draft-ietf-grow-mrt-add-paths-03.txt   rfc8050.txt 
Global Routing Operations C. Petrie Internet Engineering Task Force (IETF) C. Petrie
Internet-Draft RIPE NCC Request for Comments: 8050 RIPE NCC
Intended status: Standards Track T. King Category: Standards Track T. King
Expires: July 18, 2017 DE-CIX ISSN: 2070-1721 DE-CIX
January 14, 2017 May 2017
Multi-Threaded Routing Toolkit (MRT) Routing Information Export Format Multi-Threaded Routing Toolkit (MRT) Routing Information Export Format
with BGP Additional Paths Extensions with BGP Additional Path Extensions
draft-ietf-grow-mrt-add-paths-03
Abstract Abstract
This document updates the Multi-threaded Routing Toolkit (MRT) export This document extends the Multi-threaded Routing Toolkit (MRT) export
format for Border Gateway Protocol (BGP) routing information by format for Border Gateway Protocol (BGP) routing information by
extending it to support the Advertisement of Multiple Paths in BGP supporting the advertisement of multiple paths in BGP extensions.
extensions.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on July 18, 2017. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8050.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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skipping to change at page 2, line 13 skipping to change at page 2, line 11
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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. MRT Subtypes for Types BGP4MP/BGP4MP_ET . . . . . . . . . . . 3 3. MRT Subtypes for Types BGP4MP/BGP4MP_ET . . . . . . . . . . . 3
4. MRT Subtypes for Type TABLE_DUMP_V2 . . . . . . . . . . . . . 3 4. MRT Subtypes for Type TABLE_DUMP_V2 . . . . . . . . . . . . . 3
4.1. AFI/SAFI specific RIB Subtypes . . . . . . . . . . . . . 3 4.1. AFI/SAFI-Specific RIB Subtypes . . . . . . . . . . . . . 4
4.2. RIB_GENERIC_ADDPATH Subtype . . . . . . . . . . . . . . . 4 4.2. RIB_GENERIC_ADDPATH Subtype . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. BGP4MP/BGP4MP_ET Subtype codes: . . . . . . . . . . . . . 4 5.1. BGP4MP/BGP4MP_ET Subtype Codes . . . . . . . . . . . . . 5
5.2. TABLE_DUMP_V2 Subtype codes: . . . . . . . . . . . . . . 5 5.2. TABLE_DUMP_V2 Subtype Codes . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Normative References . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
The MRT record format [RFC6396] was developed to provide researchers The MRT record format [RFC6396] was developed to provide researchers
and engineers a means to encapsulate, export, and archive routing and engineers a means to encapsulate, export, and archive routing
protocol transactions and routing information base snapshots. protocol transactions and RIB snapshots.
The Advertisement of Multiple Paths in BGP [RFC7911] defines a BGP The Advertisement of Multiple Paths in BGP [RFC7911] defines a BGP
extension to allow the advertisement of multiple paths for the same extension to allow the advertisement of multiple paths for the same
address prefix without the new paths implicitly replacing any address prefix without the new paths implicitly replacing any
previous ones. previous ones.
This document contains an optional extension to the MRT format This document contains an optional extension to the MRT format
[RFC6396] and introduces additional definitions of MRT subtype fields [RFC6396] and introduces additional definitions of MRT subtype fields
to permit representation of multiple path advertisements [RFC7911]. to permit representation of multiple path advertisements [RFC7911].
2. Rationale 2. Rationale
MRT parsers are usually stateless. In order to parse BGP messages MRT parsers are usually stateless. In order to parse BGP messages
which contain data structures that depend on the capabilities that contain data structures that depend on the capabilities
negotiated during the BGP session setup, the so-called MRT subtypes negotiated during the BGP session setup, the MRT subtypes are
are utilized. The Advertisement of Multiple Path [RFC7911] extension utilized. The Advertisement of Multiple Paths [RFC7911] extension
for BGP alters the encoding of the BGP NLRI format for withdraws and for BGP alters the encoding of the BGP Network Layer Reachability
announcements. Therefore new BGP4MP/BGP4MP_ET subtypes as defined in Information (NLRI) format for withdraws and announcements.
[RFC6396] are required to signal to a MRT parser how to parse the Therefore, new BGP4MP/BGP4MP_ET subtypes as defined in [RFC6396] are
NLRI. required to signal to an MRT parser how to parse the NLRI.
In section 4.3 [RFC6396] of the MRT specification RIB subtypes are In Section 4.3 of the MRT specification [RFC6396], RIB subtypes are
specified. Prefix length and prefix fields are encoded in the same specified. Prefix length and prefix fields are encoded in the same
manner as the BGP NLRI encoding. In order to support path identifier manner as the BGP NLRI encoding. In order to support Path Identifier
information as defined in [RFC7911] new subtypes need to be added. information as defined in [RFC7911], new subtypes need to be added.
The following two sections define the required subtypes. The following two sections define the required subtypes.
3. MRT Subtypes for Types BGP4MP/BGP4MP_ET 3. MRT Subtypes for Types BGP4MP/BGP4MP_ET
This document defines the following new Subtypes: This document defines the following new subtypes:
o BGP4MP_MESSAGE_ADDPATH o BGP4MP_MESSAGE_ADDPATH
o BGP4MP_MESSAGE_AS4_ADDPATH o BGP4MP_MESSAGE_AS4_ADDPATH
o BGP4MP_MESSAGE_LOCAL_ADDPATH o BGP4MP_MESSAGE_LOCAL_ADDPATH
o BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH o BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH
The fields of these message types are identical to the equivalent The fields of these message types are identical to the equivalent
non-additional-path versions specified in section 4.4 [RFC6396]. non-additional-path versions specified in Section 4.4 of [RFC6396].
These enhancements continues to encapsulate the entire BGP message in These enhancements continue to encapsulate the entire BGP message in
the BGP message field. the BGP message field.
4. MRT Subtypes for Type TABLE_DUMP_V2 4. MRT Subtypes for Type TABLE_DUMP_V2
This document defines the following new Subtypes: This document defines the following new subtypes:
o RIB_IPV4_UNICAST_ADDPATH o RIB_IPV4_UNICAST_ADDPATH
o RIB_IPV4_MULTICAST_ADDPATH o RIB_IPV4_MULTICAST_ADDPATH
o RIB_IPV6_UNICAST_ADDPATH o RIB_IPV6_UNICAST_ADDPATH
o RIB_IPV6_MULTICAST_ADDPATH o RIB_IPV6_MULTICAST_ADDPATH
o RIB_GENERIC_ADDPATH o RIB_GENERIC_ADDPATH
The fields of these message types are identical to the equivalent The fields of these message types are identical to the equivalent
non-additional-path versions specified in section 4.3 [RFC6396]. non-additional-path versions specified in Section 4.3 of [RFC6396].
However, for the specific case of the 4 AFI/SAFI specific RIB However, for the case of the 4 AFI/SAFI-specific RIB subtypes, the
subtypes, the existing RIB Entries field is re-defined as detailed in existing RIB Entries field is redefined as detailed in the sections
the sections below. below.
4.1. AFI/SAFI specific RIB Subtypes 4.1. AFI/SAFI-Specific RIB Subtypes
In order to preserve the record compaction achieved by using the most In order to preserve the record compaction achieved by using the most
common subtypes, and allowing multiple RIB Entries to be stored in a common subtypes and allow multiple RIB Entries to be stored in a
single TABLE_DUMP_V2 record, the existing RIB Entries field is single TABLE_DUMP_V2 record, the existing RIB Entries field is
redefined for use within the new AFI/SAFI specific RIB Subtypes redefined for use within the new AFI/SAFI-specific RIB subtypes
defined by this document as follows: defined by this document as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Index | | Peer Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originated Time | | Originated Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Identifier | | Path Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Length | | Attribute Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BGP Attributes... (variable) | BGP Attributes... (variable)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: RIB Entries for AFI/SAFI-specific RIB Subtypes with Figure 1: RIB Entries for AFI/SAFI-Specific RIB Subtypes with
additional-paths support Support for Additional Paths
This adds a field to the RIB Entries record, to store the path This adds a field to the RIB Entries record to store the Path
identifier, when used with the RIB_IPV4_UNICAST_ADDPATH, Identifier when used with the RIB_IPV4_UNICAST_ADDPATH,
RIB_IPV4_MULTICAST_ADDPATH, RIB_IPV6_UNICAST_ADDPATH and RIB_IPV4_MULTICAST_ADDPATH, RIB_IPV6_UNICAST_ADDPATH, and
RIB_IPV6_MULTICAST_ADDPATH subtypes. RIB_IPV6_MULTICAST_ADDPATH subtypes.
4.2. RIB_GENERIC_ADDPATH Subtype 4.2. RIB_GENERIC_ADDPATH Subtype
The fields of this subtype are identical to the equivalent non- The fields of this subtype are identical to the equivalent non-
additional-path versions specified in section 4.3.3 [RFC6396]. These additional-path versions specified in Section 4.3.3 of [RFC6396].
fields continue to encapsulate the raw and additional-path enabled These fields continue to encapsulate the raw and additional-path-
AFI/SAFI/NLRI in the record, and the raw attributes in the RIB enabled AFI/SAFI/NLRI in the record, and the raw attributes in the
Entries. RIB Entries.
For clarity, the RIB Entries in this subtype are not redefined. For clarity, the RIB Entries in this subtype are not redefined.
5. IANA Considerations 5. IANA Considerations
This document requests that IANA assign the following subtype codes IANA has assigned the subtype codes defined below in the "Multi-
to the MRT name space [1]: threaded Routing Toolkit (MRT)" registry
<https://www.iana.org/assignments/mrt>.
5.1. BGP4MP/BGP4MP_ET Subtype codes: 5.1. BGP4MP/BGP4MP_ET Subtype Codes
BGP4MP_MESSAGE_ADDPATH = 8 (Section 3) The following have been registered in the "BGP4MP Subtype Codes" and
"BGP4MP_ET Subtype Codes" registries:
BGP4MP_MESSAGE_AS4_ADDPATH = 9 (Section 3) 8 BGP4MP_MESSAGE_ADDPATH (RFC 8050)
BGP4MP_MESSAGE_LOCAL_ADDPATH = 10 (Section 3) 9 BGP4MP_MESSAGE_AS4_ADDPATH (RFC 8050)
BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH = 11 (Section 3)
The values provided above are suggested as they are used in 10 BGP4MP_MESSAGE_LOCAL_ADDPATH (RFC 8050)
implementations.
5.2. TABLE_DUMP_V2 Subtype codes: 11 BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH (RFC 8050)
RIB_IPV4_UNICAST_ADDPATH = 8 (Section 4.1) 5.2. TABLE_DUMP_V2 Subtype Codes
RIB_IPV4_MULTICAST_ADDPATH = 9 (Section 4.1) The following have been registered in the "TABLE_DUMP_V2 Subtype
Codes" registry:
RIB_IPV6_UNICAST_ADDPATH = 10 (Section 4.1) 8 RIB_IPV4_UNICAST_ADDPATH (RFC 8050)
RIB_IPV6_MULTICAST_ADDPATH = 11 (Section 4.1) 9 RIB_IPV4_MULTICAST_ADDPATH (RFC 8050)
RIB_GENERIC_ADDPATH = 12 (Section 4.2) 10 RIB_IPV6_UNICAST_ADDPATH (RFC 8050)
The values provided above are suggested as they are used in 11 RIB_IPV6_MULTICAST_ADDPATH (RFC 8050)
implementations.
12 RIB_GENERIC_ADDPATH (RFC 8050)
6. Security Considerations 6. Security Considerations
It is not believed that this document adds any additional security It is not believed that this document adds any additional security
considerations. considerations. However, the security considerations of [RFC6396]
are equally applicable to this document, because this document
However, the security considerations of [RFC6396] are equally permits the export of more detailed routing data.
applicable to this document, and this document permits the export of
more detailed routing data.
An organization that uses the MRT format to store their BGP routing An organization that uses the MRT format to store their BGP routing
information should be aware that supporting these extensions permits information should be aware that supporting these extensions permits
more detailed network path information to be stored, and should more detailed network path information to be stored and should
consider the implications of this within their environment. consider the implications of this within their environment.
An organization that peers with public BGP collectors, and enables An organization that peers with public BGP collectors and enables the
the additional-paths capability on a peering session, should be aware capability for additional paths on a peering session should be aware
that it is exporting not only its best paths, but potentially other that it is exporting not only its best paths, but potentially other
paths within its networks. The BGP peer should consider any and all paths within its networks. The BGP peer should consider any and all
implications of exposing this additional data. implications of exposing this additional data.
7. References 7. Normative References
7.1. Normative References
[RFC6396] Blunk, L., Karir, M., and C. Labovitz, "Multi-Threaded [RFC6396] Blunk, L., Karir, M., and C. Labovitz, "Multi-Threaded
Routing Toolkit (MRT) Routing Information Export Format", Routing Toolkit (MRT) Routing Information Export Format",
RFC 6396, DOI 10.17487/RFC6396, October 2011, RFC 6396, DOI 10.17487/RFC6396, October 2011,
<http://www.rfc-editor.org/info/rfc6396>. <http://www.rfc-editor.org/info/rfc6396>.
[RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder, [RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder,
"Advertisement of Multiple Paths in BGP", RFC 7911, "Advertisement of Multiple Paths in BGP", RFC 7911,
DOI 10.17487/RFC7911, July 2016, DOI 10.17487/RFC7911, July 2016,
<http://www.rfc-editor.org/info/rfc7911>. <http://www.rfc-editor.org/info/rfc7911>.
7.2. URIs
[1] https://www.iana.org/assignments/mrt/mrt.xhtml
Authors' Addresses Authors' Addresses
Colin Petrie Colin Petrie
RIPE NCC RIPE NCC
Stationsplein 11 Stationsplein 11
Amsterdam 1012 AB Amsterdam 1012 AB
NL The Netherlands
Email: cpetrie@ripe.net Email: cpetrie@ripe.net
Thomas King Thomas King
DE-CIX Management GmbH DE-CIX Management GmbH
Lichtstrasse 43i Lichtstrasse 43i
Cologne 50825 Cologne 50825
Germany Germany
Email: thomas.king@de-cix.net Email: thomas.king@de-cix.net
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