draft-ietf-ospf-segment-routing-extensions-01.txt   draft-ietf-ospf-segment-routing-extensions-02.txt 
Open Shortest Path First IGP P. Psenak, Ed. Open Shortest Path First IGP P. Psenak, Ed.
Internet-Draft S. Previdi, Ed. Internet-Draft S. Previdi, Ed.
Intended status: Standards Track C. Filsfils Intended status: Standards Track C. Filsfils
Expires: January 4, 2015 Cisco Systems, Inc. Expires: February 16, 2015 Cisco Systems, Inc.
H. Gredler H. Gredler
Juniper Networks, Inc. Juniper Networks, Inc.
R. Shakir R. Shakir
British Telecom British Telecom
W. Henderickx W. Henderickx
Alcatel-Lucent Alcatel-Lucent
J. Tantsura J. Tantsura
Ericsson Ericsson
July 3, 2014 August 15, 2014
OSPF Extensions for Segment Routing OSPF Extensions for Segment Routing
draft-ietf-ospf-segment-routing-extensions-01 draft-ietf-ospf-segment-routing-extensions-02
Abstract Abstract
Segment Routing (SR) allows for a flexible definition of end-to-end Segment Routing (SR) allows for a flexible definition of end-to-end
paths within IGP topologies by encoding paths as sequences of paths within IGP topologies by encoding paths as sequences of
topological sub-paths, called "segments". These segments are topological sub-paths, called "segments". These segments are
advertised by the link-state routing protocols (IS-IS and OSPF). advertised by the link-state routing protocols (IS-IS and OSPF).
This draft describes the OSPF extensions required for Segment This draft describes the OSPF extensions required for Segment
Routing. Routing.
skipping to change at page 2, line 4 skipping to change at page 2, line 4
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 4, 2015. This Internet-Draft will expire on February 16, 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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 3 2. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 3
2.1. SID/Label sub-TLV . . . . . . . . . . . . . . . . . . . . 4 2.1. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 4
3. Segment Routing Capabilities . . . . . . . . . . . . . . . . 4 3. Segment Routing Capabilities . . . . . . . . . . . . . . . . 4
3.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 4 3.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 4
3.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 5 3.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 5
4. OSPFv2 Extended Prefix Opaque LSA . . . . . . . . . . . . . . 7 4. OSPF Extended Prefix Range TLV . . . . . . . . . . . . . . . 7
4.1. OSPF Extended Prefix TLV . . . . . . . . . . . . . . . . 8 5. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 8
4.2. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . 9 6. SID/Label Binding Sub-TLV . . . . . . . . . . . . . . . . . . 12
4.3. SID/Label Binding sub-TLV . . . . . . . . . . . . . . . . 13 6.1. ERO Metric Sub-TLV . . . . . . . . . . . . . . . . . . . 14
4.3.1. ERO Metric sub-TLV . . . . . . . . . . . . . . . . . 15 6.2. ERO Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 14
4.3.2. ERO sub-TLVs . . . . . . . . . . . . . . . . . . . . 15 6.2.1. IPv4 ERO Sub-TLV . . . . . . . . . . . . . . . . . . 15
5. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 20 6.2.2. Unnumbered Interface ID ERO Sub-TLV . . . . . . . . . 15
5.1. OSPFv2 Extended Link Opaque LSA . . . . . . . . . . . . . 20 6.2.3. IPv4 Backup ERO Sub-TLV . . . . . . . . . . . . . . . 17
5.2. OSPFv2 Extended Link TLV . . . . . . . . . . . . . . . . 21 6.2.4. Unnumbered Interface ID Backup ERO Sub-TLV . . . . . 17
5.3. Adj-SID sub-TLV . . . . . . . . . . . . . . . . . . . . . 21 7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 19
5.4. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 23 7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 19
6. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 24 7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 20
6.1. Intra-area Segment routing in OSPFv2 . . . . . . . . . . 24 8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 22
6.2. Inter-area Segment routing in OSPFv2 . . . . . . . . . . 25 8.1. Intra-area Segment routing in OSPFv2 . . . . . . . . . . 22
6.3. SID for External Prefixes . . . . . . . . . . . . . . . . 26 8.2. Inter-area Segment routing in OSPFv2 . . . . . . . . . . 22
6.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 26 8.3. SID for External Prefixes . . . . . . . . . . . . . . . . 23
6.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 26 8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 24
6.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 27 8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 24
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 24
7.1. OSPF Extend Prefix LSA TLV Registry . . . . . . . . . . . 27 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
7.2. OSPF Extend Prefix LSA sub-TLV Registry . . . . . . . . . 28 9.1. OSPF OSPF Router Information (RI) TLVs Registry . . . . . 25
7.3. OSPF Extend Link LSA TLV Registry . . . . . . . . . . . . 29 9.2. OSPF Extended Prefix LSA TLV Registry . . . . . . . . . . 25
7.4. OSPF Extend Link LSA sub-TLV Registry . . . . . . . . . . 29 9.3. OSPF Extended Prefix LSA Sub-TLV Registry . . . . . . . . 25
9.4. OSPF Extended Link LSA Sub-TLV Registry . . . . . . . . . 25
8. Security Considerations . . . . . . . . . . . . . . . . . . . 30 10. Security Considerations . . . . . . . . . . . . . . . . . . . 25
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 30 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 26
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 30 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 26
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.1. Normative References . . . . . . . . . . . . . . . . . . 30 13.1. Normative References . . . . . . . . . . . . . . . . . . 26
11.2. Informative References . . . . . . . . . . . . . . . . . 31 13.2. Informative References . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction 1. Introduction
Segment Routing (SR) allows for a flexible definition of end-to-end Segment Routing (SR) allows for a flexible definition of end-to-end
paths within IGP topologies by encoding paths as sequences of paths within IGP topologies by encoding paths as sequences of
topological sub-paths, called "segments". These segments are topological sub-paths, called "segments". These segments are
advertised by the link-state routing protocols (IS-IS and OSPF). advertised by the link-state routing protocols (IS-IS and OSPF).
Prefix segments represent an ecmp-aware shortest-path to a prefix (or Prefix segments represent an ecmp-aware shortest-path to a prefix (or
a node), as per the state of the IGP topology. Adjacency segments a node), as per the state of the IGP topology. Adjacency segments
represent a hop over a specific adjacency between two nodes in the represent a hop over a specific adjacency between two nodes in the
skipping to change at page 3, line 45 skipping to change at page 3, line 45
Segment Routing use cases are described in Segment Routing use cases are described in
[I-D.filsfils-rtgwg-segment-routing-use-cases]. [I-D.filsfils-rtgwg-segment-routing-use-cases].
2. Segment Routing Identifiers 2. Segment Routing Identifiers
Segment Routing defines various types of Segment Identifiers (SIDs): Segment Routing defines various types of Segment Identifiers (SIDs):
Prefix-SID, Adjacency-SID, LAN Adjacency SID and Binding SID. Prefix-SID, Adjacency-SID, LAN Adjacency SID and Binding SID.
For the purpose of the advertisements of various SID values, new For the purpose of the advertisements of various SID values, new
Opaque LSAs (defined in [RFC5250]) are defined. These new LSAs are Opaque LSAs [RFC5250] are defined in
defined as generic containers that can be used to advertise any [I-D.ietf-ospf-prefix-link-attr]. These new LSAs are defined as
additional attributes associated with the prefix or link. These new generic containers that can be used to advertise any additional
Opaque LSAs are complementary to the existing LSAs and are not aimed attributes associated with a prefix or link. These new Opaque LSAs
to replace any of the existing LSAs. are complementary to the existing LSAs and are not aimed to replace
any of the existing LSAs.
2.1. SID/Label sub-TLV 2.1. SID/Label Sub-TLV
SID/Label sub-TLV appears in multiple TLVs or sub-TLVs defined later The SID/Label Sub-TLV appears in multiple TLVs or Sub-TLVs defined
in this document. It is used to advertise SID or label associated later in this document. It is used to advertise the SID or label
with the prefix or adjacency. SID/Label TLV has following format: associated with a prefix or adjacency. The SID/Label TLV has
following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label (variable) | | SID/Label (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
Type: TBD, suggested value 1 Type: TBD, suggested value 1
Length: variable, 3 or 4 bytes Length: variable, 3 or 4 bytes
SID/Label: if length is set to 3, then the 20 rightmost bits SID/Label: if length is set to 3, then the 20 rightmost bits
represent a label. If length is set to 4 then the value represent a label. If length is set to 4, then the value
represents a 32 bit SID. represents a 32 bit SID.
The receiving router MUST ignore SID/Label sub-TLV if the length The receiving router MUST ignore SID/Label Sub-TLV if the length
is other then 3 or 4. is other then 3 or 4.
3. Segment Routing Capabilities 3. Segment Routing Capabilities
Segment Routing requires some additional router capabilities to be Segment Routing requires some additional router capabilities to be
advertised to other routers in the area. advertised to other routers in the area.
These SR capabilities are advertised in the Router Information Opaque These SR capabilities are advertised in the Router Information Opaque
LSA (defined in [RFC4970]). LSA (defined in [RFC4970]).
3.1. SR-Algorithm TLV 3.1. SR-Algorithm TLV
SR-Algorithm TLV is a top-level TLV of the Router Information Opaque The SR-Algorithm TLV is a top-level TLV of the Router Information
LSA (defined in [RFC4970]). Opaque LSA (defined in [RFC4970]).
The SR-Algorithm Sub-TLV is optional, it MAY only appear once inside The SR-Algorithm Sub-TLV is optional. It MAY only be advertised once
the Router Informational Opaque LSA. If the SID/Label Range TLV, as in the Router Information Opaque LSA. If the SID/Label Range TLV, as
defined in Section 3.2, is advertised, then SR-Algorithm TLV MUST defined in Section 3.2, is advertised, then SR-Algorithm TLV MUST
also be advertised. also be advertised.
As SR Router may use various algorithms when calculating reachability An SR Router may use various algorithms when calculating reachability
to OSPF routers or prefixes in an OSPF area. Examples of these to OSPF routers or prefixes in an OSPF area. Examples of these
algorithms are metric based Shortest Path First (SPF), various algorithms are metric based Shortest Path First (SPF), various
flavors of Constrained SPF, etc. The SR-Algorithm TLV allows a flavors of Constrained SPF, etc. The SR-Algorithm TLV allows a
router to advertise the algorithms that the router is currently using router to advertise the algorithms that the router is currently using
to other routers in an OSPF area. The SR-Algorithm TLV has following to other routers in an OSPF area. The SR-Algorithm TLV has following
format: format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 5, line 36 skipping to change at page 5, line 37
value is defined by this document: value is defined by this document:
0: IGP metric based Shortest Path Tree (SPT) 0: IGP metric based Shortest Path Tree (SPT)
The RI LSA can be advertised at any of the defined opaque flooding The RI LSA can be advertised at any of the defined opaque flooding
scopes (link, area, or Autonomous System (AS)). For the purpose of scopes (link, area, or Autonomous System (AS)). For the purpose of
the SR-Algorithm TLV propagation, area scope flooding is required. the SR-Algorithm TLV propagation, area scope flooding is required.
3.2. SID/Label Range TLV 3.2. SID/Label Range TLV
The SID/Label Range TLV is a top-level TLV of Router Information The SID/Label Range TLV is a top-level TLV of the Router Information
Opaque LSA (defined in [RFC4970]). Opaque LSA (defined in [RFC4970]).
The SID/Label Range TLV MAY appear multiple times and has the The SID/Label Range TLV MAY appear multiple times and has the
following format: following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 6, line 23 skipping to change at page 6, line 23
+- -+ +- -+
| | | |
+ + + +
where: where:
Type: TBD, suggested value 9 Type: TBD, suggested value 9
Length: variable Length: variable
Range Size: 3 octet of the SID/label range Range Size: 3 octets of the SID/label range
Currently the only supported Sub-TLV is the SID/Label TLV as defined Initially, the only supported Sub-TLV is the SID/Label TLV as defined
in Section 2.1. The SID/Label advertised in SID/Label TLV represents in Section 2.1. The SID/Label advertised in the SID/Label TLV
the first SID/Label in the advertised range. represents the first SID/Label in the advertised range.
Multiple occurrence of the SID/Label Range TLV MAY be advertised, in Multiple occurrence of the SID/Label Range TLV MAY be advertised, in
order to advertise multiple ranges. In such case: order to advertise multiple ranges. In such case:
o The originating router MUST encode each range into a different o The originating router MUST encode each range into a different
SID/Label Range TLV. SID/Label Range TLV.
o The originating router decides in which order the set of SID/Label o The originating router decides the order in which the set of SID/
Range TLVs are advertised inside Router Information Opaque LSA. Label Range TLVs are advertised inside the Router Information
The originating router MUST ensure the order is same after a Opaque LSA. The originating router MUST ensure the order is same
graceful restart (using checkpointing, non-volatile storage or any after a graceful restart (using checkpointing, non-volatile
other mechanism) in order to SID/label range and SID index storage or any other mechanism) in order to assure the SID/label
correspondence is preserved across graceful restarts. range and SID index correspondence is preserved across graceful
restarts.
o The receiving router must adhere to the order in which the ranges o The receiving router must adhere to the order in which the ranges
are advertised when calculating a SID/label from a SID index. are advertised when calculating a SID/label from a SID index.
The following example illustrates the advertisement of multiple The following example illustrates the advertisement of multiple
ranges: ranges:
The originating router advertises following ranges: The originating router advertises following ranges:
Range 1: [100, 199] Range 1: [100, 199]
Range 2: [1000, 1099] Range 2: [1000, 1099]
Range 3: [500, 599] Range 3: [500, 599]
The receiving routers concatenate the ranges and build the SRGB The receiving routers concatenate the ranges and build the Segment Routing Global Block
is as follows: (SRGB) is as follows:
SRGB = [100, 199] SRGB = [100, 199]
[1000, 1099] [1000, 1099]
[500, 599] [500, 599]
The indexes span multiple ranges: The indexes span multiple ranges:
index=0 means label 100 index=0 means label 100
... ...
index 99 means label 199 index 99 means label 199
index 100 means label 1000 index 100 means label 1000
index 199 means label 1099 index 199 means label 1099
... ...
index 200 means label 500 index 200 means label 500
... ...
The RI LSA can be advertised at any of the defined flooding scopes The RI LSA can be advertised at any of the defined flooding scopes
(link, area, or autonomous system (AS)). For the purposes of the SR- (link, area, or autonomous system (AS)). For the purposes of the SR-
Capability TLV propagation, area scope flooding is required. Capability TLV propagation, area scope flooding is required.
4. OSPFv2 Extended Prefix Opaque LSA 4. OSPF Extended Prefix Range TLV
A new Opaque LSA (defined in [RFC5250]) is defined in OSPFv2 in order
to advertise additional prefix attributes: OSPFv2 Extended Prefix
Opaque LSA.
Multiple OSPFv2 Extended Prefix Opaque LSAs can be advertised by an
OSPFv2 router. The flooding scope of the OSPFv2 Extended Prefix
Opaque LSA depends on the scope of the advertised prefixes and is
under the control of the advertising router. In some cases (e.g.,
mapping server deployment), the LSA flooding scope may be greater
than the scope of the corresponding prefixes.
The format of the OSPFv2 Extended Prefix Opaque LSA is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age | Options | 9, 10, or 11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque type | Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
The opaque type used by OSPFv2 Extended Prefix Opaque LSA is 7.
The format of the TLVs within the body of the LSA is the same as the
format used by the Traffic Engineering Extensions to OSPF defined in
[RFC3630]. The LSA payload consists of one or more nested
Type/Length/Value (TLV) triplets. The format of each TLV is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Length field defines the length of the value portion in octets. In some cases it is useful to advertise attributes for the range of
The TLV is padded to 4-octet alignment; padding is not included in prefixes. Segment Routing Mapping Server, which is described in
the length field. Nested TLVs are also 32-bit aligned. Unrecognized [I-D.filsfils-rtgwg-segment-routing] is an example, where we need a
types are ignored. single advertisement to advertise SIDs for multiple prefixes from a
contiguous address range.
4.1. OSPF Extended Prefix TLV OSPF Extended Prefix Range TLV, which is a new top level TLV of the
Extended Prefix LSA described in [I-D.ietf-ospf-prefix-link-attr] is
defined for this purpose.
The OSPF Extended Prefix TLV is used in order to advertise additional Multiple OSPF Extended Prefix Range TLVs MAY be advertised in each
attributes associated with the prefix. Multiple OSPF Extended Prefix OSPF Extended Prefix Opaque LSA, but all prefix ranges included in a
TLVs MAY be advertised in each OSPFv2 Extended Prefix Opaque LSA but single OSPF Extended Prefix Opaque LSA MUST have the same flooding
all prefixes included in a single OSPFv2 Extended Prefix Opaque LSA scope. The OSPF Extended Prefix Range TLV has the following format:
MUST have the same flooding scope. The OSPF Extended Prefix TLV has
the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Type | Prefix Length | AF | Reserved | | Prefix Length | AF | Range Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Prefix (variable) | | Address Prefix (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) | | Sub-TLVs (variable) |
+- -+ +- -+
| | | |
where: where:
Type: TBD, suggested value 1. Type: TBD, suggested value 2.
Length: variable Length: variable
Route type: type of the OSPF route. Supported types are:
0 - unspecified
1 - intra-area
3 - inter-area
5 - external
7 - NSSA external
If the route type is 0 (unspecified), the information inside the
OSPF External Prefix TLV applies to the prefix regardless of
prefix's route-type. This is useful when some prefix specific
attributes are advertised by some external entity, which is not
aware of the route-type associated with the prefix.
Prefix length: length of the prefix Prefix length: length of the prefix
AF: 0 - IPv4 unicast AF: 0 - IPv4 unicast
Address Prefix: the prefix itself encoded as an even multiple of Range size: represents the number of prefixes that are covered by
32-bit words, padded with zeroed bits as necessary. This encoding the advertisement. The Range Size MUST NOT exceed the number of
consumes ((PrefixLength + 31) / 32) 32-bit words. The default prefixes that could be satisfied by the prefix length without
route is represented by a prefix of length 0. including the IPv4 multicast address range (224.0.0.0/3).
4.2. Prefix SID Sub-TLV Address Prefix: the prefix, encoded as an even multiple of 32-bit
words, padded with zeroed bits as necessary. This encoding
consumes ((PrefixLength + 31) / 32) 32-bit words. The Address
Prefix represents the first prefix in the prefix range.
The Prefix SID Sub-TLV is a Sub-TLV of the OSPF Extended Prefix TLV. 5. Prefix SID Sub-TLV
It MAY appear more than once and has following format:
The Prefix SID Sub-TLV is a Sub-TLV of the OSPF Extended Prefix TLV
described in [I-D.ietf-ospf-prefix-link-attr] and the OSPF Extended
Prefix Range TLV described in Section 4. It MAY appear more than
once in the parent TLV and has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | MT-ID | Algorithm | | Flags | Reserved | MT-ID | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Range Size | Reserved +
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label (variable) | | SID/Index/Label (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
Type: TBD, suggested value 2. Type: TBD, suggested value 2.
Length: variable Length: variable
Flags: 1 octet field. The following flags are defined: Flags: 1 octet field. The following flags are defined:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
|N |NP|M |E |V |L | | | |N |NP|M |E |V |L | | |
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
where: where:
N-Flag: Node-SID flag. If set, then the Prefix-SID refers to N-Flag: Node-SID flag. If set, then the Prefix-SID refers to
the router identified by the prefix. Typically, the N-Flag is the router identified by the prefix. Typically, the N-Flag is
set on Prefix-SIDs attached to a router loopback address. The set to Prefix-SIDs corresponding to a router loopback address.
N-Flag is set when the Prefix-SID is a Node-SID, as described The N-Flag is set when the Prefix-SID is a Node-SID, as
in [I-D.filsfils-rtgwg-segment-routing]. described in [I-D.filsfils-rtgwg-segment-routing].
NP-Flag: no-PHP flag. If set, then the penultimate hop MUST NP-Flag: No-PHP flag. If set, then the penultimate hop MUST
NOT pop the Prefix-SID before delivering the packet to the node NOT pop the Prefix-SID before delivering the packet to the node
that advertised the Prefix-SID. that advertised the Prefix-SID.
M-Flag: Mapping Server Flag. If set, the SID is advertised M-Flag: Mapping Server Flag. If set, the SID is advertised
from the Segment Routing Mapping Server functionality as from the Segment Routing Mapping Server functionality as
described in [I-D.filsfils-rtgwg-segment-routing]. described in [I-D.filsfils-rtgwg-segment-routing].
E-Flag: Explicit-Null Flag. If set, any upstream neighbor of E-Flag: Explicit-Null Flag. If set, any upstream neighbor of
the Prefix-SID originator MUST replace the Prefix-SID with a the Prefix-SID originator MUST replace the Prefix-SID with a
Prefix-SID having an Explicit-NULL value (0 for IPv4) before Prefix-SID having an Explicit-NULL value (0 for IPv4) before
forwarding the packet. forwarding the packet.
The V-Flag: Value/Index Flag. If set, then the Prefix-SID V-Flag: Value/Index Flag. If set, then the Prefix-SID carries
carries an absolute value. If not set, then the Prefix-SID an absolute value. If not set, then the Prefix-SID carries an
carries an index. index.
The L-Flag: Local/Global Flag. If set, then the value/index L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set, carried by the Prefix-SID has local significance. If not set,
then the value/index carried by this subTLV has global then the value/index carried by this Sub-TLV has global
significance. significance.
Other bits: MUST be zero when sent and ignored when received. Other bits: Reserved. These MUST be zero when sent and are
ignored when received.
MT-ID: Multi-Topology ID (as defined in [RFC4915]). MT-ID: Multi-Topology ID (as defined in [RFC4915]).
Algorithm: one octet identifying the algorithm the Prefix-SID is Algorithm: one octet identifying the algorithm the Prefix-SID is
associated with as defined in Section 3.1. associated with as defined in Section 3.1.
Range size: this field provides the ability to specify a range of
addresses and their associated Prefix SIDs. It represents a
compression scheme to distribute a continuous Prefix and their
continuous, corresponding SID/Label Block. If a single SID is
advertised then the Range Size field MUST be set to one. For
range advertisements > 1, Range Size represents the number of
addresses that need to be mapped into a Prefix-SID.
SID/Index/Label: according to the V and L flags, it contains SID/Index/Label: according to the V and L flags, it contains
either: either:
A 32 bit index defining the offset in the SID/Label space A 32 bit index defining the offset in the SID/Label space
advertised by this router. advertised by this router.
A 24 bit label where the 20 rightmost bits are used for A 24 bit label where the 20 rightmost bits are used for
encoding the label value. encoding the label value.
If multiple Prefix-SIDs are advertised for the same prefix, the If multiple Prefix-SIDs are advertised for the same prefix, the
receiving router MUST use the first encoded SID and MAY use the receiving router MUST use the first encoded SID and MAY use the
subsequent ones. subsequent SIDs.
When propagating Prefix-SIDs between areas, if multiple prefix-SIDs When propagating Prefix-SIDs between areas, if multiple prefix-SIDs
are advertised for a prefix, an implementation SHOULD preserve the are advertised for a prefix, an implementation SHOULD preserve the
original ordering, when advertising prefix-SIDs to other areas. This original order when advertising prefix-SIDs to other areas. This
allows implementations that only use single Prefix-SID to have a allows implementations that only support a single Prefix-SID to have
consistent view across areas. a consistent view across areas.
When calculating the outgoing label for the prefix, the router MUST When calculating the outgoing label for the prefix, the router MUST
take into account E and P flags advertised by the next-hop router, if take into account E and P flags advertised by the next-hop router, if
next-hop router advertised the SID for the prefix. This MUST be done next-hop router advertised the SID for the prefix. This MUST be done
regardless of next-hop router contributing to the best path to the regardless of whether the next-hop router contributes to the best
prefix or not. path to the prefix.
NP-Flag (no-PHP) MUST be set on the Prefix-SIDs allocated to inter- The NP-Flag (No-PHP) MUST be set on the Prefix-SIDs allocated to
area prefixes that are originated by the ABR based on intra-area or inter-area prefixes that are originated by the ABR based on intra-
inter-area reachability between areas. In case the inter-area prefix area or inter-area reachability between areas. When the inter-area
is generated based on the prefix which is directly attached to the prefix is generated based on the prefix which is directly attached to
ABR, NP-Flag SHOULD NOT be set the ABR, NP-Flag SHOULD NOT be set
NP-flag (no-PHP) MUST NOT be set on the Prefix-SIDs allocated to The NP-Flag (No-PHP) MUST be be set on the Prefix-SIDs allocated to
redistributed prefixes, unless the redistributed prefix is directly redistributed prefixes, unless the redistributed prefix is directly
attached to ASBR, in which case the NP-flag SHOULD NOT be set. attached to ASBR, in which case the NP-flag SHOULD NOT be set.
If the NP-flag is not set then any upstream neighbor of the Prefix- If the NP-Flag is not set then any upstream neighbor of the Prefix-
SID originator MUST pop the Prefix-SID. This is equivalent to the SID originator MUST pop the Prefix-SID. This is equivalent to the
penultimate hop popping mechanism used in the MPLS dataplane. In penultimate hop popping mechanism used in the MPLS dataplane. In
such case MPLS EXP bits of the Prefix-SID are not preserved to the such case, MPLS EXP bits of the Prefix-SID are not preserved for the
ultimate hop (the Prefix-SID being removed). If the NP-flag is clear final destination (the Prefix-SID being removed). If the NP-flag is
the received E-flag is ignored. clear then the received E-flag is ignored.
If the NP-flag is set then: If the NP-flag is set then:
If the E-flag is not set then any upstream neighbor of the Prefix- If the E-flag is not set then any upstream neighbor of the Prefix-
SID originator MUST keep the Prefix-SID on top of the stack. This SID originator MUST keep the Prefix-SID on top of the stack. This
is useful when the originator of the Prefix-SID must stitch the is useful when the originator of the Prefix-SID must stitch the
incoming packet into a continuing MPLS LSP to the final incoming packet into a continuing MPLS LSP to the final
destination. This could occur at an inter-area border router destination. This could occur at an inter-area border router
(prefix propagation from one area to another) or at an inter- (prefix propagation from one area to another) or at an inter-
domain border router (prefix propagation from one domain to domain border router (prefix propagation from one domain to
another). another).
If the E-flag is set then any upstream neighbor of the Prefix-SID If the E-flag is set then any upstream neighbor of the Prefix-SID
originator MUST replace the PrefixSID with a Prefix-SID having an originator MUST replace the Prefix-SID with a Prefix-SID having an
Explicit-NULL value. This is useful, e.g., when the originator of Explicit-NULL value. This is useful, e.g., when the originator of
the Prefix-SID is the final destination for the related prefix and the Prefix-SID is the final destination for the related prefix and
the originator wishes to receive the packet with the original EXP the originator wishes to receive the packet with the original EXP
bits. bits.
When M-Flag is set, NP-flag MUST be set and E-bit MUST NOT be set. When M-Flag is set, NP-flag MUST be set and E-bit MUST NOT be set.
When a Prefix-SID is advertised in an Extended Prefix Range TLV, then
the value advertised in Prefix SID Sub-TLV is interpreted as a
starting SID value.
Example 1: if the following router addresses (loopback addresses) Example 1: if the following router addresses (loopback addresses)
need to be mapped into the corresponding Prefix SID indexes: need to be mapped into the corresponding Prefix SID indexes:
Router-A: 192.0.2.1/32, Prefix-SID: Index 1 Router-A: 192.0.2.1/32, Prefix-SID: Index 1
Router-B: 192.0.2.2/32, Prefix-SID: Index 2 Router-B: 192.0.2.2/32, Prefix-SID: Index 2
Router-C: 192.0.2.3/32, Prefix-SID: Index 3 Router-C: 192.0.2.3/32, Prefix-SID: Index 3
Router-D: 192.0.2.4/32, Prefix-SID: Index 4 Router-D: 192.0.2.4/32, Prefix-SID: Index 4
then the Prefix field in Extended Prefix TLV would be set to then the Prefix field in the Extended Prefix Range TLV would be set
192.0.2.1, Prefix Length would be set to 32, Range Size in Prefix SID to 192.0.2.1, Prefix Length would be set to 32, Range Size would be
sub-TLV would be 4 and Index value would be set to 1. set to 4 and the Index value in the Prefix-SID Sub-TLV would be set
to 1.
Example 2: If the following prefixes need to be mapped into the Example 2: If the following prefixes need to be mapped into the
corresponding Prefix-SID indexes: corresponding Prefix-SID indexes:
10.1.1/24, Prefix-SID: Index 51 10.1.1/24, Prefix-SID: Index 51
10.1.2/24, Prefix-SID: Index 52 10.1.2/24, Prefix-SID: Index 52
10.1.3/24, Prefix-SID: Index 53 10.1.3/24, Prefix-SID: Index 53
10.1.4/24, Prefix-SID: Index 54 10.1.4/24, Prefix-SID: Index 54
10.1.5/24, Prefix-SID: Index 55 10.1.5/24, Prefix-SID: Index 55
10.1.6/24, Prefix-SID: Index 56 10.1.6/24, Prefix-SID: Index 56
10.1.7/24, Prefix-SID: Index 57 10.1.7/24, Prefix-SID: Index 57
then the Prefix field in Extended Prefix TLV would be set to then the Prefix field in the Extended Prefix Range TLV would be set
10.1.1.0, Prefix Length would be set to 24, Range Size in Prefix SID to 10.1.1.0, Prefix Length would be set to 24, Range Size would be 7
sub-TLV would be 7 and Index value would be set to 51. and the Index value in the Prefix-SID Sub-TLV would be set to 51.
4.3. SID/Label Binding sub-TLV 6. SID/Label Binding Sub-TLV
The SID/Label Binding sub-TLV is used to advertise a SID/Label The SID/Label Binding Sub-TLV is used to advertise a SID/Label
mapping for a path to the prefix. mapping for a path to the prefix.
The SID/Label Binding TLV MAY be originated by any router in an OSPF The SID/Label Binding TLV MAY be originated by any router in an OSPF
domain. The router may advertise a SID/Label binding to a FEC along domain. The router may advertise a SID/Label binding to a FEC along
with at least a single 'nexthop style' anchor. The protocol supports with at least a single 'nexthop style' anchor. The protocol supports
more than one 'nexthop style' anchor to be attached to a SID/Label more than one 'nexthop style' anchor to be attached to a SID/Label
binding, which results in a simple path description language. In binding, which results in a simple path description language. In
analogy to RSVP, the terminology for this is called an 'Explicit analogy to RSVP, the terminology for this is called an 'Explicit
Route Object' (ERO). Since ERO style path notation allows to anchor Route Object' (ERO). Since ERO style path notation allows anchoring
SID/label bindings to both link and node IP addresses, any label SID/label bindings to both link and node IP addresses, any Label
switched path can be described. Additionally, SID/Label Bindings Switched Path (LSP) can be described. Additionally, SID/Label
from external protocols can be easily re-advertised. Bindings from external protocols can be easily re-advertised.
The SID/Label Binding TLV may be used for advertising SID/Label The SID/Label Binding TLV may be used for advertising SID/Label
Bindings and their associated Primary and Backup paths. In a single Bindings and their associated Primary and Backup paths. In a single
TLV, a primary ERO Path, backup ERO Path, or both can be advertised. TLV, a primary ERO Path, backup ERO Path, or both can be advertised.
If a router wants to advertise multiple parallel paths, then it can If a router wants to advertise multiple parallel paths, then it can
generate several TLVs for the same Prefix/FEC. Each occurrence of a generate several TLVs for the same Prefix/FEC. Each occurrence of a
Binding TLV for a given FEC Prefix will add a new path. Binding TLV for a given FEC Prefix will add a new path.
The SID/Label Binding sub-TLV is a sub-TLV of the OSPF Extended The SID/Label Binding Sub-TLV is a Sub-TLV of the OSPF Extended
Prefix TLV. Multiple SID/Label Binding TLVs can be present in OSPF Prefix TLV described in [I-D.ietf-ospf-prefix-link-attr] and the OSPF
Extended Prefix TLV. The SID/Label Binding sub-TLV has following Extended Prefix Range TLV described in Section 4. Multiple SID/Label
format: Binding TLVs can be present in their parent TLV. The SID/Label
Binding Sub-TLV has following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | MT-ID | Weight | | Flags | Reserved | MT-ID | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Range Size | Reserved +
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) | | Sub-TLVs (variable) |
+- -+ +- -+
| | | |
where: where:
Type: TBD, suggested value 3 Type: TBD, suggested value 3
Length: variable Length: variable
skipping to change at page 14, line 42 skipping to change at page 13, line 40
M-bit - When the bit is set the binding represents the M-bit - When the bit is set the binding represents the
mirroring context as defined in mirroring context as defined in
[I-D.minto-rsvp-lsp-egress-fast-protection]. [I-D.minto-rsvp-lsp-egress-fast-protection].
MT-ID: Multi-Topology ID (as defined in [RFC4915]). MT-ID: Multi-Topology ID (as defined in [RFC4915]).
Weight: weight used for load-balancing purposes. The use of the Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing]. weight is defined in [I-D.filsfils-rtgwg-segment-routing].
Range Size: usage is the same as described in Section 4.2.
The SID/Label Binding TLV supports the following Sub-TLVs: The SID/Label Binding TLV supports the following Sub-TLVs:
SID/Label sub-TLV as described in Section 2.1. This sub-TLV MUST SID/Label Sub-TLV as described in Section 2.1. This Sub-TLV MUST
appear in the SID/Label Binding Sub-TLV and it MUST only appear appear in the SID/Label Binding Sub-TLV and it MUST only appear
once. once.
ERO Metric sub-TLV as defined in Section 4.3.1. ERO Metric Sub-TLV as defined in Section 6.1.
ERO sub-TLVs as defined in Section 4.3.2. ERO Sub-TLVs as defined in Section 6.2.
4.3.1. ERO Metric sub-TLV 6.1. ERO Metric Sub-TLV
ERO Metric sub-TLV is a Sub-TLV of the SID/Label Binding TLV. The ERO Metric Sub-TLV is a Sub-TLV of the SID/Label Binding TLV.
The ERO Metric sub-TLV advertises the cost of an ERO path. It is The ERO Metric Sub-TLV advertises the cost of an ERO path. It is
used to compare the cost of a given source/destination path. A used to compare the cost of a given source/destination path. A
router SHOULD advertise the ERO Metric sub-TLV. The cost of the ERO router SHOULD advertise the ERO Metric Sub-TLV in an advertised ERO
Metric sub-TLV SHOULD be set to the cumulative IGP or TE path cost of TLV. The cost of the ERO Metric Sub-TLV SHOULD be set to the
the advertised ERO. Since manipulation of the Metric field may cumulative IGP or TE path cost of the advertised ERO. Since
attract or repel traffic to and from the advertised segment, it MAY manipulation of the Metric field may attract or repel traffic to and
be manually overridden. from the advertised segment, it MAY be manually overridden.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric (4 octets) | | Metric (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ERO Metric sub-TLV format ERO Metric Sub-TLV format
where: where:
Type: TBD, suggested value 8 Type: TBD, suggested value 8
Length: 4 bytes Length: Always 4
Metric: 4 bytes Metric: A 4 octet metric representing the aggregate IGP or TE path
cost.
4.3.2. ERO sub-TLVs 6.2. ERO Sub-TLVs
All 'ERO' information represents an ordered set which describes the All 'ERO' information represents an ordered set which describes the
segments of a path. The last ERO sub-TLV describes the segment segments of a path. The first ERO Sub-TLV describes the first
closest to the egress point, contrary the first ERO sub-TLV describes segment of a path. Similiarly, the last ERO Sub-TLV describes the
the first segment of a path. If a router extends or stitches a path segment closest to the egress point. If a router extends or stitches
it MUST prepend the new segments path information to the ERO list. a path, it MUST prepend the new segment's path information to the ERO
list. This applies equally to advertised backup EROs.
The above similarly applies to backup EROs.
All ERO Sub-TLVs must immediately follow the (SID)/Label Sub-TLV. All ERO Sub-TLVs must immediately follow the (SID)/Label Sub-TLV.
All Backup sub-ERO TLVs must immediately follow last ERO Sub-TLV. All Backup ERO Sub-TLVs must immediately follow the last ERO Sub-TLV.
4.3.2.1. IPv4 ERO sub-TLV 6.2.1. IPv4 ERO Sub-TLV
IPv4 ERO sub-TLV is a sub-TLV of the SID/Label Binding sub-TLV. IPv4 ERO Sub-TLV is a Sub-TLV of the SID/Label Binding Sub-TLV.
The IPv4 ERO sub-TLV describes a path segment using IPv4 Address The IPv4 ERO Sub-TLV describes a path segment using IPv4 Address
style of encoding. Its semantics have been borrowed from [RFC3209]. style encoding. Its semantics have been borrowed from [RFC3209].
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 octets) | | IPv4 Address (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 ERO sub-TLV format IPv4 ERO Sub-TLV format
where: where:
Type: TBD, suggested value 4 Type: TBD, suggested value 4
Length: 8 bytes Length: 8 bytes
Flags: 1 octet field of following flags: Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| | |L| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: where:
L-bit - If the L bit is set, then the value of the attribute is L-bit - If the L-bit is set, then the segment path is
'loose.' Otherwise, the value of the attribute is 'strict.' designated as 'loose'. Otherwise, the segment path is
designated as 'strict'.
IPv4 Address - the address of the explicit route hop. IPv4 Address - the address of the explicit route hop.
4.3.2.2. Unnumbered Interface ID ERO sub-TLV 6.2.2. Unnumbered Interface ID ERO Sub-TLV
Unnumbered Interface ID ERO sub-TLV is a sub-TLV of the SID/Label The Unnumbered Interface ID ERO Sub-TLV is a Sub-TLV of the SID/Label
Binding sub-TLV. Binding Sub-TLV.
The appearance and semantics of the 'Unnumbered Interface ID' have The appearance and semantics of the 'Unnumbered Interface ID' have
been borrowed from [RFC3477]. been borrowed from [RFC3477].
The Unnumbered Interface-ID ERO sub-TLV describes a path segment that The Unnumbered Interface-ID ERO Sub-TLV describes a path segment that
includes an unnumbered interface. Unnumbered interfaces are includes an unnumbered interface. Unnumbered interfaces are
referenced using the interface index. Interface indices are assigned referenced using the interface index. Interface indices are assigned
local to the router and therefore not unique within a domain. All local to the router and therefore not unique within a domain. All
elements in an ERO path need to be unique within a domain and hence elements in an ERO path need to be unique within a domain and hence
need to be disambiguated using a domain unique Router-ID. need to be disambiguated using a domain unique Router-ID.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID | | Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID | | Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
Unnumbered Interface ID ERO sub-TLV format Unnumbered Interface ID ERO Sub-TLV format
Type: TBD, suggested value 5 Type: TBD, suggested value 5
Length: 12 bytes Length: 12 bytes
Flags: 1 octet field of following flags: Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| | |L| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: where:
L-bit - If the L bit is set, then the value of the attribute is L-bit - If the L-bit is set, then the segment path is
'loose.' Otherwise, the value of the attribute is 'strict.' designated as 'loose'. Otherwise, the segment path is
designated as 'strict'.
Router-ID: Router-ID of the next-hop. Router-ID: Router-ID of the next-hop.
Interface ID: is the identifier assigned to the link by the router Interface ID: is the identifier assigned to the link by the router
specified by the Router-ID. specified by the Router-ID.
4.3.2.3. IPv4 Backup ERO sub-TLV 6.2.3. IPv4 Backup ERO Sub-TLV
IPv4 Prefix Backup ERO sub-TLV is a Sub-TLV of the SID/Label Binding IPv4 Prefix Backup ERO Sub-TLV is a Sub-TLV of the SID/Label Binding
sub-TLV. Sub-TLV.
The IPv4 Backup ERO sub-TLV describes a path segment using IPv4 The IPv4 Backup ERO Sub-TLV describes a path segment using IPv4
Address style of encoding. Its semantics have been borrowed from Address style of encoding. Its semantics have been borrowed from
[RFC3209]. [RFC3209].
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 octets) | | IPv4 Address (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 Backup ERO sub-TLV format IPv4 Backup ERO Sub-TLV format
where: where:
Type: TBD, suggested value 6 Type: TBD, suggested value 6
Length: 8 bytes Length: 8 bytes
Flags: 1 octet field of following flags: Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| | |L| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: where:
L-bit - If the L bit is set, then the value of the attribute is L-bit - If the L-bit is set, then the segment path is
'loose.' Otherwise, the value of the attribute is 'strict.' designated as 'loose'. Otherwise, the segment path is
designated as 'strict'.
IPv4 Address - the address of the explicit route hop. IPv4 Address - the address of the explicit route hop.
4.3.2.4. Unnumbered Interface ID Backup ERO sub-TLV 6.2.4. Unnumbered Interface ID Backup ERO Sub-TLV
Unnumbered Interface ID Backup sub-TLV is a sub-TLV of the SID/Label The Unnumbered Interface ID Backup ERO Sub-TLV is a Sub-TLV of the
Binding sub-TLV. SID/Label Binding Sub-TLV.
The appearance and semantics of the 'Unnumbered Interface ID' have The appearance and semantics of the 'Unnumbered Interface ID' have
been borrowed from [RFC3477]. been borrowed from [RFC3477].
The Unnumbered Interface-ID ERO sub-TLV describes a path segment that The Unnumbered Interface-ID Backup ERO Sub-TLV describes a path
includes an unnumbered interface. Unnumbered interfaces are segment that includes an unnumbered interface. Unnumbered interfaces
referenced using the interface index. Interface indices are assigned are referenced using the interface index. Interface indices are
local to the router and therefore not unique within a domain. All assigned local to the router and are therefore not unique within a
elements in an ERO path need to be unique within a domain and hence domain. All elements in an ERO path need to be unique within a
need to be disambiguated using a domain unique Router-ID. domain and hence need to be disambiguated with specification of the
domain unique Router-ID.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID | | Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID | | Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Unnumbered Interface ID Backup ERO sub-TLV format Unnumbered Interface ID Backup ERO Sub-TLV format
where: where:
Type: TBD, suggested value 7 Type: TBD, suggested value 7
Length: 12 bytes Length: 12 bytes
Flags: 1 octet field of following flags: Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| | |L| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: where:
L-bit - If the L bit is set, then the value of the attribute is L-bit - If the L-bit is set, then the segment path is
'loose.' Otherwise, the value of the attribute is 'strict.' designated as 'loose'. Otherwise, the segment path is
designated as 'strict'.
Router-ID: Router-ID of the next-hop. Router-ID: Router-ID of the next-hop.
Interface ID: is the identifier assigned to the link by the router Interface ID: is the identifier assigned to the link by the router
specified by the Router-ID. specified by the Router-ID.
5. Adjacency Segment Identifier (Adj-SID) 7. Adjacency Segment Identifier (Adj-SID)
An Adjacency Segment Identifier (Adj-SID) represents a router An Adjacency Segment Identifier (Adj-SID) represents a router
adjacency in Segment Routing. adjacency in Segment Routing.
5.1. OSPFv2 Extended Link Opaque LSA 7.1. Adj-SID Sub-TLV
A new Opaque LSA (defined in [RFC5250] is defined in OSPFv2 in order
to advertise additional link attributes: the OSPFv2 Extended Link
Opaque LSA.
The OSPFv2 Extended Link Opaque LSA has an area flooding scope.
Multiple OSPFv2 Extended Link Opaque LSAs can be advertised by a
single router in an area.
The format of the OSPFv2 Extended Link Opaque LSA is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age | Options | 10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque type | Instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
Opaque type used by OSPFv2 Extended Link Opaque LSA is 8.
The format of the TLVs within the body of LSA is the same as the
format used by the Traffic Engineering Extensions to OSPF defined in
[RFC3630]. The LSA payload consists of one or more nested
Type/Length/Value (TLV) triplets. The format of each TLV is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Length field defines the length of the value portion in octets.
The TLV is padded to 4-octet alignment; padding is not included in
the length field. Nested TLVs are also 32-bit aligned. Unrecognized
types are ignored.
5.2. OSPFv2 Extended Link TLV
OSPFv2 Extended Link TLV is used in order to advertise various
attributes of the link. It describes a single link and is
constructed of a set of Sub-TLVs. There are no ordering requirements
for the Sub-TLVs. Only one Extended Link TLV SHALL be advertised in
each Extended Link Opaque LSA, allowing for fine granularity changes
in the topology.
The Extended Link TLV has following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
where:
Type is 1.
Length is variable.
Link-Type: as defined in section A.4.2 of [RFC2328].
Link-ID: as defined in section A.4.2 of [RFC2328].
Link Data: as defined in section A.4.2 of [RFC2328].
5.3. Adj-SID sub-TLV
Adj-SID is an optional sub-TLV of the Extended Link TLV. It MAY
appear multiple times in the Extended Link TLV. Examples where more
than one Adj-SID may be used per neighbor are described in
[I-D.filsfils-rtgwg-segment-routing-use-cases]. The Adj-SID sub-TLV Adj-SID is an optional Sub-TLV of the Extended Link TLV defined in
[I-D.ietf-ospf-prefix-link-attr]. It MAY appear multiple times in
the Extended Link TLV. Examples where more than one Adj-SID may be
used per neighbor are described in
[I-D.filsfils-rtgwg-segment-routing-use-cases]. The Adj-SID Sub-TLV
has the following format: has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | MT-ID | Weight | | Flags | Reserved | MT-ID | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) | | SID/Label/Index (variable) |
skipping to change at page 22, line 33 skipping to change at page 19, line 44
Flags. 1 octet field of following flags: Flags. 1 octet field of following flags:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|B|V|L|S| | |B|V|L|S| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: where:
B-Flag: Backup-flag: set if the Adj-SID refers to an adjacency B-Flag: Backup Flag. If set, the Adj-SID refers to an
being protected (e.g.: using IPFRR or MPLS-FRR) as described in adjacency being protected (e.g.: using IPFRR or MPLS-FRR) as
[I-D.filsfils-rtgwg-segment-routing-use-cases]. described in [I-D.filsfils-rtgwg-segment-routing-use-cases].
The V-Flag: Value/Index Flag. If set, then the Prefix-SID The V-Flag: Value/Index Flag. If set, then the Prefix-SID
carries an absolute value. If not set, then the Prefix-SID carries an absolute value. If not set, then the Prefix-SID
carries an index. carries an index.
The L-Flag: Local/Global Flag. If set, then the value/index The L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set, carried by the Prefix-SID has local significance. If not set,
then the value/index carried by this subTLV has global then the value/index carried by this Sub-TLV has global
significance. significance.
The S-Flag. Set Flag. When set, the S-Flag indicates that the The S-Flag. Set Flag. When set, the S-Flag indicates that the
Adj-SID refers to a set of adjacencies (and therefore MAY be Adj-SID refers to a set of adjacencies (and therefore MAY be
assigned to other adjacencies as well). assigned to other adjacencies as well).
Other bits: MUST be zero when originated and ignored when Other bits: Reserved. These MUST be zero when sent and are
received. ignored when received.
MT-ID: Multi-Topology ID (as defined in [RFC4915]. MT-ID: Multi-Topology ID (as defined in [RFC4915].
Weight: weight used for load-balancing purposes. The use of the Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing]. weight is defined in [I-D.filsfils-rtgwg-segment-routing].
SID/Index/Label: according to the V and L flags, it contains SID/Index/Label: according to the V and L flags, it contains
either: either:
A 32 bit index defining the offset in the SID/Label space A 32 bit index defining the offset in the SID/Label space
advertised by this router. advertised by this router.
A 24 bit label where the 20 rightmost bits are used for A 24 bit label where the 20 rightmost bits are used for
encoding the label value. encoding the label value.
An SR capable router MAY allocate an Adj-SID for each of its An SR capable router MAY allocate an Adj-SID for each of its
adjacencies and set the B-Flag when the adjacency is protected by an adjacencies and set the B-Flag when the adjacency is protected by an
FRR mechanism (IP or MPLS) as described in FRR mechanism (IP or MPLS) as described in
[I-D.filsfils-rtgwg-segment-routing-use-cases]. [I-D.filsfils-rtgwg-segment-routing-use-cases].
5.4. LAN Adj-SID Sub-TLV 7.2. LAN Adj-SID Sub-TLV
LAN Adj-SID is an optional sub-TLV of the Extended Link TLV. It MAY LAN Adj-SID is an optional Sub-TLV of the Extended Link TLV defined
appear multiple times in Extended Link TLV. It is used to advertise in [I-D.ietf-ospf-prefix-link-attr]. It MAY appear multiple times in
SID/Label for adjacency to non-DR node on broadcast or NBMA network. the Extended-Link TLV. It is used to advertise a SID/Label for an
adjacency to a non-DR node on a broadcast or NBMA network.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved | MT-ID | Weight | | Flags | Reserved | MT-ID | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID | | Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 24, line 21 skipping to change at page 21, line 41
B-Flag: Backup-flag: set if the LAN-Adj-SID refer to an B-Flag: Backup-flag: set if the LAN-Adj-SID refer to an
adjacency being protected (e.g.: using IPFRR or MPLS-FRR) as adjacency being protected (e.g.: using IPFRR or MPLS-FRR) as
described in [I-D.filsfils-rtgwg-segment-routing-use-cases]. described in [I-D.filsfils-rtgwg-segment-routing-use-cases].
The V-Flag: Value/Index Flag. If set, then the Prefix-SID The V-Flag: Value/Index Flag. If set, then the Prefix-SID
carries an absolute value. If not set, then the Prefix-SID carries an absolute value. If not set, then the Prefix-SID
carries an index. carries an index.
The L-Flag: Local/Global Flag. If set, then the value/index The L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set, carried by the Prefix-SID has local significance. If not set,
then the value/index carried by this subTLV has global then the value/index carried by this Sub-TLV has global
significance. significance.
The S-Flag. Set Flag. When set, the S-Flag indicates that the The S-Flag. Set Flag. When set, the S-Flag indicates that the
Adj-SID refers to a set of adjacencies (and therefore MAY be Adj-SID refers to a set of adjacencies (and therefore MAY be
assigned to other adjacencies as well). assigned to other adjacencies as well).
Other bits: MUST be zero when originated and ignored when Other bits: Reserved. These MUST be zero when sent and are
received. ignored when received.
MT-ID: Multi-Topology ID (as defined in [RFC4915]. MT-ID: Multi-Topology ID (as defined in [RFC4915].
Weight: weight used for load-balancing purposes. The use of the Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing]. weight is defined in [I-D.filsfils-rtgwg-segment-routing].
SID/Index/Label: according to the V and L flags, it contains SID/Index/Label: according to the V and L flags, it contains
either: either:
A 32 bit index defining the offset in the SID/Label space A 32 bit index defining the offset in the SID/Label space
advertised by this router. advertised by this router.
A 24 bit label where the 20 rightmost bits are used for A 24 bit label where the 20 rightmost bits are used for
encoding the label value. encoding the label value.
6. Elements of Procedure 8. Elements of Procedure
6.1. Intra-area Segment routing in OSPFv2 8.1. Intra-area Segment routing in OSPFv2
The OSPFv2 node that supports segment routing MAY advertise Prefix- An OSPFv2 router that supports segment routing MAY advertise Prefix-
SIDs for any prefix to which it is advertising reachability (e.g., a SIDs for any prefix to which it is advertising reachability (e.g., a
loopback IP address as described in Section 4.2). loopback IP address as described in Section 5).
If multiple routers advertise Prefix-SID for the same prefix, then If multiple routers advertise a Prefix-SID for the same prefix, then
the Prefix-SID MUST be the same. This is required in order to allow the Prefix-SID MUST be the same. This is required in order to allow
traffic load-balancing if multiple equal cost paths to the traffic load-balancing when multiple equal cost paths to the
destination exist in the network. destination exist in the network.
Prefix-SID can also be advertised by the SR Mapping Servers (as Prefix-SID can also be advertised by the SR Mapping Servers (as
described in [I-D.filsfils-rtgwg-segment-routing-use-cases]). The described in [I-D.filsfils-rtgwg-segment-routing-use-cases]). The
Mapping Server advertises Prefix-SIDs for remote prefixes that exist Mapping Server advertises Prefix-SIDs for remote prefixes that exist
in the OSPFv2 routing domain. Multiple Mapping Servers can advertise in the OSPFv2 routing domain. Multiple Mapping Servers can advertise
Prefix-SIDs for the same prefix, in which case the same Prefix-SID Prefix-SIDs for the same prefix, in which case the same Prefix-SID
MUST be advertised by all of them. The flooding scope of the OSPF MUST be advertised by all of them. The flooding scope of the OSPF
Extended Prefix Opaque LSA that is generated by the SR Mapping Server Extended Prefix Opaque LSA that is generated by the SR Mapping Server
could be either area scoped or AS scoped and is determined based on could be either area scoped or AS scoped and is determined based on
the configuration of the SR Mapping Server. the configuration of the SR Mapping Server.
6.2. Inter-area Segment routing in OSPFv2 8.2. Inter-area Segment routing in OSPFv2
In order to support SR in a multi-area environment, OSPFv2 must In order to support SR in a multi-area environment, OSPFv2 must
propagate Prefix-SID information between areas. The following propagate Prefix-SID information between areas. The following
procedure is used in order to propagate Prefix SIDs between areas. procedure is used in order to propagate Prefix SIDs between areas.
When an OSPF ABR advertises a Type-3 Summary LSA from an intra-area When an OSPF ABR advertises a Type-3 Summary LSA from an intra-area
prefix to all its connected areas, it will also originate an Extended prefix to all its connected areas, it will also originate an Extended
Prefix Opaque LSA, as described in Section 4. The flooding scope of Prefix Opaque LSA, as described in [I-D.ietf-ospf-prefix-link-attr].
the Extended Prefix Opaque LSA type will be set to area-scope. The The flooding scope of the Extended Prefix Opaque LSA type will be set
route-type in OSPF Extended Prefix TLV is set to inter-area. The to area-scope. The route-type in the OSPF Extended Prefix TLV is set
Prefix-SID Sub-TLV will be included in this LSA and the Prefix-SID to inter-area. The Prefix-SID Sub-TLV will be included in this LSA
value will be set as follows: and the Prefix-SID value will be set as follows:
The ABR will look at its best path to the prefix in the source The ABR will look at its best path to the prefix in the source
area and find the advertising router associated with its best path area and find the advertising router associated with the best path
to that prefix. to that prefix.
The ABR will then determine if such router advertised a Prefix-SID
for the prefix and use it when advertising the Prefix-SID to other
connected areas.
If no Prefix-SID was advertised for the prefix in the source area If no Prefix-SID was advertised for the prefix in the source area
by the router that contributes to the best path to the prefix, by the router that contributes to the best path to the prefix, the
then the ABR will use the Prefix-SID advertised by any other originating ABR will use the Prefix-SID advertised by any other
router (e.g.: a Prefix-SID coming from an SR Mapping Server as router (e.g.: a Prefix-SID coming from an SR Mapping Server as
defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when
propagating the Prefix-SID for the prefix to other areas. propagating the Prefix-SID for the prefix to other areas.
When an OSPF ABR advertises Type-3 Summary LSAs from an inter-area When an OSPF ABR advertises Type-3 Summary LSAs from an inter-area
route to all its connected areas it will also originate an Extended route to all its connected areas it will also originate an Extended
Prefix Opaque LSA, as described in Section 4. The flooding scope of Prefix Opaque LSA, as described in [I-D.ietf-ospf-prefix-link-attr].
the Extended Prefix Opaque LSA type will be set to area-scope. The The flooding scope of the Extended Prefix Opaque LSA type will be set
route-type in OSPF Extended Prefix TLV is set to inter-area. The to area-scope. The route-type in OSPF Extended Prefix TLV is set to
Prefix-SID Sub-TLV will be included in this LSA and the Prefix-SID inter-area. The Prefix-SID Sub-TLV will be included in this LSA and
will be set as follows: the Prefix-SID will be set as follows:
The ABR will look at its best path to the prefix in the source The ABR will look at its best path to the prefix in the source
area and find the advertising router associated with its best path area and find the advertising router associated with the best path
to that prefix. to that prefix.
The ABR will then determine if such router advertised a Prefix-SID The ABR will then determine if such router advertised a Prefix-SID
for the prefix and use it when advertising the Prefix-SID to other for the prefix and use it when advertising the Prefix-SID to other
connected areas. connected areas.
If no Prefix-SID was advertised for the prefix in the source area If no Prefix-SID was advertised for the prefix in the source area
by the ABR that contributes to the best path to the prefix, the by the ABR that contributes to the best path to the prefix, the
originating ABR will use the Prefix-SID advertised by any other originating ABR will use the Prefix-SID advertised by any other
router (e.g.: a Prefix-SID coming from an SR Mapping Server as router (e.g.: a Prefix-SID coming from an SR Mapping Server as
defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when
propagating the Prefix-SID for the prefix to other areas. propagating the Prefix-SID for the prefix to other areas.
6.3. SID for External Prefixes 8.3. SID for External Prefixes
Type-5 LSAs are flooded domain wide. When an ASBR, which supports Type-5 LSAs are flooded domain wide. When an ASBR, which supports
SR, generates Type-5 LSAs, it should also originate an Extended SR, generates Type-5 LSAs, it should also originate an Extended
Prefix Opaque LSAs, as described in Section 4. The flooding scope of Prefix Opaque LSAs, as described in [I-D.ietf-ospf-prefix-link-attr].
the Extended Prefix Opaque LSA type is set to AS-scope. The route- The flooding scope of the Extended Prefix Opaque LSA type is set to
type in OSPF Extended Prefix TLV is set to external. The Prefix-SID AS-scope. The route-type in the OSPF Extended Prefix TLV is set to
sub-TLV is included in this LSA and the Prefix-SID value will be set external. The Prefix-SID Sub-TLV is included in this LSA and the
to the SID that has been reserved for that prefix. Prefix-SID value will be set to the SID that has been reserved for
that prefix.
When a NSSA ASBR translates Type-7 LSAs into Type-5 LSAs, it should When an NSSA ABR translates Type-7 LSAs into Type-5 LSAs, it should
also advertise the Prefix-SID for the prefix. The NSSA ABR also advertise the Prefix-SID for the prefix. The NSSA ABR
determines its best path to the prefix advertised in the translated determines its best path to the prefix advertised in the translated
Type-7 LSA and finds the advertising router associated with such Type-7 LSA and finds the advertising router associated with that
path. If such advertising router has advertised a Prefix-SID, for path. If the advertising router has advertised a Prefix-SID for the
the prefix, then the NSSA ASBR uses it when advertising the Prefix- prefix, then the NSSA ABR uses it when advertising the Prefix-SID for
SID for the Type-5 prefix. Otherwise, the Prefix-SID advertised by the Type-5 prefix. Otherwise, the Prefix-SID advertised by any other
any other router will be used (e.g.: a Prefix-SID coming from an SR router will be used (e.g.: a Prefix-SID coming from an SR Mapping
Mapping Server as defined in Server as defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]).
[I-D.filsfils-rtgwg-segment-routing-use-cases]).
6.4. Advertisement of Adj-SID 8.4. Advertisement of Adj-SID
The Adjacency Segment Routing Identifier (Adj-SID) is advertised The Adjacency Segment Routing Identifier (Adj-SID) is advertised
using the Adj-SID Sub-TLV as described in Section 5. using the Adj-SID Sub-TLV as described in Section 7.
6.4.1. Advertisement of Adj-SID on Point-to-Point Links 8.4.1. Advertisement of Adj-SID on Point-to-Point Links
Adj-SID MAY be advertised for any adjacency on a p2p link that is in An Adj-SID MAY be advertised for any adjacency on a p2p link that is
neighbor state 2-Way or higher. If the adjacency on a p2p link in neighbor state 2-Way or higher. If the adjacency on a p2p link
transitions from the FULL state, then the Adj-SID for that adjacency transitions from the FULL state, then the Adj-SID for that adjacency
MAY be removed from the area. If the adjacency transitions to a MAY be removed from the area. If the adjacency transitions to a
state lower then 2-Way, then the Adj-SID MUST be removed from the state lower then 2-Way, then the Adj-SID advertisement MUST be
area. removed from the area.
6.4.2. Adjacency SID on Broadcast or NBMA Interfaces 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces
Broadcast or NBMA networks in OSPF are represented by a star topology Broadcast or NBMA networks in OSPF are represented by a star topology
where the Designated Router (DR) is the central point all other where the Designated Router (DR) is the central point to which all
routers on the broadcast or NBMA network connect to. As a result, other routers on the broadcast or NBMA network connect. As a result,
routers on the broadcast or NBMA network advertise only their routers on the broadcast or NBMA network advertise only their
adjacency to DR and BDR. Routers that are neither DR nor BDR do not adjacency to the DR. Routers that do not act as DR do not form or
form and do not advertise adjacencies between them. They, however, advertise adjacencies with each other. They do, however, maintain
maintain a 2-Way adjacency state between them. 2-Way adjacency state with each other and are directly reachable.
When Segment Routing is used, each router on the broadcast or NBMA When Segment Routing is used, each router on the broadcast or NBMA
network MAY advertise the Adj-SID for its adjacency to DR using Adj- network MAY advertise the Adj-SID for its adjacency to the DR using
SID Sub-TLV as described in Section 5.3. Adj-SID Sub-TLV as described in Section 7.1.
SR capable router MAY also advertise Adj-SID for other neighbors
(e.g. BDR, DR-OTHER) on broadcast or NBMA network using the LAN ADJ-
SID Sub-TLV as described in section 5.1.1.2. Section 5.4.
7. IANA Considerations
This specification updates two existing OSPF registries.
Opaque Link-State Advertisements (LSA) Option Types:
o suggested value 7 - OSPFv2 Extended Prefix Opaque LSA
o suggested value 8 - OSPFv2 Extended Link Opaque LSA
OSPF Router Information (RI) TLVs:
o suggested value 8 - SR-Algorithm TLV
o suggested value 9 - SID/Label Range TLV
This specification also creates four new registries:
- OSPF Extended Prefix LSA TLVs and sub-TLVs
- OSPF Extended Link LSA TLVs and sub-TLVs
7.1. OSPF Extend Prefix LSA TLV Registry
The OSPF Extend Prefix LSA TLV registry will define top-level TLVs
for Extended Prefix LSAs and should be placed in the existing OSPF
IANA registry. New values can be allocated via IETF Consensus or
IESG Approval.
Following initial values are allocated:
o 0 - Reserved
o 1 - OSPF Extended Prefix TLV
Types in the range 32768-32023 are for experimental use; these will
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 32023-65535 are not to be assigned at this time.
Before any assignments can be made in this range, there MUST be a
Standards Track RFC that specifies IANA Considerations that covers
the range being assigned.
7.2. OSPF Extend Prefix LSA sub-TLV Registry
The OSPF Extended Prefix sub-TLV registry will define will define
sub-TLVs at any level of nesting for Extended Prefix LSAs and should
be placed in the existing OSPF IANA registry. New values can be
allocated via IETF Consensus or IESG Approval.
Following initial values are allocated:
o 0 - Reserved SR capable routers MAY also advertise an Adj-SID for other neighbors
(e.g. BDR, DR-OTHER) on the broadcast or NBMA network using the LAN
ADJ-SID Sub-TLV as described in Section 7.2.
o 1 - SID/Label sub-TLV 9. IANA Considerations
o 2 - Prefix SID sub-TLV This specification updates several existing OSPF registries.
o 3 - SID/Label Binding sub-TLV 9.1. OSPF OSPF Router Information (RI) TLVs Registry
o 4 - IPv4 ERO sub-TLV o 8 (IANA Preallocated) - SR-Algorithm TLV
o 5 - Unnumbered Interface ID ERO sub-TLV o 9 (IANA Preallocated) - SID/Label Range TLV
o 6 - IPv4 Backup ERO sub-TLV 9.2. OSPF Extended Prefix LSA TLV Registry
o 7 - Unnumbered Interface ID Backup ERO sub-TLV Following values are allocated:
o 8 - ERO Metric sub-TLV o 2 - OSPF Extended Prefix Range TLV
Types in the range 32768-32023 are for experimental use; these will 9.3. OSPF Extended Prefix LSA Sub-TLV Registry
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 32023-65535 are not to be assigned at this time. Following values are allocated:
Before any assignments can be made in this range, there MUST be a
Standards Track RFC that specifies IANA Considerations that covers
the range being assigned.
7.3. OSPF Extend Link LSA TLV Registry o 1 - SID/Label Sub-TLV
The OSPF Extend Link LSA TLV registry will define top-level TLVs for o 2 - Prefix SID Sub-TLV
Extended Link LSAs and should be placed in the existing OSPF IANA
registry. New values can be allocated via IETF Consensus or IESG
Approval.
Following initial values are allocated: o 3 - SID/Label Binding Sub-TLV
o 0 - Reserved o 4 - IPv4 ERO Sub-TLV
o 1 - OSPFv2 Extended Link TLV o 5 - Unnumbered Interface ID ERO Sub-TLV
Types in the range 32768-32023 are for experimental use; these will o 6 - IPv4 Backup ERO Sub-TLV
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 32023-65535 are not to be assigned at this time. o 7 - Unnumbered Interface ID Backup ERO Sub-TLV
Before any assignments can be made in this range, there MUST be a
Standards Track RFC that specifies IANA Considerations that covers
the range being assigned.
7.4. OSPF Extend Link LSA sub-TLV Registry o 8 - ERO Metric Sub-TLV
The OSPF Extended Link LSA sub-TLV registry will define will define 9.4. OSPF Extended Link LSA Sub-TLV Registry
sub-TLVs at any level of nesting for Extended Link LSAs and should be
placed in the existing OSPF IANA registry. New values can be
allocated via IETF Consensus or IESG Approval.
Following initial values are allocated: Following initial values are allocated:
o 1 - SID/Label sub-TLV o 1 - SID/Label Sub-TLV
o 2 - Adj-SID sub-TLV o 2 - Adj-SID Sub-TLV
o 3 - LAN Adj-SID/Label Sub-TLV o 3 - LAN Adj-SID/Label Sub-TLV
Types in the range 32768-32023 are for experimental use; these will 10. Security Considerations
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 32023-65535 are not to be assigned at this time.
Before any assignments can be made in this range, there MUST be a
Standards Track RFC that specifies IANA Considerations that covers
the range being assigned.
8. Security Considerations
In general, new LSAs defined in this document are subject to the same Implementations must assure that malformed TLV and Sub-TLV
security concerns as those described in [RFC2328]. Additionally,
implementations must assure that malformed TLV and Sub-TLV
permutations do not result in errors which cause hard OSPF failures. permutations do not result in errors which cause hard OSPF failures.
9. Contributors 11. Contributors
The following people gave a substantial contribution to the content The following people gave a substantial contribution to the content
of this document: Acee Lindem, Ahmed Bashandy, Martin Horneffer, of this document: Acee Lindem, Ahmed Bashandy, Martin Horneffer,
Bruno Decraene, Stephane Litkowski, Igor Milojevic, Rob Shakir and Bruno Decraene, Stephane Litkowski, Igor Milojevic, Rob Shakir and
Saku Ytti. Saku Ytti.
10. Acknowledgements 12. Acknowledgements
We would like to thank Anton Smirnov for his contribution. We would like to thank Anton Smirnov for his contribution.
Many thanks to Yakov Rekhter, John Drake and Shraddha Hedge for their Many thanks to Yakov Rekhter, John Drake and Shraddha Hedge for their
contribution on earlier incarnations of the "Binding / MPLS Label contribution on earlier incarnations of the "Binding / MPLS Label
TLV" in [I-D.gredler-ospf-label-advertisement]. TLV" in [I-D.gredler-ospf-label-advertisement].
Thanks to Acee Lindem for the detail review of the draft, Thanks to Acee Lindem for the detail review of the draft,
corrections, as well as discussion about details of the encoding. corrections, as well as discussion about details of the encoding.
11. References 13. References
11.1. Normative References 13.1. Normative References
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001. Tunnels", RFC 3209, December 2001.
skipping to change at page 31, line 16 skipping to change at page 27, line 8
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC
4915, June 2007. 4915, June 2007.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. [RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007. Router Capabilities", RFC 4970, July 2007.
[RFC5250] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The [RFC5250] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
OSPF Opaque LSA Option", RFC 5250, July 2008. OSPF Opaque LSA Option", RFC 5250, July 2008.
11.2. Informative References 13.2. Informative References
[I-D.filsfils-rtgwg-segment-routing] [I-D.filsfils-rtgwg-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R., Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe, Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing Architecture", draft-filsfils-rtgwg- "Segment Routing Architecture", draft-filsfils-rtgwg-
segment-routing-01 (work in progress), October 2013. segment-routing-01 (work in progress), October 2013.
[I-D.filsfils-rtgwg-segment-routing-use-cases] [I-D.filsfils-rtgwg-segment-routing-use-cases]
Filsfils, C., Francois, P., Previdi, S., Decraene, B., Filsfils, C., Francois, P., Previdi, S., Decraene, B.,
skipping to change at page 31, line 38 skipping to change at page 27, line 30
Ytti, S., Henderickx, W., Tantsura, J., Kini, S., and E. Ytti, S., Henderickx, W., Tantsura, J., Kini, S., and E.
Crabbe, "Segment Routing Use Cases", draft-filsfils-rtgwg- Crabbe, "Segment Routing Use Cases", draft-filsfils-rtgwg-
segment-routing-use-cases-02 (work in progress), October segment-routing-use-cases-02 (work in progress), October
2013. 2013.
[I-D.gredler-ospf-label-advertisement] [I-D.gredler-ospf-label-advertisement]
Gredler, H., Amante, S., Scholl, T., and L. Jalil, Gredler, H., Amante, S., Scholl, T., and L. Jalil,
"Advertising MPLS labels in OSPF", draft-gredler-ospf- "Advertising MPLS labels in OSPF", draft-gredler-ospf-
label-advertisement-03 (work in progress), May 2013. label-advertisement-03 (work in progress), May 2013.
[I-D.ietf-ospf-prefix-link-attr]
Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", draft-ietf-ospf-prefix-link-attr-00 (work
in progress), August 2014.
[I-D.minto-rsvp-lsp-egress-fast-protection] [I-D.minto-rsvp-lsp-egress-fast-protection]
Jeganathan, J., Gredler, H., and Y. Shen, "RSVP-TE LSP Jeganathan, J., Gredler, H., and Y. Shen, "RSVP-TE LSP
egress fast-protection", draft-minto-rsvp-lsp-egress-fast- egress fast-protection", draft-minto-rsvp-lsp-egress-fast-
protection-03 (work in progress), November 2013. protection-03 (work in progress), November 2013.
Authors' Addresses Authors' Addresses
Peter Psenak (editor) Peter Psenak (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
Apollo Business Center Apollo Business Center
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