> The initial hardware was a Cisco 5428-2(iscsi)/2109-F16(fc)/3592 tape > combo over a 1Gb connection. We have a Cisco 9216i to replace the > 5428/2109-F16 combo and are looking at etherchannel or maybe even a 10 > Gb link in the next few months. >
I also agree with Wanda that having a directly accessible library or disk at the remote site is the optimal solution. The 9216i's are a great solution for FCIP. I haven't used them at distances of 200 miles either. I think the biggest factor in that distance would involve how many hops are involved and what is the latency. Also is the connection direct, shared, etc. What kind of ms response do you get on pings (at least 1500 bytes) between the 2 locations? There are a lot of buffer and performance settings to accommodate high latency networks on the 9216i but I would certainly want to try and test that distance before committing to it. I think if you find out your ping response ahead of time that will help. Another point I would make is that all of the FCIP implementations I've been involved with have dedicated links for the FCIP traffic (all 1Gb/sec or more). It is not shared with any other IP traffic so you don't have to muck around with QoS or any of that junk. In addition to bandwidth and latency, I think the biggest performance factor is MTU size. The 9216i is excellent when you can use jumbo frames, but then every single piece of network equipment in between the locations must support those larger MTUs. Not likely if it is a leased line. Here is a little snippet from a Cisco document on an example FCIP configuration regarding MTU size: !--- Note that Gig4/1 in the default state is configured with an MTU size of !--- 1500 bytes, if the network topology allows for larger end-to-end frame !--- sizes known as jumbo frames. !--- The default value may be changed to a higher value. A good value is !--- 3000 bytes, because this would avoid the fragmentation of full 2048 FC !--- frames into multiple TCP segments. Not all networking equipment can handle !--- jumbo frames, so the default value of 1500 bytes is a conservative !--- approach to avoid connectivity issues while bringing up the FCIP tunnel.
