subrate SFP?

Saku Ytti saku at
Thu Aug 29 13:08:30 UTC 2013

How do people deal with situation where you need <=48 SFP/SFP+ ports, but
you occasionally need one or two cu 10/100 ports?

For some reason it's becoming quite rare for SFP port to natively support
10M and 100M rates.

Technically obviously solution to me would be subrate SFP, which presents
itself as 1GE to host, offering 100M or 10M to client. This would obviously
break QoS at the host as host would still think it's 1GE and SFP itself
would need to drop+buffer. But for my applications it would be fine, the
10M or 100M ports are typical some MGMT access interfaces.
I can't imagine such SFP being complex or expensive, considering we have E1
over IP in a SFP, which includes control-plane and forwarding-plane inside
SFP form-factor

Is this demand peculiar? Could I source such SFP somewhere by showing there
is demand?

Putting 2 port switches or fibre converters with external PSU just to
support few ports seem dirty.

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