FCIP - Turning compression off IP tunnels

[Wulbur]

We are currently looking at a performance issue on our SRDF links where we are seeing a lot of latency between sites (approx 10 miles).

We have case number 39102824 open and being investigated

One of the things we have been asked to test ,  is to turn Compression off on our FCIP tunnels

Can anyone advise on the commands to do this ?  Can this be done non-disruptively ? and does anyone have an opinion if this should be an issue or not on a short WAN (meant to be low latency link)

[dynamox]

fcip tunnel on Cisco MDS ?

[Wulbur]

FC/IP tunnel is in Brocade 7800

[andreas.scht]

Hi,

if you have ipsec configured on your fciptunnels it is not possible to change this tunnel. So you have to delete and recreate your fciptunnels. If you have not ipsec in use you could change your setting by:

portcfg fciptunnel ge[PORT] modify <TUNNEL-ID> -c 0 (-c for compression, 0 -> disable, 1 -> enable)

But this "disrupts the traffic on the specified FCIP tunnel for a brief period of time". For further information look into your FOS command reference guide. (Powerlink -> Support -> Technical Docu -> Hardware -> Connectrix)

We have three 7500 for fcip use by ipsec with compression, fast write and tape pipelining enabled. We had solved some problems with SRDF / A dropps by setting comm_rate to special value.

Regards,

Andreas

You have to modify (delete / recreate) tunnels on BOTH sites!!!

[h1pan1]

Hi Andreas

Would you please share with me what special value you were setting in the comm_rate ?

Thanks in advance & looking forward to hear from you.

Henry

[andreas.scht]

Hi,

we have a SDH triangle (site A <-> site B <-> site C <-> Site A) for SRDF / A replication (site A -> site B) with a bandwith around ~850Mbit for each segment. So we have to set comm_rate to around 40% (350.000 kbit/s) and not to maximum rate!!

Regards,

Andreas