True Speed of a 3 mbps line?

[bluewhaleCA]

We recently moved both offices data lines to XO, upgrading to 3mbps lines at the same time. We were told they would provide that actual speed, however now find that the VOIP routers they chose are taking some 15% of the throughput in overhead, even tho we do not use VOIP.

XO is offering a small refund, and will move the circuits over to pure data if we chose to do so, however they obviously do not wish to go to that expense if they do not have to. They indicate that any improvement in performance caused by leaving the Cisco IAD routers and building circuits on a normal Cisco router ( 26xx ? ) will be minimal.

The lines would not be bonded for some reason. This does mean that should one T1 go down the other will continue to function which is fine, however I'm really curious about average throughput on normal 3 mbps lines. The XO manager we just spoke to indicates that XO can not provide ANY information on speed along these lines.

Could any of you? I understand that the circuit design, implementation and equipment are all factors. But were I to go to a dozen of their customers and do timing trials at dslreports.com or downloading large files from Microsoft's site I know I could average them out.

Any thoughts on what one should expect in throughput on a 3 mbps line?


Thanks in advance.

Paul

 

[KiscoKid]

This is a tough question to answer because you have to account for data link overhead to be able to ascertain what the payload throughput will be.

Whilst I acknowledge it's a decent initial indicator, downloads from the internet are not a true measure of the achievable payload throughput - there are just too many variables to account for.

For a lot of my installs nowadays I use a proper traffic generator that just can just throw megabits.. even gigabits of data down a WAN pipe. Traffic generators can range from free to extremely expensive. A free one I've used in the past is available from Ixia and it's called Qcheck (available here

http://www.ixiacom.com/products/performance_applications/pa_display.php?skey=pa_q_check

)

Expensive ones could include network analysissoftware with traffic generation abilities (such as Observer) or even specialist WAN testing tools. I've used a nice handheld capacity tester from Sunrise Telecom before. These solutions can cost anything between 1-5 grand.

I hope this helps