draft-ietf-lsr-ospf-prefix-originator-02.txt   draft-ietf-lsr-ospf-prefix-originator-03.txt 
LSR Working Group A. Wang LSR Working Group A. Wang
Internet-Draft China Telecom Internet-Draft China Telecom
Intended status: Standards Track A. Lindem Intended status: Standards Track A. Lindem
Expires: February 26, 2020 Cisco Systems Expires: February 28, 2020 Cisco Systems
J. Dong J. Dong
Huawei Technologies Huawei Technologies
K. Talaulikar
P. Psenak P. Psenak
K. Talaulikar
Cisco Systems Cisco Systems
August 25, 2019 August 27, 2019
OSPF Extension for Prefix Originator OSPF Extension for Prefix Originator
draft-ietf-lsr-ospf-prefix-originator-02 draft-ietf-lsr-ospf-prefix-originator-03
Abstract Abstract
This document describes Open Shortest Path First (OSPF) v2 and OSPFv3 This document describes Open Shortest Path First (OSPF) v2 and OSPFv3
encodings to advertise the router-id of the originator of inter-area encodings to advertise the router-id of the originator of inter-area
prefixes for OSPFv2 and OSPFv3 Link-State Advertisement (LSA), which prefixes for OSPFv2 and OSPFv3 Link-State Advertisement (LSA), which
are needed in several use cases in multi-area OSPF use cases. are needed in several use cases in multi-area OSPF use cases.
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-
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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 February 26, 2020. This Internet-Draft will expire on February 28, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://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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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Conventions used in this document . . . . . . . . . . . . . . 4 4. Conventions used in this document . . . . . . . . . . . . . . 4
5. Scenario Description . . . . . . . . . . . . . . . . . . . . 4 5. Scenario Description . . . . . . . . . . . . . . . . . . . . 4
6. Prefix Source Router-ID sub-TLV . . . . . . . . . . . . . . . 5 6. Prefix Source Router-ID sub-TLV . . . . . . . . . . . . . . . 5
7. Extended LSA Elements of Procedure . . . . . . . . . . . . . 6 7. Extended LSA Elements of Procedure . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6 8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . 7 11.1. Normative References . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . 8 11.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Inter-Area Topology Retrieval Process . . . . . . . 8 Appendix A. Inter-Area Topology Retrieval Process . . . . . . . 9
Appendix B. Special Considerations on Inter-Area Topology Appendix B. Special Considerations on Inter-Area Topology
Retrieval . . . . . . . . . . . . . . . . . . . . . 9 Retrieval . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
[I-D.ietf-ospf-mpls-elc] defines mechanisms to Entropy Readable Label [I-D.ietf-ospf-mpls-elc] defines mechanisms to Entropy Readable Label
Depth (ERLD) for ingress Label Switching Router (LSR) to discover Depth (ERLD) for ingress Label Switching Router (LSR) to discover
each LSR's capability of performing Entropy Label (EL) -based load- each LSR's capability of performing Entropy Label (EL) -based load-
balancing in Multi Protocol Label Switch (MPLS) networks. The balancing in Multi Protocol Label Switch (MPLS) networks. The
ingress LSR can use this information to push the appropriate label ingress LSR can use this information to push the appropriate label
stack for specific traffic, especially in segment routing stack for specific traffic, especially in segment routing
environments and other stacked LSPs scenarios. environments and other stacked LSPs scenarios.
However, in inter-area scenarios, the Area Border Router (ABR) does However, in inter-area scenarios, the Area Border Router (ABR) does
not advertise the originating OSPF router-id for inter-area prefixes. not advertise the originating OSPF router-id for inter-area prefixes.
An OSPF router in one area doesn't know where the prefixes really An OSPF router in one area doesn't know where the prefixes really
came from and can't determine the router that originated inter-area came from and can't determine the router that originated inter-area
prefixes and then can't judge the ERLD capabilities of the prefixes and then can't judge the ERLD capabilities of the
destination. It is necessary to transfer the originator information destination. It is necessary to transfer the originator information
of these inter-area prefixes to ensure the ingress LSR constructs the of these inter-area prefixes to ensure the ingress LSR constructs the
right Label stack. right label stack.
More generally, draft [RFC8476] defines a mechanism to advertise More generally, [RFC8476] defines a mechanism to advertise multiple
multiple types of supported Maximum SID Depths (MSD) at node and/or types of supported Maximum SID Depths (MSD) at node and/or link
link granularity. This information will be referred when the head- granularity. This information will be referred when the head-end
end router starts to send traffic to destination prefixes. In inter- router starts to send traffic to destination prefixes. In inter-area
area scenario, it is also necessary for the sender to learn the scenario, it is also necessary for the sender to learn the
capabilities of the receivers associated with the inter-area capabilities of the receivers associated with the inter-area
prefixes. prefixes.
There is also another scenario where knowing the originator of inter- There is also another scenario where knowing the originator of inter-
area prefixes is useful. For example, Border Gateway Protocol Link- area prefixes is useful. For example, Border Gateway Protocol Link-
State (BGP-LS) [RFC7752] describes mechanisms using the BGP protocol State (BGP-LS) [RFC7752] describes mechanisms using the BGP protocol
to advertise Link-State information. This can enable an Soft to advertise Link-State information. This can enable an Software
Definition Network (SDN) controller to collect the underlay network Definition Network (SDN) controller to collect the underlay network
topology automatically. topology automatically.
But if the underlay network is divided into multiple areas and But if the underlay network is divided into multiple areas and
running the OSPF protocol, it is not easy for the SDN controller to running the OSPF protocol, it is not easy for the SDN controller to
rebuild the multi-area topology, because normally an ABR that rebuild the multi-area topology, because normally an ABR that
connects multiple areas will hide the detailed topology information connects multiple areas will hide the detailed topology information
for these non-backbone areas. If only the router in backbone area for these non-backbone areas. If only the internal routers within
runs the BGP-LS protocol, it just learn and report the summary backbone area run the BGP-LS protocol, they just learn and report the
network information from the non-backbone areas. If the SDN summary network information from the non-backbone areas. If the SDN
controller can learn the originator of the inter-area prefixes, it is controller can learn the originator of the inter-area prefixes, it is
possible for them to rebuild the inter-area topology automatically. possible to rebuild the inter-area topology automatically.
[RFC7794] introduces the Intermediate System to Intermediate System [RFC7794] introduces the Intermediate System to Intermediate System
(IS-IS) "IPv4/IPv6 Source Router IDs" Type-Length-Value (TLV) to (IS-IS) "IPv4/IPv6 Source Router IDs" Type-Length-Value (TLV) to
advertise the source of the prefixes redistributed from a different advertise the source of the prefixes redistributed from a different
IS-IS level. This TLV can be used in the above scenarios. Such IS-IS level. This TLV can be used in the above scenarios. Such
solution can also be applied in networks that run the OSPF protocol, solution can also be applied in networks that run the OSPF protocol,
but the related LSAs TLV must be extended. but the related LSAs TLV must be extended.
This draft provides such solution for the OSPFv2 and OSPFv3 This draft provides such solution for the OSPFv2 and OSPFv3
protocols. protocols.
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o ERLD: Entropy Readable Label Depth o ERLD: Entropy Readable Label Depth
o EL: Entropy Label o EL: Entropy Label
o IS-IS: Intermediate System to Intermediate System o IS-IS: Intermediate System to Intermediate System
o LSA: Link-State Advertisement o LSA: Link-State Advertisement
o MSD: Maximum SID Depths o MSD: Maximum SID Depths
o NLRI: Network Layer Reachability Information
o OSPF: Open Shortest Path First o OSPF: Open Shortest Path First
o SID: Segment IDentifier o SID: Segment IDentifier
o SDN: Software Definition Network
4. Conventions used in this document 4. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] . document are to be interpreted as described in [RFC2119] .
5. Scenario Description 5. Scenario Description
Figure 1 illustrates the topology scenario when OSPF is running in Figure 1 illustrates the topology scenario when OSPF is running in
multi-area. R0-R4 are routers in backbone area, S1-S4,T1-T4 are multi-area. R0-R4 are routers in backbone area, S1-S4,T1-T4 are
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If S1 wants to send traffic to prefix Lt1 that is connected T1 in If S1 wants to send traffic to prefix Lt1 that is connected T1 in
another area, it should know the ERLD, and MSD values that are another area, it should know the ERLD, and MSD values that are
associated with the node T1, and then construct the right label stack associated with the node T1, and then construct the right label stack
at the ingress node for the target traffic. at the ingress node for the target traffic.
In another scenario, If R0 has some method to learn the originator of In another scenario, If R0 has some method to learn the originator of
network N1 and reports such information to IP SDN controller, then it network N1 and reports such information to IP SDN controller, then it
is possible for the controller to retrieval the topology in non- is possible for the controller to retrieval the topology in non-
backbone area. The topology retrieval process and its usage backbone area. The topology retrieval process and its usage
limitation are described in the Appendix A and Appendix B. limitation are described in the Appendix A and Appendix B .
From the above scenarios, we can conclude it is useful to introduce From the above scenarios, we can conclude it is useful to introduce
and define the prefix originator sub TLV within OSPF. and define the prefix originator sub TLV within OSPF.
6. Prefix Source Router-ID sub-TLV 6. Prefix Source Router-ID sub-TLV
[RFC7684] and [RFC8362] define the TLV extensions for OSPFv2 and [RFC7684] and [RFC8362] define the TLV extensions for OSPFv2 and
OSPFv3 respectively. These documents facilitate addition of new OSPFv3 respectively. These documents facilitate addition of new
attributes for prefixes. Based on these formats, we can define new attributes for prefixes. Based on these formats, we can define new
sub-TLV to advertise the "Prefix Source Router ID", as that defined sub-TLV to advertise the "Prefix Source Router ID", as that defined
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+---------------------------------------------------------------+ +---------------------------------------------------------------+
Figure 2: Prefix Source Router-ID sub-TLV Format Figure 2: Prefix Source Router-ID sub-TLV Format
o Source Router-ID Sub-TLV Type: TBD1[RFC7684] or TBD2 [RFC8362] o Source Router-ID Sub-TLV Type: TBD1[RFC7684] or TBD2 [RFC8362]
o Length: 4 o Length: 4
o Value: Router-ID of OSPFv2/OSPFv3 source router o Value: Router-ID of OSPFv2/OSPFv3 source router
For OSPFv2, this sub-TLV is a sub-TLV of OSPFv2 Extended Prefix TLV, For OSPFv2, this sub-TLV is a sub-TLV of OSPFv2 Extended Prefix TLV,
which is included in the "OSPFv2 Extended Prefix Opaque LSA" which SHOULD be included in the "OSPFv2 Extended Prefix Opaque LSA" .
[RFC7684].
For OSPFv3, this sub-TLV is a sub-TLV of "Inter-Area-Prefix TLV", For OSPFv3, this sub-TLV is a sub-TLV of "Inter-Area-Prefix TLV",
which is included in the "E-Inter-Area-Prefix-LSA". which SHOULD be included in the "E-Inter-Area-Prefix-LSA".
7. Extended LSA Elements of Procedure 7. Extended LSA Elements of Procedure
When an ABR, for example R2 in Fig.1, receives the Router-LSA When an ABR, for example R2 in Figure 1, receives the Router-LSA
announcement in area 2, it should originate the corresponding "OSPFv2 announcement in area 2, it should originate the corresponding "OSPFv2
Extended Prefix Opaque LSA" for OSPFv2 or "E-Inter-Area-Prefix-LSA" Extended Prefix Opaque LSA" for OSPFv2 or "E-Inter-Area-Prefix-LSA"
for OSPFv3 that includes the Source Router-ID sub-TLV for the network for OSPFv3 that includes the Source Router-ID sub-TLV for the network
prefixes, e.g., for prefix Lt1, N2. etc., which identifies the source prefixes, e.g., for prefix Lt1, N2. etc., which identifies the source
router that advertised the prefix. router that advertised the prefix.
When S1 in another area receives such LSA, it then can learn that When S1 in another area receives such LSA, it then can learn that
prefix Lt1 is associated with node T1, check the ERLD, or MSD value prefix Lt1 is associated with node T1, check the ERLD, or MSD value
according to its necessity, and construct the right label stack at according to its necessity, and construct the right label stack at
the ingress node S1 for the traffic destined to Lt1. the ingress node S1 for the traffic destined to Lt1.
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includes it in the prefix information advertised to an SDN controller includes it in the prefix information advertised to an SDN controller
as described in[I-D.ietf-idr-bgp-ls-segment-routing-ext]. The SDN as described in[I-D.ietf-idr-bgp-ls-segment-routing-ext]. The SDN
controller can then use such information to build the inter-area controller can then use such information to build the inter-area
topology according to the process described in the Appendix A. The topology according to the process described in the Appendix A. The
topology retrieval process may not suitable for some environments as topology retrieval process may not suitable for some environments as
stated in Appendix B. stated in Appendix B.
8. Security Considerations 8. Security Considerations
Security concerns for OSPF are addressed in [RFC5709] Security concerns for OSPF are addressed in [RFC5709]
Advertisement of the additional information defined in this document Advertisement of the additional information defined in this document
introduces no new security concerns introduces no new security concerns
9. IANA Considerations 9. IANA Considerations
This specification defines one Prefix Source Router-ID sub-TLV as This specification defines one Prefix Source Router-ID sub-TLV as
described in Section 6. This value should be added to the existing described in Section 6. This value should be added to the existing
OSPFv2 Extended Prefix TLV Sub-TLVs registry and OSPFv3 Extended-LSA "OSPFv2 Extended Prefix TLV Sub-TLVs" registry and "OSPFv3 Extended-
Sub-TLVs registry respectively. LSA Sub-TLVs registry" respectively.
Th following new sub-TLV is added to the registry of "OSPFv2 Extended The following new sub-TLV is added to the registry of "OSPFv2
Prefix TLV Sub-TLVs". The allocation policy is IETF Review that Extended Prefix TLV Sub-TLVs". The allocation policy is IETF Review
defined in [RFC7684] that defined in [RFC7684]
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
| Code Point | Description | Status | | Code Point | Description | Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
| TBD | Prefix Source Sub-TLV | Allocation from IANA | | TBD | Prefix Source Sub-TLV | Allocation from IANA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
Figure 3: Prefix Source sub-TLV CodePoint from OSPFv2 Extended Prefix TLV Sub-TLVs Figure 3: CodePoint in "OSPFv2 Extended Prefix TLV Sub-TLVs"
The following sub-TLV is added to the registry of "OSPFv3 Extended-
LSA Sub-TLVs". The allocation is IETF Review that defined in The following new sub-TLV is added to the registry of "OSPFv3
[RFC8362] Extended-LSA Sub-TLVs". The allocation policy is IETF Review that
defined in [RFC8362]
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
| Code Point | Description | Status | | Code Point | Description | Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
| TBD | Prefix Source Sub-TLV | Allocation from IANA | | TBD | Prefix Source Sub-TLV | Allocation from IANA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++++++
Figure 4: Prefix Source sub-TLV CodePoint from OSPFv3 Extended-LSA Sub-TLVs Figure 4: CodePoint in "OSPFv3 Extended-LSA Sub-TLVs"
10. Acknowledgement 10. Acknowledgement
Many thanks to Les Ginsberg for his valuable suggestions on this Many thanks to Les Ginsberg for his valuable suggestions on this
draft. And also thanks Jeff Tantsura,Rob Shakir, Van De Velde draft. And also thanks Jeff Tantsura,Rob Shakir, Van De Velde
Gunter, Goethals Dirk, Shaofu Peng, John E Drake for their valuable Gunter, Goethals Dirk, Shaofu Peng, John E Drake for their valuable
comments on this draft. comments on this draft.
11. References 11. References
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[I-D.ietf-ospf-mpls-elc] [I-D.ietf-ospf-mpls-elc]
Xu, X., Kini, S., Psenak, P., Filsfils, C., and S. Xu, X., Kini, S., Psenak, P., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability and Entropy Litkowski, "Signaling Entropy Label Capability and Entropy
Readable Label-stack Depth Using OSPF", draft-ietf-ospf- Readable Label-stack Depth Using OSPF", draft-ietf-ospf-
mpls-elc-08 (work in progress), May 2019. mpls-elc-08 (work in progress), May 2019.
Appendix A. Inter-Area Topology Retrieval Process Appendix A. Inter-Area Topology Retrieval Process
When an IP SDN Controller receives this information, it should When an IP SDN Controller receives this information, it should
compare the prefix NLRI that included in the BGP-LS packet. When it compare the prefix Network Layer Reachability Information (NLRI) that
encounters the same prefix but with different source router ID, it included in the BGP-LS packet. When it encounters the same prefix
should extract the corresponding area-ID, rebuild the link between but with different source router ID, it should extract the
these two different source routers in non-backbone area. Belows is corresponding area-ID, rebuild the link between these two different
one example that based on the Fig.1: source routers in non-backbone area. Belows is one example that
based on the Figure 1:
Assuming we want to rebuild the connection between router S1 and Assuming we want to rebuild the connection between router S1 and
router S2 that locates in area 1: router S2 that locates in area 1:
a. Normally, router S1 will advertise prefix N1 within its router- a. Normally, router S1 will advertise prefix N1 within its router-
LSA. LSA.
b. When this router-LSA reaches the ABR router R1, it will convert b. When this router-LSA reaches the ABR router R1, it will convert
it into summary-LSA, add the Prefix Source Router-ID sub-TLV, it into summary-LSA, add the Prefix Source Router-ID sub-TLV,
which is router id of S1 in this example. which is router id of S1 in this example.
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BGP-LS protocol with IP SDN Controller. The controller then BGP-LS protocol with IP SDN Controller. The controller then
knows the prefixes of N1 is from S1. knows the prefixes of N1 is from S1.
d. Router S2 will do the similar process, and the controller will d. Router S2 will do the similar process, and the controller will
also learn that prefixes N1 is also from S2. also learn that prefixes N1 is also from S2.
e. Then it can reconstruct the link between S1 and S2, using the e. Then it can reconstruct the link between S1 and S2, using the
prefix N1. The topology within Area 1 can then be reconstructed prefix N1. The topology within Area 1 can then be reconstructed
accordingly. accordingly.
Iterating the above process continuously, an IP SDN controller can Iterating the above process continuously, the IP SDN controller can
retrieve a detailed topology that spans multiple areas. retrieve a detailed topology that spans multiple areas.
Appendix B. Special Considerations on Inter-Area Topology Retrieval Appendix B. Special Considerations on Inter-Area Topology Retrieval
The above topology retrieval process can be applied in the case where The above topology retrieval process can be applied in the case where
each link between routers is assigned a unique prefix. However, each link between routers is assigned a unique prefix. However,
there are some situations where this heuristic cannot be applied. there are some situations where this heuristic cannot be applied.
Specifically, the cases where the link is unnumbered or the prefix Specifically, the cases where the link is unnumbered or the prefix
corresponding to the link is an anycast prefix and is not unique. corresponding to the link is an anycast prefix.
The Appendix A heuristic to rebuild the topology can normally be used The Appendix A heuristic to rebuild the topology can normally be used
if all links are numbered and the anycast prefixes correspond to if all links are numbered. For anycast prefixes, if it corresponds
loopbacks and have a host prefix length, i.e., 32 for IPv4 prefixes to the loopback interface and has a host prefix length, i.e., 32 for
and 128 for IPv6 prefixes. IPv4 prefixes and 128 for IPv6 prefixes, Appendix A can also apply.
Authors' Addresses Authors' Addresses
Aijun Wang Aijun Wang
China Telecom China Telecom
Beiqijia Town, Changping District Beiqijia Town, Changping District
Beijing 102209 Beijing 102209
China China
Email: wangaj3@chinatelecom.cn Email: wangaj3@chinatelecom.cn
skipping to change at page 10, line 4 skipping to change at page 10, line 22
Email: wangaj3@chinatelecom.cn Email: wangaj3@chinatelecom.cn
Acee Lindem Acee Lindem
Cisco Systems Cisco Systems
301 Midenhall Way 301 Midenhall Way
Cary, NC 27513 Cary, NC 27513
USA USA
Email: acee@cisco.com Email: acee@cisco.com
Jie Dong Jie Dong
Huawei Technologies Huawei Technologies
Beijing Beijing
China China
Email: jie.dong@huawei.com Email: jie.dong@huawei.com
Ketan Talaulikar
Cisco Systems
S.No. 154/6, Phase I, Hinjawadi
Pune 411 057
India
Email: ketant@cisco.com
Peter Psenak Peter Psenak
Cisco Systems Cisco Systems
Pribinova Street 10 Pribinova Street 10
Bratislava, Eurovea Centre, Central 3 81109 Bratislava, Eurovea Centre, Central 3 81109
Slovakia Slovakia
Email: ppsenak@cisco.com Email: ppsenak@cisco.com
Ketan Talaulikar
Cisco Systems
S.No. 154/6, Phase I, Hinjawadi
Pune 411 057
India
Email: ketant@cisco.com
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