L2/L3 Network Design Core Distribution Acces

[cypress73]

Hello,

i have designed this kind of Network Solution and it works but one Question i have:

Should i config the Links between the 2 Distribution L3 Swithces, the links between the Distri.the Core (Uplinks) and between the 2 Cores as

Etherchannel Links or its not nessasary?

[Jon Marshall]

If you can use etherchannels ie. you have the ports and fiber runs then you should.

Two main reasons -

1) greater throughput

2) redundancy ie. one of the links fails you still have at least one more link.

The most important place to run them is between each switch pair.

Depending on where your L2/L3 boundary is some of the etherchannels will be L2 and some will be L3.

Jon

[cypress73]

Hey Jon,

thanks for reply,

ok greater throughput is nice.

My Boundary is at the Distribution Switches. I run EIGRP as Routing. Need i really Etherchannel for

redundancy? is the Routing Protokol running not enough redundancy?

[Jon Marshall]

It depends really on quite a few factors.

What you are looking for with a design is redundancy, which you have, but also you are trying to avoid sub optimal paths in case of failure of one or more links.

So the links connecting your each pair of switches to the other pair of switches are fine as single links because you have EIGRP and it will see two equal cost paths to all remote subnets.

The links between each pair of switches would work fine as well but if either of the links fail the pair cannot send traffic direct to each other and can only get to each other via another layer.

This isn't necessarily a bad thing and it certainly doesn't necessarily mean it won't work. but for the sake of a second link and an etherchannel between each pair there seems little point in not doing it.

But yes it would work as is.

Jon

[cypress73]

Thank you Jon that helps :)