PIX 501, Unable to get Full Bandwidth with single Stream

[jackdobiash]

Ok, I'm not sure exactly how to describe this issue, but here it goes. We have two PIX 501's connected as VPN to each other, across links that have at least the capability of 1mpbs both ways. The issue is, when I go to test the bandwidth capability of the line, the PDM only shows about 500k being used per file transfer. But if I start to copy more than one file, the bandwidth goes up until it hits at least 1mpbs (usually around 800k for 2, then 1mps for 3+). Is there some reason why it is limiting the bandwidth for individual streams (sessions?)? I'd like it to just use the full bandwidth all the time, even if there is only one thing going across it. Any tips are appreciated, thanks!

Jack Dobiash

[ehirsel]

When there is one stream, the protocol overhead comes into play. Are you using TCP to send the data? If so, then you have NAGLE, tcp slow-start, buffer and windo sizes to contend with. What OS platforms are involved in the file transfer?

I attended a class for a product by IXIA called Chariot - it used to be a NetIQ product, but I believe that NetIQ was acquired by IXIA. The net support staff at my org, uses the Chariot product to insure that bandwith is available on the backbone and remote-site links. This product is worth getting.

One other note: if you are using the ms win smb protocol to do the copy, then you have even more protocol overhead.

Let me know if this helps.