[c-nsp] NPE-400 vs. NSE-1 for ATM-DSL aggregation

[Miquel van Smoorenburg]

On Thu, 16 Sep 2004 21:03:25, Matthew Crocker wrote:
> >> Any suggestions on which would be the better replacement engine in  
> >> this
> >> scenario?  Yes, I know about the 1G, but OSI layer 8 (the financial  
> >> layer)
> >> is having compatibility issues with that solution.
> >
> 
> Layer 8 may have a problem with a switch in platform but I have to go  
> with Andy on this.  The Redback SMS is an AWESOME box.  We started with  
> a 7507, VIP4-50, RSP4s to handle our PPPoE sessions.  Ya, I know it  
> isn't built to handle that but it was all I had.  At about 75 customers  
> the router completely melted.  We switched to a SMS 1800, CE3,FE3 and  
> haven't looked back.
> 
> The SMS has two processing blades the CE handles the radius requests,  
> router management and the FE which handles the PPPoE terminations, IP  
> traffic and such.  Redback says a 1800 with CE3/FE3 can handle 8-10k  
> PPPoE sessions.

We have an SMS1800. It cannot forward more than just over 200 mbit/sec
of "normal" traffic, then the FE3 is saturated.

We wanted to terminate 4xOC3 ATM traffic on it, with 6xFastEthernet
outgoing. Redback told us that was no problem so we bought one. At
full price (a few years ago). However it can't forward more
than 1.5 OC3s, then it starts dropping packets. Bugger ...

Something to keep in mind. You might be able to handle 8000 PPPoE
sessions on the CE3, just as long as they don't use more than
25 kbit/sec each average because of the FE3.

> Check eBay you can get SMSs pretty cheap.  I HIGHLY recommend you send  
> it into Redback to get it recertified and get a support contract.
> 
> Our current stats
> 
> [local]redback1#show process cpu
> THU SEP 16 19:02:08 2004
> CPU Utilization for 5 seconds: 3%   1 Minute: 2%   5 Minutes: 1%

That's the CE (control engine), doesn't say anything about the
FE (forwarding engine) which is very limited in pps - I think
that the FE3 maxes out at around 70.000 pps, where pps is
defined as in+out, so 35.000 pps forwarding. Keep in mind that
every outgoing TCP packet results in an incoming ACK and that's
just over 200 mbit/sec with full-sized packets.

Other than that, if you can get them on e-bay on the cheap,
they're featureful boxes. You just might have to buy more
than one with the standard FE3.

There is a faster replacement for that FE3 nowadays, the SL series,
but don't expect it to do more than 400 mbit/sec - the backplane
is still standard 32 bits PCI.

We just bought a bunch of 6400s on ebay - cheaper than redback,
4xOC3, built-in ATM switch (dual NSP), 6xNRP1 - works fine
up to 3 OC3s (2 NRPs can handle the traffic of about one OC3).
We're about to put an OC12 into one of them soon. Will handle
part of that on local NRPs, ATM route part of it to another
6400 over OC3s. Again, for a few percent of list-price, on e-bay ...

Mike.