draft-ietf-idr-bgpls-segment-routing-epe-16.txt   draft-ietf-idr-bgpls-segment-routing-epe-17.txt 
Inter-Domain Routing S. Previdi, Ed. Inter-Domain Routing S. Previdi, Ed.
Internet-Draft Individual Internet-Draft Individual
Intended status: Standards Track K. Talaulikar Intended status: Standards Track K. Talaulikar
Expires: April 18, 2019 C. Filsfils Expires: April 22, 2019 C. Filsfils
Cisco Systems, Inc. Cisco Systems, Inc.
K. Patel K. Patel
Arrcus, Inc. Arrcus, Inc.
S. Ray S. Ray
Individual Contributor Individual Contributor
J. Dong J. Dong
Huawei Technologies Huawei Technologies
October 15, 2018 October 19, 2018
BGP-LS extensions for Segment Routing BGP Egress Peer Engineering BGP-LS extensions for Segment Routing BGP Egress Peer Engineering
draft-ietf-idr-bgpls-segment-routing-epe-16 draft-ietf-idr-bgpls-segment-routing-epe-17
Abstract Abstract
Segment Routing (SR) leverages source routing. A node steers a Segment Routing (SR) leverages source routing. A node steers a
packet through a controlled set of instructions, called segments, by packet through a controlled set of instructions, called segments, by
prepending the packet with an SR header. A segment can represent any prepending the packet with an SR header. A segment can represent any
instruction, topological or service-based. SR segments allow instruction, topological or service-based. SR segments allow
steering a flow through any topological path and service chain while steering a flow through any topological path and service chain while
maintaining per-flow state only at the ingress node of the SR domain. maintaining per-flow state only at the ingress node of the SR domain.
skipping to change at page 2, line 10 skipping to change at page 2, line 10
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 April 18, 2019. This Internet-Draft will expire on April 22, 2019.
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
(https://trustee.ietf.org/license-info) in effect on the date of (https://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
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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. Segment Routing Documents . . . . . . . . . . . . . . . . . . 4 2. Segment Routing Documents . . . . . . . . . . . . . . . . . . 4
3. BGP Peering Segments . . . . . . . . . . . . . . . . . . . . 4 3. BGP Peering Segments . . . . . . . . . . . . . . . . . . . . 4
4. BGP-LS NLRI for BGP . . . . . . . . . . . . . . . . . . . . . 5 4. BGP-LS NLRI for BGP . . . . . . . . . . . . . . . . . . . . . 5
4.1. BGP Router ID and Member ASN . . . . . . . . . . . . . . 6 4.1. BGP Router ID and Member ASN . . . . . . . . . . . . . . 6
4.2. Mandatory BGP Node Descriptors . . . . . . . . . . . . . 6 4.2. Mandatory BGP Node Descriptors . . . . . . . . . . . . . 7
4.3. Optional BGP Node Descriptors . . . . . . . . . . . . . . 7 4.3. Optional BGP Node Descriptors . . . . . . . . . . . . . . 7
5. BGP-LS Attributes for BGP Peering Segments . . . . . . . . . 7 5. BGP-LS Attributes for BGP Peering Segments . . . . . . . . . 8
5.1. Peer-Node-SID . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Peer-Node-SID . . . . . . . . . . . . . . . . . . . . . . 10
5.2. Peer-Adj-SID . . . . . . . . . . . . . . . . . . . . . . 11 5.2. Peer-Adj-SID . . . . . . . . . . . . . . . . . . . . . . 11
5.3. Peer-Set-SID . . . . . . . . . . . . . . . . . . . . . . 12 5.3. Peer-Set-SID . . . . . . . . . . . . . . . . . . . . . . 12
6. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 12 6. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Reference Diagram . . . . . . . . . . . . . . . . . . . . 12 6.1. Reference Diagram . . . . . . . . . . . . . . . . . . . . 13
6.2. Peer-Node-SID for Node D . . . . . . . . . . . . . . . . 14 6.2. Peer-Node-SID for Node D . . . . . . . . . . . . . . . . 15
6.3. Peer-Node-SID for Node F . . . . . . . . . . . . . . . . 15 6.3. Peer-Node-SID for Node F . . . . . . . . . . . . . . . . 15
6.4. Peer-Node-SID for Node E . . . . . . . . . . . . . . . . 15 6.4. Peer-Node-SID for Node E . . . . . . . . . . . . . . . . 15
6.5. Peer-Adj-SID for Node E, Link 1 . . . . . . . . . . . . . 16 6.5. Peer-Adj-SID for Node E, Link 1 . . . . . . . . . . . . . 16
6.6. Peer-Adj-SID for Node E, Link 2 . . . . . . . . . . . . . 16 6.6. Peer-Adj-SID for Node E, Link 2 . . . . . . . . . . . . . 16
7. Implementation Status . . . . . . . . . . . . . . . . . . . . 16 7. Implementation Status . . . . . . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8.1. New BGP-LS Protocol-ID . . . . . . . . . . . . . . . . . 18 8.1. New BGP-LS Protocol-ID . . . . . . . . . . . . . . . . . 18
8.2. Node Descriptors and Link Attribute TLVs . . . . . . . . 18 8.2. Node Descriptors and Link Attribute TLVs . . . . . . . . 18
9. Manageability Considerations . . . . . . . . . . . . . . . . 18 9. Manageability Considerations . . . . . . . . . . . . . . . . 19
10. Security Considerations . . . . . . . . . . . . . . . . . . . 19 10. Security Considerations . . . . . . . . . . . . . . . . . . . 20
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . 20 13.1. Normative References . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
Segment Routing (SR) leverages source routing. A node steers a Segment Routing (SR) leverages source routing. A node steers a
packet through a controlled set of instructions, called segments, by packet through a controlled set of instructions, called segments, by
prepending the packet with an SR header with segment identifiers prepending the packet with an SR header with segment identifiers
(SID). A SID can represent any instruction, topological or service- (SID). A SID can represent any instruction, topological or service-
based. SR segments allows to enforce a flow through any topological based. SR segments allows to enforce a flow through any topological
path or service function while maintaining per-flow state only at the path or service function while maintaining per-flow state only at the
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4. BGP-LS NLRI for BGP 4. BGP-LS NLRI for BGP
This section describes the BGP-LS NLRI encodings that describe the This section describes the BGP-LS NLRI encodings that describe the
BGP peering and link connectivity between BGP routers. BGP peering and link connectivity between BGP routers.
This document specifies the advertisement of BGP peering topology This document specifies the advertisement of BGP peering topology
information via BGP-LS NLRI which requires use of a new BGP protocol information via BGP-LS NLRI which requires use of a new BGP protocol
identifier. identifier.
Protocol-ID : BGP (codepoint 7 assigned by IANA Section 8 from the Protocol-ID : BGP (codepoint 7 Early Allocation by IANA Section 8
registry "BGP-LS Protocol-IDs") from the registry "BGP-LS Protocol-IDs")
The use of a new Protocol-ID allows separation and differentiation The use of a new Protocol-ID allows separation and differentiation
between the BGP-LS NLRI carrying BGP information from the NLRI between the BGP-LS NLRI carrying BGP information from the NLRI
carrying IGP link-state information as defined in [RFC7752]. carrying IGP link-state information as defined in [RFC7752].
The BGP Peering information along with their Peering Segments are The BGP Peering information along with their Peering Segments are
advertised using BGP-LS Link NLRI with the protocol ID set to BGP. advertised using BGP-LS Link NLRI with the protocol ID set to BGP.
The BGP-LS Link NLRI uses the descriptor TLVs and BGP-LS Attribute The BGP-LS Link NLRI uses the descriptor TLVs and BGP-LS Attribute
TLVs as defined in [RFC7752]. In order to correctly describe BGP TLVs as defined in [RFC7752]. In order to correctly describe BGP
nodes, new TLVs are defined in this section. nodes, new TLVs are defined in this section.
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| Identifier | | Identifier |
| (64 bits) | | (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptors // // Local Node Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Remote Node Descriptors // // Remote Node Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Link Descriptors // // Link Descriptors //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: BGP-LS Link NLRI
Node Descriptors and Link Descriptors are defined in [RFC7752]. Node Descriptors and Link Descriptors are defined in [RFC7752].
4.1. BGP Router ID and Member ASN 4.1. BGP Router ID and Member ASN
Two new Node Descriptors TLVs are defined in this document: Two new Node Descriptors TLVs are defined in this document:
o BGP Router Identifier (BGP Router-ID): o BGP Router Identifier (BGP Router-ID):
Type: 516 (assigned by IANA Section 8 from the registry "BGP-LS Type: 516 (Early Allocation by IANA Section 8 from the registry
Node Descriptor, Link Descriptor, Prefix Descriptor, and "BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor,
Attribute TLVs"). and Attribute TLVs").
Length: 4 octets Length: 4 octets
Value: 4 octet unsigned non-zero integer representing the BGP Value: 4 octet unsigned non-zero integer representing the BGP
Identifier as defined in [RFC4271] and [RFC6286]. Identifier as defined in [RFC4271] and [RFC6286].
o Confederation Member ASN (Member-ASN) o Confederation Member ASN (Member-ASN)
Type: 517 (assigned by IANA Section 8 from the registry "BGP-LS Type: 517 (Early Allocation by IANA Section 8 from the registry
Node Descriptor, Link Descriptor, Prefix Descriptor, and "BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor,
Attribute TLVs"). and Attribute TLVs").
Length: 4 octets Length: 4 octets
Value: 4 octet unsigned non-zero integer representing the Value: 4 octet unsigned non-zero integer representing the
Member ASN inside the Confederation [RFC5065]. Member ASN inside the Confederation [RFC5065].
4.2. Mandatory BGP Node Descriptors 4.2. Mandatory BGP Node Descriptors
The following Node Descriptors TLVs MUST be included in BGP-LS NLRI The following Node Descriptors TLVs MUST be included in BGP-LS NLRI
as Local Node Descriptors when distributing BGP information: as Local Node Descriptors when distributing BGP information:
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| Point | | | | Point | | |
+----------+---------------------------+----------+ +----------+---------------------------+----------+
| 1101 | Peer Node Segment | variable | | 1101 | Peer Node Segment | variable |
| | Identifier (Peer-Node-SID)| | | | Identifier (Peer-Node-SID)| |
| 1102 | Peer Adjacency Segment | variable | | 1102 | Peer Adjacency Segment | variable |
| | Identifier (Peer-Adj-SID) | | | | Identifier (Peer-Adj-SID) | |
| 1103 | Peer Set Segment | variable | | 1103 | Peer Set Segment | variable |
| | Identifier (Peer-Set-SID) | | | | Identifier (Peer-Set-SID) | |
+----------+---------------------------+----------+ +----------+---------------------------+----------+
Figure 1: BGP-LS TLV code points for BGP-EPE Figure 2: BGP-LS TLV code points for BGP-EPE
Peer-Node-SID, Peer-Adj-SID, and Peer-Set-SID have all the same Peer-Node-SID, Peer-Adj-SID, and Peer-Set-SID have all the same
format defined here below: format defined here below:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Weight | Reserved | | Flags | Weight | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) | | SID/Label/Index (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: Figure 3: BGP-LS Peering SIDs TLV Format
Figure 2
o Type: 1101, 1102 or 1103 (assigned by IANA (Section 8) from the o Type: 1101, 1102 or 1103 (Early Allocation by IANA (Section 8)
registry "BGP-LS Node Descriptor, Link Descriptor, Prefix from the registry "BGP-LS Node Descriptor, Link Descriptor, Prefix
Descriptor, and Attribute TLVs"). Descriptor, and Attribute TLVs").
o Length: variable. o Length: variable.
o Flags: one octet of flags with the following definition: o Flags: one octet of flags with the following definition:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|V|L|B|P| | |V|L|B|P| Rsvd |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: Figure 4: Peering SID TLV Flags Format
* V-Flag: Value flag. If set, then the SID carries a label * V-Flag: Value flag. If set, then the SID carries a label
value. By default the flag is SET. value. By default the flag is SET.
* L-Flag: Local Flag. If set, then the value/index carried by * L-Flag: Local Flag. If set, then the value/index carried by
the SID has local significance. By default the flag is SET. 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 * B-Flag: Backup Flag. If set, the SID refers to a path that is
eligible for protection. eligible for protection.
* P-Flag: Persistent Flag: If set, the SID is persistently * P-Flag: Persistent Flag: If set, the SID is persistently
allocated, i.e., the SID value remains consistent across router allocated, i.e., the SID value remains consistent across router
restart and session/interface flap. restart and session/interface flap.
* Other bits: MUST be zero when originated and ignored when * Rsvd bits: Reserved for future use and MUST be zero when
received. originated and ignored when received.
o Weight: 1 octet. The value represents the weight of the SID for 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 the purpose of load balancing. An example use of the weight is
described in [RFC8402]. described in [RFC8402].
o SID/Index/Label. According to the TLV length and to the V and L o SID/Index/Label. According to the TLV length and to the V and L
flags settings, it contains either: flags settings, it contains either:
* A 3 octet local label where the 20 rightmost bits are used for * 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 encoding the label value. In this case, the V and L flags MUST
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* IPv4 Neighbor Address (TLV 260) contains the BGP session IPv4 * IPv4 Neighbor Address (TLV 260) contains the BGP session IPv4
peer address. peer address.
* IPv6 Interface Address (TLV 261) contains the BGP session IPv6 * IPv6 Interface Address (TLV 261) contains the BGP session IPv6
local address. local address.
* IPv6 Neighbor Address (TLV 262) contains the BGP session IPv6 * IPv6 Neighbor Address (TLV 262) contains the BGP session IPv6
peer address. peer address.
o Link Attribute TLVs include the Peer-Node-SID TLV as defined in o Link Attribute TLVs include the Peer-Node-SID TLV as defined in
Figure 2. Figure 3.
5.2. Peer-Adj-SID 5.2. Peer-Adj-SID
The Peer-Adj-SID TLV includes a SID associated with the underlying The Peer-Adj-SID TLV includes a SID associated with the underlying
link to the BGP peer node that is described by a BGP-LS Link NLRI as link to the BGP peer node that is described by a BGP-LS Link NLRI as
specified in Section 4. specified in Section 4.
The Peer-Adj-SID, at the BGP node advertising it, has the following The Peer-Adj-SID, at the BGP node advertising it, has the following
semantics: semantics:
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the local interface through which the BGP session is the local interface through which the BGP session is
established. established.
* IPv4 Neighbor Address (Sub-TLV 260) contains the IPv4 address * IPv4 Neighbor Address (Sub-TLV 260) contains the IPv4 address
of the peer interface used by the BGP session. of the peer interface used by the BGP session.
* IPv6 Neighbor Address (Sub-TLV 262) contains the IPv6 address * IPv6 Neighbor Address (Sub-TLV 262) contains the IPv6 address
of the peer interface used by the BGP session. of the peer interface used by the BGP session.
o Link Attribute TLVs include the Peer-Adj-SID TLV as defined in o Link Attribute TLVs include the Peer-Adj-SID TLV as defined in
Figure 2. Figure 3.
5.3. Peer-Set-SID 5.3. Peer-Set-SID
The Peer-Set-SID TLV includes a SID that is shared amongst BGP peer The Peer-Set-SID TLV includes a SID that is shared amongst BGP peer
nodes or the underlying links that are described by BGP-LS Link NLRI nodes or the underlying links that are described by BGP-LS Link NLRI
as specified in Section 4. as specified in Section 4.
The Peer-Set-SID, at the BGP node advertising it, has the following The Peer-Set-SID, at the BGP node advertising it, has the following
semantics: semantics:
o SR header operation: NEXT (as defined in [RFC8402]). o SR header operation: NEXT (as defined in [RFC8402]).
o Next-Hop: load balance across any connected interface to any peer o Next-Hop: load balance across any connected interface to any peer
in the associated peer set. in the associated peer set.
The Peer-Set-SID TLV containing the same SID value (encoded as The Peer-Set-SID TLV containing the same SID value (encoded as
defined in Figure 2) is included in the BGP-LS Attribute for all of defined in Figure 3) is included in the BGP-LS Attribute for all of
the BGP-LS Link NLRI corresponding to the Peer Node or Peer Adjacency the BGP-LS Link NLRI corresponding to the Peer Node or Peer Adjacency
segments associated with the peer set. segments associated with the peer set.
6. Illustration 6. Illustration
6.1. Reference Diagram 6.1. Reference Diagram
The following reference diagram is used throughout this section. The The following reference diagram is used throughout this section. The
solution is illustrated for IPv6 with MPLS-based SIDs and the BGP-EPE solution is illustrated for IPv6 with MPLS-based SIDs and the BGP-EPE
topology is based on EBGP sessions between external peers. topology is based on EBGP sessions between external peers.
This illustration is non-normative text provided as an example for This illustration is non-normative text provided as an example for
implementers and describes the BGP-LS advertisements for the Central implementers and describes the BGP-LS advertisements for the Central
EPE use-case. EPE use-case.
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| X |/ +------+ \ | Z |---L/8 | X |/ +------+ \ | Z |---L/8
A C---+ \| | A C---+ \| |
| |\\ \ +------+ /| AS 4 |---M/8 | |\\ \ +------+ /| AS 4 |---M/8
| AS1 | \\ +-F |/ +------+ | AS1 | \\ +-F |/ +------+
| | \\ | G | | \\ | G
+----P----+ +===E AS 3 | +----P----+ +===E AS 3 |
| +--Q---+ | +--Q---+
| | | |
+----------------+ +----------------+
Figure 3: Reference Diagram Figure 5: Reference Diagram
IP addressing: IP addressing:
o C's IP address of interface to D: 2001:db8:cd::c/64, D's o C's IP address of interface to D: 2001:db8:cd::c/64, D's
interface: 2001:db8:cd::d/64 interface: 2001:db8:cd::d/64
o C's IP address of interface to F: 2001:db8:cf::c/64, F's o C's IP address of interface to F: 2001:db8:cf::c/64, F's
interface: 2001:db8:cf::f/64 interface: 2001:db8:cf::f/64
o C's IP address of upper interface to E: 2001:db8:ce1::c/64, E's o C's IP address of upper interface to E: 2001:db8:ce1::c/64, E's
skipping to change at page 14, line 35 skipping to change at page 14, line 44
o A Peer-Node-SID is allocated to each peer (D, F and E). 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 o An Peer-Adj-SID is defined for each recursing interface to a
multi-hop peer (CE upper and lower interfaces). multi-hop peer (CE upper and lower interfaces).
o A Peer-Set-SID is defined to include all peers in AS3 (peers F and o A Peer-Set-SID is defined to include all peers in AS3 (peers F and
E). E).
A BGP-LS Link NLRI is used in order to encode C's connectivity. The A BGP-LS Link NLRI is used in order to encode C's connectivity. The
Link NLRI uses the Protocol-ID for BGP (value 7) as assigned by IANA. Link NLRI uses the Protocol-ID for BGP (value 7 as per Early
Allocation by IANA).
Once the BGP-LS update is originated by C, it may be advertised to Once the BGP-LS update is originated by C, it may be advertised to
internal (IBGP) as well as external (EBGP) neighbors supporting the internal (IBGP) as well as external (EBGP) neighbors supporting the
BGP-LS EPE extensions defined in this document. Note that the BGP-LS BGP-LS EPE extensions defined in this document. Note that the BGP-LS
sessions may be completely separate and different from the normal BGP sessions may be completely separate and different from the normal BGP
routing sessions described above - e.g. to a central EPE controller. routing sessions described above - e.g. to a central EPE controller.
6.2. Peer-Node-SID for Node D 6.2. Peer-Node-SID for Node D
Descriptor TLVs used in the BGP-LS Link NLRI: Descriptor TLVs used in the BGP-LS Link NLRI:
skipping to change at page 17, line 33 skipping to change at page 17, line 41
| Codepoint | Description | | Codepoint | Description |
+---------------------------------------+ +---------------------------------------+
| 7 | Protocol-ID BGP | | 7 | Protocol-ID BGP |
| 516 | BGP Router-ID | | 516 | BGP Router-ID |
| 517 | BGP Confederation Member | | 517 | BGP Confederation Member |
| 1101 | Peer-Node-SID | | 1101 | Peer-Node-SID |
| 1102 | Peer-Adj-SID | | 1102 | Peer-Adj-SID |
| 1103 | Peer-Set-SID | | 1103 | Peer-Set-SID |
+------------+--------------------------+ +------------+--------------------------+
IANA has now confirmed the assignment of the above codepoints. See Figure 6: BGP-LS New Codepoints
Section 8.
IANA has now confirmed the Early Allocation of the above codepoints.
See Section 8.
8. IANA Considerations 8. IANA Considerations
This document defines: This document defines:
A new Protocol-ID: BGP. The codepoint is from the "BGP-LS A new Protocol-ID: BGP. The codepoint is from the "BGP-LS
Protocol-IDs" registry. Protocol-IDs" registry.
Two new TLVs: BGP-Router-ID and BGP Confederation Member. The Two new TLVs: BGP-Router-ID and BGP Confederation Member. The
codepoints are in the "BGP-LS Node Descriptor, Link Descriptor, codepoints are in the "BGP-LS Node Descriptor, Link Descriptor,
skipping to change at page 18, line 10 skipping to change at page 18, line 18
Three new BGP-LS Attribute TLVs: Peer-Node-SID, Peer-Adj-SID and 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, Peer-Set-SID. The codepoints are in the "BGP-LS Node Descriptor,
Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry. Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry.
8.1. New BGP-LS Protocol-ID 8.1. New BGP-LS Protocol-ID
This document defines a new value in the registry "BGP-LS Protocol- This document defines a new value in the registry "BGP-LS Protocol-
IDs": IDs":
+----------------------------------------------+ +------------------------------------------------------+
| Codepoint | Description | Status | | Codepoint | Description | Status |
+----------------------------------------------+ +------------------------------------------------------+
| 7 | BGP | Assigned by IANA | | 7 | BGP | Early Allocation by IANA |
+----------------------------------------------+ +------------------------------------------------------+
Figure 7: BGP Protocol Codepoint
8.2. Node Descriptors and Link Attribute TLVs 8.2. Node Descriptors and Link Attribute TLVs
This document defines 5 new TLVs in the registry "BGP-LS Node This document defines 5 new TLVs in the registry "BGP-LS Node
Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs": Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs":
o Two new node descriptor TLVs o Two new node descriptor TLVs
o Three new link attribute TLVs o Three new link attribute TLVs
All the new 5 codepoints are in the same registry: "BGP-LS Node All the new 5 codepoints are in the same registry: "BGP-LS Node
Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs". Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs".
The following new Node Descriptors TLVs are defined: The following new Node Descriptors TLVs are defined:
+-----------------------------------------------------------+ +-------------------------------------------------------------------+
| Codepoint | Description | Status | | Codepoint | Description | Status |
+-----------------------------------------------------------+ +-------------------------------------------------------------------+
| 516 | BGP Router-ID | Assigned by IANA | | 516 | BGP Router-ID | Early Allocation by IANA |
| 517 | BGP Confederation Member | Assigned by IANA | | 517 | BGP Confederation Member | Early Allocation by IANA |
+------------+----------------------------------------------+ +------------+------------------------------------------------------+
Figure 8: BGP-LS Descriptor TLVs Codepoints
The following new Link Attribute TLVs are defined: The following new Link Attribute TLVs are defined:
+-----------------------------------------------------------+ +-------------------------------------------------------------------+
| Codepoint | Description | Status | | Codepoint | Description | Status |
+-----------------------------------------------------------+ +-------------------------------------------------------------------+
| 1101 | Peer-Node-SID | Assigned by IANA | | 1101 | Peer-Node-SID | Early Allocation by IANA |
| 1102 | Peer-Adj-SID | Assigned by IANA | | 1102 | Peer-Adj-SID | Early Allocation by IANA |
| 1103 | Peer-Set-SID | Assigned by IANA | | 1103 | Peer-Set-SID | Early Allocation by IANA |
+------------+----------------------------------------------+ +------------+------------------------------------------------------+
Figure 9: BGP-LS Attribute TLVs Codepoints
9. Manageability Considerations 9. Manageability Considerations
The new protocol extensions introduced herein augment the existing The new protocol extensions introduced in this document augment the
IGP topology information BGP-LS distribution [RFC7752] by adding existing IGP topology information BGP-LS distribution [RFC7752] by
support for distribution of BGP peering topology information. As adding support for distribution of BGP peering topology information.
such, the Manageability Considerations section of [RFC7752] applies As such, the Manageability Considerations section of [RFC7752]
to these new extensions as well. applies to these new extensions as well.
Specifically, the malformed NLRI attribute tests for syntactic checks Specifically, the malformed NLRI attribute tests for syntactic checks
in the Fault Management section of [RFC7752] now apply to the TLVs in the Fault Management section of [RFC7752] now apply to the TLVs
for the BGP-LS NLRI TLVs defined in this document. The semantic or for the BGP-LS NLRI TLVs defined in this document. The semantic or
content checking for the TLVs specified in this document and their content checking for the TLVs specified in this document and their
association with the BGP-LS NLRI types or their associated BGP-LS association with the BGP-LS NLRI types or their associated BGP-LS
Attributes is left to the consumer of the BGP-LS information (e.g. an Attributes is left to the consumer of the BGP-LS information (e.g. an
application or a controller) and not the BGP protocol. application or a controller) and not the BGP protocol.
A consumer of the BGP-LS information is retrieving this information
from a BGP protocol component, that is doing the signaling over a
BGP-LS session, via some APIs or a data model (refer Section 1 and 2
of [RFC7752]). The handling of semantic or content errors by the
consumer would be dictated by the nature of its application usage and
hence is beyond the scope of this document. It may be expected that
an error detected in the NLRI descriptor TLVs would result in that
specific NLRI update being unusable and hence its update to be
discarded along with an error log. While an error in Attribute TLVs
would result in only that specific attribute being discarded with an
error log.
The operator MUST be provided with the options of configuring, The operator MUST be provided with the options of configuring,
enabling, and disabling the advertisement of each of the Peer-Node- enabling, and disabling the advertisement of each of the Peer-Node-
SID, Peer-Adj-SID, and Peer-Set-SID as well as control of which SID, Peer-Adj-SID, and Peer-Set-SID as well as control of which
information is advertised to which internal or external peer. This information is advertised to which internal or external peer. This
is not different from what is required by a BGP speaker in terms of is not different from what is required by a BGP speaker in terms of
information origination and advertisement. information origination and advertisement.
BGP Peering Segments are associated with the normal BGP routing BGP Peering Segments are associated with the normal BGP routing
peering sessions. However, the BGP peering information along with peering sessions. However, the BGP peering information along with
these Peering Segments themselves are advertised via a distinct BGP- these Peering Segments themselves are advertised via a distinct BGP-
LS peering session. It is expected that this isolation as described LS peering session. It is expected that this isolation as described
in [RFC7752] is followed when advertising BGP peering topology in [RFC7752] is followed when advertising BGP peering topology
information via BGP-LS. information via BGP-LS.
BGP-EPE functionality enables the capability for instantiation of an BGP-EPE functionality enables the capability for instantiation of an
SR path for traffic engineering a flow via an egress BGP router to a SR path for traffic engineering a flow via an egress BGP router to a
specific peer, bypassing the normal BGP best path routing for that specific peer, bypassing the normal BGP best path routing for that
flow and any routing policies implemented in BGP on that egress BGP flow and any routing policies implemented in BGP on that egress BGP
router. As with any traffic engineering solution, the controller or router. As with any traffic engineering solution, the controller or
application implementing the policy needs to ensure that there is no application implementing the policy needs to ensure that there is no
looping or mis-routing of traffic. looping or mis-routing of traffic. Traffic counters corresponding to
the MPLS label of the BGP Peering SID on the router would indicate
the traffic being forwarded based on the specific EPE path.
Monitoring these counters and the flows hitting the corresponding
MPLS forwarding entry would help identify issues, if any, with
traffic engineering over the EPE paths.
10. Security Considerations 10. Security Considerations
[RFC7752] defines BGP-LS NLRI to which the extensions defined in this [RFC7752] defines BGP-LS NLRI to which the extensions defined in this
document apply. The Security Considerations section of [RFC7752] document apply. The Security Considerations section of [RFC7752]
also applies to these extensions. also applies to these extensions.
BGP-EPE enables engineering of traffic when leaving the BGP-EPE enables engineering of traffic when leaving the
administrative domain via an egress BGP router. Therefore precaution administrative domain via an egress BGP router. Therefore precaution
is necessary to ensure that the BGP peering information collected via is necessary to ensure that the BGP peering information collected via
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