10G ports connected to 1G ports

[IS34lyf]

Say we have a Cat3850 48x1G and a Nexus 3k. 24x10G

I have a connection between them and can verify that both are running 1G speed between links.

Is there a Cisco tech/feature where i can increase the speed between links without upgrading the devices? If not, what would be a better case scenario? Would etherchannel be a solution?

[Seb Rupik]

Hi there,

If you have a modular 3850 the obvious answer is to buy a 10g network module with SPF+ transceivers and connect them to the Nexus.

Since you don't want to buy additional hardware, your only other option as you mention is to aggregate as many as possible 1G connections between the two switches (which is 8 for the 3850, 16 for the n3k).

cheers,

Seb,

[Joseph W. Doherty]

Just to add to Seb's info, about aggregating connection (i.e. Etherchannel), although Etherchannel does provide more aggregate bandwidth, any one flow will still only use one link. Further, since Etherchannel doesn't dynamically load balance, it's possible flows will be sent to an already "busy" link, providing no effective bandwidth increase (NB: all flows might use just one link with "worse case" hashing). Lastly, unless you already have them, at some point, often, a number of gig transceivers will cost more than a 10 gig transceiver.

So, ideally, if you really need a large increase in bandwidth, it's generally better to go with the 10g vs. gig. However, Etherchannel does provide redundancy.