--- 1/draft-ietf-idr-bgp-prefix-sid-20.txt 2018-05-29 14:13:20.362545590 -0700 +++ 2/draft-ietf-idr-bgp-prefix-sid-21.txt 2018-05-29 14:13:20.398546461 -0700 @@ -1,32 +1,32 @@ IDR S. Previdi, Ed. Internet-Draft C. Filsfils Intended status: Standards Track A. Lindem, Ed. -Expires: November 9, 2018 Cisco Systems +Expires: November 30, 2018 Cisco Systems A. Sreekantiah H. Gredler RtBrick Inc. - May 8, 2018 + May 29, 2018 Segment Routing Prefix SID extensions for BGP - draft-ietf-idr-bgp-prefix-sid-20 + draft-ietf-idr-bgp-prefix-sid-21 Abstract The Segment Routing (SR) architecture allows a node to steer a packet flow through any topological path and service chain by leveraging source routing. The ingress node prepends an SR header to a packet containing a set of segment identifiers (SID). Each SID represents a topological or a service-based instruction. Per-flow state is - maintained only on the ingress node of the SR domain. Ah SR domain + maintained only on the ingress node of the SR domain. An SR domain is defined as a single administrative domain for global SID assignment. This document defines an optional, transitive BGP attribute for announcing BGP Prefix Segment Identifiers (BGP Prefix-SID) information. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", @@ -43,21 +43,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on November 9, 2018. + This Internet-Draft will expire on November 30, 2018. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -103,25 +103,25 @@ assignment. It may be comprised of a single AS or multiple ASes under consolidated global SID administration. Typically, the ingress node of the SR domain prepends an SR header containing segments identifiers (SIDs) to an incoming packet. 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 SID consists of a label. [I-D.ietf-spring-segment-routing] also describes how segment routing - can be applied to an IPv6 dataplane - [I-D.ietf-6man-segment-routing-header] (SRv6) using a new IPv6 - routing header containing a stack of SR SIDs encoded as IPv6 - addresses. The applicability and support for Segment Routing over - IPv6 is beyond the scope of this document. + can be applied to an IPv6 dataplane (SRv6) using an IPv6 routing + header containing a stack of SR SIDs encoded as IPv6 addresses + [I-D.ietf-6man-segment-routing-header]. The applicability and + support for Segment Routing over IPv6 is beyond the scope of this + document. 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 ([I-D.ietf-spring-segment-routing]) within the SR/BGP domain (i.e., the set of Autonomous Systems under a common administration and control and where SR is used) and identifies an instruction to forward the packet over the ECMP-aware best-path computed by BGP to 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 by the BGP Prefix-SID. @@ -427,25 +427,24 @@ When a BGP Prefix-SID attribute changes and transitions from "conflicting" to "acceptable", the BGP Prefix-SID attributes for other prefixes may also transition to "acceptable" as well. Implementations SHOULD assure all impacted prefixes revert to using the label indices corresponding to these newly "acceptable" BGP Prefix-SID attributes. The outgoing label is always programmed as per classic Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC8277]) operation. Specifically, a BGP speaker receiving a prefix with a BGP Prefix-SID attribute and a - label NLRI field of Implicit NULL [IANA-MPLS-SPECIAL-LABEL] from a - neighbor MUST adhere to standard behavior and program its MPLS - dataplane to pop the top label when forwarding traffic to the prefix. - The label NLRI defines the outbound label that MUST be used by the - receiving node. + label NLRI field of Implicit NULL [RFC3032] from a neighbor MUST + adhere to standard behavior and program its MPLS dataplane to pop the + top label when forwarding traffic to the prefix. The label NLRI + defines the outbound label that MUST be used by the receiving node. 5. Advertising BGP Prefix-SID Attribute The BGP Prefix-SID attribute MAY be attached to labeled BGP prefixes (IPv4/IPv6) [RFC8277]. In order to prevent distribution of the BGP Prefix-SID attribute beyond its intended scope of applicability, attribute filtering SHOULD be deployed to remove the BGP Prefix-SID attribute at the administrative boundary of the segment routing domain. @@ -473,21 +472,21 @@ Since the label index value must be unique within an SR domain, by default an implementation SHOULD NOT advertise the BGP Prefix-SID attribute outside an Autonomous System unless it is explicitly configured to do so. In all cases, the label field of the advertised NLRI ([RFC8277], [RFC4364]) MUST be set to the local/incoming label programmed in the MPLS dataplane for the given advertised prefix. If the prefix is associated with one of the BGP speaker's interfaces, this is the usual MPLS label (such as the Implicit or Explicit NULL label - [IANA-MPLS-SPECIAL-LABEL]). + [RFC3032]). 6. Error Handling of BGP Prefix-SID Attribute When a BGP Speaker receives a BGP Update message containing a malformed or invalid BGP Prefix-SID attribute attached to a Labeled IPv4/IPv6 unicast prefix [RFC8277], it MUST ignore the received BGP Prefix-SID attributes and not advertise it to other BGP peers. In this context, a malformed BGP Prefix-SID attribute is one that cannot be parsed due to not meeting the minimum attribute length requirement, contains a TLV length that doesn't conform to the length @@ -694,45 +693,45 @@ [RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017, . 12.2. Informative References [I-D.ietf-6man-segment-routing-header] Previdi, S., Filsfils, C., Leddy, J., Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header - (SRH)", draft-ietf-6man-segment-routing-header-12 (work in - progress), April 2018. + (SRH)", draft-ietf-6man-segment-routing-header-13 (work in + progress), May 2018. [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-06 - (work in progress), April 2018. + Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-08 + (work in progress), May 2018. [I-D.ietf-idr-bgpls-segment-routing-epe] Previdi, S., Filsfils, C., Patel, K., Ray, S., and J. Dong, "BGP-LS extensions for Segment Routing BGP Egress Peer Engineering", draft-ietf-idr-bgpls-segment-routing- epe-15 (work in progress), March 2018. [I-D.ietf-spring-segment-routing-msdc] Filsfils, C., Previdi, S., Mitchell, J., Aries, E., and P. Lapukhov, "BGP-Prefix Segment in large-scale data centers", draft-ietf-spring-segment-routing-msdc-08 (work in progress), December 2017. - [IANA-MPLS-SPECIAL-LABEL] - "IANA Special-Purpose Multiprotocol Label Switching (MPLS) - Label Values Registry", . + [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., + Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack + Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, + . [RFC5004] Chen, E. and S. Sangli, "Avoid BGP Best Path Transitions from One External to Another", RFC 5004, DOI 10.17487/RFC5004, September 2007, . [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,