Internet DRAFT - draft-ni-l3vpn-pm-bgp-ext
draft-ni-l3vpn-pm-bgp-ext
Network Working Group H. Ni
Internet-Draft S. Zhuang
Intended status: Standards Track Z. Li
Expires: August 17, 2014 Huawei Technologies
February 13, 2014
BGP Extension For L3VPN Performance Monitoring
draft-ni-l3vpn-pm-bgp-ext-01
Abstract
This document describes a new VT address family in BGP to exchange
information required for apply performance monitoring in MPLS/BGP
VPN, as described in [I-D.dong-l3vpn-pm-framework].
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 17, 2014.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The New VT Sub Address Family . . . . . . . . . . . . . . . . 3
3.1. VT Sub Address Family . . . . . . . . . . . . . . . . . . 3
3.2. VT NLRI . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2.1. VT VPN-membership A-D Route . . . . . . . . . . . . . 5
3.2.2. VT Labeled Route . . . . . . . . . . . . . . . . . . 5
4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. VRF-to-VRF VPN Membership Auto Discovery . . . . . . . . 6
4.2. VRF-to-VRF Labeled Route Exchange . . . . . . . . . . . . 7
4.2.1. VT Labeled Route Update . . . . . . . . . . . . . . . 7
4.2.2. VT Labeled Route Withdrawal . . . . . . . . . . . . . 7
4.3. VRF-to-VRF Labeled Route Application . . . . . . . . . . 8
5. VT Route Selection Consideration . . . . . . . . . . . . . . 8
6. Deployment Consideration . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
This document describes the BGP encodings and procedures for
exchanging the information elements required by applying traffic
performance monitoring in MPLS/BGP VPN, as specified in [ID.draft-
dong-l3vpn-pm-framework-01].
Current BGP Labeled VPN Route exchange procedure combines VRF VPN-
membership Auto-Discovery and L3VPN Label allocation together. While
applying PM for L3VPN needs BGP extended to support VPN membership
Auto-Discovery and L3VPN Label allocation in a VRF-to-VRF manner. To
achieve this, a new Sub address family, called VRF-to-VRF Tunnel(VT)
Subsequent Address Family, is introduced.
This document defines two kinds of routes for VT NLRI:
VPN-Membership A-D Route: for the use of doing VRF VPN membership
auto-discovery in VRF-to-VRF manner
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VT Labeled Route: for the use of allocating VT Label from Local VRF
to Remote VRF to setup VRF-to-VRF Tunnel between the pair of VRFs.
2. Terminologies
This document uses the terminologies defined in [RFC4026]:
ERT: Export Route Target
IRT: Import Route Target
PE: Provider Edge
RD: Route Distinguisher
VRF: Virtual Routing and Forwarding
VT: VRF-to-VRF Tunnel
3. The New VT Sub Address Family
The BGP Multiprotocol Extensions [RFC4760] allow BGP to carry routes
from multiple "address families". In this document a new Subsequent
Address Family is introduced, called "VT Sub Address Family".
3.1. VT Sub Address Family
VT Address Family uses AFI 1/2 to present IPv4/IPv6 Address Family
and a specific VT_SAFI(TBD) to present VT Subsequent Address Family.
VT MP_REACH_NLRI and MP_UNREACH_NLRI are formatted as described in
[RFC4760]
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+---------------------------------------------------+
| Address Family Identifier (2 octets): 1/2 |
+---------------------------------------------------+
| Subsequent AFI (1 octet): VT_SAFI (TBD) |
+---------------------------------------------------+
| Length of Next Hop (1 octet): 4 |
+---------------------------------------------------+
| Next Hop: IPv4 Address |
+---------------------------------------------------+
| Reserved (1 octet) |
+---------------------------------------------------+
| BGP VT NLRI (Variable) |
+---------------------------------------------------+
Figure 1 VT MP_REACH_NLRI
+---------------------------------------------------+
| Address Family Identifier (2 octets): 1/2 |
+---------------------------------------------------+
| Subsequent AFI (1 octet): VT_SAFI (TBD) |
+---------------------------------------------------+
| BGP VT NLRI (Variable) |
+---------------------------------------------------+
Figure 2 VT MP_UNREACH_NLRI
3.2. VT NLRI
BGP VT NLRI has format as depicted in following diagram
+---------------------------------------------------+
| Route Type (1 octet) |
+---------------------------------------------------+
| Length (1 octet) |
+---------------------------------------------------+
| Route Type Specific (Variable) |
+---------------------------------------------------+
Figure 3 IPv4 VT-Family NLRI
Route Type indicates type of route under VT SAFI.
Type 1: VT VPN membership A-D Route
Type 2: VT Labeled Route
Length defines Route Type specific routes length in octets
Route Type specific route information field, encoded according to
Route Type definition.
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3.2.1. VT VPN-membership A-D Route
VT VPN membership A-D Route, concisely named as VT A-D Route
hereafter, is utilized for VRF-to-VRF VPN Membership Auto-Discovery
between PEs.
Its format is defined as following diagram:
+--------------------------------------------------+
| RD (8 octets) |
+--------------------------------------------------+
| Local Router's IP Address |
+--------------------------------------------------+
Figure 4 VT VPN Membership A-D Route
a) RD RD of one VRF on advertising PE, encoded as described in
[RFC4364].
b) Local Router's IP Address Advertising PE's IPv4/IPv6 address <RD,
Local Router's IP Address> is defined as Prefix of VT A-D Route.
3.2.2. VT Labeled Route
VT Labeled Route is utilized for VRF-To-VRF Label(s) allocation and
advertisement, its format is defined as following diagram.
+---------------------------------------------------+
| Local RD (8 octets) |
+---------------------------------------------------+
| Local Router's IP Address |
+---------------------------------------------------+
| Remote VRF's RD (8 octets) |
+---------------------------------------------------+
| Remote Router's IP Address |
+---------------------------------------------------+
| Label (3 octets) |
+---------------------------------------------------+
Figure 5 VT Labeled Route Format
a) Local RD Route Distinguisher value of one VRF on advertising PE,
encoded as described in [RFC4364].
b) Local Router's IP Address Advertising PE's IPv4/IPv6 address.
c) Remote VRF's RD Route Distinguisher value of Remote VRF encoded as
described in [RFC4364].
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d) Remote Router's IP Address: Remote PE's IPv4/IPv6 address.
e) Label The Label field carries one or more labels that corresponds
to the stack of labels [RFC3032]. Each label is encoded as 3 octets,
where the high-order 20 bits contain the label value, and the low-
order bit contains "Bottom of Stack" as defined in [RFC3032].
<Local RD, Local Router's IP Address, Remote VRF's RD, Remote
Router's IP Address> which indicates a pair of VRFs is defined as the
Prefix of VT Labeled Route.
4. Operations
4.1. VRF-to-VRF VPN Membership Auto Discovery
For every PE, it needs to process all its VRF configured and generate
one VT A-D Route for each VRF respectively.
RD field MUST be filled with the VRF's RD value.
Local Router's IP Address field MUST filled with the Advertising
Router's IP address.
The VT A-D Route MUST carry all IRTs of the VRF in BGP Update's Ext-
Community Path Attribute, route importing request of one VRF is
described by its corresponding VT A-D route. In contrast VPN Labeled
Routes carry ERTs in BGP Update's Ext-Community Path Attribute.
If a VRF is created, then its corresponding VT A-D Route MUST be
generated and advertised.
If the VRF whose VT A-D Route has been advertised is deleted, then
the VT A-D Route Withdrawal message MUST be generated and advertised.
If IRT of the VRF whose VT A-D Route has been advertised is changed,
then a VT A-D Route Update with same Prefix and latest IRTs MUST be
advertised.
When receiving PE receives VT A-D Route, VPN relationship matching
MUST be checked between IRTs in VT A-D Route and ERTs of each Local
VRF, this process is called VRF-to-VRF VPN membership Auto Discovery.
Either finding one VRF-to-VRF VPN membership newly formed or
released, receiving PE MUST proceed to the VT Labeled Route
processing described in next section.
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4.2. VRF-to-VRF Labeled Route Exchange
4.2.1. VT Labeled Route Update
If Receiving PE finds one new VRF-to-VRF VPN membership formed, it
MUST allocate one VT MPLS Label for the VRF-to-VRF VPN membership and
the label is advertised to the Remote VRF by VT Labeled Route.
Local RD MUST filled with RD value of the Local VRF which is found
belong to the same VPN with Remote VRF.
Local Router's IP Address Must filled with the advertising PE's IPv4/
IPv6 address.
Remote VRF's RD MUST filled with RD value of the Remote VRF which
belongs to a same VPN with the Local VRF.
Remote Router's IP Address: Remote PE's IPv4/IPv6 address.
Label: MUST be filled with one or more MPLS Labels allocated by
advertising PE for the pair of VRFs.
Only both sides of a pair of VRFs learnt each other's VT Labeled
Route advertisement, the VRF-to-VRF tunnel between the pair of VRFs
is considered setup.
4.2.2. VT Labeled Route Withdrawal
If receiving PE finds one existing VRF-to-VRF VPN membership released
then it MUST send out the VT Labeled Route Withdrawal message, then
release the MPLS Label(s) allocated.
Local RD MUST be filled with RD value of the Local VRF.
Local Router's IP Address MUST be filled with the advertising PE's
IPv4/IPv6 address.
Remote VRF's RD MUST be filled with RD value of the Remote VRF.
Remote Router's IP Address: MUST be filled with Remote PE's IPv4/IPv6
address.
Label: MUST be filled with ZERO or the MPLS Labels value allocated
for the VT Labeled Route.
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4.3. VRF-to-VRF Labeled Route Application
To achieve the goal of converting normal L3VPN MP2P forwarding model
into P2P model which is required in [ID.draft-zheng-l3vpn-pm-
analysis-01], after VPNv4 routes received, Receiving PE MUST apply VT
Labels when downloading VPNv4 Route into Data Plan which is in detail
described in [I-D.dong-l3vpn-pm-framework].
Between a pair of PEs both support VT capability, It COULD be an
implementation option that VPNv4 Routes from a remote VRF WOULD NOT
be downloaded into a Local VRF's Forwarding Plan until a VT Labeled
route received from same Remote VRF for the Local VRF.
If VT Labeled Route withdrawal message is received, receiving PE MUST
delete VT Labels from Forwarding Plane and VPNv4 Routes MUST be kept
on Forwarding Plane with original VPNv4 Label as inner Label.
5. VT Route Selection Consideration
When receiving and processing VT A-D Route, the BGP best route
selection procedure described in [RFC4271] MUST be followed.
When receiving and processing VT Labeled Route, the BGP best route
selection procedure described in [RFC4271] COULD be followed.
Especially VT Labeled Route MUST be advertised ONLY to the BGP peer
from which the best VT A-D route is received, the VT A-D route
contains the Remote VRF's RD and Remote PE's IP address.
If a Peer receives VT A-D or VT Labeled Route originated from itself,
the route MUST be ignored.
6. Deployment Consideration
This document currently supports deploying VT SAFI in following two
manners:
a) Inner-AS L3VPN with Full-mesh IBGP sessions or Router Reflectors.
b)Inter-AS L3VPN with Option A(VRF-to-VRF)[RFC4364].
How to support Inter-AS L3VPN Option B(MP-EBGP) and Option-C
[RFC4364] will be described in this draft's future version.
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7. Security Considerations
This extension to BGP does not change the underlying security issues.
8. IANA Considerations
A new SAFI value to present VT Subsequent Address Family is required
and to be allocated by IANA.
9. References
9.1. Normative References
[I-D.dong-l3vpn-pm-framework]
Dong, J., Li, Z., and B. Parise, "A Framework for L3VPN
Performance Monitoring", draft-dong-l3vpn-pm-framework-02
(work in progress), January 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, January 2001.
[RFC4026] Andersson, L. and T. Madsen, "Provider Provisioned Virtual
Private Network (VPN) Terminology", RFC 4026, March 2005.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, February 2006.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, April 2006.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760, January
2007.
9.2. Informative References
[I-D.zheng-l3vpn-pm-analysis]
Zheng, L., Li, Z., Aldrin, S., and B. Parise, "Performance
Monitoring Analysis for L3VPN", draft-zheng-l3vpn-pm-
analysis-02 (work in progress), October 2013.
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Authors' Addresses
Hui Ni
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: nihui@huawei.com
Shunwan Zhuang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
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