Internet DRAFT - draft-psenak-ospf-segment-routing-ospfv3-extension
draft-psenak-ospf-segment-routing-ospfv3-extension
Open Shortest Path First IGP P. Psenak, Ed.
Internet-Draft S. Previdi, Ed.
Intended status: Standards Track C. Filsfils
Expires: January 3, 2015 Cisco Systems, Inc.
H. Gredler
Juniper Networks, Inc.
R. Shakir
British Telecom
W. Henderickx
Alcatel-Lucent
J. Tantsura
Ericsson
July 2, 2014
OSPFv3 Extensions for Segment Routing
draft-psenak-ospf-segment-routing-ospfv3-extension-02
Abstract
Segment Routing (SR) allows for a flexible definition of end-to-end
paths within IGP topologies by encoding paths as sequences of
topological sub-paths, called "segments". These segments are
advertised by the link-state routing protocols (IS-IS and OSPF).
This draft describes the necessary OSPFv3 extensions that need to be
introduced for Segment Routing.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on January 3, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 3
2.1. SID/Label sub-TLV . . . . . . . . . . . . . . . . . . . . 3
3. Segment Routing Capabilities . . . . . . . . . . . . . . . . 4
3.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 4
3.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 5
4. Prefix SID Identifier . . . . . . . . . . . . . . . . . . . . 7
4.1. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . 7
4.2. SID/Label Binding sub-TLV . . . . . . . . . . . . . . . . 11
4.2.1. ERO Metric sub-TLV . . . . . . . . . . . . . . . . . 13
4.2.2. ERO sub-TLVs . . . . . . . . . . . . . . . . . . . . 13
5. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 19
5.1. Adj-SID sub-TLV . . . . . . . . . . . . . . . . . . . . . 20
5.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 21
6. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 23
6.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 23
6.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 24
6.3. SID for External Prefixes . . . . . . . . . . . . . . . . 25
6.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 25
6.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 25
6.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 25
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
7.1. OSPF Router Information (RI) TLVs Registry . . . . . . . 26
7.2. OSPFv3 Extend-LSA sub-TLV registry . . . . . . . . . . . 26
8. Security Considerations . . . . . . . . . . . . . . . . . . . 27
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 27
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 27
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
11.1. Normative References . . . . . . . . . . . . . . . . . . 27
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11.2. Informative References . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
Segment Routing (SR) allows for a flexible definition of end-to-end
paths within IGP topologies by encoding paths as sequences of
topological sub-paths, called "segments". These segments are
advertised by the link-state routing protocols (IS-IS and OSPF).
Prefix segments represent an ecmp-aware shortest-path to a prefix (or
a node), as per the state of the IGP topology. Adjacency segments
represent a hop over a specific adjacency between two nodes in the
IGP. A prefix segment is typically a multi-hop path while an
adjacency segment, in most of the cases, is a one-hop path. SR's
control-plane can be applied to both IPv6 and MPLS data-planes, and
do not require any additional signaling (other than the regular IGP).
For example, when used in MPLS networks, SR paths do not require any
LDP or RSVP-TE signaling. Still, SR can interoperate in the presence
of LSPs established with RSVP or LDP .
This draft describes the necessary OSPFv3 extensions that need to be
introduced for Segment Routing.
Segment Routing architecture is described in
[I-D.filsfils-rtgwg-segment-routing].
Segment Routing use cases are described in
[I-D.filsfils-rtgwg-segment-routing-use-cases].
2. Segment Routing Identifiers
Segment Routing defines various types of Segment Identifiers (SIDs):
Prefix-SID, Adjacency-SID, LAN Adjacency SID and Binding SID.
2.1. SID/Label sub-TLV
SID/Label sub-TLV appears in multiple TLVs or Sub-TLVs defined later
in this document. It is used to advertise SID or label associated
with the prefix or adjacency. SID/Label TLV has following format:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: TBD, suggested value 1
Length: variable, 3 or 4 bytes
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
represents a 32 bit SID.
The receiving router MUST ignore SID/Label sub-TLV if the length
is other then 3 or 4.
3. Segment Routing Capabilities
Segment Routing requires some additional capabilities of the router
to be advertised to other routers in the area.
These SR capabilities are advertised in OSPFv3 Router Information
Opaque LSA (defined in [RFC4970]).
3.1. SR-Algorithm TLV
SR-Algorithm TLV is a TLV of Router Information Opaque LSA (defined
in [RFC4970]).
Router may use various algorithms when calculating reachability to
other nodes in area or to prefixes attached to these nodes. Examples
of these algorithms are metric based Shortest Path First (SPF),
various sorts of Constrained SPF, etc. SR-Algorithm TLV allows a
router to advertise algorithms that router is currently using to
other routers in an area. SR-Algorithm TLV has following structure:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Algorithm 1 | Algorithm... | Algorithm n | |
+- -+
| |
+ +
where:
Type: TBD, suggested value 8
Length: variable
Algorithm: one octet identifying the algorithm. The following
value has been defined:
0: IGP metric based SPT.
RI LSA can be advertised at any of the defined flooding scopes (link,
area, or autonomous system (AS)). For the purpose of the SR-
Algorithm TLV propagation area scope flooding is required.
3.2. SID/Label Range TLV
The SID/Label Range TLV is a TLV of Router Information Opaque LSA
(defined in [RFC4970]).
SID/Label Sub-TLV MAY appear multiple times and 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Range Size | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
+ +
where:
Type: TBD, suggested value 9
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Length: variable
Range Size: 3 octets of SID/label range
Currently the only supported Sub-TLV is the SID/Label TLV as defined
in Section 2.1. SID/Label advertised in SID/Label TLV represents the
first SID/Label from the advertised range.
Multiple occurrence of the SID/Label Range TLV MAY be advertised, in
order to advertise multiple ranges. In such case:
o The originating router MUST encode each range into a different
SID/Label Range TLV.
o The originating router decides in which order the set of SID/Label
Range TLVs are advertised inside Router Information Opaque LSA.
The originating router MUST ensure the order is same after a
graceful restart (using checkpointing, non-volatile storage or any
other mechanism) in order to guarantee the same order before and
after graceful restart.
o Receiving router must adhere to the order in which the ranges are
advertised when calculating a SID/label from the SID index.
o A router not supporting multiple occurrences SID/Label Range TLV
MUST take into consideration the first occurrence in the received
set.
Here follows an example of advertisement of multiple ranges:
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The originating router advertises following ranges:
Range 1: [100, 199]
Range 2: [1000, 1099]
Range 3: [500, 599]
The receiving routers concatenate the ranges and build the SRGB
is as follows:
SRGB = [100, 199]
[1000, 1099]
[500, 599]
The indexes span multiple ranges:
index=0 means label 100
...
index 99 means label 199
index 100 means label 1000
index 199 means label 1099
...
index 200 means label 500
...
RI LSA can be advertised at any of the defined flooding scopes (link,
area, or autonomous system (AS)). For the purpose of the SR-
Capability TLV propagation area scope flooding is required.
4. Prefix SID Identifier
A new extended OSPFv3 LSAs as defined in
[I-D.ietf-ospf-ospfv3-lsa-extend] are used to advertise SID or label
values associated with the prefix in OSPFv3.
4.1. Prefix SID Sub-TLV
The Prefix SID Sub-TLV is a Sub-TLV of the following OSPFv3 TLVs as
defined in [I-D.ietf-ospf-ospfv3-lsa-extend]:
Intra-Area Prefix TLV
Inter-Area Prefix TLV
External Prefix TLV
It MAY appear more than once and has following format:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Range Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: TBD, suggested value 2.
Length: variable
Flags: 1 octet field. The following flags are defined:
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|N|P|M|E|V|L| |
+-+-+-+-+-+-+-+-+
where:
N-Flag: Node-SID flag. If set, then the Prefix-SID refers to
the router identified by the prefix. Typically, the N-Flag is
set on Prefix-SIDs attached to a router loopback address. The
N-Flag is set when the Prefix-SID is a Node- SID as described
in [I-D.filsfils-rtgwg-segment-routing].
P-Flag: no-PHP flag. If set, then the penultimate hop MUST NOT
pop the Prefix-SID before delivering the packet to the node
that advertised the Prefix-SID.
M-Flag: Mapping Server Flag. If set, the SID is advertised
from the Segment Routing Mapping Server functionality as
described in [I-D.filsfils-rtgwg-segment-routing-use-cases].
E-Flag: Explicit-Null Flag. If set, any upstream neighbor of
the Prefix-SID originator MUST replace the Prefix-SID with a
Prefix-SID having an Explicit-NULL value (0 for IPv4) before
forwarding the packet.
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 index.
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The L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set,
then the value/index carried by this subTLV has global
significance.
Other bits: MUST be zero when sent and ignored when received.
Algorithm: one octet identifying the algorithm the Prefix-SID is
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 1. For range
advertisements > 1, Range Size represents the number of addresses
that need to be mapped into a Prefix-SID.
SID/Index/Label: label or index value depending on the V-bit
setting.
Examples:
A 32 bit global index defining the offset in the SID/Label
space advertised by this router - in this case the V and L
flags MUST be unset.
A 24 bit local label where the 20 rightmost bits are used
for encoding the label value - in this case the V and L
flags MUST be set.
If multiple Prefix-SIDs are advertised for the same prefix, the
receiving router MUST use the first encoded SID and MAY use the
subsequent ones.
When propagating Prefix-SIDs between areas, if multiple prefix-SIDs
are advertised for a prefix, an implementation SHOULD preserve the
original ordering, when advertising prefix-SIDs to other areas. This
allows implementations that only use single Prefix-SID to have a
consistent view across areas.
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
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
prefix or not.
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P-Flag (no-PHP) MUST be set on the Prefix-SIDs allocated to inter-
area prefixes that are originated by the ABR based on intra-area or
inter-area reachability between areas. In case the inter-area prefix
is generated based on the prefix which is directly attached to the
ABR, P-Flag SHOULD NOT be set
P-Flag (no-PHP) MUST NOT be set on the Prefix-SIDs allocated to
redistributed prefixes, unless the redistributed prefix is directly
attached to ASBR, in which case the P-Flag SHOULD NOT be set.
If the P-flag is not set then any upstream neighbor of the Prefix-SID
originator MUST pop the Prefix-SID. This is equivalent to the
penultimate hop popping mechanism used in the MPLS dataplane. In
such case MPLS EXP bits of the Prefix-SID are not preserved to the
ultimate hop (the Prefix-SID being removed). If the P-flag is unset
the received E-flag is ignored.
If the P-flag is set then:
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
is useful when the originator of the Prefix-SID must stitch the
incoming packet into a continuing MPLS LSP to the final
destination. This could occur at an inter-area border router
(prefix propagation from one area to another) or at an inter-
domain border router (prefix propagation from one domain to
another).
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
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 originator wishes to receive the packet with the original EXP
bits.
When M-Flag is set, P-flag MUST be set and E-bit MUST NOT be set.
Example 1: if the following router addresses (loopback addresses)
need to be mapped into the corresponding Prefix SID indexes:
Router-A: 192::1/128, Prefix-SID: Index 1
Router-B: 192::2/128, Prefix-SID: Index 2
Router-C: 192::3/128, Prefix-SID: Index 3
Router-D: 192::4/128, Prefix-SID: Index 4
then the Address Prefix field in Intra-Area Prefix TLV, Inter-Area
Prefix TLV or External Prefix TLV is set to 192::1, Prefix Length in
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these TLVs would be set to 128, Range Size in Prefix SID sub-TLV
would be set to 4 and Index value would be set to 1.
Example 2: If the following prefixes need to be mapped into the
corresponding Prefix-SID indexes:
10:1:1::0/120, Prefix-SID: Index 51
10:1:1::100/120, Prefix-SID: Index 52
10:1:1::200/120, Prefix-SID: Index 53
10:1:1::300/120, Prefix-SID: Index 54
10:1:1::400/120, Prefix-SID: Index 55
10:1:1::500/120, Prefix-SID: Index 56
10:1:1::600/120, Prefix-SID: Index 57
then the Address Prefix field in Intra-Area Prefix TLV, Inter-Area
Prefix TLV or External Prefix TLV is set to 10:1:1::0, Prefix Length
in these TLVs would be set to 120, Range Size in Prefix SID sub-TLV
would be set to 7 and Index value would be set to 51.
4.2. SID/Label Binding sub-TLV
SID/Label Binding sub-TLV is used to advertise SID/Label mapping for
a path to the prefix.
The SID/Label Binding TLV MAY be originated by any router in an
OSPFv3 domain. The router may advertise a SID/Label binding to a FEC
along with at least a single 'nexthop style' anchor. The protocol
supports more than one 'nexthop style' anchor to be attached to a
SID/Label binding, which results into a simple path description
language. In analogy to RSVP the terminology for this is called an
'Explicit Route Object' (ERO). Since ERO style path notation allows
to anchor SID/label bindings to both link and node IP addresses any
label switched path, can be described. Furthermore also SID/Label
Bindings from external protocols can get easily re-advertised.
The SID/Label Binding TLV may be used for advertising SID/Label
Bindings and their associated Primary and Backup paths. In one
single TLV either a primary ERO Path, a backup ERO Path or both are
advertised. If a router wants to advertise multiple parallel paths
then it can generate several TLVs for the same Prefix/FEC. Each
occurrence of a Binding TLV with respect with a given FEC Prefix has
accumulating and not canceling semantics.
SID/Label Binding sub-TLV is a sub-TLV of the following OSPFv3 TLVs,
as defined in [I-D.ietf-ospf-ospfv3-lsa-extend]:
Intra-Area Prefix TLV
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Inter-Area Prefix TLV
External Prefix TLV
Multiple SID/Label Binding sub-TLVs can be present in above mentioned
TLVs. SID/Label Binding sub-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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Weight | Range Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
where:
Type: TBD, suggested value 5
Length: variable
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|M| |
+-+-+-+-+-+-+-+-+
where:
M-bit - When the bit is set the binding represents the
mirroring context as defined in
[I-D.minto-rsvp-lsp-egress-fast-protection].
Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing].
Range Size: usage is the same as described in Section 4.1
SID/Label Binding sub-TLV currently supports following Sub-TLVs:
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
once.
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ERO Metric sub-TLV as defined in Section 4.2.1.
ERO sub-TLVs as defined in Section 4.2.2.
4.2.1. ERO Metric sub-TLV
ERO Metric sub-TLV is a Sub-TLV of the SID/Label Binding TLV.
The ERO Metric sub-TLV carries the cost of an ERO path. It is 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 Metric
sub-TLV SHOULD be set to the cumulative IGP or TE path cost of the
advertised ERO. Since manipulation of the Metric field may attract
or distract traffic from and to the advertised segment it MAY be
manually overridden.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ERO Metric sub-TLV format
where:
Type: TBD, suggested value 6
Length: 4 bytes
Metric: 4 bytes
4.2.2. ERO sub-TLVs
All 'ERO' information represents an ordered set which describes the
segments of a path. The last ERO sub-TLV describes the segment
closest to the egress point, contrary the first ERO sub-TLV describes
the first segment of a path. If a router extends or stitches a path
it MUST prepend the new segments path information to the ERO list.
The above similarly applies to backup EROs.
All ERO Sub-TLVs must immediately follow the (SID)/Label Sub-TLV.
All Backup ERO sub-TLVs must immediately follow last ERO Sub-TLV.
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4.2.2.1. IPv4 ERO 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
style of encoding. Its semantics have been borrowed from [RFC3209].
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 ERO sub-TLV format
where:
Type: TBD, suggested value 7
Length: 8 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
IPv4 Address - the address of the explicit route hop.
4.2.2.2. IPv6 ERO sub-TLV
IPv6 ERO sub-TLV is a sub-TLV of the SID/Label Binding sub-TLV.
The IPv6 ERO sub-TLV (Type TBA) describes a path segment using IPv6
Address style of encoding. Its semantics have been borrowed from
[RFC3209].
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- -+
| |
+- IPv6 Address -+
| |
+- -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv6 ERO sub-TLV format
where:
Type: TBD, suggested value 8
Length: 8 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
IPv6 Address - the address of the explicit route hop.
4.2.2.3. Unnumbered Interface ID ERO sub-TLV
Unnumbered Interface ID ERO sub-TLV is a sub-TLV of the SID/Label
Binding sub-TLV.
The appearance and semantics of the 'Unnumbered Interface ID' have
been borrowed from [RFC3477].
The Unnumbered Interface-ID ERO sub-TLV describes a path segment that
spans over an unnumbered interface. Unnumbered interfaces are
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referenced using the interface index. Interface indices are assigned
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
need to be disambiguated using a domain unique Router-ID.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Unnumbered Interface ID ERO sub-TLV format
Type: TBD, suggested value 9
Length: 12 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
Router-ID: Router-ID of the next-hop.
Interface ID: is the identifier assigned to the link by the router
specified by the Router-ID.
4.2.2.4. IPv4 Backup ERO sub-TLV
IPv4 Prefix Backup ERO sub-TLV is a sub-TLV of the SID/Label Binding
sub-TLV.
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The IPv4 Backup ERO sub-TLV describes a path segment using IPv4
Address style of encoding. Its semantics have been borrowed from
[RFC3209].
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 Backup ERO sub-TLV format
where:
Type: TBD, suggested value 10
Length: 8 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
IPv4 Address - the address of the explicit route hop.
4.2.2.5. IPv6 Backup ERO sub-TLV
IPv6 ERO sub-TLV is a sub-TLV of the SID/Label Binding sub-TLV.
The IPv6 Backup ERO sub-TLV describes a Backup path segment using
IPv6 Address style of encoding. Its appearance and semantics have
been borrowed from [RFC3209].
The 'L' bit in the Flags is a one-bit attribute. If the L bit is
set, then the value of the attribute is 'loose.' Otherwise, the
value of the attribute is 'strict.'
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- -+
| |
+- IPv6 Address -+
| |
+- -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv6 Backup ERO sub-TLV format
where:
Type: TBD, suggested value 11
Length: 8 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
IPv6 Address - the address of the explicit route hop.
4.2.2.6. Unnumbered Interface ID Backup ERO sub-TLV
Unnumbered Interface ID Backup sub-TLV is a sub-TLV of the SID/Label
Binding sub-TLV.
The appearance and semantics of the 'Unnumbered Interface ID' have
been borrowed from [RFC3477].
The Unnumbered Interface-ID ERO sub-TLV describes a path segment that
spans over an unnumbered interface. Unnumbered interfaces are
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referenced using the interface index. Interface indices are assigned
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
need to be disambiguated using a domain unique Router-ID.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Unnumbered Interface ID Backup ERO sub-TLV format
where:
Type: TBD, suggested value 12
Length: 12 bytes
Flags: 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L| |
+-+-+-+-+-+-+-+-+
where:
L-bit - If the L bit is set, then the value of the attribute is
'loose.' Otherwise, the value of the attribute is 'strict.'
Router-ID: Router-ID of the next-hop.
Interface ID: is the identifier assigned to the link by the router
specified by the Router-ID.
5. Adjacency Segment Identifier (Adj-SID)
An Adjacency Segment Identifier (Adj-SID) represents a router
adjacency in Segment Routing. At the current stage of Segment
Routing architecture it is assumed that the Adj-SID value has local
significance (to the router).
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5.1. Adj-SID sub-TLV
A new extended OSPFv3 LSAs, as defined in
[I-D.ietf-ospf-ospfv3-lsa-extend], are used to advertise prefix SID
in OSPFv3
Adj-SID sub-TLV is an optional sub-TLV of the Router-Link TLV as
defined in [I-D.ietf-ospf-ospfv3-lsa-extend]. It MAY appear multiple
times in Router-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 structure of the
Adj-SID Sub-TLV 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Weight | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) |
+---------------------------------------------------------------+
where:
Type: TBD, suggested value 10.
Length: variable.
Flags. 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|V|L|S| |
+-+-+-+-+-+-+-+-+
where:
B-Flag: Backup-flag: set if the Adj-SID refer to an adjacency
being protected (e.g.: using IPFRR or MPLS-FRR) as described in
[I-D.filsfils-rtgwg-segment-routing-use-cases].
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 index.
The L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set,
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then the value/index carried by this subTLV has global
significance.
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
assigned to other adjacencies as well).
Other bits: MUST be zero when originated and ignored when
received.
Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing].
SID/Index/Label: label or index value depending on the V-bit
setting.
Examples:
A 32 bit global index defining the offset in the SID/Label
space advertised by this router - in this case the V and L
flags MUST be unset.
A 24 bit local label where the 20 rightmost bits are used
for encoding the label value - in this case the V and L
flags MUST be set.
16 octet IPv6 address - in this case the V-flag MUST be set.
The L-flag MUST be set for link-local IPv6 address and MUST
be unset for IPv6 global unicast address.
A SR capable router MAY allocate an Adj-SID for each of its
adjacencies and set the B-Flag when the adjacency is protected by a
FRR mechanism (IP or MPLS) as described in
[I-D.filsfils-rtgwg-segment-routing-use-cases].
5.2. LAN Adj-SID Sub-TLV
LAN Adj-SID is an optional sub-TLV of the Router-Link TLV. It MAY
appear multiple times in Router-Link TLV. It is used to advertise
SID/Label for adjacency to non-DR node on broadcast or NBMA network.
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Weight | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) |
+---------------------------------------------------------------+
where:
Type: TBD, suggested value 11.
Length: variable.
Flags. 1 octet field of following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|V|L|S| |
+-+-+-+-+-+-+-+-+
where:
B-Flag: Backup-flag: set if the LAN-Adj-SID refer to an
adjacency being protected (e.g.: using IPFRR or MPLS-FRR) as
described in [I-D.filsfils-rtgwg-segment-routing-use-cases].
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 index.
The L-Flag: Local/Global Flag. If set, then the value/index
carried by the PrefixSID has local significance. If not set,
then the value/index carried by this subTLV has global
significance.
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
assigned to other adjacencies as well).
Other bits: MUST be zero when originated and ignored when
received.
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Weight: weight used for load-balancing purposes. The use of the
weight is defined in [I-D.filsfils-rtgwg-segment-routing].
SID/Index/Label: label or index value depending on the V-bit
setting.
Examples:
A 32 bit global index defining the offset in the SID/Label
space advertised by this router - in this case the V and L
flags MUST be unset.
A 24 bit local label where the 20 rightmost bits are used
for encoding the label value - in this case the V and L
flags MUST be set.
16 octet IPv6 address - in this case the V-flag MUST be set.
The L-flag MUST be set for link-local IPv6 address and MUST
be unset for IPv6 global unicast address.
6. Elements of Procedure
6.1. Intra-area Segment routing in OSPFv3
The OSPFv3 node that supports segment routing MAY advertise Prefix-
SIDs for any prefix that it is advertising reachability for (e.g.
loopback IP address) as described in Section 4.1.
If multiple routers advertise Prefix-SID for the same prefix, then
the Prefix-SID MUST be the same. This is required in order to allow
traffic load-balancing if multiple equal cost paths to the
destination exist in the network.
Prefix-SID can also be advertised by the SR Mapping Servers (as
described in [I-D.filsfils-rtgwg-segment-routing-use-cases]). The
Mapping Server advertises Prefix-SID for remote prefixes that exist
in the network. Multiple Mapping Servers can advertise Prefix-SID
for the same prefix, in which case the same Prefix-SID MUST be
advertised by all of them. SR Mapping Server could use either area
scope or autonomous system flooding scope when advertising Prefix SID
for prefixes, based on the configuration of the SR Mapping Server.
Depending on the flooding scope used, SR Mapping Server chooses the
LSA that will be used. If the area flooding scope is needed, E-
Intra-Area-Prefix-LSA ([I-D.ietf-ospf-ospfv3-lsa-extend]) is used.
If autonomous system flooding scope is needed, E-AS-External-LSA
([I-D.ietf-ospf-ospfv3-lsa-extend]) is used.
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When Prefix-SID is advertised by the Mapping Server, which is
indicated by the M-flag in the Prefix-SID sub-TLV (Section 4.1),
route-type as indicated by the LSA type which is being used for
flooding is ignored. Prefix SID is bound to a prefix, in which case
route-type becomes unimportant.
Advertisement of the Prefix-SID by the Mapping Server using Inter-
Area Prefix TLV, External Prefix TLV or Intra-Area-Prefix TLV
([I-D.ietf-ospf-ospfv3-lsa-extend]) does not itself contribute to the
prefix reachability. NU-bit MUST be set in the PrefixOptions field
of the LSA which is used by the Mapping Server to advertise SID or
SID range, which prevents such advertisement to contribute to the
prefix reachability.
6.2. Inter-area Segment routing in OSPFv3
In order to support SR in a multi-area environment, OSPFv3 must
propagate Prefix-SID information between areas. The following
procedure is used in order to propagate Prefix SIDs between areas.
When an OSPFv3 ABR advertises a Inter-Area-Prefix-LSA from an intra-
area prefix to all its connected areas, it will also include Prefix-
SID sub-TLV, as described in Section 4.1. The Prefix-SID value will
be set as follows:
The ABR will look at its best path to the prefix in the source
area and find out the advertising router associated with its best
path to that prefix.
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,
then the ABR will use the Prefix-SID advertised by any other
router (e.g.: a Prefix-SID coming from an SR Mapping Server as
defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when
propagating Prefix-SID for the prefix to other areas.
When an OSPFv3 ABR advertises Inter-Area-Prefix-LSA LSAs from an
inter-area route to all its connected areas it will also include
Prefix-SID sub-TLV, as described in Section 4.1. The Prefix-SID
value will be set as follows:
The ABR will look at its best path to the prefix in the source
area and find out the advertising router associated with its best
path to that prefix.
The ABR will then look if such router advertised a Prefix-SID for
the prefix and use it when advertising the Prefix-SID to other
connected areas.
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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
originating ABR will use the Prefix-SID advertised by any other
router (e.g.: a Prefix-SID coming from an SR Mapping Server as
defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]) when
propagating Prefix-SID for the prefix to other areas.
6.3. SID for External Prefixes
AS-External-LSAs are flooded domain wide. When an ASBR, which
supports SR, generates AS-External-LSA, it should also include
Prefix-SID sub-TLV, as described in Section 4.1 Prefix-SID value will
be set to the SID that has been reserved for that prefix.
When a NSSA ASBR translates NSSA-LSA into AS-External-LSA, it should
also advertise the Prefix-SID for the prefix. The NSSA ABR
determines its best path to the prefix advertised in the translated
NSSA-LSA and finds the advertising router associated with such path.
If such advertising router has advertised a Prefix-SID for the
prefix, then the NSSA ASBR uses it when advertising the Prefix-SID in
AS-External-LSA. Otherwise the Prefix-SID advertised by any other
router will be used (e.g.: a Prefix-SID coming from an SR Mapping
Server as defined in [I-D.filsfils-rtgwg-segment-routing-use-cases]).
6.4. Advertisement of Adj-SID
The Adjacency Segment Routing Identifier (Adj-SID) is advertised
using the Adj-SID Sub-TLV as described in Section 5.
6.4.1. Advertisement of Adj-SID on Point-to-Point Links
Adj-SID MAY be advertised for any adjacency on p2p link that is in a
state 2-Way or higher. If the adjacency on a p2p link transitions
from the FULL state, then the Adj-SID for that adjacency 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 area.
6.4.2. Adjacency SID on Broadcast or NBMA Interfaces
Broadcast or NBMA networks in OSPFv3 are represented by a star
topology where the Designated Router (DR) is the central point all
other routers on the broadcast or NBMA network connect to. As a
result, routers on the broadcast or NBMA network advertise only their
adjacency to DR and BDR. Routers that are neither DR nor BDR do not
form and do not advertise adjacencies between them. They, however,
maintain a 2-Way adjacency state between them.
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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-
SID Sub-TLV as described in Section 5.1.
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 5.2.
7. IANA Considerations
This specification updates two existing OSPF registries.
7.1. OSPF Router Information (RI) TLVs Registry
o suggested value 8 - SR-Algorithm TLV
o suggested value 9 - SID/Label Range TLV
7.2. OSPFv3 Extend-LSA sub-TLV registry
o suggested value 1 - SID/Label sub-TLV
o suggested value 2 - Prefix SID sub-TLV
o suggested value 3 - Adj-SID sub-TLV
o suggested value 4 - LAN Adj-SID sub-TLV
o suggested value 5 - SID/Label Binding sub-TLV
o suggested value 6 - ERO Metric sub-TLV
o suggested value 7 - IPv4 ERO sub-TLV
o suggested value 8 - IPv6 ERO sub-TLV
o suggested value 9 - Unnumbered Interface ID ERO sub-TLV
o suggested value 10 - IPv4 Backup ERO sub-TLV
o suggested value 11 - IPv6 Backup ERO sub-TLV
o suggested value 12 - Unnumbered Interface ID Backup ERO sub-TLV
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8. Security Considerations
Implementations must assure that malformed permutations of the newly
defined sub-TLvs do not result in errors which cause hard OSPFv3
failures.
9. Contributors
The following people gave a substantial contribution to the content
of this document: Ahmed Bashandy, Martin Horneffer, Bruno Decraene,
Stephane Litkowski, Igor Milojevic, Rob Shakir and Saku Ytti.
10. Acknowledgements
We would like to thank Anton Smirnov for his contribution.
Many thanks to Yakov Rekhter, John Drake and Shraddha Hedge for their
contribution on earlier incarnations of the "Binding / MPLS Label
TLV" in [I-D.gredler-ospf-label-advertisement].
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007.
11.2. Informative References
[I-D.filsfils-rtgwg-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing Architecture", draft-filsfils-rtgwg-
segment-routing-01 (work in progress), October 2013.
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[I-D.filsfils-rtgwg-segment-routing-use-cases]
Filsfils, C., Francois, P., Previdi, S., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., Kini, S., and E.
Crabbe, "Segment Routing Use Cases", draft-filsfils-rtgwg-
segment-routing-use-cases-02 (work in progress), October
2013.
[I-D.gredler-ospf-label-advertisement]
Gredler, H., Amante, S., Scholl, T., and L. Jalil,
"Advertising MPLS labels in OSPF", draft-gredler-ospf-
label-advertisement-03 (work in progress), May 2013.
[I-D.ietf-ospf-ospfv3-lsa-extend]
Lindem, A., Mirtorabi, S., Roy, A., and F. Baker, "OSPFv3
LSA Extendibility", draft-ietf-ospf-ospfv3-lsa-extend-03
(work in progress), May 2014.
[I-D.minto-rsvp-lsp-egress-fast-protection]
Jeganathan, J., Gredler, H., and Y. Shen, "RSVP-TE LSP
egress fast-protection", draft-minto-rsvp-lsp-egress-fast-
protection-03 (work in progress), November 2013.
Authors' Addresses
Peter Psenak (editor)
Cisco Systems, Inc.
Apollo Business Center
Mlynske nivy 43
Bratislava 821 09
Slovakia
Email: ppsenak@cisco.com
Stefano Previdi (editor)
Cisco Systems, Inc.
Via Del Serafico, 200
Rome 00142
Italy
Email: sprevidi@cisco.com
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Clarence Filsfils
Cisco Systems, Inc.
Brussels
Belgium
Email: cfilsfil@cisco.com
Hannes Gredler
Juniper Networks, Inc.
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
US
Email: hannes@juniper.net
Rob Shakir
British Telecom
London
UK
Email: rob.shakir@bt.com
Wim Henderickx
Alcatel-Lucent
Copernicuslaan 50
Antwerp 2018
BE
Email: wim.henderickx@alcatel-lucent.com
Jeff Tantsura
Ericsson
300 Holger Way
San Jose, CA 95134
US
Email: Jeff.Tantsura@ericsson.com
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