ATM IMA links, whats the bandwidth?

alan.blake · ‎01-18-2008

Hi

Ive a router thats bundled ATM interfaces togthers to creat an IMA interface, however, if I wanted to find out the true Bandwidth capacity available to me on that link where would (which command) i find that? Is it - sh int atm0/ima0 and read the BW statement?

thanks

paolo bevilacqua · ‎01-18-2008

None of these.

Knowing encapsulation, and average packet length, you can calculate overhead, or true bandwidth.

For a discussion, see:

http://www.patton.com/solutions/atm_vs_ppp_white_paper.pdf

Hope this helps, please rate post if it does!

alan.blake · ‎01-21-2008

thanks for your post. Your link is not what im after. Im looking for a command that will tell me what my total BW is on an IMA interface if say 1 out of 3 atm grouped interfaces failed.At the moment im taking the WAN providers word that each ATM circuit is 2mb for example.

cheers

paolo bevilacqua · ‎01-21-2008

Is 2 mpbs before the calculations mentioned the the document linked. If one of three links fail, you will have two thirds of the original bandwidth, because all links carry the same amount of traffic.

It is also possible that due to a link failure, it won't be possible to respect the contractual ATM service level (usually SCR), in that case the entire bundle will fail.

There are configuration commands that control that (min links, etc).