draft-ietf-idr-bgp-prefix-sid-08.txt   draft-ietf-idr-bgp-prefix-sid-09.txt 
IDR S. Previdi, Ed. IDR S. Previdi, Ed.
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track A. Lindem Intended status: Standards Track A. Lindem
Expires: July 6, 2018 Cisco Systems Expires: July 9, 2018 Cisco Systems
A. Sreekantiah A. Sreekantiah
H. Gredler H. Gredler
RtBrick Inc. RtBrick Inc.
January 2, 2018 January 5, 2018
Segment Routing Prefix SID extensions for BGP Segment Routing Prefix SID extensions for BGP
draft-ietf-idr-bgp-prefix-sid-08 draft-ietf-idr-bgp-prefix-sid-09
Abstract Abstract
Segment Routing (SR) architecture allows a node to steer a packet Segment Routing (SR) architecture allows a node to steer a packet
flow through any topological path and service chain by leveraging flow through any topological path and service chain by leveraging
source routing. The ingress node prepends a SR header to a packet source routing. The ingress node prepends an SR header to a packet
containing a set of segment identifiers (SID). Each SID represents a containing a set of segment identifiers (SID). Each SID represents a
topological or a service-based instruction. Per-flow state is topological or a service-based instruction. Per-flow state is
maintained only on the ingress node of the SR domain. maintained only on the ingress node of the SR domain.
This document defines an optional, transitive BGP attribute for This document defines an optional, transitive BGP attribute for
announcing BGP Prefix Segment Identifiers (BGP Prefix-SID) announcing BGP Prefix Segment Identifiers (BGP Prefix-SID)
information. information.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 2119 [RFC2119] "OPTIONAL" in this document are to be interpreted as described in BCP
only when they appear in all upper case. They may also appear in 14 [RFC2119] [RFC8174] when, and only when, they appear in all
lower or mixed case as English words, without any normative meaning. capitals, as shown here.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 6, 2018. This Internet-Draft will expire on July 9, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 30 skipping to change at page 2, line 30
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. BGP-Prefix-SID . . . . . . . . . . . . . . . . . . . . . . . 4 2. BGP-Prefix-SID . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. MPLS BGP Prefix SID . . . . . . . . . . . . . . . . . . . 4 2.1. MPLS BGP Prefix SID . . . . . . . . . . . . . . . . . . . 4
2.2. IPv6 Prefix Segment . . . . . . . . . . . . . . . . . . . 5 2.2. IPv6 Prefix Segment . . . . . . . . . . . . . . . . . . . 5
3. BGP-Prefix-SID Attribute . . . . . . . . . . . . . . . . . . 5 3. BGP Prefix-SID Attribute . . . . . . . . . . . . . . . . . . 5
3.1. Label-Index TLV . . . . . . . . . . . . . . . . . . . . . 6 3.1. Label-Index TLV . . . . . . . . . . . . . . . . . . . . . 6
3.2. IPv6 SID . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. IPv6 SID . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Originator SRGB TLV . . . . . . . . . . . . . . . . . . . 7 3.3. Originator SRGB TLV . . . . . . . . . . . . . . . . . . . 7
4. Receiving BGP-Prefix-SID Attribute . . . . . . . . . . . . . 9 4. Receiving BGP Prefix-SID Attribute . . . . . . . . . . . . . 9
4.1. MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . . 9 4.1. MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . . 9
4.2. IPv6 Dataplane . . . . . . . . . . . . . . . . . . . . . 10 4.2. IPv6 Dataplane . . . . . . . . . . . . . . . . . . . . . 10
5. Announcing BGP-Prefix-SID Attribute . . . . . . . . . . . . . 10 5. Advertising BGP Prefix-SID Attribute . . . . . . . . . . . . 10
5.1. MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . . 10 5.1. MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . . 11
5.2. IPv6 Dataplane . . . . . . . . . . . . . . . . . . . . . 11 5.2. IPv6 Dataplane . . . . . . . . . . . . . . . . . . . . . 11
6. Error Handling of BGP-Prefix-SID Attribute . . . . . . . . . 11 6. Error Handling of BGP Prefix-SID Attribute . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Manageability Considerations . . . . . . . . . . . . . . . . 12 8. Manageability Considerations . . . . . . . . . . . . . . . . 12
9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.1. Normative References . . . . . . . . . . . . . . . . . . 14 12.1. Normative References . . . . . . . . . . . . . . . . . . 14
12.2. Informative References . . . . . . . . . . . . . . . . . 14 12.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
Segment Routing (SR) architecture leverages the source routing Segment Routing (SR) architecture leverages the source routing
paradigm. A group of inter-connected nodes that use SR forms a SR paradigm. A group of inter-connected nodes that use SR forms an SR
domain. A segment represents either a topological instruction such domain. A segment represents either a topological instruction such
as "go to prefix P following shortest path" or a service instruction as "go to prefix P following shortest path" or a service instruction
(e.g.: "pass through deep packet inspection"). Other types of (e.g.: "pass through deep packet inspection"). Other types of
segments may be defined in the future. segments may be defined in the future.
A segment is identified through a Segment Identifier (SID). A segment is identified through a Segment Identifier (SID).
Typically, the ingress node of the SR domain prepends a SR header Typically, the ingress node of the SR domain prepends an SR header
containing segments identifiers (SIDs) to an incoming packet. containing segments identifiers (SIDs) to an incoming packet.
As described in [I-D.ietf-spring-segment-routing], when SR is applied As described in [I-D.ietf-spring-segment-routing], when SR is applied
to the MPLS dataplane ([I-D.ietf-spring-segment-routing-mpls]) the to the MPLS dataplane ([I-D.ietf-spring-segment-routing-mpls]) the
SID consists of a label while when SR is applied to the IPv6 SID consists of a label while when SR is applied to the IPv6
dataplane the SID consists of an IPv6 address. dataplane the SID consists of an IPv6 address.
A BGP-Prefix Segment (and its BGP Prefix-SID), is a BGP segment A BGP-Prefix Segment (and its BGP Prefix-SID), is a BGP segment
attached to a BGP prefix. A BGP Prefix-SID is always a global SID attached to a BGP prefix. A BGP Prefix-SID is always a global SID
([I-D.ietf-spring-segment-routing]) within the SR/BGP domain (i.e., ([I-D.ietf-spring-segment-routing]) within the SR/BGP domain (i.e.,
skipping to change at page 3, line 39 skipping to change at page 3, line 39
the related prefix. The BGP Prefix-SID is the identifier of the BGP the related prefix. The BGP Prefix-SID is the identifier of the BGP
prefix segment. In this document, we always refer to the BGP Segment prefix segment. In this document, we always refer to the BGP Segment
by the BGP Prefix-SID. by the BGP Prefix-SID.
This document describes the BGP extension to signal the BGP Prefix- This document describes the BGP extension to signal the BGP Prefix-
SID. Specifically, this document defines a BGP attribute known as SID. Specifically, this document defines a BGP attribute known as
the BGP Prefix-SID attribute and specifies the rules to originate, the BGP Prefix-SID attribute and specifies the rules to originate,
receive, and handle error conditions for the attribute. receive, and handle error conditions for the attribute.
The BGP Prefix-SID attribute defined in this document can be attached The BGP Prefix-SID attribute defined in this document can be attached
to prefixes from AFI/SAFI: to prefixes from AFI/SAFI combinations:
Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]). Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]).
Multiprotocol BGP ([RFC4760]) unlabeled IPv6 Unicast. Multiprotocol BGP ([RFC4760]) unlabeled IPv6 Unicast.
[I-D.ietf-spring-segment-routing-msdc] describes example use cases [I-D.ietf-spring-segment-routing-msdc] describes example use cases
where the Prefix-SID is used for the above AFI/SAFI. where the BGP Prefix-SID is used for the above AFI/SAFI combinations.
It should be noted that: It should be noted that:
o A BGP Prefix-SID MAY be global between domains when the o A BGP Prefix-SID MAY be global between domains when the
interconnected domains agree on the SID allocation scheme. interconnected domains agree on the SID allocation scheme.
Alternatively, when interconnecting domains, the ASBRs of each Alternatively, when interconnecting domains, the ASBRs of each
domain will have to handle the advertisement of unique SIDs. The domain will have to handle the advertisement of unique SIDs. The
mechanisms for such interconnection are outside the scope of the mechanisms for such interconnection are outside the scope of the
protocol extensions defined in this document. protocol extensions defined in this document.
skipping to change at page 4, line 25 skipping to change at page 4, line 25
The BGP Prefix-SID attached to a BGP prefix P represents the The BGP Prefix-SID attached to a BGP prefix P represents the
instruction "go to Prefix P" along its BGP best path (potentially instruction "go to Prefix P" along its BGP best path (potentially
ECMP-enabled). ECMP-enabled).
2.1. MPLS BGP Prefix SID 2.1. MPLS BGP Prefix SID
The BGP Prefix-SID is realized on the MPLS dataplane The BGP Prefix-SID is realized on the MPLS dataplane
([I-D.ietf-spring-segment-routing-mpls]) in the following way: ([I-D.ietf-spring-segment-routing-mpls]) in the following way:
The operator assigns a globally unique "index", L_I, to a locally The operator assigns a globally unique label index, L_I, to a
sourced prefix of a BGP speaker N which is advertised to all other locally sourced prefix of a BGP speaker N which is advertised to
BGP speakers in the SR domain. all other BGP speakers in the SR domain.
According to [I-D.ietf-spring-segment-routing], each BGP speaker According to [I-D.ietf-spring-segment-routing], each BGP speaker
is configured with a label block called the Segment Routing Global is configured with a label block called the Segment Routing Global
Block (SRGB). While [I-D.ietf-spring-segment-routing] recommends Block (SRGB). While [I-D.ietf-spring-segment-routing] recommends
to use the same SRGB across all the nodes within the SR domain, to use the same SRGB across all the nodes within the SR domain,
the SRGB of a node is a local property and could be different on the SRGB of a node is a local property and could be different on
different speakers. The drawbacks of the use case where BGP different speakers. The drawbacks of the use case where BGP
speakers have different SRGBs are documented in speakers have different SRGBs are documented in
[I-D.ietf-spring-segment-routing] and [I-D.ietf-spring-segment-routing] and
[I-D.ietf-spring-segment-routing-msdc]. [I-D.ietf-spring-segment-routing-msdc].
If traffic-engineering within the SR domain is required, each node If traffic-engineering within the SR domain is required, each node
may also be required to advertise topological information and may also be required to advertise topological information and
Peering SID's for each of its links and peers. This information Peering SIDs for each of its links and peers. This information is
is required to perform the explicit path computation and to required to perform the explicit path computation and to express
express any explicit path into a list of SIDs. The advertisement an explicit path as a list of SIDs. The advertisement of
of topological information and Peer segments (Peer SIDs) is topological information and Peer segments (Peer SIDs) is done
assumed to be done through through [I-D.ietf-idr-bgpls-segment-routing-epe].
[I-D.ietf-idr-bgpls-segment-routing-epe].
If the BGP speakers are not all configured with the same SRGB, and If the BGP speakers are not all configured with the same SRGB, and
if traffic-engineering within the SR domain is required, each node if traffic-engineering within the SR domain is required, each node
may be required to advertise its local SRGB in addition to the may be required to advertise its local SRGB in addition to the
topological information. topological information.
This documents assumes that BGP-LS is the preferred method for This documents assumes that BGP-LS is the preferred method for
collecting both topological, peer segments (Peer SIDs) and SRGB collecting both peer segments (Peer SIDs) and SRGB information
information through [RFC7752], through [RFC7752], [I-D.ietf-idr-bgpls-segment-routing-epe], and
[I-D.ietf-idr-bgpls-segment-routing-epe] and
[I-D.ietf-idr-bgp-ls-segment-routing-ext]. However, as an [I-D.ietf-idr-bgp-ls-segment-routing-ext]. However, as an
optional alternative for the advertisement of the local SRGB optional alternative for the advertisement of the local SRGB
without the topology nor the peer SID's, hence without without the topology nor the peer SIDs, hence without
applicability for TE, the Originator SRGB TLV of the prefix-SID applicability for TE, the Originator SRGB TLV of the prefix-SID
attribute, is specified in Section 3.3 of this document. attribute is specified in Section 3.3 of this document.
As defined in [I-D.ietf-spring-segment-routing-mpls], the index As defined in [I-D.ietf-spring-segment-routing], the label index
L_I is an offset in the SRGB. Each BGP speaker derives its local L_I is an offset into the SRGB. Each BGP speaker derives its
MPLS label, L, by adding L_I to the start value of its own SRGB, local MPLS label, L, by adding L_I to the start value of its own
and programs L in its MPLS dataplane as its incoming/local label SRGB, and programs L in its MPLS dataplane as its incoming/local
for the prefix. It should be noted that while SRGBs and SIDs are label for the prefix. It should be noted that while SRGBs and
advertised using 32-bit values, the derived label is to be SIDs are advertised using 32-bit values, the derived label is
considered as the 20 right-most bits. See Section 4.1 for more advertised in the 20 right-most bits. See Section 4.1 for more
details. details.
The outgoing label for the prefix is found in the NLRI of the The outgoing label for the prefix is found in the NLRI of the
Multiprotocol BGP labeled IPv4/IPv6 Unicast prefix advertisement. Multiprotocol BGP labeled IPv4/IPv6 Unicast prefix advertisement.
The index L_I is only used as a hint to derive the local/incoming The label index L_I is only used as a hint to derive the local/
label. incoming label.
Section 3.1 of this document specifies the Label-Index TLV of the Section 3.1 of this document specifies the Label-Index TLV of the
BGP Prefix-SID attribute; this TLV can be used to advertise the BGP Prefix-SID attribute; this TLV can be used to advertise the
label index of a given prefix. label index for a given prefix.
In order to advertise the label index of a given prefix P and, In order to advertise the label index of a given prefix P and,
optionally, the SRGB, an extension to BGP is needed: the BGP Prefix- optionally, the SRGB, an extension to BGP is needed: the BGP Prefix-
SID attribute. This extension is described in subsequent sections. SID attribute. This extension is described in subsequent sections.
2.2. IPv6 Prefix Segment 2.2. IPv6 Prefix Segment
When SR is used over an IPv6 dataplane, the BGP Prefix-SID consists When SR is used over an IPv6 dataplane, the BGP Prefix-SID consists
of an IPv6 address assigned to the BGP speaker. of an IPv6 address assigned to the BGP speaker.
3. BGP-Prefix-SID Attribute 3. BGP Prefix-SID Attribute
The BGP Prefix-SID attribute is an optional, transitive BGP path The BGP Prefix-SID attribute is an optional, transitive BGP path
attribute. The attribute type code 40 has been assigned by IANA (see attribute. The attribute type code 40 has been assigned by IANA (see
Section 7). Section 7).
The BGP Prefix-SID attribute is defined here to be a set of elements The BGP Prefix-SID attribute is defined here to be a set of elements
encoded as "Type/Length/Value" (i.e., a set of TLVs). The following encoded as "Type/Length/Value" tuples (i.e., a set of TLVs). The
TLVs are defined: following TLVs are defined:
o Label-Index TLV o Label-Index TLV
o IPv6 SID TLV o IPv6 SID TLV
o Originator SRGB TLV o Originator SRGB TLV
Label-Index and Originator SRGB TLVs are used only when SR is applied The Label-Index and Originator SRGB TLVs are used only when SR is
to the MPLS dataplane. applied to the MPLS dataplane.
IPv6 SID TLV is used only when SR is applied to the IPv6 dataplane. The IPv6 SID TLV is used only when SR is applied to the IPv6
dataplane.
3.1. Label-Index TLV 3.1. Label-Index TLV
The Label-Index TLV MUST be present in the Prefix-SID attribute The Label-Index TLV MUST be present in the BGP Prefix-SID attribute
attached to Labeled IPv4/IPv6 unicast prefixes ([RFC8277]) and has attached to Labeled IPv4/IPv6 unicast prefixes ([RFC8277]). It will
the following format: be ignored when received for other BGP AFI/SAFI combinations. The
Label-Index TLV has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | RESERVED | | Type | Length | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Label Index | | Flags | Label Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Index | | Label Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
o Type is 1. o Type is 1.
o Length: is 7, the total length of the value portion of the TLV. o Length: is 7, the total length in octets of the value portion of
the TLV.
o RESERVED: 8-bit field. MUST be clear on transmission and MUST be o RESERVED: 8-bit field. MUST be clear on transmission and MUST be
ignored on reception. ignored on reception.
o Flags: 16 bits of flags. None are defined by this document. The o Flags: 16 bits of flags. None are defined by this document. The
flag field MUST be clear on transmission and MUST be ignored on flag field MUST be clear on transmission and MUST be ignored on
reception. reception.
o Label Index: 32-bit value representing the index value in the SRGB o Label Index: 32-bit value representing the index value in the SRGB
space. space.
3.2. IPv6 SID 3.2. IPv6 SID
The IPv6-SID TLV MAY be present in the Prefix-SID attribute attached The IPv6 SID TLV MAY be present in the BGP Prefix-SID attribute
to MP-BGP unlabeled IPv6 unicast prefixes ([RFC4760]) and has the attached to MP-BGP unlabeled IPv6 unicast prefixes ([RFC4760]). It
following format: will be ignored for other BGP AFI/SAFI combinations. The IPv6 SID
TLV has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | RESERVED | | Type | Length | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | | | RESERVED | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| IPv6 SID (16 octets) | | IPv6 SID (16 octets) |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
o Type is 2. o Type is 2.
o Length: is 19, the total length of the value portion of the TLV. o Length: is 19, the total length in octets of the value portion of
the TLV.
o RESERVED: 24-bit field for future use. MUST be clear on o RESERVED: 24-bit field for future use. MUST be clear on
transmission and MUST be ignored on reception. transmission and MUST be ignored on reception.
o IPv6 SID: 16 octets. o IPv6 SID: 16 octets.
3.3. Originator SRGB TLV 3.3. Originator SRGB TLV
The Originator SRGB TLV is an optional TLV and has the following The Originator SRGB TLV is an optional TLV and has the following
format: format:
skipping to change at page 8, line 29 skipping to change at page 8, line 29
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRGB n (6 octets) | | SRGB n (6 octets) |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
o Type is 3. o Type is 3.
o Length is the total length of the value portion of the TLV: 2 + o Length is the total length in octets of the value portion of the
multiple of 6. TLV: 2 + multiple of 6.
o Flags: 16 bits of flags. None are defined in this document. o Flags: 16 bits of flags. None are defined in this document.
Flags MUST be clear on transmission and MUST be ignored on Flags MUST be clear on transmission and MUST be ignored on
reception. reception.
o SRGB: 3 octets of base followed by 3 octets of range. Note that o SRGB: 3 octets of base followed by 3 octets of range. Note that
the SRGB field MAY appear multiple times. If the SRGB field the SRGB field MAY appear multiple times. If the SRGB field
appears multiple times, the SRGB consists of multiple ranges. appears multiple times, the SRGB consists of multiple ranges.
The Originator SRGB TLV contains the SRGB of the node originating the The Originator SRGB TLV contains the SRGB of the node originating the
prefix to which the BGP Prefix-SID is attached. The Originator SRGB prefix to which the BGP Prefix-SID is attached. The Originator SRGB
TLV MUST NOT be changed during the propagation of the BGP update. TLV MUST NOT be changed during the propagation of the BGP update.
The originator SRGB describes the SRGB of the node where the BGP The originator SRGB describes the SRGB of the node where the BGP
Prefix SID is attached. It is used to build segment routing policies Prefix SID is attached. It is used to build segment routing policies
when different SRGBs are used in the fabric, for example when different SRGBs are used in the fabric, for example
([I-D.ietf-spring-segment-routing-msdc]). ([I-D.ietf-spring-segment-routing-msdc]).
The originator SRGB may only appear on Prefix-SID attribute attached The originator SRGB may only appear in a BGP Prefix-SID attribute
to prefixes of SAFI 4 (labeled unicast, [RFC8277]). attached to Labeled IPv4/IPv6 unicast prefixes ([RFC8277]). It will
be ignored when received for other BGP AFI/SAFI combinations.
4. Receiving BGP-Prefix-SID Attribute 4. Receiving BGP Prefix-SID Attribute
A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP
neighbor residing outside the boundaries of the SR domain, SHOULD neighbor residing outside the boundaries of the SR domain, MUST
discard the attribute unless it is configured to accept the attribute discard the attribute unless it is configured to accept the attribute
from the EBGP neighbor. A BGP speaker MAY log an error for further from the EBGP neighbor. A BGP speaker MAY log an error for further
analysis when discarding an attribute. analysis when discarding an attribute.
4.1. MPLS Dataplane: Labeled Unicast 4.1. MPLS Dataplane: Labeled Unicast
A Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]) session A Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]) session
type is required. type is required.
A BGP speaker MAY be locally configured with an SRGB=[SRGB_Start, A BGP speaker may be locally configured with an SRGB=[SRGB_Start,
SRGB_End]. The preferred method for deriving the SRGB is a matter of SRGB_End]. The preferred method for deriving the SRGB is a matter of
local node configuration. local node configuration.
Given a label_index L_I, we call L = L_I + SRGB_Start as the derived Given a label index L_I, we call L = L_I + SRGB_Start as the derived
label. A BGP Prefix-SID attribute is designated "unacceptable" for a label. A BGP Prefix-SID attribute is designated "unacceptable" for a
speaker M if the derived label value L lies outside the SRGB speaker M if the derived label value L lies outside the SRGB
configured on M. Otherwise the Label Index attribute is designated configured on M. Otherwise the Label-Index TLV is designated
"acceptable" to speaker M. "acceptable" to speaker M.
The mechanisms through which a given label_index value is assigned to The mechanisms through which a given label index value is assigned to
a given prefix are outside the scope of this document. The label- a given prefix are outside the scope of this document. The label-
index value associated with a prefix is locally configured at the BGP index value associated with a prefix is locally configured at the BGP
node originating the prefix. node originating the prefix.
The Prefix-SID attribute MUST contain the Label-Index TLV and MAY The BGP Prefix-SID attribute MUST contain the Label-Index TLV and MAY
contain the Originator SRGB TLV. A BGP Prefix-SID attribute received contain the Originator SRGB TLV. A BGP Prefix-SID attribute received
without a Label-Index TLV MUST be considered as "unacceptable" by the without a Label-Index TLV MUST be considered as "unacceptable" by the
receiving speaker. receiving speaker.
If multiple prefixes are received with the same label_index value, If multiple prefixes are received with the same label index value,
all these prefixes MUST have their BGP Prefix-SID attribute all these prefixes MUST have their BGP Prefix-SID attribute
considered as "unacceptable" by the receiving speaker. considered as "unacceptable" by the receiving speaker.
When a BGP speaker receives a path from a neighbor with an acceptable When a BGP speaker receives a path from a neighbor with an acceptable
BGP Prefix-SID attribute, it MUST program the derived label as the BGP Prefix-SID attribute, it MUST program the derived label as the
local label for the prefix in its MPLS dataplane. In case of any local label for the prefix in its MPLS dataplane. In case of an
error, a BGP speaker MUST follow to the error handling rules error, a BGP speaker MUST follow to the error handling rules
specified in Section 6. A BGP speaker MAY log an error for further specified in Section 6. A BGP speaker MAY log an error for further
analysis. analysis.
When a BGP speaker receives a path from a neighbor with an When a BGP speaker receives a path from a neighbor with an
unacceptable BGP Prefix-SID attribute or when a BGP speaker receives unacceptable BGP Prefix-SID attribute or when a BGP speaker receives
a path from a neighbor with a BGP Prefix-SID attribute but is unable a path from a neighbor with a BGP Prefix-SID attribute but is unable
to process it (it does not have the capability or local policy to process it (it does not have the capability or local policy
disables the capability), it MUST treat the path as if it came disables the capability), it MUST treat the path as if it came
without a Prefix-SID attribute. For the purposes of local label without a BGP Prefix-SID attribute. For the purposes of local label
allocation, a BGP speaker MUST assign a local (also called dynamic) allocation, a BGP speaker MUST assign a local (also called dynamic)
label (non-SRGB) for such a prefix as per classic Multiprotocol BGP label (non-SRGB) for such a prefix as per classic Multiprotocol BGP
labeled IPv4/IPv6 Unicast ([RFC8277]) operation. A BGP speaker MAY labeled IPv4/IPv6 Unicast ([RFC8277]) operation. A BGP speaker MAY
log an error for further analysis. log an error for further analysis.
The outgoing label is always programmed as per classic Multiprotocol The outgoing label is always programmed as per classic Multiprotocol
BGP labeled IPv4/IPv6 Unicast (RFC8277 [RFC8277]) operation. BGP labeled IPv4/IPv6 Unicast ([RFC8277]) operation.
Specifically, a BGP speaker receiving a prefix with a Prefix-SID Specifically, a BGP speaker receiving a prefix with a BGP Prefix-SID
attribute and a label NLRI field of implicit-null from a neighbor attribute and a label NLRI field of Implicit NULL from a neighbor
MUST adhere to standard behavior and program its MPLS dataplane to MUST adhere to standard behavior and program its MPLS dataplane to
pop the top label when forwarding traffic to the prefix. The label pop the top label when forwarding traffic to the prefix. The label
NLRI defines the outbound label that MUST be used by the receiving NLRI defines the outbound label that MUST be used by the receiving
node. The Label Index gives the information to the receiving node on node. The label index gives the information to the receiving node on
which local/incoming label the BGP speaker SHOULD use. which local/incoming label the BGP speaker SHOULD assign.
4.2. IPv6 Dataplane 4.2. IPv6 Dataplane
When an SR IPv6 BGP speaker receives a IPv6 Unicast BGP Update with a When an SR IPv6 BGP speaker receives an IPv6 Unicast BGP Update with
prefix having the BGP Prefix-SID attribute attached, it checks a prefix having the BGP Prefix-SID attribute attached, it checks
whether the IPv6 SID TLV is present. If present, then the receiver whether the IPv6 SID TLV is present. If present and the chosen as
assumes that the originator supports SR on the IPv6 dataplane. the best path, the prefix is installed into the Segment Routing IPv6
dataplane as described in [I-D.ietf-spring-segment-routing].
The Originator SRGB MUST be ignored on reception. The Originator SRGB MUST be ignored on reception.
A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP 5. Advertising BGP Prefix-SID Attribute
neighbor residing outside the boundaries of the SR domain, SHOULD
discard the attribute unless it is configured to accept the attribute
from the EBGP neighbor. A BGP speaker MAY log an error for further
analysis when discarding an attribute.
5. Announcing BGP-Prefix-SID Attribute
The BGP Prefix-SID attribute MAY be attached to labeled BGP prefixes The BGP Prefix-SID attribute MAY be attached to labeled BGP prefixes
(IPv4/IPv6) [RFC8277] or to IPv6 prefixes [RFC4760]. In order to (IPv4/IPv6) [RFC8277] or to IPv6 unicast prefixes [RFC4760]. In
prevent distribution of the BGP Prefix-SID attribute beyond its order to prevent distribution of the BGP Prefix-SID attribute beyond
intended scope of applicability, attribute filtering SHOULD be its intended scope of applicability, attribute filtering SHOULD be
deployed. deployed.
A BGP speaker that advertises a path received from one of its
neighbors SHOULD advertise the BGP Prefix-SID received with the path
without modification, as long as the BGP Prefix-SID was acceptable.
If the path did not come with a BGP Prefix-SID attribute, the speaker
MAY attach a BGP Prefix-SID to the path if configured to do so. The
content of the TLVs present in the BGP Prefix-SID is determined by
the configuration.
5.1. MPLS Dataplane: Labeled Unicast 5.1. MPLS Dataplane: Labeled Unicast
A BGP speaker that originates a prefix attaches the Prefix-SID A BGP speaker that originates a prefix attaches the BGP Prefix-SID
attribute when it advertises the prefix to its neighbors via attribute when it advertises the prefix to its neighbors via
Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]). The value Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]). The value
of the Label-Index in the Label-Index TLV is determined by of the label index in the Label-Index TLV is determined by
configuration. configuration.
A BGP speaker that originates a Prefix-SID attribute MAY optionally A BGP speaker that originates a BGP Prefix-SID attribute MAY
announce Originator SRGB TLV along with the mandatory Label-Index optionally announce the Originator SRGB TLV along with the mandatory
TLV. The content of the Originator SRGB TLV is determined by the Label-Index TLV. The content of the Originator SRGB TLV is
configuration. determined by configuration.
Since the Label-index value must be unique within an SR domain, by Since the label index value must be unique within an SR domain, by
default an implementation SHOULD NOT advertise the BGP Prefix-SID default an implementation SHOULD NOT advertise the BGP Prefix-SID
attribute outside an Autonomous System unless it is explicitly attribute outside an Autonomous System unless it is explicitly
configured to do so. configured to do so.
A BGP speaker that advertises a path received from one of its
neighbors SHOULD advertise the Prefix-SID received with the path
without modification, regardless of whether the Prefix-SID was
acceptable. If the path did not come with a Prefix-SID attribute,
the speaker MAY attach a Prefix-SID to the path if configured to do
so. The content of the TLVs present in the Prefix-SID is determined
by the configuration.
In all cases, the label field of the advertised NLRI ([RFC8277], In all cases, the label field of the advertised NLRI ([RFC8277],
[RFC4364]) MUST be set to the local/incoming label programmed in the [RFC4364]) MUST be set to the local/incoming label programmed in the
MPLS dataplane for the given advertised prefix. If the prefix is MPLS dataplane for the given advertised prefix. If the prefix is
associated with one of the BGP speaker's interfaces, this label is associated with one of the BGP speaker's interfaces, this is the
the usual MPLS label (such as the implicit or explicit NULL label). usual MPLS label (such as the Implicit or Explicit NULL label).
5.2. IPv6 Dataplane 5.2. IPv6 Dataplane
A BGP speaker that originates an IPv6 prefix with the Prefix-SID A BGP speaker that originates an IPv6 prefix with the BGP Prefix-SID
attribute, MAY include the IPv6 SID TLV. attribute MAY include the IPv6 SID TLV.
A BGP speaker that advertises a path received from one of its
neighbors SHOULD advertise the Prefix-SID received with the path
without modification, regardless of whether the Prefix-SID was
acceptable. If the path did not come with a Prefix-SID attribute,
the speaker MAY attach a Prefix-SID to the path if configured to do
so.
6. Error Handling of BGP-Prefix-SID Attribute 6. Error Handling of BGP Prefix-SID Attribute
When a BGP Speaker receives a BGP Update message containing a When a BGP Speaker receives a BGP Update message containing a
malformed BGP Prefix-SID attribute, it MUST ignore the received BGP malformed or unacceptable BGP Prefix-SID attribute attached to a
Prefix-SID attributes and not pass it to other BGP peers. This is Labeled IPv4/IPv6 unicast prefix [RFC8277], it MUST ignore the
equivalent to the "Attribute discard" action specified in [RFC7606]. received BGP Prefix-SID attributes and not advertise it to other BGP
When discarding an attribute, a BGP speaker MAY log an error for peers. This is equivalent to the "Attribute discard" action
further analysis. specified in [RFC7606]. When discarding an attribute, a BGP speaker
SHOULD log an error for further analysis.
If the BGP Prefix-SID attribute appears more than once in an BGP When a BGP Speaker receives a BGP Update message containing a
Update message, then, according to [RFC7606], all the occurrences of malformed or unacceptable BGP Prefix-SID attribute attached to an
the attribute other than the first one SHALL be discarded and the BGP unlabeled IPv6 unicast prefix [RFC4760], it MUST treat the
Update message SHALL continue to be processed. advertisement as a withdrawal. This is equivalent to the "Treat-as-
withdraw" action specified in [RFC7606]. This action is required
since simply ignoring the BGP Prefix-SID attribute would modify the
installed path and the "Attribute discard" option is not applicable
in this case [RFC7606]. When withdrawing the prefix, a BGP speaker
SHOULD log an error for further analysis.
When a BGP speaker receives an unacceptable Prefix-SID attribute, it Consistent with [RFC7606], only the first occurrence of the BGP
MAY log an error for further analysis. Prefix-SID attribute will be considered and subsequent occurrences
will be discarded.
7. IANA Considerations 7. IANA Considerations
This document defines a BGP path attribute known as the BGP Prefix- This document defines a BGP path attribute known as the BGP Prefix-
SID attribute. This document requests IANA to assign an attribute SID attribute. This document requests IANA to assign an attribute
code type (suggested value: 40) for BGP the Prefix-SID attribute from code type (suggested value: 40) the BGP Prefix-SID attribute from the
the BGP Path Attributes registry. BGP Path Attributes registry.
Currently, IANA temporarily assigned the following: Currently, IANA temporarily assigned the following:
40 BGP Prefix-SID (TEMPORARY - registered 2015-09-30, expires 40 BGP Prefix-SID (TEMPORARY - registered 2015-09-30, expires
2016-09-30) [draft-ietf-idr-bgp-prefix-sid] 2016-09-30) [draft-ietf-idr-bgp-prefix-sid]
This document defines 3 TLVs for BGP Prefix-SID attribute. These This document defines 3 TLVs for the BGP Prefix-SID attribute. These
TLVs need to be registered with IANA. We request IANA to create a TLVs need to be registered with IANA. We request IANA to create a
registry for BGP Prefix-SID Attribute TLVs as follows: registry for BGP Prefix-SID Attribute TLVs as follows:
Under "Border Gateway Protocol (BGP) Parameters" registry, "BGP Under "Border Gateway Protocol (BGP) Parameters" registry, "BGP
Prefix-SID attribute Types" Reference: draft-ietf-idr-bgp-prefix-sid Prefix-SID TLV Types" Reference: draft-ietf-idr-bgp-prefix-sid
Registration Procedure(s): Values 1-254 First Come, First Served, Registration Procedure(s): Values 1-254 First Come, First Served,
Value 0 and 255 reserved Value 0 and 255 reserved
Value Type Reference Value Type Reference
0 Reserved this document 0 Reserved this document
1 Label-Index this document 1 Label-Index this document
2 IPv6 SID this document 2 IPv6 SID this document
3 Originator SRGB this document 3 Originator SRGB this document
4-254 Unassigned 4-254 Unassigned
255 Reserved this document 255 Reserved this document
This document also creates a registry for the 16 bits of flags in the
Label-Index TLV. Initially, the registry will be empty. Flag bits
will be allocated First-Come, First Served consistent with the BGP-
SID TLV Types registry.
Finally, this document creates a registry for the 16 bits of flags in
the SRGB Originator TLV. Initially, the registry will be empty.
Flag bits will be allocated First-Come, First Served consistent with
the BGP-SID TLV Types registry.
8. Manageability Considerations 8. Manageability Considerations
This document defines a BGP attribute to address use cases such as This document defines a BGP attribute to address use cases such as
the one described in [I-D.ietf-spring-segment-routing-msdc]. It is the one described in [I-D.ietf-spring-segment-routing-msdc]. It is
assumed that the BGP Prefix-SID attribute advertisement is controlled assumed that advertisement of the BGP Prefix-SID attribute is
by the operator in order to: controlled by the operator in order to:
o Prevent undesired origination/advertisement of the BGP Prefix-SID o Prevent undesired origination/advertisement of the BGP Prefix-SID
attribute. By default, a BGP Prefix-SID attribute SHOULD NOT be attribute. By default, a BGP Prefix-SID attribute SHOULD NOT be
originated and attached to a prefix. The operator MUST be capable attached to a prefix and advertised. Hence, BGP Prefix-SID
of explicitly enabling BGP Prefix-SID origination. advertisement SHOULD require explicit enablement.
o Prevent any undesired propagation of the BGP Prefix-SID attribute. o Prevent any undesired propagation of the BGP Prefix-SID attribute.
By default, the BGP Prefix-SID is not advertised outside the By default, the BGP Prefix-SID is not advertised outside the
boundary of an AS. The propagation to other ASs MUST be boundary of a single SR/administrative domain which may include
one or more ASes. The propagation to other ASes MUST be
explicitly configured. explicitly configured.
The deployment model described in The deployment model described in
[I-D.ietf-spring-segment-routing-msdc] assumes multiple Autonomous [I-D.ietf-spring-segment-routing-msdc] assumes multiple Autonomous
Systems (AS) under a common administrative domain. For this use Systems (ASes) under a common administrative domain. For this use
case, the BGP Prefix-SID advertisement is applicable to the inter-AS case, the BGP Prefix-SID advertisement is applicable to the inter-AS
context, i.e., EBGP, while it is confined to a single administrative context, i.e., EBGP, while it is confined to a single administrative
domain. domain.
9. Security Considerations 9. Security Considerations
This document introduces a BGP attribute (BGP Prefix-SID) which This document introduces a BGP attribute (BGP Prefix-SID) which
inherits the security considerations expressed in: [RFC4271] and inherits the security considerations expressed in: [RFC4271],
[RFC8277]. [RFC8277], and [I-D.ietf-spring-segment-routing].
It should be noted, as described in Section 8, that this document It should be noted that, as described in Section 8, this document
refers to a deployment model where all nodes are under the single refers to a deployment model where all nodes are under the single
administrative domain. In this context, we assume that the operator administrative domain. In this context, we assume that the operator
doesn't want to leak outside of the domain any information related to doesn't want to leak any information related to internal prefixes and
internal prefixes and topology. The internal information includes topology outside of the administrative domain. The internal
the BGP Prefix-SID. In order to prevent such leaking, the standard information includes the BGP Prefix-SID. In order to prevent such
BGP mechanisms (filters) are applied on the boundary of the SR leaking, the standard BGP mechanisms (filters) are applied at the
domain. boundary of the SR/administrative domain.
10. Contributors 10. Contributors
Keyur Patel Keyur Patel
Arrcus, Inc. Arrcus, Inc.
US US
Email: Keyur@arrcus.com Email: Keyur@arrcus.com
Saikat Ray Saikat Ray
Unaffiliated Unaffiliated
US US
Email: raysaikat@gmail.com Email: raysaikat@gmail.com
11. Acknowledgements 11. Acknowledgements
The authors would like to thanks Satya Mohanty for his contribution The authors would like to thank Satya Mohanty for his contribution to
to this document. this document.
The authors would like to thank Alvaro Retana for substantive
comments as part of the Routing AD review.
12. References 12. References
12.1. Normative References 12.1. Normative References
[I-D.ietf-spring-segment-routing] [I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-14 (work Architecture", draft-ietf-spring-segment-routing-14 (work
in progress), December 2017. in progress), December 2017.
skipping to change at page 14, line 35 skipping to change at page 14, line 48
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271, Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006, <https://www.rfc- DOI 10.17487/RFC4271, January 2006, <https://www.rfc-
editor.org/info/rfc4271>. editor.org/info/rfc4271>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>. 2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007, <https://www.rfc-
editor.org/info/rfc4760>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K. [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages", Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015, RFC 7606, DOI 10.17487/RFC7606, August 2015,
<https://www.rfc-editor.org/info/rfc7606>. <https://www.rfc-editor.org/info/rfc7606>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address [RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address
Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017, Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
<https://www.rfc-editor.org/info/rfc8277>. <https://www.rfc-editor.org/info/rfc8277>.
12.2. Informative References 12.2. Informative References
[I-D.ietf-idr-bgp-ls-segment-routing-ext] [I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Psenak, P., Filsfils, C., Gredler, H., and M. Previdi, S., Psenak, P., Filsfils, C., Gredler, H., and M.
Chen, "BGP Link-State extensions for Segment Routing", Chen, "BGP Link-State extensions for Segment Routing",
draft-ietf-idr-bgp-ls-segment-routing-ext-03 (work in draft-ietf-idr-bgp-ls-segment-routing-ext-03 (work in
skipping to change at page 15, line 17 skipping to change at page 15, line 38
Dong, "BGP-LS extensions for Segment Routing BGP Egress Dong, "BGP-LS extensions for Segment Routing BGP Egress
Peer Engineering", draft-ietf-idr-bgpls-segment-routing- Peer Engineering", draft-ietf-idr-bgpls-segment-routing-
epe-14 (work in progress), December 2017. epe-14 (work in progress), December 2017.
[I-D.ietf-spring-segment-routing-msdc] [I-D.ietf-spring-segment-routing-msdc]
Filsfils, C., Previdi, S., Mitchell, J., Aries, E., and P. Filsfils, C., Previdi, S., Mitchell, J., Aries, E., and P.
Lapukhov, "BGP-Prefix Segment in large-scale data Lapukhov, "BGP-Prefix Segment in large-scale data
centers", draft-ietf-spring-segment-routing-msdc-08 (work centers", draft-ietf-spring-segment-routing-msdc-08 (work
in progress), December 2017. in progress), December 2017.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007, <https://www.rfc-
editor.org/info/rfc4760>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752, Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, <https://www.rfc- DOI 10.17487/RFC7752, March 2016, <https://www.rfc-
editor.org/info/rfc7752>. editor.org/info/rfc7752>.
Authors' Addresses Authors' Addresses
Stefano Previdi (editor) Stefano Previdi (editor)
Cisco Systems Cisco Systems
skipping to change at page 15, line 35 skipping to change at page 16, line 4
DOI 10.17487/RFC7752, March 2016, <https://www.rfc- DOI 10.17487/RFC7752, March 2016, <https://www.rfc-
editor.org/info/rfc7752>. editor.org/info/rfc7752>.
Authors' Addresses Authors' Addresses
Stefano Previdi (editor) Stefano Previdi (editor)
Cisco Systems Cisco Systems
IT IT
Email: stefano@previdi.net Email: stefano@previdi.net
Clarence Filsfils Clarence Filsfils
Cisco Systems Cisco Systems
Brussels Brussels
Belgium Belgium
Email: cfilsfils@cisco.com Email: cfilsfils@cisco.com
Acee Lindem Acee Lindem
Cisco Systems Cisco Systems
170 W. Tasman Drive 301 Midenhall Way
San Jose, CA 95124 95134 Cary, NC 27513
USA USA
Email: acee@cisco.com Email: acee@cisco.com
Arjun Sreekantiah Arjun Sreekantiah
Email: arjunhrs@gmail.com Email: arjunhrs@gmail.com
Hannes Gredler Hannes Gredler
RtBrick Inc. RtBrick Inc.
Email: hannes@rtbrick.com Email: hannes@rtbrick.com
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