Internet DRAFT - draft-manral-isis-trill-multi-topo
draft-manral-isis-trill-multi-topo
TRILL Working Group Vishwas Manral
INTERNET-DRAFT Hewlett-Packard Co.
Intended status: Proposed Standard Donald Eastlake
Expires: December 21, 2012 Mingui Zhang
Huawei
Ayan Banerjee
Cisco Systems
June 22, 2012
Multiple Topology Routing Extensions for Transparent Interconnection
of Lots of Links (TRILL)
draft-manral-isis-trill-multi-topo-04.txt
Abstract
This document describes optional extensions to the TRILL protocol's
use of IS-IS (Intermediate System to Intermediate Systems). These
extensions support multiple topologies (MT) within the same TRILL
campus and protocol instance of IS-IS.
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 to the TRILL working group
mailing list <rbridge@postel.org>.
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Table of Contents
1. Introduction............................................3
2. Terminology.............................................3
3. TLV Enhancements for Multiple Topology..................4
4. Multi-Topology Changes to Appointed Forwarders..........5
5. Security Considerations.................................6
6. IANA Considerations.....................................6
7. Acknowledgements........................................6
8. References..............................................7
8.1 Normative References...................................7
8.2 Informative References.................................7
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1. Introduction
Maintaining Multiple Topologies (MT) in an Rbridge campus requires
extensions to the base TRILL protocol use of IS-IS [ISIStrill].
These extensions change the packet encoding on the wire. This
document describes such extensions so that multiple topologies can be
supported as described in [RFC5120].
2. Terminology
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].
IS-IS: Intermediate-System to Intermediate-System
LSP: Link State Protocol Data Unit (PDU)
Rbridge: Routing Bridge
SPF: Shortest Path First Algorithm
TRILL: Transparent Interconnection with Lots of Links
TLV: Type, Length and Value
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3. TLV Enhancements for Multiple Topology
Currently the Router Capability TLV is specified in [RFC4971]. For
TRILL, many sub-TLV's are specified as being carried in the Router
Capability TLV which carries information only for a single Topology.
The following extensions are required to TRILL use of IS-IS to
support multi-topology:
1. The Nicknames sub-TLV, Trees sub-TLV, Tree Identifiers sub-TLV,
Trees Used Identifiers sub-TLV, and VLAN Group sub-TLV, MAY be
encapsulated in the MT-CAP TLV (TLV #144) [ISISieee].
2. The Multi-Topology TLV [RFC5120] MAY be advertized in the TRILL
LAN Hellos and RBridge LSPs. It will contain topology identifiers
for one or more topologies in which the Rbridge is participating.
An RBridge is considered MT aware as long at it advertises at
least one MT TLV in its LSP.
3. The MTU sub-TLV [ISIStrill] MAY occur in the MT ISN TLV #222
[RFC5120] as well as in the Extended IS Reachability TLV #22.
4. The Topology Mapping (TOPO-MAP) sub-TLV, which occurs within a
Router Capapbilities TLV (TLV #242) for MT Aware RBridges [trill-
mt] is specified below. This sub-TLV may occur more than once in
the same or in multiple Router Capapbilities TLVs.
+-+-+-+-+-+-+-+-+
|Type = TOPO-MAP| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
| RESV |TAS| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R| ABR | Topology 1 | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R| ABR | Topology 2 | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R| ABR | Topology N | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: Router Capability sub-TLV Type, set to TBD (TOPO-MAP).
o Length: 1 + 2*n where n is the number of topology to
topology mapping entries.
o RESV: Five reserved bits, must be sent as zero and ignored
on receipt.
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o TAS: Topology Abbreviation Size as apecified in [trill-mt].
o R: Reserved bit. must be sent as zero and ignored on
receipt.
o ABR, Topology: Each 2-byte mapping entries specifies that
ABR is the abbreviation for the 12-bit topology number
given.
4. Multi-Topology Changes to Appointed Forwarders
The TRILL IS-IS DRB election protocol is a bit different from Layer-3
IS-IS as described in [RFCadj]. The DRB corresponds to the DIS
(Designated Intermediate System) and is responsible for specifing the
Designated VLAN for communication between the RBridges on the Link
[RFCtrill]. As in [RFC5120], there is only one DRB on a link.
However, the DRB also handles all native frames being ingressed from
or egressed to the like, as it chooses, or may appoint other RBridges
on the link Appointed Forwarder [RFCaf] for one or more VLANs.
Appointed Forwarders are per topology. The appointed forwarder sub-
TLV is already a part of the MT-PORT-CAP TLV, which is Multi-Topology
Aware.
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5. Security Considerations
The extensions to TRILL use of IS-IS specified herein add no new
Security Considerations beyond those already present with multi-
topology IS-IS and TRILL. See [RFC5120] for IS-IS multi-topology
security considerations. See [RFCtrill] for TRILL base protocol
security considerations.
6. IANA Considerations
IANA is requested to update the subregistry of the IS-IS TLV Code
points Registry which shows permitted occurrence of sub-TLVs within
TLVs #22, #141, and #222 to show that the MTU sub-TLV is permitted in
TLV #222 as well as in TLV #22.
IANA is requested to assign sub-TLV numbers within the MT-CAP TLV
(TLV #144) [ISISieee] for the Nicknames sub-TLV, Trees sub-TLV, Tree
Identifiers sub-TLV, Trees Used Identifiers sub-TLV, and VLAN Group
sub-TLV [ISIStrill]. Noting that there is no conflict between the
numbers of these sub-TLVs within the Router Capabilities TLV #242 and
with any other number so far assigned within the MT-CAP TLV, it is
requested that these sub-TLVs be assigned the same number within the
MT-CAP TLV as they have within the Router Capabilities TLV #242.
IANA is request to assign a sub-TLV number within the Router
Capabilities TLV (TV #242) for the TOPO-MAP sub-TLV.
7. Acknowledgements
The authors would like to thank Meenakshi Kaushik and Dinesh Dutta.
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8. References
Normative and informative references for this document are given
below.
8.1 Normative References
[RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4971] - Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
[RFC5120] - Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Intermediate
Systems (IS-ISs)", RFC 5120, February 2008.
[RFCtrill] - R. Perlman, D. Eastlake, D. Dutt, S. Gai, and A.
Ghanwani, "RBridges: Base Protocol Specification", draft-ietf-
trill-rbridge-protocol-16.txt, in RFC Editor queue.
[ISIStrill] - D. Eastlake, A. Banerjee, D. Dutt, R. Perlman, A.
Ghanwani, "TRILL Use of IS-IS", draft-ietf-isis-trill-05.txt,
work in progress.
[RFCadj] - D. Eastlake, R. Perlman, A. Ghanwani, D. Dutt, V. Manral,
"RBridges: Adjacency", draft-ietf-trill-adj, work in progress.
[ISISieee] - D. Fedyk, P. Ashwood-Smith, "IS-IS Extensions Supporting
IEEE 802.1aq Shortest Path Bridging", draft-ietf-isis-ieee-
aq-05.txt, in RFC Editor queue.
[RFCaf] - Perlman, R., D. Eastlake, Y. Li, A. Banerjee, H. Fangwei,
"RBridges: Appointed Forwarders", draft-ietf-trill-rbridge-
af-04, work in progress.
[trill-mt] - Perlman, R., D. Eastlake, M. Zhang, A. Banerjee, V.
Manral, "RBridges: Multiple Topology TRILL", draft-eastlake-
trill-rbridge-multi-topo-00.txt, work in progress.
8.2 Informative References
None.
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Authors' Addresses
Vishwas Manral
Hewlett-Packard Co.
19111 Pruneridge Ave.
Cupertino, CA 95014 USA
Phone: 1-408-447-0000
Email: vishwas.manral@hp.com
Donald Eastlake 3rd
Huawei Technologies (USA)
155 Beaver Street
Milford, MA 01757 USA
Phone: 1-508-333-2270
Email: d3e3e3@gmail.com
Mingui Zhang
Huawei Technologies Co.,Ltd
HuaWei Building, No.3 Xinxi Rd., Shang-Di
Information Industry Base, Hai-Dian District,
Beijing, 100085 P.R. China
Email: zhangmingui@huawei.com
Ayan Banerjee
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134 USA
Email: ayabaner@cisco.com
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