[c-nsp] 8E1 (ATM) over a 3825?

Anton Kapela tk at 5ninesdata.com
Wed Dec 27 17:17:23 EST 2006


 
 
> Hello all,
> 
>    I have a 3825 with 2 cards AIM-ATM-4E1. My problem is that 
> i need to use a 12Mbps of BW, but the router don't let me 
> because CISCO says ...

Great, those are supported!

> "for applications that require eight T1 or E1 ATM IMA ports 
> is the PA-A3-8T1IMA or PA-A3-8E1IMA in the Cisco 7200 or 
> Cisco 7400 platform, especially if IMA groups of five ports 
> or more are required. For feature comparison see table below. "

Indeed, you're hosed there using 8 port nm.

> Is it possible to do a trick to configure both cards AIM 
> cards over the same PVC? I need 6 (or 7) E1 running  with 
> IMA, but not sure what to do.

You'll be unable to spam the two NM's with the same IMA pvc(s), so your
best bet would be to mlppp over two separate ATM PVC's, say, one group
with 4 links, the other, two links. MLPPP over the pair of IMA groups
will yield end to end sequence preservation. You also gain something
from LFI (link frag/interleave) if any of your applications benefit from
lower jitter (rtp for voip/video). 

Short of mlppp over the ima, you could always use pplb (per-packet load
balancing; this is considered 'dirty') or ecmp with layer 3 or 4 hashing
(equal cost multipath with layer 3 or 4 hashing; this is considered
'better' in most cases). 

Best of luck,

-Tk



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