[c-nsp] Redback SMS 1800 replacement

[Kristofer Sigurdsson]

2006/1/18, Matthew Crocker <matthew at crocker.com>:
>
> Hello,
>
>   I have a Redback SMS 1800 handling a DS-3 ATM circuit running PPPoE
> & Bridged Ethernet DSL customer,  Approx 50 PVCs,  1k users,
> 20mbps.   What  cisco box would you recommend I get to replace
> this?    Ideally I would like power & process redundancy and the
> ability to grow to OC-3 ATM in the future.   Optionally it would be

A 7200VXR (NPE-G1 or NPE-400) or a 7301 would be ideal.  Neither offers process
redundancy, but both offer redundant power supplies.  For processor
redundancy, you'd
have to go to a 7600 with the MWAM module, which I understand is not recommended
for PPPoE termination, not to mention the price.  For the price of
just the MWAM module,
not including the router, you can buy at least two 7301's, so that's a
better path if you
need redundancy...

> nice if I could also terminate a couple GigE interfaces with customer
> facing 'Metro Ethernet' from some of my IP DSLAMS,  couple hundred VLANs

The 7301 and the 7200VXR/NPE-G1 both have three on-board GigE interfaces,
you can get up to 6 PA slots in the 7200, but there's just one in the
7301.  If you
foresee the need to terminate more than two (I'm assuming you are using one PA
slot for the ATM module and one GigE as an uplink) GigE's from your DSLAMs,
7301 is out of the picture in favour of a 7200 (unless you'll settle
with a switch in front of it and a VLAN trunk).

>
> I'm thinking a 7301 with broadband licensing would work pretty well
> but I don't have any experience running PPPoE on Cisco gear.

A 7301 will probably serve you well, but this is, of course, heavily
dependant on
how many users it's suppose to terminate (how many users from your own IP DSLAMs
will be added?) and the bandwidth throughput.

>
> Also, the Redback has 10 or so 'contexts' which are like VRFs and
> customers are placed into an appropriate context by their @domain and
> with RADIUS attributes (Redback-Context =  Internet) for example.

Cisco can do this via use of the cisco-av-pairs RADIUS attribute, also, if you
use L2TP (you can have the LAC and the LNS on the same box), you can
filter this automatically on the router based on the @domain in the username.
Beware, though, changing from local termination with PPPoE to a LAC/LNS
model on the same router comes with a heavy performance penalty.

-Kristo