2900 for iSCSI?

[Christie Brinker]

We have a couple 2960 gigabit switches and we are about to implement a Dell EqualLogic SAN. We are already using VLAN's so it would be easy to make a new VLAN for the iSCSI traffic, but I have not been able to determine if the 2960's have any issues with iSCSI traffic or if it is even supported. We will not even be using jumbo frames.

I have read that ISL is required, is this true?

Also, if this is the case and I should not use the 2960's, I could make a private network for the iSCSI traffic with their own switches no problem. Any recommendation on what switch to use? It will only be gigabit speeds.

[Peter Paluch]

Hi Christie,

iSCSI is primarily an IP traffic. If deployed over Ethernet switched network, it is encapsulated into normal Ethernet frames and carried across the switched infrastructure. For an Ethernet switch, the iSCSI is simply a flow of frames, just like any other data flow. Hence, every switch is capable of carrying iSCSI traffic without any issues.

ISL is a trunking protocol, i.e. a protocol allowing to carry frames from multiple VLANs on trunk interconnections between switches while keeping information about which VLAN each frame belongs to. ISL has no direct relation to iSCSI.

Best regards,

Peter

[Christie Brinker]

Thanks for your response Peter. I had found a similar thread where people were posting that ISL was required for trunking when an EqualLogic was involved and this is what I have read from Dell

"two or more switches configured for inter-switch communications with standard ports for uplink or stacked using proprietary stacking technology"

and

"distribute network connections across one or more switches, connected using interswitch links that have sufficient bandwidth to handle the iSCSI traffic"

Maybe I read this too detailed and as long as the switches can communicate it's good to go?

[Peter Paluch]

Hello Christie,

Those two statements are, in my opinion, somewhat vague. That may be caused by the fact that their context is not entirely known. However, I am sure that ISL trunking is not required. You are correct that once the switches can talk together, be it through an access port, or a 802.1Q trunk, the iSCSI will be capable of flowing between them. After all, iSCSI is a TCP application. We've never heard of a TCP application requiring ISL, did we?

Best regards,

Peter