Open Shortest Path First IGP P. Psenak, Ed.
Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems, Inc.
Expires: July 30, 2018 S. Previdi, Ed.
Individual
H. Gredler
RtBrick Inc.
R. Shakir
Google, Inc.
W. Henderickx
Nokia
J. Tantsura
Nuage Networks
January 26, 2018
OSPFv3 Extensions for Segment Routing
draft-ietf-ospf-ospfv3-segment-routing-extensions-11
Abstract
Segment Routing (SR) allows 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 OSPFv3 extensions required 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 [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 https://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
Psenak, et al. Expires July 30, 2018 [Page 1]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 30, 2018.
Copyright Notice
Copyright (c) 2018 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
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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 . . . . . . . . . . . . . . . . . . . 6
3.3. SR Local Block TLV . . . . . . . . . . . . . . . . . . . 8
3.4. SRMS Preference TLV . . . . . . . . . . . . . . . . . . . 10
4. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 11
5. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 14
6. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 17
6.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 17
6.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 19
7. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 20
7.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 20
7.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 22
7.3. Segment Routing for External Prefixes . . . . . . . . . . 23
7.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 23
7.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 23
7.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 23
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
8.1. OSPFv3 Extend-LSA TLV Registry . . . . . . . . . . . . . 24
8.2. OSPFv3 Extend-LSA Sub-TLV registry . . . . . . . . . . . 24
9. Security Considerations . . . . . . . . . . . . . . . . . . . 24
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
Psenak, et al. Expires July 30, 2018 [Page 2]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1. Normative References . . . . . . . . . . . . . . . . . . 25
12.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
Segment Routing (SR) allows 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 cases, is a one-hop path. SR's control-plane can be applied to
both IPv6 and MPLS data-planes, and does not require any additional
signalling (other than IGP extensions). The IPv6 data plane is out
of the scope of this specification - OSPFv3 extension for SR with
IPv6 data plane will be specified in a separate document. When used
in MPLS networks, SR paths do not require any LDP or RSVP-TE
signalling. However, SR can interoperate in the presence of LSPs
established with RSVP or LDP.
There are additional segment types, e.g., Binding SID defined in
[I-D.ietf-spring-segment-routing].
This draft describes the OSPFv3 extensions required for Segment
Routing with MPLS data plane.
Segment Routing architecture is described in
[I-D.ietf-spring-segment-routing].
Segment Routing use cases are described in [RFC7855].
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
The SID/Label Sub-TLV appears in multiple TLVs or Sub-TLVs defined
later in this document. It is used to advertise the SID or label
associated with a prefix or adjacency. The SID/Label Sub-TLV has
following format:
Psenak, et al. Expires July 30, 2018 [Page 3]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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: 7
Length: Variable, 3 or 4 octets
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 the SID/Label Sub-TLV if the
length is other then 3 or 4.
3. Segment Routing Capabilities
Segment Routing requires some additional router capabilities to be
advertised to other routers in the area.
These SR capabilities are advertised in the OSPFv3 Router Information
Opaque LSA (defined in [RFC7770]).
3.1. SR-Algorithm TLV
The SR-Algorithm TLV is a top-level TLV of the OSPFv3 Router
Information Opaque LSA (defined in [RFC7770]).
The SR-Algorithm TLV is optional. It SHOULD only be advertised once
in the OSPFv3 Router Information Opaque LSA. If the SR-Algorithm TLV
is not advertised by the node, such node is considered as not being
segment routing capable.
An SR router can use various algorithms when calculating reachability
to OSPFv3 routers or prefixes in an OSPFv3 area. Examples of these
algorithms are metric based Shortest Path First (SPF), various
flavors of Constrained SPF, etc. The SR-Algorithm TLV allows a
router to advertise the algorithms currently used by the router to
other routers in an OSPFv3 area. The SR-Algorithm TLV has following
format:
Psenak, et al. Expires July 30, 2018 [Page 4]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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: 8
Length: Variable, in octets, dependent on number of algorithms
advertised.
Algorithm: Single octet identifying the algorithm. The following
values are defined by this document:
0: Shortest Path First (SPF) algorithm based on link metric.
This is the standard shortest path algorithm as computed by the
OSPFv3 protocol. Consistent with the deployed practice for
link-state protocols, Algorithm 0 permits any node to overwrite
the SPF path with a different path based on its local policy.
If the SR-Algorithm TLV is advertised, Algorithm 0 MUST be
included.
1: Strict Shortest Path First (SPF) algorithm based on link
metric. The algorithm is identical to Algorithm 0 but
Algorithm 1 requires that all nodes along the path will honor
the SPF routing decision. Local policy at the node claiming
support for Algorithm 1 MUST NOT alter the SPF paths computed
by Algorithm 1.
When multiple SR-Algorithm TLVs are received from a given router, the
receiver MUST use the first occurrence of the TLV in the OSPFV3
Router Information Opaque LSA. If the SR-Algorithm TLV appears in
multiple OSPFv3 Router Information Opaque LSAs that have different
flooding scopes, the SR-Algorithm TLV in the OSPFv3 Router
Information Opaque LSA with the area-scoped flooding scope MUST be
used. If the SR-Algorithm TLV appears in multiple OSPFv3 Router
Information Opaque LSAs that have the same flooding scope, the SR-
Algorithm TLV in the OSPFv3 Router Information Opaque LSA with the
numerically smallest Instance ID MUST be used and subsequent
instances of the SR-Algorithm TLV MUST be ignored.
Psenak, et al. Expires July 30, 2018 [Page 5]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
The OSPFv3 Router Information Opaque LSA can be advertised at any of
the defined opaque flooding scopes (link, area, or Autonomous System
(AS)). For the purpose of SR-Algorithm TLV advertisement, area-
scoped flooding is REQUIRED.
3.2. SID/Label Range TLV
Prefix SIDs MAY be advertised in a form of an index as described in
Section 5. Such index defines the offset in the SID/Label space
advertised by the router. The SID/Label Range TLV is used to
advertise such SID/Label space.
The SID/Label Range TLV is a top-level TLV of the OSPFv3 Router
Information Opaque LSA (defined in [RFC7770]).
The SID/Label Range TLV MAY appear multiple times and has the
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: 9
Length: Variable, in octets, dependent on Sub-TLVs.
Range Size: 3-octet SID/label range size (i.e., the number of SIDs
or labels in the range including the first SID/label). It MUST be
greater than 0.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Initially, the only supported Sub-TLV is the SID/Label Sub-TLV as
defined in Section 2.1. The SID/Label Sub-TLV MUST be included in
the SID/Label Range TLV. The SID/Label advertised in the SID/Label
Sub-TLV represents the first SID/Label in the advertised range.
Psenak, et al. Expires July 30, 2018 [Page 6]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
Only a single SID/Label Sub-TLV MAY be advertised in SID/Label Range
TLV. If more then one SID/Label Sub-TLVs are present, the SID/Label
Range TLV MUST be ignored.
Multiple occurrences 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 the order in which the set of SID/
Label Range TLVs are advertised inside the Router Information
Opaque LSA. The originating router MUST ensure the order is the
same after a graceful restart (using checkpointing, non-volatile
storage, or any other mechanism) in order to assure the SID/label
range and SID index correspondence is preserved across graceful
restarts.
o The receiving router MUST adhere to the order in which the ranges
are advertised when calculating a SID/label from a SID index.
o The originating router MUST NOT advertise overlapping ranges.
o When a router receives multiple overlapping ranges, it MUST
conform to the procedures defined in
[I-D.ietf-spring-conflict-resolution].
The following example illustrates the advertisement of multiple
ranges:
Psenak, et al. Expires July 30, 2018 [Page 7]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
The originating router advertises the following ranges:
Range 1: Range Size: 100 SID/Label Sub-TLV: 100
Range 1: Range Size: 100 SID/Label Sub-TLV: 1000
Range 1: Range Size: 100 SID/Label Sub-TLV: 500
The receiving routers concatenate the ranges and build the Segment
Routing Global Block (SRGB) 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
...
The OSPFv3 Router Information Opaque LSA can be advertised at any of
the defined flooding scopes (link, area, or autonomous system (AS)).
For the purpose of SID/Label Range TLV advertisement, area-scoped
flooding is REQUIRED.
3.3. SR Local Block TLV
The SR Local Block TLV (SRLB TLV) contains the range of labels the
node has reserved for local SIDs. SIDs from the SRLB MAY be used for
Adjacency-SIDs, but also by components other than the OSPFv3
protocol. As an example, an application or a controller can instruct
the router to allocate a specific local SID. Some controllers or
applications can use the control plane to discover the available set
of local SIDs on a particular router. In such cases, the SRLB is
advertised in the control plane. The requirement to advertise the
SRLB is further described in [I-D.ietf-spring-segment-routing-mpls].
The SRLB TLV is used to advertise the SRLB.
The SRLB TLV is a top-level TLV of the OSPFv3 Router Information
Opaque LSA (defined in [RFC7770]).
The SRLB TLV MAY appear multiple times in the OSPFv3 Router
Information Opaque LSA and has the following format:
Psenak, et al. Expires July 30, 2018 [Page 8]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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: 14
Length: Variable, in octets, dependent on Sub-TLVs.
Range Size: 3-octet SID/label range size (i.e., the number of SIDs
or labels in the range including the first SID/label). It MUST be
greater than 0.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Initially, the only supported Sub-TLV is the SID/Label Sub-TLV as
defined in Section 2.1. The SID/Label Sub-TLV MUST be included in
the SRLB TLV. The SID/Label advertised in the SID/Label Sub-TLV
represents the first SID/Label in the advertised range.
Only a single SID/Label Sub-TLV MAY be advertised in the SRLB TLV.
If more then one SID/Label Sub-TLVs are present, the SRLB TLV MUST be
ignored.
The originating router MUST NOT advertise overlapping ranges.
Each time a SID from the SRLB is allocated, it SHOULD also be
reported to all components (e.g., controller or applications) in
order for these components to have an up-to-date view of the current
SRLB allocation. This is required to avoid collisions between
allocation instructions.
Within the context of OSPFv3, the reporting of local SIDs is done
through OSPFv3 Sub-TLVs such as the Adjacency-SID (Section 6).
However, the reporting of allocated local SIDs can also be done
through other means and protocols which are outside the scope of this
document.
Psenak, et al. Expires July 30, 2018 [Page 9]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
A router advertising the SRLB TLV MAY also have other label ranges,
outside of the SRLB, used for its local allocation purposes which are
not advertised in the SRLB TLV. For example, it is possible that an
Adjacency-SID is allocated using a local label that is not part of
the SRLB.
The OSPFv3 Router Information Opaque LSA can be advertised at any of
the defined flooding scopes (link, area, or autonomous system (AS)).
For the purpose of SRLB TLV advertisement, area-scoped flooding is
REQUIRED.
3.4. SRMS Preference TLV
The Segment Routing Mapping Server Preference TLV (SRMS Preference
TLV) is used to advertise a preference associated with the node that
acts as an SR Mapping Server. The role of an SRMS is described in
[I-D.ietf-spring-segment-routing-ldp-interop]. SRMS preference is
defined in [I-D.ietf-spring-conflict-resolution].
The SRMS Preference TLV is a top-level TLV of the OSPFv3 Router
Information Opaque LSA (defined in [RFC7770]).
The SRMS Preference TLV MAY only be advertised once in the OSPFv3
Router Information Opaque LSA and has the 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preference | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: 15
Length: 4 octets
Preference: 1 octet. SRMS preference value from 0 to 255.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
When multiple SRMS Preference TLVs are received from a given router,
the receiver MUST use the first occurrence of the TLV in the OSPFv3
Router Information Opaque LSA. If the SRMS Preference TLV appears in
multiple OSPFv3 Router Information Opaque LSAs that have different
Psenak, et al. Expires July 30, 2018 [Page 10]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
flooding scopes, the SRMS Preference TLV in the OSPFv3 Router
Information Opaque LSA with the narrowest flooding scope MUST be
used. If the SRMS Preference TLV appears in multiple OSPFv3 Router
Information Opaque LSAs that have the same flooding scope, the SRMS
Preference TLV in the OSPFv3 Router Information Opaque LSA with the
numerically smallest Instance ID MUST be used and subsequent
instances of the SRMS Preference TLV MUST be ignored.
The OSPFv3 Router Information Opaque LSA can be advertised at any of
the defined flooding scopes (link, area, or autonomous system (AS)).
For the purpose of the SRMS Preference TLV advertisement, AS-scoped
flooding SHOULD be used. This is because SRMS servers can be located
in a different area then consumers of the SRMS advertisements. If
the SRMS advertisements from the SRMS server are only used inside the
SRMS server's area, area-scoped flooding MAY be used.
4. OSPFv3 Extended Prefix Range TLV
In some cases it is useful to advertise attributes for a range of
prefixes. The Segment Routing Mapping Server, which is described in
[I-D.ietf-spring-segment-routing-ldp-interop], is an example where we
need a single advertisement to advertise SIDs for multiple prefixes
from a contiguous address range.
The OSPFv3 Extended Prefix Range TLV, is defined for this purpose.
The OSPFv3 Extended Prefix Range TLV is a top level TLV of the
following LSAs defined in [I-D.ietf-ospf-ospfv3-lsa-extend]:
E-Intra-Area-Prefix-LSA
E-Inter-Area-Prefix-LSA
E-AS-External-LSA
E-Type-7-LSA
Multiple OSPFv3 Extended Prefix Range TLVs MAY be advertised in each
LSA mentioned above. The OSPFv3 Extended Prefix Range TLV has the
following format:
Psenak, et al. Expires July 30, 2018 [Page 11]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | AF | Range Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Prefix (variable) |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
where:
Type: 9
Length: Variable, in octets, dependent on Sub-TLVs.
Prefix length: Length of prefix in bits.
AF: Address family for the prefix.
AF: 0 - IPv4 unicast
AF: 1 - IPv6 unicast
Range size: Represents the number of prefixes that are covered by
the advertisement. The Range Size MUST NOT exceed the number of
prefixes that could be satisfied by the prefix length without
including:
IPv4 multicast address range (224.0.0.0/3), if the AF is IPv4
unicast
addresses from other than the IPv6 unicast address class, if
the AF is IPv6 unicast
Flags: Single octet field. The following flags are defined:
Psenak, et al. Expires July 30, 2018 [Page 12]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+
|IA| | | | | | | |
+--+--+--+--+--+--+--+--+
where:
IA-Flag: Inter-Area flag. If set, advertisement is of inter-
area type. An ABR that is advertising the OSPFv3 Extended
Prefix Range TLV between areas MUST set this bit.
This bit is used to prevent redundant flooding of Prefix Range
TLVs between areas as follows:
An ABR only propagates an inter-area Prefix Range
advertisement from the backbone area to connected non-
backbone areas if the advertisement is considered to be the
best one. The following rules are used to select the best
range from the set of advertisements for the same Prefix
Range:
An ABR always prefers intra-area Prefix Range
advertisements over inter-area advertisements.
An ABR does not consider inter-area Prefix Range
advertisements coming from non-backbone areas.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Address Prefix:
For the address family IPv4 unicast, the prefix itself is
encoded as a 32-bit value. The default route is represented by
a prefix of length 0.
For the address family IPv6 unicast, 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.
Prefix encoding for other address families is beyond the scope
of this specification.
Psenak, et al. Expires July 30, 2018 [Page 13]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
5. 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] and in Section 4:
Intra-Area Prefix TLV
Inter-Area Prefix TLV
External Prefix TLV
OSPFv3 Extended Prefix Range TLV
It MAY appear more than once in the parent TLV and has the 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 | Algorithm | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: 4
Length: 7 or 8 octets, dependent on the V-flag
Flags: Single octet field. The following flags are defined:
0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+
| |NP|M |E |V |L | | |
+--+--+--+--+--+--+--+--+
where:
NP-Flag: No-PHP flag. If set, then the penultimate hop MUST
NOT pop the Prefix-SID before delivering packets to the node
that advertised the Prefix-SID.
M-Flag: Mapping Server Flag. If set, the SID was advertised by
a Segment Routing Mapping Server as described in
[I-D.ietf-spring-segment-routing-ldp-interop].
Psenak, et al. Expires July 30, 2018 [Page 14]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
E-Flag: Explicit-Null Flag. If set, any upstream neighbor of
the Prefix-SID originator MUST replace the Prefix-SID with the
Explicit-NULL label (0 for IPv4, 2 for IPv6) before forwarding
the packet.
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.
L-Flag: Local/Global Flag. If set, then the value/index
carried by the Prefix-SID has local significance. If not set,
then the value/index carried by this Sub-TLV has global
significance.
Other bits: Reserved. These MUST be zero when sent and are
ignored when received.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Algorithm: Single octet identifying the algorithm the Prefix-SID
is associated with as defined in Section 3.1.
A router receiving a Prefix-SID from a remote node and with an
algorithm value that such remote node has not advertised in the
SR-Algorithm Sub-TLV (Section 3.1) MUST ignore the Prefix-SID Sub-
TLV.
SID/Index/Label: According to the V and L flags, it contains
either:
A 32-bit index defining the offset in the SID/Label space
advertised by this router.
A 24-bit label where the 20 rightmost bits are used for
encoding the label value.
If an OSPFv3 router advertises multiple Prefix-SIDs for the same
prefix, topology and algorithm, all of them MUST be ignored.
When calculating the outgoing label for the prefix, the router MUST
take into account, as described below, the E, NP and M flags
advertised by the next-hop router if that router advertised the SID
for the prefix. This MUST be done regardless of whether the next-hop
router contributes to the best path to the prefix.
The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for
Prefix-SIDs allocated to inter-area prefixes that are originated by
Psenak, et al. Expires July 30, 2018 [Page 15]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
the ABR based on intra-area or inter-area reachability between areas,
unless the advertised prefix is directly attached to the ABR.
The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for
Prefix-SIDs allocated to redistributed prefixes, unless the
redistributed prefix is directly attached to the ASBR.
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
penultimate hop popping mechanism used in the MPLS dataplane. If the
NP-flag is not set, then the received E-flag is ignored.
If the NP-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 need
to stitch the incoming packet into a continuing MPLS LSP to the
final destination. This could occur at an Area Border Router
(prefix propagation from one area to another) or at an AS Boundary
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 Prefix-SID with an Explicit-NULL
label. 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 the M-Flag is set, the NP-flag and the E-flag MUST be ignored at
reception.
As the Mapping Server does not specify the originator of a prefix
advertisement, it is not possible to determine PHP behavior solely
based on the Mapping Server advertisement. However, PHP behavior
SHOULD be done in following cases:
The Prefix is intra-area type and the downstream neighbor is the
originator of the prefix.
The Prefix is inter-area type and downstream neighbor is an ABR,
which is advertising prefix reachability and is setting LA-bit in
the Prefix Options as described in
[I-D.ietf-ospf-ospfv3-lsa-extend].
The Prefix is external type and downstream neighbor is an ASBR,
which is advertising prefix reachability and is setting LA-bit in
Psenak, et al. Expires July 30, 2018 [Page 16]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
the Prefix Options as described in
[I-D.ietf-ospf-ospfv3-lsa-extend].
When a Prefix-SID is advertised in the OSPFv3 Extended Prefix Range
TLV, then the value advertised in the Prefix SID Sub-TLV is
interpreted as a starting SID/Label value.
Example 1: If the following router addresses (loopback addresses)
need to be mapped into the corresponding Prefix SID indexes:
Router-A: 2001:DB8::1/128, Prefix-SID: Index 1
Router-B: 2001:DB8::2/128, Prefix-SID: Index 2
Router-C: 2001:DB8::3/128, Prefix-SID: Index 3
Router-D: 2001:DB8::4/128, Prefix-SID: Index 4
then the Address Prefix field in the OSPFv3 Extended Prefix Range TLV
would be set to 2001:DB8::1, Prefix Length would be set to 128, Range
Size would be 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
corresponding Prefix-SID indexes:
2001:DB8:1::0/120, Prefix-SID: Index 51
2001:DB8:1::100/120, Prefix-SID: Index 52
2001:DB8:1::200/120, Prefix-SID: Index 53
2001:DB8:1::300/120, Prefix-SID: Index 54
2001:DB8:1::400/120, Prefix-SID: Index 55
2001:DB8:1::500/120, Prefix-SID: Index 56
2001:DB8:1::600/120, Prefix-SID: Index 57
then the Prefix field in the OSPFv3 Extended Prefix Range TLV would
be set to 2001:DB8:1::0, Prefix Length would be set to 120, Range
Size would be set to 7, and the Index value in the Prefix-SID Sub-TLV
would be set to 51.
6. Adjacency Segment Identifier (Adj-SID)
An Adjacency Segment Identifier (Adj-SID) represents a router
adjacency in Segment Routing.
6.1. Adj-SID Sub-TLV
Adj-SID 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
the Router-Link TLV. The Adj-SID Sub-TLV has the following format:
Psenak, et al. Expires July 30, 2018 [Page 17]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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: 5
Length: 7 or 8 octets, dependent on the V flag.
Flags: Single octet field containing the following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|V|L|G|P| |
+-+-+-+-+-+-+-+-+
where:
B-Flag: Backup Flag. If set, the Adj-SID refers to an
adjacency that is eligible for protection (e.g., using IPFRR or
MPLS-FRR) as described in section 3.5 of
[I-D.ietf-spring-segment-routing].
The V-Flag: Value/Index Flag. If set, then the Adj-SID carries
an absolute value. If not set, then the Adj-SID carries an
index.
The L-Flag: Local/Global Flag. If set, then the value/index
carried by the Adj-SID has local significance. If not set,
then the value/index carried by this Sub-TLV has global
significance.
The G-Flag: Group Flag. When set, the G-Flag indicates that
the Adj-SID refers to a group of adjacencies (and therefore MAY
be assigned to other adjacencies as well).
P-Flag. Persistent flag. When set, the P-Flag indicates that
the Adj-SID is persistently allocated, i.e., the Adj-SID value
remains consistent across router restart and/or interface flap.
Psenak, et al. Expires July 30, 2018 [Page 18]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
Other bits: Reserved. These MUST be zero when sent and are
ignored when received.
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Weight: Weight used for load-balancing purposes. The use of the
weight is defined in [I-D.ietf-spring-segment-routing].
SID/Index/Label: According to the V and L flags, it contains
either:
A 32-bit index defining the offset in the SID/Label space
advertised by this router.
A 24-bit label where the 20 rightmost bits are used for
encoding the label value.
An SR capable router MAY allocate an Adj-SID for each of its
adjacencies and set the B-Flag when the adjacency is eligible for
protection by an FRR mechanism (IP or MPLS) as described in
[I-D.ietf-spring-segment-routing].
An SR capable router MAY allocate more than one Adj-SID to an
adjacency
An SR capable router MAY allocate the same Adj-SID to different
adjacencies
When the P-flag is not set, the Adj-SID MAY be persistent. When the
P-flag is set, the Adj-SID MUST be persistent.
6.2. LAN Adj-SID Sub-TLV
LAN Adj-SID is an optional Sub-TLV of the Router-Link TLV. It MAY
appear multiple times in the Router-Link TLV. It is used to
advertise a SID/Label for an adjacency to a non-DR router on a
broadcast, NBMA, or hybrid [RFC6845] network.
Psenak, et al. Expires July 30, 2018 [Page 19]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
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: 6
Length: 11 or 12 octets, dependent on V-flag.
Flags: same as in Section 6.1
Weight: Weight used for load-balancing purposes. The use of the
weight is defined in [I-D.ietf-spring-segment-routing].
Reserved: SHOULD be set to 0 on transmission and MUST be ignored
on reception.
Neighbor ID: The Router ID of the neighbor for which the LAN-Adj-
SID is advertised.
SID/Index/Label: According to the V and L flags, it contains
either:
A 32-bit index defining the offset in the SID/Label space
advertised by this router.
A 24-bit label where the 20 rightmost bits are used for
encoding the label value.
When the P-flag is not set, the Adj-SID MAY be persistent. When
the P-flag is set, the Adj-SID MUST be persistent.
7. Elements of Procedure
7.1. Intra-area Segment routing in OSPFv3
An OSPFv3 router that supports segment routing MAY advertise Prefix-
SIDs for any prefix to which it is advertising reachability (e.g., a
loopback IP address as described in Section 5).
Psenak, et al. Expires July 30, 2018 [Page 20]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
A Prefix-SID can also be advertised by the SR Mapping Servers (as
described in [I-D.ietf-spring-segment-routing-ldp-interop]). A
Mapping Server advertises Prefix-SIDs for remote prefixes that exist
in the OSPFv3 routing domain. Multiple Mapping Servers can advertise
Prefix-SIDs for the same prefix, in which case the same Prefix-SID
MUST be advertised by all of them. The 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, the SR
Mapping Server chooses the OSPFv3 LSA type 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.
When a Prefix-SID is advertised by the Mapping Server, which is
indicated by the M-flag in the Prefix-SID Sub-TLV (Section 5), the
route type as implied by the LSA type is ignored and the Prefix-SID
is bound to the corresponding prefix independent of the route type.
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. The 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 the advertisement to contribute to the
prefix reachability.
An SR Mapping Server MUST use the OSPFv3 Extended Prefix Range TLVs
when advertising SIDs for prefixes. Prefixes of different route-
types can be combined in a single OSPFv3 Extended Prefix Range TLV
advertised by an SR Mapping Server.
Area-scoped OSPFv3 Extended Prefix Range TLVs are propagated between
areas. Similar to propagation of prefixes between areas, an ABR only
propagates the OSPFv3 Extended Prefix Range TLV that it considers to
be the best from the set it received. The rules used to pick the
best OSPFv3 Extended Prefix Range TLV are described in Section 4.
When propagating an OSPFv3 Extended Prefix Range TLV between areas,
ABRs MUST set the IA-Flag, that is used to prevent redundant flooding
of the OSPFv3 Extended Prefix Range TLV between areas as described in
Section 4.
Psenak, et al. Expires July 30, 2018 [Page 21]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
7.2. 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 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 5. 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 the advertising router associated with the best path
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
by the router that contributes to the best path to the prefix, the
originating ABR will use the Prefix-SID advertised by any other
router when propagating the 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 5. The Prefix-SID value
will be set as follows:
The ABR will look at its best path to the prefix in the backbone
area and find the advertising router associated with the best path
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 backbone
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 when propagating the Prefix-SID for the prefix to
other areas.
Psenak, et al. Expires July 30, 2018 [Page 22]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
7.3. Segment Routing for External Prefixes
AS-External-LSAs are flooded domain wide. When an ASBR, which
supports SR, generates E-AS-External-LSA, it SHOULD also include
Prefix-SID Sub-TLV, as described in Section 5. The Prefix-SID value
will be set to the SID that has been reserved for that prefix.
When an NSSA [RFC3101] ABR translates an E-NSSA-LSA into an E-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 E-NSSA-LSA and finds the advertising router associated
with that path. If the advertising router has advertised a Prefix-
SID for the prefix, then the NSSA ABR uses it when advertising the
Prefix-SID for the E-AS-External-LSA. Otherwise, the Prefix-SID
advertised by any other router will be used.
7.4. Advertisement of Adj-SID
The Adjacency Segment Routing Identifier (Adj-SID) is advertised
using the Adj-SID Sub-TLV as described in Section 6.
7.4.1. Advertisement of Adj-SID on Point-to-Point Links
An Adj-SID MAY be advertised for any adjacency on a P2P link that is
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
MAY be removed from the area. If the adjacency transitions to a
state lower then 2-Way, then the Adj-SID advertisement MUST be
withdrawn from the area.
7.4.2. Adjacency SID on Broadcast or NBMA Interfaces
Broadcast, NBMA, or hybrid [RFC6845] networks in OSPFv3 are
represented by a star topology where the Designated Router (DR) is
the central point to which all other routers on the broadcast, NBMA,
or hybrid network connect. As a result, routers on the broadcast,
NBMA, or hybrid network advertise only their adjacency to the DR.
Routers that do not act as DR do not form or advertise adjacencies
with each other. They do, however, maintain 2-Way adjacency state
with each other and are directly reachable.
When Segment Routing is used, each router on the broadcast, NBMA, or
hybrid network MAY advertise the Adj-SID for its adjacency to the DR
using the Adj-SID Sub-TLV as described in Section 6.1.
SR capable routers MAY also advertise a LAN-Adj-SID for other
neighbors (e.g., BDR, DR-OTHER) on the broadcast, NBMA, or hybrid
network using the LAN-Adj-SID Sub-TLV as described in Section 6.2.
Psenak, et al. Expires July 30, 2018 [Page 23]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
8. IANA Considerations
This specification updates several existing OSPFv3 registries.
8.1. OSPFv3 Extend-LSA TLV Registry
Following values are allocated:
o suggested value 9 - OSPFv3 Extended Prefix Range TLV
8.2. OSPFv3 Extend-LSA Sub-TLV registry
o 4 - Prefix SID Sub-TLV
o 5 - Adj-SID Sub-TLV
o 6 - LAN Adj-SID Sub-TLV
o 7 - SID/Label Sub-TLV
9. Security Considerations
With the OSPFv3 segment routing extensions defined herein, OSPFv3
will now program the MPLS data plane [RFC3031] in addition to the IP
data plane. Previously, LDP [RFC5036] or another label distribution
mechanism was required to advertise MPLS labels and program the MPLS
data plane.
In general, the same types of attacks that can be carried out on the
IP control plane can be carried out on the MPLS control plane
resulting in traffic being misrouted in the respective data planes.
However, the latter can be more difficult to detect and isolate.
Existing security extensions as described in [RFC5340] and
[I-D.ietf-ospf-ospfv3-lsa-extend] apply to these segment routing
extensions. While OSPFv3 is under a single administrative domain,
there can be deployments where potential attackers have access to one
or more networks in the OSPFv3 routing domain. In these deployments,
stronger authentication mechanisms such as those specified in
[RFC4552] SHOULD be used.
Implementations MUST assure that malformed TLV and Sub-TLV defined in
this document are detected and do not provide a vulnerability for
attackers to crash the OSPFv3 router or routing process. Reception
of malformed TLV or Sub-TLV SHOULD be counted and/or logged for
further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be
rate-limited to prevent a Denial of Service (DoS) attack (distributed
or otherwise) from overloading the OSPFv3 control plane.
Psenak, et al. Expires July 30, 2018 [Page 24]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
10. Contributors
Acee Lindem gave a substantial contribution to the content of this
document.
11. Acknowledgements
We would like to thank Anton Smirnov for his contribution.
12. References
12.1. Normative References
[I-D.ietf-ospf-ospfv3-lsa-extend]
Lindem, A., Roy, A., Goethals, D., Vallem, V., and F.
Baker, "OSPFv3 LSA Extendibility", draft-ietf-ospf-ospfv3-
lsa-extend-23 (work in progress), January 2018.
[I-D.ietf-spring-conflict-resolution]
Ginsberg, L., Psenak, P., Previdi, S., and M. Pilka,
"Segment Routing MPLS Conflict Resolution", draft-ietf-
spring-conflict-resolution-05 (work in progress), July
2017.
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018.
[I-D.ietf-spring-segment-routing-ldp-interop]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., and
S. Litkowski, "Segment Routing interworking with LDP",
draft-ietf-spring-segment-routing-ldp-interop-09 (work in
progress), September 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
Psenak, et al. Expires July 30, 2018 [Page 25]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
[RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option",
RFC 3101, DOI 10.17487/RFC3101, January 2003,
<https://www.rfc-editor.org/info/rfc3101>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <https://www.rfc-editor.org/info/rfc5036>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC6845] Sheth, N., Wang, L., and J. Zhang, "OSPF Hybrid Broadcast
and Point-to-Multipoint Interface Type", RFC 6845,
DOI 10.17487/RFC6845, January 2013,
<https://www.rfc-editor.org/info/rfc6845>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
12.2. Informative References
[I-D.ietf-spring-segment-routing-mpls]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-11
(work in progress), October 2017.
[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
<https://www.rfc-editor.org/info/rfc4552>.
[RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
Litkowski, S., Horneffer, M., and R. Shakir, "Source
Packet Routing in Networking (SPRING) Problem Statement
and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
2016, <https://www.rfc-editor.org/info/rfc7855>.
Psenak, et al. Expires July 30, 2018 [Page 26]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
Authors' Addresses
Peter Psenak (editor)
Cisco Systems, Inc.
Eurovea Centre, Central 3
Pribinova Street 10
Bratislava 81109
Slovakia
Email: ppsenak@cisco.com
Clarence Filsfils
Cisco Systems, Inc.
Brussels
Belgium
Email: cfilsfil@cisco.com
Stefano Previdi (editor)
Individual
Email: stefano.previdi@net
Hannes Gredler
RtBrick Inc.
Austria
Email: hannes@rtbrick.com
Rob Shakir
Google, Inc.
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: robjs@google.com
Psenak, et al. Expires July 30, 2018 [Page 27]
Internet-Draft OSPFv3 Extensions for Segment Routing January 2018
Wim Henderickx
Nokia
Copernicuslaan 50
Antwerp 2018
BE
Email: wim.henderickx@nokia.com
Jeff Tantsura
Nuage Networks
US
Email: jefftant.ietf@gmail.com
Psenak, et al. Expires July 30, 2018 [Page 28]
