Internet DRAFT - draft-sun-bess-vpn-orf-extension
draft-sun-bess-vpn-orf-extension
INTERNET-DRAFT Chunxia Sun
Intended status: Proposed Standard Yaokun Zhang
Donald Eastlake 3rd
Huawei
Expires: April 21, 2019 October 22, 2018
Controlling VPN Routes More Precisely by ORF Extension
draft-sun-bess-vpn-orf-extension-00
Abstract
RFC 4684 defines Multi-Protocol BGP (MP-BGP) procedures that allow
BGP speakers to exchange Route Target reachability information which
can be used to build a route distribution graph in order to limit the
propagation of Virtual Private Network (VPN) Network Layer
Reachability Information (NLRI) between different autonomous systems
or distinct clusters of the same autonomous system.
However, according to RFC 4684, in some scenarios, more routes will
be sent than need to be sent.
This document extends RFC 4684. This extension allows a BGP speaker
to advertise VPN routes more precisely.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Distribution of this document is unlimited. Comments should be sent
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Sun, Zhang, & Eastlake [Page 1]
Internet-Draft VPN ORF Extension
Table of Contents
1. Introduction............................................3
1.1 Requirements Language..................................3
1.2 Terminology............................................3
2. Solution................................................5
3. BGP Encoding............................................6
4. Security Considerations.................................7
5. IANA Considerations.....................................7
Normative References.......................................8
Informative References.....................................8
Acknowledgments............................................8
Authors' Addresses.........................................9
Sun, Zhang, & Eastlake [Page 2]
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1. Introduction
[RFC4684] defines Multi-Protocol BGP (MP-BGP) procedures that allow
BGP speakers to exchange Route Target reachability information which
can be used to build a route distribution graph in order to limit the
propagation of Virtual Private Network (VPN) Network Layer
Reachability Information (NLRI) between different autonomous systems
or distinct clusters of the same autonomous system.
However, according to the extension of BGP protocol by [RFC4684], in
some scenarios, for example, when the same route targets exist in
different BGP address families, more routes will be sent than need to
be sent, which violates the original intention of the ORF
implementation.
This document extends [RFC4684]. This extension allows a BGP speaker
to advertise VPN routes more precisely when BGP speaker has the same
route target in different address families.
1.1 Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2 Terminology
AFI: Address Family Identifier(a BGP address type)
SAFI: Subsequence Address Family Identifier (a BGP address sub-type)
BGP: Border Gateway Protocol
VPN: Virtual Private Network
PE: Provider Edge device
CE: Customer Edge(router)
EVPN: Ethernet Virtual Private Network
L3VPN: Layer 3 Virtual Private Network
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iBGP: Internal BGP (i.e., a BGP peering session that connects two
routers within an autonomous system)
MP-BGP: MultiProtocol-Border Gateway Protocol
MPLS: MultiProtocol Label Switching
NLRI: Network Layer Reachability Information
ORF: Outbound Route Filtering
RT: Route Target
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2. Solution
In the Section 4 of [RFC4684], the packet structure of the ORF route
is defined. The ORF route prefix carries only the original AS and
route-target information, and does not carry the address family
information corresponding to the route-target.
Let us give an example of the problem of route advertisement in
[RFC4684]. For example, RTA and RTB are neighbors in EVPN and
neighbors in L3VPN. The route-target of the EVPN instance on RTA is
100:1, the route- target of the L3VPN instance on RTA is 200:1, and
the route-target of the EVPN instance on RTB is 100:1, the route-
target of the L3VPN instance on RTB is 100:1. The ORF capability is
enabled on both RTA and RTB. After the neighbor relationship between
RTA and RTB is established, RTA sends ORF routes to inform RTB routes
with a route- target of 100:1 and 200:1 are required. After receiving
the ORF routes of RTA, RTB sends the routes with the route-target of
100:1 to RTA, including the EVPN routes with the route-target of
100:1 and L3VPN routes with route-target of 100:1. In fact, RTA is
not required for L3VPN routes with route-target of 100:1.
In order to solve the problem above, [RFC4684] is extended, the RT-
ORF-DOMAIN attribute is added to the ORF routes, and the address
families corresponding to the route target is carried in the
attribute, for example: EVPN, VPNv4, etc.;
In the above example, the ORF routes sent by RTA to RTB carry the
information that RTA wants to receive the routes of EVPN address
family with the route target of 100:1 and the routes of VPNv4 address
family with the route target of 200:1. After receiving the ORF routes
from RTA, RTB will only send the routes of the EVPN address family
with the route target of 100:1 to RTA.
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3. BGP Encoding
[RFC4684] defines the packet structure of the ORF route, including
the route prefix and attributes. This document extends [RFC4684] and
adds the RT-ORF-DOMAIN attribute to the ORF route. This attribute is
composed as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attr. Flags |Attr. Type Code|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI | SAFI |
| AFI | SAFI |
| ...... | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
RT-ORF-DOMAIN is an optional transitive attribute, and the attribute
type is to be assigned. The role of this attribute has been described
in Section 2.
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4. Security Considerations
TBD
5. IANA Considerations
TBD
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Normative References
[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>.
[RFC4684] R. Bonica, " Constrained Route Distribution for Border
Gateway Protocol/MultiProtocol Label Switching
(BGP/MPLS)Internet Protocol (IP) Virtual Private Networks
(VPNs) ", RFC 4684, November 2006.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119
Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May
2017, <https://www.rfc-editor.org/info/rfc8174>.
Informative References
TBD
Acknowledgments
The authors would like to thank the following for their valuable
contributions of this document:
TBD
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Authors' Addresses
Chunxia Sun
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: sunchunxia@huawei.com
Yaokun Zhang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhangyaokun@huawei.com
Donald Eastlake 3rd
Huawei Technologies
1424 Pro Shop Court
Davenport, FL 33896
USA
Phone: +1-508-333-2270
Email: Donald.Eastlake@huawei.com
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Sun, Zhang, & Eastlake [Page 10]
