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Cisco 802.3X PAUSE Today

Level 8
Level 8

Hi -

Haven't been on this board for a while, so a big hello to my "friends" on here

Anyway, years ago, Cisco disabled the 802.3X PAUSE method of link-level flow control by default on - I think - all of its Ethernet switches because the shared memory and line rate forwarding capability were seen as sufficient to avoid input buffer overruns and thus precluded the need for flow control. What they did allow as a compromise was for an Ethernet switch port to receive a PAUSE frame and - I think - actually act on it, but not to send the PAUSE frame or pass it on.

What is the status for today's switches? I am talking about Catalyst switches, not Nexus, as I know that 802.1Qbb is deployed.

Do Cisco switches participate in the 802.3X PAUSE mechanism? If so, to what degree? Moreover, is it a zero-sum-game, where QoS/CoS on an interface automatically prevents 802.3X from being enabled because of how disruptive the PAUSE frame is to packet scheduling and forwarding algorithms?



1 Reply 1

Level 8
Level 8

Hmmm, nobody from Cisco can answer this question?

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