the IP header * R_dest_addr = destination address in the IP header
If no matching address is found:
o If the Destination Address of the IP header belongs to one of the
router's 1-hop symmetric neighbors, the datagram is forwarded to
the neighbor router.
o Or else, the datagram is forwarded according OLSRv2 routing
process.
9. Configuration Parameters 9. Configuration Parameters
This section gives default values and guideline for setting This section gives default values and guideline for setting
parameters defined in Section 5. Network administrator may wish to parameters defined in Section 5. Network administrator may wish to
change certain, or all the parameters for different network change certain, or all the parameters for different network
scenarios. As an experimental track protocol, the users of this scenarios. As an experimental track protocol, the users of this
protocol are also encouraged to explore different parameter setting protocol are also encouraged to explore different parameter setting
in various network environments, and provide feedback. in various network environments, and provide feedback.
o NUMBER_OF_PATHS = 3. This parameter defines the number of o NUMBER_OF_PATHS = 3. This parameter defines the number of
parallel paths used in datagram forwarding. Setting it to one parallel paths used in datagram forwarding. Setting it to one
makes the specification identical to OLSRv2. Setting it to too makes the specification identical to OLSRv2. Setting it to too
big value can lead to unnecessary computational overhead and big value can lead to unnecessary computational overhead and
inferior paths. inferior paths.
o MAX_SRC_HOPS = 10. o MAX_SRC_HOPS = 10.
o MR_HOLD_TIME = 10 seconds. o MR_HOLD_TIME = 10 seconds.
o MP_OLSR_HOLD_TIME = 10 seconds.
o fp(c) = 4*c, where c is the original cost of the link. o fp(c) = 4*c, where c is the original cost of the link.
o fe(c) = 2*c, where c is the original cost of the link. o fe(c) = 2*c, where c is the original cost of the link.
The setting of cost functions fp and fc defines the preference of The setting of cost functions fp and fc defines the preference of
obtained multiple disjoint paths. If id is the identity functions, 3 obtained multiple disjoint paths. If id is the identity functions, 3
cases are possible: cases are possible:
o if id=fe<fp paths tend to be link disjoint; o if id=fe<fp paths tend to be link disjoint;
 End of changes. 32 change blocks. 
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