FTP Window size and latency differences

[unable24]

All,

My client has discrepancies in their FTP transfer rates based on where they originate their jobs. They transfer at a rate of about 500k/sec from a site with a 9ms next hop DS3 (distance 175 miles), while experiencing only 200k/sec FTP transfer rates from a site with a 40ms next hop DS3 (covers about 1300 miles). Otherwise the paths are the same across their Cisco routed network (same hardware and configurations).

Q: Is latency directly related to latency b/c FTP is TCP based and requires acknowledgments between packets?
Q2: How can FTP/TCP window sizes be set or measured - a sniffer?

Your help is appreciated....

 

[thedaver]

Q1: Yes
Q2: ifconfig MTU size for default TCP packet size limit.

Are you comfortable with 500K/sec on 9ms?? Seems quite low for a DS3! Is that bits or Bytes?

Surfinbox.com Business Internet Services - National Dialup, DSL, T-1 and more.

http://www.surfinbox.com/business/

 

[unable24]

Daver,

Checked MTU size on DS3 router Int's - 4470 bytes both sides - it's not spelled out in the config so perhaps that's default???

Transfer rate is K-BYTES per second...

 

[thedaver]

Same FTP server on the remote ends? I know you asked about trying to find the window size(s), I don't know that. Just trying to figure out if maybe one of the ftp servers uses a different default from another.

Surfinbox.com Business Internet Services - National Dialup, DSL, T-1 and more.

http://www.surfinbox.com/business/