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New Member

How do 40GE and 100GE transceivers distribute traffic flows on MMF lanes or SMF wavelengths?


Wikipedia ( states that 40 GE transceivers use 4 optical lanes for 40GBASE-SR4 and 4 wavelengths for 40GBASE-LR4, each with 10.3125 Gbit/s. 100 GE transceivers work in a similar way.

Does anybody know how this effects tcp/udp flows; can a single flow use 40GE or only 10GE in this case?
How is the traffic distributed on the 4 lanes/wavelengths, similar to port-channel hash method?

Where can I find some documentation in the web concerning this?


Many thanks in advance

Thorsten Steffen



Everyone's tags (1)
Hall of Fame Super Silver

I was able to find one

I was able to find one reference in a whitepaper specific to the Cat 6k.

It states:

"Independent flows are load-balanced across the four ingress channels, using a configurable hash algorithm similar to EtherChannel. The default hash input is src-dst-ip.

Note: The 40 Gigabit Ethernet input hash computation is independent of (and/or in addition to) the EtherChannel hash computation of the Forwarding Engine ASIC (PFC4/DFC4)."

I would venture a guess that similar setup applies to the other platforms.

New Member

I already read this document

I already read this document before. In my understanding it states the method of sharing ingress traffic of the 40GE module to the four internal 16GE lines.

Maybe egress behaviour is similar, unfortunately it seems that there is no documentation in cco concerning this.