Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Standards Track H. Shah
Expires: January 2, 2017 Ciena Corp
Y. Fan
China Telecom
July 1, 2016
NVo3 Control Plane Protocol Using IS-IS
draft-xu-nvo3-isis-cp-02
Abstract
This document describes the use of IS-IS as a light-weight control
plane protocol for Network Virtualization over L3 (NVo3) overlay
networks. This light-weight control plane protocol is intended for
small and even medium sized enterprise campus networks where the NVo3
technology is to be used.
Status of This Memo
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This Internet-Draft will expire on January 2, 2017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. VN Membership Auto-discovery . . . . . . . . . . . . . . . . 3
3.1. VN Membership Info Sub-TLV . . . . . . . . . . . . . . . 3
4. Tunnel Encapsulation Capability Advertisement . . . . . . . . 4
5. MAC Address Learning . . . . . . . . . . . . . . . . . . . . 5
5.1. Control-plane based MAC Learning for Remote CE Hosts . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[RFC7364] discusses the need of an overlay-based network
virtualization approach, referred to as Network Virtualization over
Layer3 (NVo3), for providing multi-tenancy capabilities in large data
centers networks and outlines the needs for a control plane protocol
to facilitate running these NVo3 overlay networks. [RFC7365]
provides a framework for NVo3 overlay networks and meanwhile
describes the needs for a control plane protocol to provide the
following capabilities such as auto-provisioning/service discovery,
address mapping advertisement and tunnel management.
Due to the succuss of the NVo3 technology in data center networks,
more and more enterpises are considering the deployment of this
technology in their campus networks so as to replace the old spanning
tree protocols. Although BGP or Software Defined Network (SDN)
controller could still be used as the control plane protocol in
campus networks, both of them seem a bit heavyweight, especially for
small and even medium sized campus networks.
IS-IS protocol [IS-IS] is a much proven and well-known routing
protocol which has been widely deployed in campus networks for many
years. Due to its extendibility, IS-IS protocol now is not only used
for propagating IP reachability information in Layer3 networks (see
[RFC1195]), but also used for propagating MAC reachability
information in Layer2 networks or Layer2 overlay networks [RFC6165].
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By using IS-IS as a lightweight control plane protocol for NVo3
overlay networks, the network provisiong is greatly simplified
((e.g., only a single protocol to be deployed)), which is much
significant to campus networks.
This IS-IS based NVo3 control plane protocol could support any
specific NVo3 data encapsulation formats such as VXLAN [RFC7348],
VXLAN-GPE [I-D.ietf-nvo3-vxlan-gpe] , and NVGRE [RFC7637].
1.1. 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].
2. Terminology
This memo makes use of the terms defined in [RFC7365] and
[I-D.ietf-bier-architecture].
3. VN Membership Auto-discovery
By propagating the VN membership info among Network Virtualization
Edges (NVEs), NVEs belonging to the same VN instance could discover
one another automatically. The VN membership info is carried in a VN
Membership Info sub-TLV (as shown in Section 3.1) of the following
TLVs originated by that NVE:
1. TLV-135 (IPv4) defined in [RFC5305].
2. TLV-236 (IPv6) defined in [RFC5308]
When the above TLV is propagated across level boundaries, the VN
Membership Info sub-TLV contained in that TLV SHOULD be kept.
3.1. VN Membership Info Sub-TLV
The VN Membership Info sub-TLV has the following format:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VN ID |S| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-domain ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VN ID |S| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-domain ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD;
Length: Variable;
VN ID: This field is filled with a 24-bit globally significant VN
ID for a particular attached VN instance.
S-Flag: This field indicates the existence of the Sub-domain ID
field. When the S-Flag is set, the Sub-domain ID field MUST be
filled with a valid sub-domain ID. Otherwise, it SHOULD be set to
zero.
Sub-domain ID: This field is filled with a 8-bit BIER sub-domain
ID to which the VN has been associated
[I-D.ietf-bier-architecture]. The field is only useful in the
case where the Broadcast, Unknown-unicast and Multicast (BUM)
packets within a VN are transported across the underlay by using
the BIER forwarding mode.
4. Tunnel Encapsulation Capability Advertisement
To reach a consensus on what specific tunnel encapsulation format to
be used between ingress and egress NVE pairs automatically, egress
NVEs SHOULD advertise their own tunnel encapsulation capabilities by
using the Encapsulation Capability sub-TLV as defined in
[I-D.xu-isis-encapsulation-cap]
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5. MAC Address Learning
MAC addresses of local CE hosts would still be learnt by NVEs as
normal bridges. As for learning MAC addresses of remote CE hosts,
there are two options: 1) data-plane based MAC learning and 2)
control- plane based MAC learning. If unknown unicast flood
suppression is strongly required even at the cost of consuming more
forwarding table resources, the control-plane based MAC learning
option could be considered. Otherwise, the data-plane based MAC
learning option is RECOMMENDED.
5.1. Control-plane based MAC Learning for Remote CE Hosts
In the control-plane based MAC address learning mechanism, MAC
reachability information of a given VN instance would be exchanged
across NVEs of that VN instance via IS-IS as well. Upon learning MAC
addresses of their local TES's somehow, NVEs SHOULD immediately
advertise these MAC addresses to remote NVEs of the same VN instance
by using the MAC-Reachability TLV as defined in [RFC6165]. One or
more MAC-Reachability TLVs are carried in a LSP which in turn is
encapsulated with an Ethernet header. The source MAC address is the
originating NVE's MAC address whereas the destination MAC address is
a to-be-defined multicast MAC address specifically identifying all
NVEs. Such Ethernet frames containing IS-IS LSPs are forwarded
towards remote NVEs as if they were customer multicast Ethernet
frames. Egress NVEs receiving the above frames SHOULD intercept them
and accordingly process them. The routable IP address of the NVE
originating these MAC routes could be derived either from the "IP
Interface Address" field contained in the corresponding LSPs (Note
that the IP address here SHOULD be identical to the routable IP
address associated with the VN membership Info) or from the tunnel
source IP address of the NVo3 encapsulated packet containing such MAC
routes. Since these LSPs are fully transparent to core routers of
the underlying networks (i.e., non-NVE routers), there is no impact
on the control plane of core routers at all.
6. IANA Considerations
The type code for VN Membership Info sub-TLV is required to be
allocated by IANA.
7. Security Considerations
This document doesn't introduce additional security risk to IS-IS,
nor does it provide any additional security feature for IS-IS.
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8. Acknowledgements
TBD
9. References
9.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971,
DOI 10.17487/RFC4971, July 2007,
<http://www.rfc-editor.org/info/rfc4971>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <http://www.rfc-editor.org/info/rfc5305>.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308,
DOI 10.17487/RFC5308, October 2008,
<http://www.rfc-editor.org/info/rfc5308>.
9.2. Informative References
[I-D.ietf-bier-architecture]
Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
S. Aldrin, "Multicast using Bit Index Explicit
Replication", draft-ietf-bier-architecture-03 (work in
progress), January 2016.
[I-D.ietf-nvo3-vxlan-gpe]
Kreeger, L. and U. Elzur, "Generic Protocol Extension for
VXLAN", draft-ietf-nvo3-vxlan-gpe-02 (work in progress),
April 2016.
[I-D.xu-isis-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Chunduri, U., Contreras,
L., and L. Jalil, "Advertising Tunnelling Capability in
IS-IS", draft-xu-isis-encapsulation-cap-06 (work in
progress), November 2015.
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[IS-IS] "ISO/IEC 10589, "Intermediate System to Intermediate
System Intra-Domain Routing Exchange Protocol for use in
Conjunction with the Protocol for Providing the
Connectionless-mode Network Service (ISO 8473)", 2005.".
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, DOI 10.17487/RFC1195,
December 1990, <http://www.rfc-editor.org/info/rfc1195>.
[RFC6165] Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2
Systems", RFC 6165, DOI 10.17487/RFC6165, April 2011,
<http://www.rfc-editor.org/info/rfc6165>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>.
[RFC7364] Narten, T., Ed., Gray, E., Ed., Black, D., Fang, L.,
Kreeger, L., and M. Napierala, "Problem Statement:
Overlays for Network Virtualization", RFC 7364,
DOI 10.17487/RFC7364, October 2014,
<http://www.rfc-editor.org/info/rfc7364>.
[RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
2014, <http://www.rfc-editor.org/info/rfc7365>.
[RFC7637] Garg, P., Ed. and Y. Wang, Ed., "NVGRE: Network
Virtualization Using Generic Routing Encapsulation",
RFC 7637, DOI 10.17487/RFC7637, September 2015,
<http://www.rfc-editor.org/info/rfc7637>.
Authors' Addresses
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Himanshu Shah
Ciena Corp
Email: hshah@ciena.com
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Yongbing Fan
China Telecom
Email: fanyb@gsta.com
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