Re: [Isis-wg] I-D Action:draft-ietf-isis-layer2-11.txt

Vishwas, couple of points below.

> In the way TRILL works (or SPB), they encapsulate the inner Ethernet
> packet and transport it across the domain. The domain itself uses just
> one VLAN (Designated VLAN) for forwarding, except at the edge.

SPB uses up to 16 backbone VLANs not just one. They are used to provide
diversity of routing and also tennant routing isolation in the core network.
I.e. tenant A and B do not share a given link or node. Infact more than 16
could be used where the first 16 belong to Multi Topology #1 and an
additional set belong to a different Multi Topology.

>To map services to SPB uses I-SID (which is different from the outer
>VLAN) - see 802.1ah. TRILL also has a plan to optionally add such a
>field in the packet. As this is end to end, it may not affect
>forwarding on the intermediate devices. If this has to be transported
>in the IS-IS, we may require a TLV you have mentioned.

It is only true that an ISID does not affect core devices if you do not wish
to scope multicast to just members of that ISID or if you wish not to do
multicast and instead do serial unicast. Usually however we want to scope
the multicast and wish to do tandem replication in which case the ISID has
to be considered in the construction of the state for tandem multicast.

Cheers,

Peter

2011/2/27 Xu Xiaohu <xuxh@huawei.com>:
> Hi all,
>
> As I heard from some could data center operators, 4096 VLANs would not be
> enough for isolating the huge amount of tenants in their future data
center
> networks. Besides, the VLAN translation is a desirable feature in some
> scenarios (e.g., the same VLAN ID in different parts of the data center
> network is used for different tenants while different VLAN IDs in
different
> parts of the data center network are used to connect a single tenant).
>
> Hence, I wonder whether it is possible to replace the fixed-length VLAN ID
> field (e.g., the VLAN-ID field in the MAC-reachability TLV as shown below)
> with a tenant/VPN instance ID TLV. With such TLV, at least the two
problems
> mentioned above can be solved easily.
>
> Best wishes,
> Xiaohu
>
> ========================================================================
> 2.1.  The MAC-Reachability TLV
>
>   The MAC-Reachability (MAC-RI) TLV is IS-IS TLV type 141 and has the
>   following format:
>
>   +-+-+-+-+-+-+-+-+
>   | Type= MAC-RI  |                  (1 byte)
>   +-+-+-+-+-+-+-+-+
>   |   Length      |                  (1 byte)
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |   Topology-Id/ Nickname       |  (2 bytes)
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |   Confidence  |                  (1 byte)
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |  RESV |      VLAN-ID          |  (2 bytes)
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |                          MAC (1)    (6 bytes)                 |
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |                   .................                           |
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   |                          MAC (N)    (6 bytes)                 |
>   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>
>
>
>> -----邮件原件-----
>> 发件人: isis-wg-bounces@ietf.org [mailto:isis-wg-bounces@ietf.org] 代表
>> Internet-Drafts@ietf.org
>> 发送时间: 2011年2月10日 4:00
>> 收件人: i-d-announce@ietf.org
>> 抄送: isis-wg@ietf.org
>> 主题: [Isis-wg] I-D Action:draft-ietf-isis-layer2-11.txt
>>
>> A New Internet-Draft is available from the on-line Internet-Drafts
>> directories.
>> This draft is a work item of the IS-IS for IP Internets Working Group of
> the
>> IETF.
>>
>>
>>       Title           : Extensions to IS-IS for Layer-2 Systems
>>       Author(s)       : A. Banerjee, D. Ward
>>       Filename        : draft-ietf-isis-layer2-11.txt
>>       Pages           : 11
>>       Date            : 2011-02-09
>>
>> This document specifies the Intermediate System to Intermediate
>> System (IS-IS) extensions necessary to support link state routing for
>> any protocols running directly over Layer-2.  While supporting this
>> concept involves several pieces, this document only describes
>> extensions to IS-IS.  Furthermore, the Type, Length, Value pairs
>> (TLVs) described in this document are generic Layer-2 additions and
>> specific ones as needed are defined in the IS-IS technology specific
>> extensions.  We leave it to the systems using these IS-IS extensions
>> to explain how the information carried in IS-IS is used.
>>
>> A URL for this Internet-Draft is:
>> http://www.ietf.org/internet-drafts/draft-ietf-isis-layer2-11.txt
>>
>> Internet-Drafts are also available by anonymous FTP at:
>> ftp://ftp.ietf.org/internet-drafts/
>>
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>
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