draft-ietf-bess-virtual-subnet-fib-reduction-01.txt   draft-ietf-bess-virtual-subnet-fib-reduction-02.txt 
Network Working Group X. Xu Network Working Group X. Xu
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Informational C. Jacquenet Intended status: Informational C. Jacquenet
Expires: January 31, 2016 Orange Expires: September 1, 2016 Orange
T. Boyes T. Boyes
Bloomberg LP Bloomberg LP
B. Fee B. Fee
Extreme Networks Extreme Networks
W. Henderickx W. Henderickx
Alcatel-Lucent Alcatel-Lucent
July 30, 2015 February 29, 2016
FIB Reduction in Virtual Subnet FIB Reduction in Virtual Subnet
draft-ietf-bess-virtual-subnet-fib-reduction-01 draft-ietf-bess-virtual-subnet-fib-reduction-02
Abstract Abstract
Virtual Subnet is a BGP/MPLS IP VPN-based subnet extension solution Virtual Subnet is a BGP/MPLS IP VPN-based subnet extension solution
which is intended for building Layer3 network virtualization overlays which is intended for building Layer3 network virtualization overlays
within and/or between data centers. This document describes a within and/or between data centers. This document describes a
mechanism for reducing the FIB size of PE routers in the Virtual mechanism for reducing the FIB size of PE routers in the Virtual
Subnet context. Subnet context.
Status of This Memo Status of This Memo
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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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 January 31, 2016. This Internet-Draft will expire on September 1, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2016 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Terminology 2. Terminology
This memo makes use of the terms defined in [RFC4364]. This memo makes use of the terms defined in [RFC4364].
3. Solution Description 3. Solution Description
+----------+ +----------+
+----+PE/RR(APR)+----+ +----+PE/RR(APR)+----+
+-----------------+ | +----------+ | +-----------------+ +------------------+ | +----------+ | +---------------_--+
|VPN_A:10.1.1.1/24| | | |VPN_A:10.1.1.1/24| |VPN_A:192.0.2.1/24| | | |VPN_A:192.0.2.1/24|
| \ | | | | / | | \ | | | | / |
| +------+ \++---+-+ +-+---++/ +------+ | | +------+ \ ++---+-+ +-+---++/ +------+ |
| |Host A+------+ PE-1 | | PE-2 +------+Host B| | | |Host A+------_+ PE-1 | | PE-2 +------+Host B| |
| +------+\ ++-+-+-+ +-+-+-++ /+------+ | | +------+\ ++-+-+-+ +-+-+-++ /+------+ |
| 10.1.1.2/24 | | | | | | 10.1.1.3/24 | | 192.0.2.2/24 | | | | | | 192.0.2.3/24 |
| | | | | | | | | | | | | | | |
| DC West | | | IP/MPLS Backbone | | | DC East | | DC West | | | IP/MPLS Backbone | | | DC East |
+-----------------+ | | | | +-----------------+ +------------------+ | | | | +------------------+
| +--------------------+ | | +--------------------+ |
| | | |
VRF: V VRF:V VRF: V VRF:V
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
| Prefix- | Nexthop |Protocol|In_FIB| | Prefix | Nexthop |Protocol|In_FIB| | Prefix | Nexthop |Protocol|In_FIB| | Prefix | Nexthop |Protocol|In_FIB|
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.1/32 |127.0.0.1| Direct | Yes | |10.1.1.1/32 |127.0.0.1| Direct | Yes | |192.0.2.1/32 |127.0.0.1| Direct | Yes | |192.0.2.1/32 |127.0.0.1| Direct | Yes |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.2/32 |10.1.1.2 | Direct | Yes | |10.1.1.2/32 | PE-1 | IBGP | No | |192.0.2.2/32 |192.0.2.2| Direct | Yes | |192.0.2.2/32 | PE-1 | IBGP | No |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.3/32 | PE-2 | IBGP | No | |10.1.1.3/32 |10.1.1.3 | Direct | Yes | |192.0.2.3/32 | PE-2 | IBGP | No | |192.0.2.3/32 |192.0.2.3| Direct | Yes |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.0/25 | APR | IBGP | Yes | |10.1.1.0/25 | APR | IBGP | Yes | |192.0.2.0/25 | APR | IBGP | Yes | |192.0.2.0/25 | APR | IBGP | Yes |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.128/25| APR | IBGP | Yes | |10.1.1.128/25| APR | IBGP | Yes | |192.0.2.128/25| APR | IBGP | Yes | |192.0.2.128/25| APR | IBGP | Yes |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
|10.1.1.0/24 | 10.1.1.1| Direct | Yes | |10.1.1.0/24 |10.1.1.1 | Direct | Yes | |192.0.2.0/24 |192.0.2.1| Direct | Yes | |192.0.2.0/24 |192.0.2.1| Direct | Yes |
+-------------+---------+--------+------+ +-------------+---------+--------+------+ +--------------+---------+--------+------+ +--------------+---------+--------+------+
Figure 1: Selective FIB Installation Example Figure 1: Selective FIB Installation Example
To reduce the FIB size of PE routers, the selective FIB installation To reduce the FIB size of PE routers, the selective FIB installation
concept as described in [I-D.ietf-grow-va] can be leveraged in the concept as described in [I-D.ietf-grow-va] can be leveraged in the
Virtual Subnet context. Take the VPN instance demonstrated in Virtual Subnet context. Take the VPN instance demonstrated in
Figure 1 as an example, the FIB reduction procedures are described as Figure 1 as an example, the FIB reduction procedures are described as
follows: follows:
1. Multiple more specific prefixes (e.g., 1.1.1.0/25 and 1. Multiple more specific prefixes (e.g., 192.0.2.0/25 and
1.1.1.128/25) corresponding to an extended subnet (i.e., 192.0.2.128/25) corresponding to an extended subnet (i.e.,
1.1.1.0/24) are specified as Virtual Prefixes (VPs). Meanwhile, 192.0.2.0/24) are specified as Virtual Prefixes (VPs).
one or more PE routers (or route reflectors) are configured as
Aggregation Point Routers (APR) for each VP. The APRs for a Meanwhile, one or more PE routers (or route reflectors) are
given VP would install a null route to that VP while propagating configured as Aggregation Point Routers (APR) for each VP. The
a route to that VP via the L3VPN signaling. APRs for a given VP would install a null route to that VP while
propagating a route to that VP via the L3VPN signaling.
2. For a given host route in the routing table which is learnt from 2. For a given host route in the routing table which is learnt from
any remote PE router, PE routers which are non-APRs for any VP any remote PE router, PE routers which are non-APRs for any VP
covering this host route would not install it into the FIB by covering this host route would not install it into the FIB by
default. In contrast, PE routers (or route reflectors) which are default. In contrast, PE routers (or route reflectors) which are
APRs for any VP covering that host route would install it into APRs for any VP covering that host route would install it into
the FIB. If one or more particular remote host routes need to be the FIB. If one or more particular remote host routes need to be
installed by non-APR PE routers by default as well for whatever installed by non-APR PE routers by default as well for whatever
reasons, the best way to realize such goal is to attach a special reasons, the best way to realize such goal is to attach a special
extended communities attribute to those particular host routes extended communities attribute to those particular host routes
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Raszuk and Bruno Decraene for their valuable suggestions on this Raszuk and Bruno Decraene for their valuable suggestions on this
document. document.
5. IANA Considerations 5. IANA Considerations
The type value for the Extended Communities Attributes as described The type value for the Extended Communities Attributes as described
in this doc is required to be allocated by the IANA. in this doc is required to be allocated by the IANA.
6. Security Considerations 6. Security Considerations
This document does not introduce any new security risk. Those security considerations as described in
[I-D.ietf-bess-virtual-subnet] are applicable to this document. This
document does not introduce any new security risk.
7. References 7. References
7.1. Normative References 7.1. Normative References
[I-D.ietf-bess-virtual-subnet] [I-D.ietf-bess-virtual-subnet]
Xu, X., Raszuk, R., Jacquenet, C., Boyes, T., and B. Fee, Xu, X., Jacquenet, C., Raszuk, R., Boyes, T., and B. Fee,
"Virtual Subnet: A BGP/MPLS IP VPN-based Subnet Extension "Virtual Subnet: A BGP/MPLS IP VPN-based Subnet Extension
Solution", draft-ietf-bess-virtual-subnet-00 (work in Solution", draft-ietf-bess-virtual-subnet-07 (work in
progress), June 2015. progress), December 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <http://www.rfc-editor.org/info/rfc4364>. 2006, <http://www.rfc-editor.org/info/rfc4364>.
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