[c-nsp] Is this possible to do with 2 switches?

[Stephen Fisher]

On Mon, Dec 13, 2004 at 01:52:29PM -0500, Tuc wrote:

> Right now we have a 2924 with a port group :

> They are 4 ports to a single NetApp Filer. We then have the servers 
> elsewhere on the switch.
> 
> I've become concerned that the switch is a single point of failure.
>
> I now want to try to distribute it over 2 switches.

Good idea.

> I'm not sure 100% how to best accomplish this. I was wondering if I 
> did the following, would it work.....
> 
> Switch 1:
> 	Port 1 - X-Over to Port 1 on Switch 2 - Port Group 1
> 	Port 2 - What is currently on FA0/4 - Port Group 1
> 	Port 3 - What is currently on FA0/7 - Port Group 1
> 	Port 4 - Server 1
> 	Port 5 - Server 3
> 	Port 6 - Server 5
> 
> Switch 2:
> 	Port 1 - X-Over to Port 1 on Switch 1 - Port Group 1
> 	Port 2 - What is currently on FA0/16 - Port Group 1
> 	Port 3 - What is currently on FA0/22 - Port Group 1
> 	Port 4 - Server 2
> 	Port 5 - Server 5
> 
> First question is will this even work. Will it allow the port group to 
> include a X-over to another switch.

No, you would just be creating a single link port group (EtherChannel) 
between the switches in addition to two separate two link port groups to 
the NetApp.  It has no way of sending the frame to another switch for 
distribution across a port group there.

> Second is if Switch 1, Port 2 gives up, will the others be able to 
> take over for it?
> 
> Third, is there some other issue I'm not thinking of that I need to?

I would use failover functionality on the NetApp (same IP on different 
LAN cards) and then set up a two (or four) link port group between the 
NetApp and each switch.  Connect the switches together with the same 
VLAN the NetApps are on (or using a trunk which includes that VLAN) and 
you're all set.

More information about EtherChannel (port groups) can be found by 
searching for "document id 12023" on cisco.com.


Steve