High Speed WAN connection

[Guest]

All,
I have just installed a DS3 (45Mpbs) circuit between 2 offices. For
some reason, our windows 2000/2003 servers do not see the full bandwidth. I
have tested the circuit using an application from our service provider and
can load the circuit up to about 36 Mbps. The servers do not use more than
about 3 Mbps of the bandwidth. Has anyone dealt with this type of issue? The
routers are Cisco 7206 IOS12.2 . The network is Dell 5224 switches with Gig
cards in all the servers.

Any help is appreciated.

Thanks,

Mike

 

[Neteng]

How are you testing with the Servers? What tool are you using to track the
servers NIC utilization? We have multiple DS-3's and the only time they show
high utilization is during backup. You need long sustained data transfers to
see the utilization.

 

[Ed Horley]

For testing try out iPerf:
http://dast.nlanr.net/Projects/Iperf/

As far as filling the pipe you have to take several things into account. Is
the traffic udp or tcp, are you doing path mtu discovery (PMTU - RFC 1191 I
think), tcp window size is important and have you tuned the stack (for tcp)
to work with bigger pipes with higher latency (well, higher then your local
LAN). You can read more about this at http://www.net100.org/ and at
http://www.web100.org/

Regards,
Ed