Wired Intelligent Edge

Hi,

i've a doubt about stacking speed of two 2930F.

How much would it impacts performance if you made a 1Gbps VSF stack while having 10Gbps uplinks?

Essentially, what are the VSF speed requirements while designing the infrastructure?

Thanks.

Hi! it's all about design...and to start doing a good design you need to start with some assumptions and some good questions.

As example, what amount of traffic and what traffic directions you are expecting to traverse (or not) your VSF stack? I mean...either considering potential traffic between hosts connected to the same VSF member or potential traffic between hosts connected to different VSF members...or, again, are you expecting more North-South traffic than east-west traffic? will those types of traffic traverse the VSF links in the worst case scenario (think what would happen just in case of a VSF member failure...)...and where the routing is exactly  going to happen (traffic between routed networks needs to reach the router to be routed...)? on the VSF itself? or on a Firewall uplinked from the VSF?...and so on.

Another thing to consider is the number, type and speed of access and uplink ports with respect to VSF links to estabilish a possible ratio in case VSF links are involved in switching traffic (e.g theoretically you could end up with 48 or 24 1G ports of VSF member 1 in full communication with other 48 or 24 1G ports of VSF member 2...it's clear that a single 10G VSF link will become easily saturated).

Generally VSF links should be the fastest possible (compared to both uplinks and/or downlinks to access devices) because your deployment could reach a scenario where a considerable amount of traffic will traverse the VSF links (worst case).

Please also consider that a VSF implementation implies that uplinks/downlinks are properly set up to be "multi-homed" with physical links (generally, where it is possible, using LAGs - Links Aggregations - with LACP) terminating on each VSF member (that's for resiliency, redundancy and load distribution). That's the basic assumption when VSF is deployed.