Inter-Domain Routing S. Previdi, Ed.
Internet-Draft Individual
Intended status: Standards Track C. Filsfils
Expires: September 6, 2018 Cisco Systems, Inc.
K. Patel
Arrcus, Inc.
S. Ray
Individual Contributor
J. Dong
Huawei Technologies
March 5, 2018
BGP-LS extensions for Segment Routing BGP Egress Peer Engineering
draft-ietf-idr-bgpls-segment-routing-epe-15
Abstract
Segment Routing (SR) leverages source routing. A node steers a
packet through a controlled set of instructions, called segments, by
prepending the packet with an SR header. A segment can represent any
instruction, topological or service-based. SR allows to enforce a
flow through any topological path and service chain while maintaining
per-flow state only at the ingress node of the SR domain.
The Segment Routing architecture can be directly applied to the MPLS
dataplane with no change on the forwarding plane. It requires minor
extension to the existing link-state routing protocols.
This document outline a BGP-LS extension for exporting BGP peering
node topology information (including its peers, interfaces and
peering ASs) in a way that is exploitable in order to compute
efficient BGP Peering Engineering policies and strategies.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on September 6, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Segment Routing Documents . . . . . . . . . . . . . . . . . . 4
3. BGP Peering Segments . . . . . . . . . . . . . . . . . . . . 4
4. Link NLRI for BGP-EPE Connectivity Description . . . . . . . 5
4.1. BGP Router ID and Member ASN . . . . . . . . . . . . . . 6
4.2. Mandatory BGP-EPE Node Descriptors . . . . . . . . . . . 6
4.3. Optional BGP-EPE Node Descriptors . . . . . . . . . . . . 7
4.4. Link Attributes . . . . . . . . . . . . . . . . . . . . . 7
5. Peer-Node and Peer-Adj SIDs . . . . . . . . . . . . . . . . . 9
5.1. Peer-Node-SID . . . . . . . . . . . . . . . . . . . . . . 10
5.2. Peer-Adj-SID . . . . . . . . . . . . . . . . . . . . . . 11
5.3. Peer-Set-SID . . . . . . . . . . . . . . . . . . . . . . 12
6. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Reference Diagram . . . . . . . . . . . . . . . . . . . . 12
6.2. Peer-Node-SID for Node D . . . . . . . . . . . . . . . . 14
6.3. Peer-Node-SID for Node F . . . . . . . . . . . . . . . . 15
6.4. Peer-Node-SID for Node E . . . . . . . . . . . . . . . . 15
6.5. Peer-Adj-SID for Node E, Link 1 . . . . . . . . . . . . . 15
6.6. Peer-Adj-SID for Node E, Link 2 . . . . . . . . . . . . . 16
7. Implementation Status . . . . . . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
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8.1. New BGP-LS Protocol-ID . . . . . . . . . . . . . . . . . 17
8.2. Node Descriptors and Link Attribute TLVs . . . . . . . . 17
9. Manageability Considerations . . . . . . . . . . . . . . . . 18
10. Security Considerations . . . . . . . . . . . . . . . . . . . 18
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
13.1. Normative References . . . . . . . . . . . . . . . . . . 19
13.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction
Segment Routing (SR) leverages source routing. A node steers a
packet through a controlled set of instructions, called segments, by
prepending the packet with an SR header with segment identifiers
(SID). A SID can represent any instruction, topological or service-
based. SR allows to enforce a flow through any topological path and
service chain while maintaining per-flow state only at the ingress
node of the SR domain.
The Segment Routing architecture can be directly applied to the MPLS
dataplane with no change on the forwarding plane. It requires minor
extension to the existing link-state routing protocols.
This document outline a BGP-LS extension for exporting BGP peering
node topology information (including its peers, interfaces and
peering ASs) in a way that is exploitable in order to compute
efficient BGP Egress Peer Engineering (BGP-EPE) policies and
strategies.
This document defines the BGP-LS extensions required to support the
Peer Node SID describing the BGP session between two nodes, the Peer
Adjacency SID describing the link (one or more) that is used by the
BGP session and the Peer Set SID describing an arbitrary set of
sessions or links between the local BGP node and its peers. These
SIDs represent the segments defined in
[I-D.ietf-spring-segment-routing-central-epe].
While an egress point topology usually refers to eBGP sessions
between external peers, there's nothing in the extensions defined in
this document that would prevent the use of these extensions in the
context of iBGP sessions.
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2. Segment Routing Documents
The main reference for this document is the SR architecture defined
in [I-D.ietf-spring-segment-routing].
The Segment Routing BGP Egress Peer Engineering (BGP-EPE)
architecture is described in
[I-D.ietf-spring-segment-routing-central-epe].
3. BGP Peering Segments
As defined in [I-D.ietf-spring-segment-routing-central-epe], a BGP-
EPE enabled Egress PE node MAY advertise SIDs corresponding to its
attached peers. These SIDs are called BGP peering segments or BGP
Peering SIDs. In case of eBGP, they enable the expression of source-
routed inter-domain paths.
An ingress border router of an AS may compose a list of SIDs to steer
a flow along a selected path within the AS, towards a selected egress
border router C of the AS and through a specific peer. At minimum, a
BGP-EPE policy applied at an ingress PE involves two SIDs: the Node
SID of the chosen egress PE and then the BGP Peering SID for the
chosen egress PE peer or peering interface.
This document defines the BGP-LS extensions for the BGP-EPE Peering
SIDs:
o Peer Node Segment (Peer-Node-SID)
o Peer Adjacency Segment (Peer-Adj-SID)
o Peer Set Segment (Peer-Set-SID)
that have been defined in
[I-D.ietf-spring-segment-routing-central-epe].
Each BGP session MUST be described by a Peer Node SID. The
description of the BGP session MAY be augmented by additional
Adjacency SIDs. Finally, each Peer Node SID and Peer Adjacency SID
MAY be part of the same group/set so to be able to group EPE
resources under a common Peer-Set SID.
Therefore, when the extensions defined in this document are applied
to the use case defined in
[I-D.ietf-spring-segment-routing-central-epe]:
o One Peer-Node-SID MUST be present.
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o One or more Peer-Adj-SID MAY be present.
o Each of the Peer-Node-SID Peer-Adj-SID MAY use the same Peer-Set-
SID.
While an egress point topology usually refers to eBGP sessions
between external peers, there's nothing in the extensions defined in
this document that would prevent the use of these extensions in the
context of iBGP sessions.
4. Link NLRI for BGP-EPE Connectivity Description
This section describes the NLRI used for describing the connectivity
of the BGP Egress router. The connectivity is based on links and
remote peers/ASs and therefore the existing Link NLRI Type (defined
in [RFC7752]) is used. A new Protocol-ID is used: BGP (codepoint 7
assigned by IANA (Section 8) from the registry "BGP-LS Protocol-
IDs").
The use of a new Protocol-ID allows separation and differentiation
between the NLRIs carrying BGP-EPE descriptors from the NLRIs
carrying IGP link-state information as defined in [RFC7752]. The
Link NLRI Type uses descriptors and attributes already defined in
[RFC7752] in addition to new TLVs defined in the following sections
of this document.
The extensions defined in this document apply to both internal and
external BGP-LS EPE advertisements.
[RFC7752] defines Link NLRI Type is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+
| Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Remote Node Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Link Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Node Descriptors and Link Descriptors are defined in [RFC7752].
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4.1. BGP Router ID and Member ASN
Two new Node Descriptors Sub-TLVs are defined in this document:
o BGP Router Identifier (BGP Router-ID):
Type: 516 (assigned by IANA (Section 8) from the registry "BGP-
LS Node Descriptor, Link Descriptor, Prefix Descriptor, and
Attribute TLVs").
Length: 4 octets
Value: 4 octet unsigned integer representing the BGP Identifier
as defined in [RFC4271] and [RFC6286].
o Confederation Member ASN (Member-ASN)
Type: 517 (assigned by IANA (Section 8) from the registry "BGP-
LS Node Descriptor, Link Descriptor, Prefix Descriptor, and
Attribute TLVs").
Length: 4 octets
Value: 4 octet unsigned integer representing the Member ASN
inside the Confederation.[RFC5065].
4.2. Mandatory BGP-EPE Node Descriptors
The following Node Descriptors Sub-TLVs MUST appear in the Link NLRI
as Local Node Descriptors:
o BGP Router-ID, which contains the BGP Identifier of the local BGP-
EPE capable node.
o Autonomous System Number, which contains the local ASN or local
confederation identifier (ASN) if confederations are used.
It has to be noted that [RFC6286] (section 2.1) requires the BGP
identifier (router-id) to be unique within an Autonomous System.
Therefore, the <ASN, BGP Router-ID> tuple is globally unique.
The following Node Descriptors Sub-TLVs MUST appear in the Link NLRI
as Remote Node Descriptors:
o BGP Router-ID, which contains the BGP Identifier of the peer node.
o Autonomous System Number, which contains the peer ASN or the peer
confederation identifier (ASN), if confederations are used.
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4.3. Optional BGP-EPE Node Descriptors
The following Node Descriptors Sub-TLVs MAY appear in the Link NLRI
as Local Node Descriptors:
o Member-ASN, which contains the ASN of the confederation member
(when BGP confederations are used).
o Node Descriptors as defined in [RFC7752].
The following Node Descriptors Sub-TLVs MAY appear in the Link NLRI
as Remote Node Descriptors:
o Member-ASN, which contains the ASN of the confederation member
(when BGP confederations are used).
o Node Descriptors as defined in defined in [RFC7752].
4.4. Link Attributes
The following BGP-LS Link attributes TLVs are used with the Link
NLRI:
+----------+---------------------------+----------+
| TLV Code | Description | Length |
| Point | | |
+----------+---------------------------+----------+
| 1101 | Peer Node Segment | variable |
| | Identifier (Peer-Node-SID)| |
| 1102 | Peer Adjacency Segment | variable |
| | Identifier (Peer-Adj-SID) | |
| 1103 | Peer Set Segment | variable |
| | Identifier (Peer-Set-SID) | |
+----------+---------------------------+----------+
Figure 1: BGP-LS TLV code points for BGP-EPE
Peer-Node-SID, Peer-Adj-SID and Peer-Set-SID have all the same format
defined here below:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Weight | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 2
o Type: 1101 or 1102 or 1103 (assigned by IANA (Section 8) from the
registry "BGP-LS Node Descriptor, Link Descriptor, Prefix
Descriptor, and Attribute TLVs").
o Length: variable.
o Flags: one octet of flags used when advertising a Peer-Adj-SID
(Peer-Node and Peer-Set SIDs don't have flags defined). The
following Peer-Adj-SID flags have been defined:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|V|L|B|P| |
+-+-+-+-+-+-+-+-+
where:
* V-Flag: Value flag. If set, then the SID carries a label
value. By default the flag is SET.
* L-Flag: Local Flag. If set, then the value/index carried by
the SID has local significance. By default the flag is SET.
* B-Flag: Backup Flag. If set, the SID refers to a path that is
eligible for protection.
* P-Flag: Persistent Flag: If set, the SID is persistently
allocated, i.e., the SID value remains consistent across router
restart and session/interface flap.
* Other bits: MUST be zero when originated and ignored when
received.
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o Weight: 1 octet. The value represents the weight of the SID for
the purpose of load balancing. An example use of the weight is
described in [I-D.ietf-spring-segment-routing].
o SID/Index/Label. According to the TLV length and to the V and L
flags settings, it contains either:
* A 3 octet local label where the 20 rightmost bits are used for
encoding the label value. In this case the V and L flags MUST
be set.
* A 4 octet index defining the offset in the SRGB (Segment
Routing Global Block as defined in
[I-D.ietf-spring-segment-routing] advertised by this router.
In this case, the SRGB MUST be advertised using the extensions
defined in [I-D.ietf-idr-bgp-ls-segment-routing-ext].
The values of the Peer-Node-SID, Peer-Adj-SID and Peer-Set-SID Sub-
TLVs SHOULD be persistent across router restart.
The Peer-Node-SID MUST be present when BGP-LS is used for the use
case described in [I-D.ietf-spring-segment-routing-central-epe] and
MAY be omitted for other use cases.
The Peer-Adj-SID and Peer-Set-SID SubTLVs MAY be present when BGP-LS
is used for the use case described in
[I-D.ietf-spring-segment-routing-central-epe] and MAY be omitted for
other use cases.
In addition, BGP-LS Node and Link Attributes, as defined in [RFC7752]
MAY be inserted in order to advertise the characteristics of the
link.
5. Peer-Node and Peer-Adj SIDs
In this section the following SIDs are defined:
Peer Node Segment Identifier (Peer-Node-SID)
Peer Adjacency Segment Identifier (Peer-Adj-SID)
Peer Set Segment Identifier (Peer-Set-SID)
The Peer-Node, Peer-Adj and Peer-Set SIDs can be either a local or a
global (depending on the setting of the V and L flags defined in
Figure 2.
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5.1. Peer-Node-SID
The Peer-Node-SID describes the BGP session peer (neighbor). It MUST
be present when describing a BGP-EPE topology as defined in
[I-D.ietf-spring-segment-routing-central-epe]. The Peer-Node-SID is
encoded within the BGP-LS Link NLRI specified in Section 4.
The Peer-Node-SID, at the BGP node advertising it, has the following
semantic:
o SR header operation: NEXT (as defined in
[I-D.ietf-spring-segment-routing]).
o Next-Hop: the connected peering node to which the segment is
related.
The Peer-Node-SID is advertised with a Link NLRI, where:
o Local Node Descriptors contains
* Local BGP Router-ID of the BGP-EPE enabled egress PE.
* Local ASN.
o Remote Node Descriptors contains
* Peer BGP Router-ID (i.e.: the peer BGP ID used in the BGP
session).
* Peer ASN.
o Link Descriptors Sub-TLVs, as defined in [RFC7752], contain the
addresses used by the BGP session:
* IPv4 Interface Address (Sub-TLV 259) contains the BGP session
IPv4 local address.
* IPv4 Neighbor Address (Sub-TLV 260) contains the BGP session
IPv4 peer address.
* IPv6 Interface Address (Sub-TLV 261) contains the BGP session
IPv6 local address.
* IPv6 Neighbor Address (Sub-TLV 262) contains the BGP session
IPv6 peer address.
o Link Attribute contains the Peer-Node-SID TLV as defined in
Section 4.4.
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o In addition, BGP-LS Link Attributes, as defined in [RFC7752], MAY
be inserted in order to advertise the characteristics of the link.
5.2. Peer-Adj-SID
The Peer-Adj-SID, at the BGP node advertising it, has the following
semantic:
o SR header operation: NEXT (as defined in
[I-D.ietf-spring-segment-routing]).
o Next-Hop: the interface peer address.
The Peer-Adj-SID is advertised with a Link NLRI, where:
o Local Node Descriptors contains
* Local BGP Router-ID of the BGP-EPE enabled egress PE.
* Local ASN.
o Remote Node Descriptors contains
* Peer BGP Router-ID (i.e.: the peer BGP ID used in the BGP
session).
* Peer ASN.
o Link Descriptors Sub-TLVs, as defined in [RFC7752], MUST contain
the following TLVs:
* Link Local/Remote Identifiers (Sub-TLV 258) contains the
4-octet Link Local Identifier followed by the 4-octet value 0
indicating the Link Remote Identifier in unknown [RFC5307].
o In addition, Link Descriptors Sub-TLVs, as defined in [RFC7752],
MAY contain the following TLVs:
* IPv4 Interface Address (Sub-TLV 259) contains the address of
the local interface through which the BGP session is
established.
* IPv6 Interface Address (Sub-TLV 261) contains the address of
the local interface through which the BGP session is
established.
* IPv4 Neighbor Address (Sub-TLV 260) contains the IPv4 address
of the peer interface used by the BGP session.
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* IPv6 Neighbor Address (Sub-TLV 262) contains the IPv6 address
of the peer interface used by the BGP session.
o Link attribute used with the Peer-Adj-SID contains the TLV as
defined in Section 4.4.
In addition, BGP-LS Link Attributes, as defined in [RFC7752], MAY be
inserted in order to advertise the characteristics of the link.
5.3. Peer-Set-SID
The Peer-Set-SID, at the BGP node advertising it, has the following
semantic:
o SR header operation: NEXT (as defined in
[I-D.ietf-spring-segment-routing]).
o Next-Hop: load balance across any connected interface to any peer
in the related set.
The Peer-Set-SID is advertised within a Link NLRI (describing a Peer
Node Segment or a Peer Adjacency segment) as a BGP-LS attribute.
The Link Attribute contains the Peer-Set-SID TLV, defined in
Section 4.4 identifying the set of which the Peer-Node-SID or Peer-
Adj-SID is a member.
6. Illustration
6.1. Reference Diagram
The following reference diagram is used throughout this document.
The solution is illustrated for IPv6 with MPLS-based SIDs and the
BGP-EPE topology is based on eBGP sessions between external peers.
As stated in Section 3, the solution illustrated hereafter is equally
applicable to an iBGP session topology. In other words, the solution
also applies to the case where C, D, F, and E are in the same AS and
run iBGP sessions between each other.
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+------+
| |
+---D H
+---------+ / | AS 2 |\ +------+
| X |/ +------+ \ | Z |---L/8
A C---+ \| |
| |\\ \ +------+ /| AS 4 |---M/8
| AS1 | \\ +-F |/ +------+
| | \\ | G
+----P----+ +===E AS 3 |
| +--Q---+
| |
+----------------+
Figure 3: Reference Diagram
IP addressing:
o C's IP address of interface to D: 2001:db8:cd::c/64, D's
interface: 2001:db8:cd::d/64
o C's IP address of interface to F: 2001:db8:cf::c/64, F's
interface: 2001:db8:cf::f/64
o C's IP address of upper interface to E: 2001:db8:ce1::c/64, E's
interface: 2001:db8:ce1::e
o C's local identifier of upper interface to E: 0.0.0.1.0.0.0.0
o C's IP address of lower interface to E: 2001:db8:ce2::c, E's
interface: 2001:db8:ce2::e
o C's local identifier of lower interface to E: 0.0.0.2.0.0.0.0
o Loopback of E used for eBGP multi-hop peering to C:
2001:db8:e::e/128
o C's loopback is 2001:db8:c::c/128 with SID 64
BGP Router-IDs are C, D, F and E.
o C's BGP Router-ID: 192.0.2.3
o D's BGP Router-ID: 192.0.2.4
o E's BGP Router-ID: 192.0.2.5
o F's BGP Router-ID: 192.0.2.6
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C's BGP peering:
o Single-hop eBGP peering with neighbor 2001:db8:cd::d (D)
o Single-hop eBGP peering with neighbor 2001:db8:cf::f (F)
o Multi-hop eBGP peering with E on ip address 2001:db8:e::e (E)
C's resolution of the multi-hop eBGP session to E:
o Static route 2001:db8:e::e/128 via 2001:db8:ce1::e
o Static route 2001:db8:e::e/128 via 2001:db8:ce2::e
Node C configuration is such that:
o A Peer-Node-SID is allocated to each peer (D, F and E).
o An Peer-Adj-SID is defined for each recursing interface to a
multi-hop peer (CE upper and lower interfaces).
o A Peer-Set-SID is defined to include all peers in AS3 (peers F and
E).
The Link NLRI Type is used in order to encode C's connectivity. The
Link NLRI uses the Protocol-ID for BGP value 7 assigned by IANA.
Once the BGP-LS update is originated by C, it may be advertised to
internal (iBGP) as well as external (eBGP) neighbors supporting the
BGP-LS EPE extensions defined in this document.
6.2. Peer-Node-SID for Node D
Descriptors:
o Local Node Descriptors (BGP Router-ID, local ASN): 192.0.2.3, AS1
o Remote Node Descriptors (BGP Router-ID, peer ASN): 192.0.2.4, AS2
o Link Descriptors (BGP session IPv6 local address, BGP session IPv6
neighbor address): 2001:db8:cd::c, 2001:db8:cd::d
Attributes:
o Peer-Node-SID: 1012
o Link Attributes: see section 3.3.2 of [RFC7752]
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6.3. Peer-Node-SID for Node F
Descriptors:
o Local Node Descriptors (BGP Router-ID, ASN): 192.0.2.3, AS1
o Remote Node Descriptors (BGP Router-ID ASN): 192.0.2.6, AS3
o Link Descriptors (BGP session IPv6 local address, BGP session IPv6
peer address): 2001:db8:cf::c, 2001:db8:cf::f
Attributes:
o Peer-Node-SID: 1022
o Peer-Set-SID: 1060
o Link Attributes: see section 3.3.2 of [RFC7752]
6.4. Peer-Node-SID for Node E
Descriptors:
o Local Node Descriptors (BGP Router-ID, ASN): 192.0.2.3, AS1
o Remote Node Descriptors (BGP Router-ID, ASN): 192.0.2.5, AS3
o Link Descriptors (BGP session IPv6 local address, BGP session IPv6
peer address): 2001:db8:c::c, 2001:db8:e::e
Attributes:
o Peer-Node-SID: 1052
o Peer-Set-SID: 1060
6.5. Peer-Adj-SID for Node E, Link 1
Descriptors:
o Local Node Descriptors (BGP Router-ID, ASN): 192.0.2.3, AS1
o Remote Node Descriptors (BGP Router-ID, ASN): 192.0.2.5, AS3
o Link Descriptors (local interface identifier, IPv6 peer interface
address): 0.0.0.1.0.0.0.0 , 2001:db8:ce1::e
Attributes:
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o Peer-Adj-SID: 1032
o LinkAttributes: see section 3.3.2 of [RFC7752]
6.6. Peer-Adj-SID for Node E, Link 2
Descriptors:
o Local Node Descriptors (BGP Router-ID, ASN): 192.0.2.3, AS1
o Remote Node Descriptors (BGP Router-ID, ASN): 192.0.2.5, AS3
o Link Descriptors (local interface identifier, IPv6 peer interface
address): 0.0.0.2.0.0.0.0 , 2001:db8:ce2::e
Attributes:
o Peer-Adj-SID: 1042
o LinkAttributes: see section 3.3.2 of [RFC7752]
7. Implementation Status
Note to RFC Editor: Please remove this section prior to publication,
as well as the reference to RFC 7942.
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
Several early implementations exist and will be reported in detail in
a forthcoming version of this document. For purposes of early
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interoperability testing, when no FCFS code point was available,
implementations have made use of the following values:
+---------------------------------------+
| Codepoint | Description |
+---------------------------------------+
| 7 | Protocol-ID BGP |
| 516 | BGP Router-ID |
| 517 | BGP Confederation Member |
| 1101 | Peer-Node-SID |
| 1102 | Peer-Adj-SID |
| 1103 | Peer-Set-SID |
+------------+--------------------------+
IANA has now confirmed the assignment of the above coidepoints.
SeeSection 8.
8. IANA Considerations
This document defines:
A new Protocol-ID: BGP. The codepoint is from the "BGP-LS
Protocol-IDs" registry.
Two new TLVs: BGP-Router-ID and BGP Confederation Member. The
codepoints are in the "BGP-LS Node Descriptor, Link Descriptor,
Prefix Descriptor, and Attribute TLVs" registry.
Three new BGP-LS Attribute TLVs: Peer-Node-SID, Peer-Adj-SID and
Peer-Set-SID. The codepoints are in the "BGP-LS Node Descriptor,
Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry.
8.1. New BGP-LS Protocol-ID
This document defines a new value in the registry "BGP-LS Protocol-
IDs":
+----------------------------------------------+
| Codepoint | Description | Status |
+----------------------------------------------+
| 7 | BGP | Assigned by IANA |
+----------------------------------------------+
8.2. Node Descriptors and Link Attribute TLVs
This document defines 5 new TLVs in the registry "BGP-LS Node
Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs":
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o Two new node descriptor TLVs
o Three new link attribute TLVs
All the new 5 codepoints are in the same registry: "BGP-LS Node
Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs".
However, the registry is organized in ranges (node descriptors, link
descriptors, node attributes, link attributes).
The following new Node Descriptors TLVs are defined:
+-----------------------------------------------------------+
| Codepoint | Description | Status |
+-----------------------------------------------------------+
| 516 | BGP Router-ID | Assigned by IANA |
| 517 | BGP Confederation Member | Assigned by IANA |
+------------+----------------------------------------------+
The following new Link Attribute TLVs are defined:
+-----------------------------------------------------------+
| Codepoint | Description | Status |
+-----------------------------------------------------------+
| 1101 | Peer-Node-SID | Assigned by IANA |
| 1102 | Peer-Adj-SID | Assigned by IANA |
| 1103 | Peer-Set-SID | Assigned by IANA |
+------------+----------------------------------------------+
9. Manageability Considerations
The BGP-LS ([RFC7752]) extensions that are described in this document
consist of additional BGP-LS descriptors and TLVs that will follow
the same manageability functions of BGP-LS, described in [RFC7752].
The operator MUST be capable of configuring, enabling, disabling the
advertisement of each of the Peer-Node-SID, Peer-Adj-SID and Peer-
Set-SID as well as to control which information is advertised to
which internal or external peer. This is not different from what is
required by a BGP speaker in terms of information origination and
advertisement. In addition, the advertisement of EPE information
MUST conform to standard BGP advertisement and propagation rules
(iBGP, eBGP, Route-Reflectors, Confederations).
10. Security Considerations
[RFC7752] defines BGP-LS NLRIs to which the extensions defined in
this document apply.
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The Security Section of [RFC7752] also applies to:
o New Node Descriptors Sub-TLVs: BGP-Router-ID and BGP-
Confederation-Member;
o New BGP-LS Attributes TLVs: Peer-Node-SID, Peer-Adj-SID and Peer-
Set-SID.
The extensions defined in this document do not introduce any
additional security aspects of BGP-LS.
11. Contributors
Mach (Guoyi) Chen
Huawei Technologies
China
Email: mach.chen@huawei.com
Acee Lindem
Cisco Systems Inc.
US
Email: acee@cisco.com
Ketan Talaulikar
Cisco Systems Inc.
India
Email: ketant@cisco.com
12. Acknowledgements
The authors would like to thank Jakob Heitz, Howard Yang, Hannes
Gredler, Peter Psenak, Arjun Sreekantiah and Bruno Decraene for their
feedback and comments.
13. References
13.1. Normative References
[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.
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[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>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous
System Confederations for BGP", RFC 5065,
DOI 10.17487/RFC5065, August 2007,
<https://www.rfc-editor.org/info/rfc5065>.
[RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
<https://www.rfc-editor.org/info/rfc5307>.
[RFC6286] Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP
Identifier for BGP-4", RFC 6286, DOI 10.17487/RFC6286,
June 2011, <https://www.rfc-editor.org/info/rfc6286>.
13.2. Informative References
[I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-04
(work in progress), January 2018.
[I-D.ietf-spring-segment-routing-central-epe]
Filsfils, C., Previdi, S., Dawra, G., Aries, E., and D.
Afanasiev, "Segment Routing Centralized BGP Egress Peer
Engineering", draft-ietf-spring-segment-routing-central-
epe-10 (work in progress), December 2017.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
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Authors' Addresses
Stefano Previdi (editor)
Individual
Email: stefano@previdi.net
Clarence Filsfils
Cisco Systems, Inc.
Brussels
Belgium
Email: cfilsfil@cisco.com
Keyur Patel
Arrcus, Inc.
Email: Keyur@arrcus.com
Saikat Ray
Individual Contributor
Email: raysaikat@gmail.com
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
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