[c-nsp] PPPoe Access Concetrators

Kristofer Sigurdsson kristo at ipf.is
Thu Aug 11 09:34:34 EDT 2005


On Thu, 2005-08-11 at 10:06 -0300, Tim Devries wrote:
> It's one that had occurred to us, but I'd like to know what else is out
> there, what others are using, and if they have had good experiences with
> those products.  And of course cost is always a consideration ;)

Cisco's portfolio of broadband aggregation consists of the 7200 series
(including it's spinoffs, 7401 and 7301), 7600 series and 10000 series.

For the 7200 series (NPE-G1 or 7301), you can realistically expect to
be able to serve about 5000 users.  They claim 8000.

For the 7600 series, they're claiming 32000 users per MWAM card (doing
this without an MWAM card is a feature which will be implemented, nobody
knows when).  This means you can expand a 7600 chassis to at least 4 
MWAM cards (4 x 32000 = 128000 users).  I have no expirience with this,
so I don't know how this works in practise.

The 10000 series are claiming 60000 users.  I known nothing about the 
specifics here.

If you go for 7301, you might want to check out MPF (Multi Processor 
Forwarding), which, as I understand it, uses a second CPU in the 7301
for the LAC part, if you buy a license for $10,000 USD (list price).  
This is a new feature and doesn't seem to be in widespread use (ie. 
you're on your own).

Another interesting possibility is to use smaller routers for LAC's,
eg. ISR routers (1800, 2800, 3800 series) and do the LNS thing only
on your existing 7200's.  If you can seperate the customers you are
aggregating (by geographic locations, or something else), you might
be best of buying a bunch of 2800's and put in one for each segment.

All in all, distributed design is likely to work best, as your system
will be more tolerant (if one box breaks, it doesn't take all the users
with it) and it's more flexible.

Kristófer Sigurðsson           Tel: +354 414 1600
Netrekstur/Network Operations  IP Fjarskipti ehf.

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