[c-nsp] 72000VXR vs Juniper ERS-310 for PPPoE termination

[sthaug at nethelp.no]

> > When it comes to the real throughput per uses, sessions and performance, 
> > which one is the best?
> > Pros and cons ..
> 
> I suppose that depends on the number of sessions you have and how much
> bandwidth they're running.  ERX-310 has a hard number of sessions at
> 4000 or 8000 or something (hardware-based cards and there are only a
> couple of slots, or maybe one once you actually put a wan interface in
> it, I don't remember correctly).

As you correctly observe, ERX-310 is a hardware based forwarding type
box, while 7200 is software based forwarding. To me this is one of the
big differences between the platforms.

We have found that what if you use the ERX for what is was meant for
(e.g. terminating a large number of customers), it does this rather
well. For PPPoE the documented maximum is 8000 interfaces per line
card, 16000 per chassis - see the "System Maximums" document at

http://www.juniper.net/techpubs/software/erx/junose72/sw-rn-erx720/html/sw-rn-erx720-app-A-sysmax2.html

We have found empirically that many of the limits specified here are
*not* hard limits - for instance, we have had 310s in production with
well over 9000 IP interfaces per line card even if the documented max
is 8000, with no apparent ill effects.

In general we have found the 310 to be a more capable aggregation & 
termination box than the 7200. It's also somewhat more expensive. YMMV.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no