Subject: re: Is fate-sharing a must for the bidirectional TE LSP?

From: Xu Xiaohu <[email-masked]>
Date: Thu, 02 Aug 2007 15:13:33 +0200

Hi Julien,

Thanks a lot for your opinion.

Best regards,
 
Xu Xiaohu

-----邮件原件-----
发件人: [email-masked] [mailto:[email-masked]] 代表
MEURIC Julien RD-CORE-LAN
发送时间: 2007年7月27日 18:16
收件人: Xu Xiaohu; [email-masked]
主题: RE: Is fate-sharing a must for the bidirectional TE LSP?

Hi Steven.

Please find some pieces of answer below. I hope it will help.

Regards,

Julien

________________________________

From: [email-masked] [mailto:[email-masked]] On
Behalf Of Xu Xiaohu

In the current PWE3 standard, although there is no requirement for
fate-sharing on the outer LSP tunnels, bidirectional service, including
CES, ATM and FR, can be supported well over PWE3. Is there some
difference between the service requirements on PWE3 and those on
bidirectional TE LSP?

 [JM] As you say, in PWE3 these are "service requirements", while when
talking about TE-LSPs, we are considering various layers, from packet
down to optical. As a results, requirements are different regarding the
layer you are considering and the operationnal constrains you have on
operating that specific layer.

With the deployment of P2MP TE LSP, the bandwidth consumption over a
link will become more asymmetric. The bidirectional TE LSP without
fate-sharing requirement will maximize the utilization of the total
network bandwidth resource because the forward LSP and backward LSP can
travel over the different physical paths.

 [JM] For instance, lambdas over a core network may be more likely to
have symmetrical needs than packet-based application over an aggregation
network. In the latter case, having different routes or bandwidths on
both direction could help optimization whereas in the former case,
lambdas are prefered to be co-routed in both directions, otherwise it
may become more complicated to operate and a mess for network planning.

Any comment is welcomed.

Best regards,

Steven Xu