Internet DRAFT - draft-pengzhang-bier-global-vpnid
draft-pengzhang-bier-global-vpnid
BIER Shaofu. Peng
Internet-Draft Zheng. Zhang
Intended status: Standards Track ZTE Corporation
Expires: December 30, 2018 June 28, 2018
Global vpnid advertisement in BIER overlay
draft-pengzhang-bier-global-vpnid-00
Abstract
This document specifies a method to achieve multipoint VPN
interconnection through a BIER domain.
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 RFC2119.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
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
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 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
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Problem statement . . . . . . . . . . . . . . . . . . . . . . 2
3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Advertisement . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Encapsulation . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Decapsulation . . . . . . . . . . . . . . . . . . . . . . 4
3.4. Formats . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Terminology
This document uses terminologies defined in [RFC8279], [RFC6513],
[RFC6514], [I-D.ietf-bier-mld].
2. Problem statement
BIER (Bit Indexed Explicit Replication) [RFC8279] introduces an
architecture for the forwarding of multicast data packet. It
provides optimal forwarding of multicast packet through a 'multicast
domain'. It does not require explicitly building multicast
distribution trees, nor does require intermediate nodes to maintain
any per-flow state.
BIER MVPN [I-D.ietf-bier-mvpn] introduces a method which using BIER
as multicast tunnels (P-tunnels) to carry multicast traffic across
the BIER domain. The advertising method from [RFC6513] and [RFC6514]
is general and flexible, but it is complicated in some situations at
the same time because of the program of many parameters, like RD, RT,
etc. In many situations which only interconnect different sites
across a domain, the comprehensive MVPN configuration increases the
network administrative complication.
In the other hand, BIER MVPN using upstream assigned label to
indicate the corresponding multicast flow in a MVPN. The pair of
ingress PE and upsteam assigned labels increases label administration
and flow forwarding complication.
[I-D.zzhang-bess-mvpn-evpn-aggregation-label] arises a discussion
about using common label assigned by controller in MVPN. But in a
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network without a controller, it is still a problem to achieve the
multipoint interconnection without MVPN configuration.
So for the networks that need flow isolation across domain but do not
need complicated configuration, this document specifies a method to
achieve multipoint VPN interconnection across a BIER domain by
advertising global vpn-id in BIER forwarding overlay, and defines
encapsulation and forwarding functions to carry and execute the
global vpn-id. It is similar as the usage of VNI-VSID in case of
EVPN VXLAN/ NVGRE described in [I-D.ietf-bier-evpn].
3. Solution
The multipoint VPN here means some flows should be forwarded to
multiple edge routers across a domain. In the simple multipoint
interconnection situations that does not deploy MVPN configuration
like RD, RT, etc., a global vpn-id is used to indicate the
corresponding VPN. This global vpn-id is encapsulated between BIER
header and actual data packet. The BIER forwarding function is also
modified to execute this kind of packet.
3.1. Advertisement
BIER overlay protocols include BMLD [I-D.ietf-bier-mld], MVPN
[I-D.ietf-bier-mvpn], and PIM [I-D.ietf-bier-pim-signaling], EVPN
[I-D.ietf-bier-evpn]. Global vpn-id extension should be added in
these BIER overlay protocols by a TLV format. When using BGP as BIER
overlay protocol to advertise global vpn-id, specific VPN parameters
like RD, RT defined in [RFC6513] and [RFC6514] need not be used.
A BIER domain edge router can belong to several VPNs. A unique
global vpn-id is assigned to a particular VPN. An edge router
belongs to several VPNs is assigned several global vpn-ids.
Edge routers belong to a same VPN should be assigned a same global
vpn-id. The two edge routers which have same global vpn-id indicates
that the two routers belong to a same particular VPN.
When BIER domain edge routers exchange BIER overlay information, the
edge routers belong to one or more VPNs should advertise the
corresponding global vpn-ids extension.
After a router receives global vpn-id extensions from the other edge
routers, the router MUST store the edge routers which have same
global vpn-ids with local VPNs.
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The router SHOULD store the edge routers which have different global
vpn-ids with local VPNs in order to increase converged efficiency
that caused by configuration modification.
3.2. Encapsulation
After ingress router gathers the information of edge routers which
have same global vpn-ids, ingress router generates forwarding items
which include global vpn-id and BFR-ids of egress routers.
When ingress router encapsulates the data packet which should be sent
to the egress routers according to a global vpn-id, the value of
global vpn-id MUST be added between BIER header and actual data
packet. The encapsulation function is the same as [RFC8296], the
'Proto' field in BIER header should be set to the value for a new
type of global vpn-id.
The forwarding of intermediate routers is unchanged according to the
forwarding function defined in [RFC8279].
3.3. Decapsulation
Finally the packet reaches egress routers. Egress router looks for
the forwarding items indexed by the global vpn-id according to the
'Proto' field in BIER header. After decapsulation, egress router
forwards data packet to corresponding local receivers.
3.4. Formats
[RFC2685] defines a globally unique VPN identifier to connect same
VPN in different sites. The format of global vpn-id defined in
[RFC2685] is 7 octets. But in actually deployment, a global vpn-id
with 20 bits is enough to indicate the corresponding VPN. So the
global vpn-id can be used as BIFT-ID defined in [RFC8296]directly.
When MLD protocol is used as BIER overlay, a new type of TLV is added
in BMLD report messages.
When BGP protocol is used as BIER overlay, a new type of TLV is added
in BGP update message.
When PIM protocol is used as BIER overlay, a new type of TLV is added
in PIM join/ prune messages.
For the edge routers which act as ingress routers or egress routers,
the corresponding global vpn-ids are carried in the new TLV. And the
BFR-id of the router itself is also included in the TLV.
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4. IANA Considerations
A new type which indicates the global vpn-id should be added in BIER
'Proto' assignment. A new type of global vpn-id extension should be
added in each BIER overlay protocols, includes MLD, PIM, BGP.
5. Security Considerations
There is no further security requirements in this document.
6. Normative References
[I-D.ietf-bier-evpn]
Zhang, Z., Przygienda, T., Sajassi, A., and J. Rabadan,
"EVPN BUM Using BIER", draft-ietf-bier-evpn-01 (work in
progress), April 2018.
[I-D.ietf-bier-mld]
Pfister, P., Wijnands, I., Venaas, S., Wang, C., Zhang,
Z., and M. Stenberg, "BIER Ingress Multicast Flow Overlay
using Multicast Listener Discovery Protocols", draft-ietf-
bier-mld-00 (work in progress), June 2017.
[I-D.ietf-bier-mvpn]
Rosen, E., Sivakumar, M., Aldrin, S., Dolganow, A., and T.
Przygienda, "Multicast VPN Using BIER", draft-ietf-bier-
mvpn-11 (work in progress), March 2018.
[I-D.ietf-bier-pim-signaling]
Bidgoli, H., Dolganow, A., Kotalwar, J., Xu, F., mishra,
m., and Z. Zhang, "PIM Signaling Through BIER Core",
draft-ietf-bier-pim-signaling-03 (work in progress), June
2018.
[I-D.zzhang-bess-mvpn-evpn-aggregation-label]
Zhang, Z., Rosen, E., Lin, W., Li, Z., and I. Wijnands,
"MVPN/EVPN Tunnel Aggregation with Common Labels", draft-
zzhang-bess-mvpn-evpn-aggregation-label-01 (work in
progress), April 2018.
[RFC2685] Fox, B. and B. Gleeson, "Virtual Private Networks
Identifier", RFC 2685, DOI 10.17487/RFC2685, September
1999, <https://www.rfc-editor.org/info/rfc2685>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <https://www.rfc-editor.org/info/rfc6513>.
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[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<https://www.rfc-editor.org/info/rfc6514>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
Authors' Addresses
Shaofu Peng
ZTE Corporation
EMail: peng.shaofu@zte.com.cn
Zheng(Sandy) Zhang
ZTE Corporation
EMail: zzhang_ietf@hotmail.com
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