Subject: [PCN] A general concern on ECMP and IEA measurements

From: <[email-masked]>
Date: Wed, 8 Jul 2009 16:07:25 +0200

Tom,

while I read your drafts I noticed that a scenario with two (parallel)
ECMP links passed by the same IEA may be an issue under the following 
condition:

- link 1 is in termination state
- link 2 is in stop admission state

Is an egress node able to determine which traffic to account for which 
link?

Regards,

Ruediger

Deutsche Telekom Netzproduktion GmbH 
Zentrum Technik Einführung 
Technik Internet Backbone, TE142-19
Rüdiger Geib
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---

From: Michael Menth <[email-masked]>
Date: Thu, 09 Jul 2009 23:56:57 +0200

Hi Ruediger,

> Is an egress node able to determine which traffic to account for which 
 From my perspective this is not possible. Nevertheless, CL does the 
termination right when the termination process takes into account which 
flows were marked, otherwise CL leads to overtermination as traffic on 
the AR-precongested link is also terminated. With SM this is worse since 
it is not always possible to detect SR-overload and if detected, the 
termination process leads to over- and undertermination on the two 
links. An extensive analyis of this issue can be found in Section 4.7 of
http://www3.informatik.uni-wuerzburg.de/~menth/Publications/papers/Menth08-Sub-9b.pdf

Regards,

    Michael

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