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WS-X6748-GE-TX bandwidth

This module is listed as having 40 gigabit bandwidth. I know from the documentation that this is comprised of two 20 gig fabric paths. My questions are:

  1. Is the 40 gig a unidirectional claim or is it 20 gig each direction? The difference being does the card top out when 21 ports push data out at line rate or when 41 ports hit line rate.

  1. Are the 48 ports split between the two 20 gig fabric paths or does any port have access to either fabric path.

JD

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JD
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In article , JD wrote: :This module is listed as having 40 gigabit bandwidth. I know from the :documentation that this is comprised of two 20 gig fabric paths. My :questions are:

:1. Is the 40 gig a unidirectional claim or is it 20 gig each direction? : The difference being does the card top out when 21 ports push data out :at line rate or when 41 ports hit line rate.

formatting link
dCEF720 Interface Modules-Use the distributed Cisco Express Forwarding engine on the DFC3 (located on the interface module), connect to the 720-Gbps fabric located on the supervisor engine with dual 20-Gbps full-duplex fabric connections, and forward packets at up to 400 mpps of sustained performance

Now the question is whether the "20-Gbps full-duplex" means 20 in +

20 out, or 10 in + 10 out...

:2. Are the 48 ports split between the two 20 gig fabric paths or does :any port have access to either fabric path.

I do not know when it is used in dCEF720 mode, but if you drop it into the other busses then the ports are split, with groups of ports sharing a single 1 Gb link and unable to access the remaining bandwidth. The exact pattern of sharing is not consistant between the various 48 and 96 port cards: in some it is consequative ports, in others it is interleaved, and in some of the 48 port cards [if memory serves] two of the ports have dedicated Gb links and the remaining 6 Gb bandwidth is shared in groupings of 8 ports. But that's the situation for cards used in CEF256 mode; I don't know what happens when the same card is put into dCEF720.

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Walter Roberson

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