[c-nsp] Migrating to a 7200 for DSL aggregation

[Andy Dills]

For the last decade, we've been using a Redback SMS 500 to terminate our 
DSL customers, delivered via ATM DS3.

Recently, however, a few customers (as well as the partners of the 
company) have expressed a desire to bond 2 DSL circuits.

Unfortunately, we've discovered that the customers who have Comtrend 
modems cannot negotiate LCP with the Redback when ppp multilink is 
enabled...after working through this with Comtrend, they demonstrated that 
the Redback is violating RFC 1990, and because of this and the fact that 
the Comtrend modem didn't support MP, it was unable to negotiate LCP.

At the same time, we're starting to get a little nervous about relying on 
Redback as a platform, given that all the equipment we currently use is 
EOL and Redback has long since been acquired. We have spares, but clearly 
it's a deadend.

So, we're investigating migrating to a 7200(VXR) platform for DSL 
aggregation.

I was curious about a couple of things:

1) Given that Verizon delivers all of the DSL connections on a 
region-based series of UBR PVCs, what is the best way to bond two DSL 
circuits, given that they would not be on private PVCs? Is MLPPP possible 
in that configuration? Or would I need to do CEF per-packet? Given the 
archives on this list, I'm leaning toward per-packet CEF via radius 
assigned routes. I know we won't get ideal performance, but it should be 
an improvement over a single DSL connection nonetheless.

2) What IOS do people suggest for ATM DSL aggregation...the router won't 
be doing anything else other than OSPF.

Thanks,
Andy

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Andy Dills
Xecunet, Inc.
www.xecu.net
301-682-9972
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