Taming piggish flows via QoS

Unanswered Question
Jun 29th, 2007

We have 10Mbit Metro Ethernet TLS between sites that use 100Mbit internally. Of the various QoS types available in Cisco midrange routers & 2960/3550 switches, can any enforce that no single flow use more than, say, 7 Mbits? And can that rule adjust after business hours so backups get 100%

I have this problem too.
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pnicolette Mon, 07/02/2007 - 11:38

Thank you for the quick response and link to timed ACL info.

If I understand the example, policing per class will restrict total bandwidth available to an ACL-defined group or "class" of flows. Can Cisco QoS create a per-flow restriction which applies to ANY SINGLE flow?

This is different from limiting a predefined flow or list of flows, and also different from limiting the summed bandwidth of multiple flows. It's more like creating an individual class for every new flow and imposing a standard constraint. If Cisco QoS cannot do this yet, might it be considered in future?

andrew.burns Wed, 07/04/2007 - 00:34


The feature you need is UBRL (User-Based Rate Limiting) but it's only available on the Sup720 - you probably won't ever see it on the low end switches because it's PFC3 based but you never know.




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