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Re: Cisco 7200 + NPE-G1 / 7301

  • From: Robert E.Seastrom
  • Date: Fri Nov 18 16:04:53 2005


"Ben Butler" <ben.butler@c2internet.net> writes:

> Anyone got any comments about how good or otherwise the Cisco 7200 +
> NPE-G1 or 7301, both with 1GB of RAM, is as a eBGP router + L2TP
> terminator for DSL subs, in terms of scalability for bandwidth through
> put & the number of VPDN sessions it can terminate before it dies.  Are
> the two solutions effectively the same box or are there more technical
> differences beyond the obvious number of slots.

Well, the number of vpdn sessions that you can put on a VXR or a 7301
is going to have a lot more to do with your average customer's
bandwidth use profile (ie, pps) than anything else.

Right now, I'm looking at a 7206VXR/NPE300 in the US/Eastern time zone
(so mid afternoon; all the gamer kids are home from school) that is
serving as an LNS.  1811 callers, 52.5 Mbit/sec (10.5kpps) down, 33
Mbit/sec (9600 Kpps) up.  79% CPU.  We offer an "unlimited" program,
so there are some pretty heavy users in there - the hockey stick is
pretty sharp.

We did a side by side bakeoff several months ago of the 7301 vs. the
7206VXR/NPE300, and discovered that as a rule of thumb, the Kpps/1%cpu
ratio was 3.8x as good as the VXR/NPE300.  The used market for the
7301 is practically nonexistant, and new prices are about 3.2x the
price of a used VXR loaded up with the interface complement we need.
The interfaces on the VXR are fast ethernet not gige, but then again
we weren't going to be able to saturate the faste anyway.

Anyway, the sweet spot in the price/performance curve seems to be the
7206VXR with NPE-G1, if you can shop around and get the NPE for a good
price.  Junipers are as a rule more pricey, bigger physically, and
more scaleable.  Assuming you can share the traffic around via
multiple tunnels, a farm of 7206VXRs with NPE300s offers box-level
redundancy at a reasonable price.  L2TPNS
(http://sourceforge.net/projects/l2tpns) to which I was directed some
time ago, shows promise but was lacking some critical features that we
needed, and I was left coordinating an office move rather than writing
software.  Such is life.  :(

Anyway, it turned out that in our case, having a lot of box-level
redundancy was more important than saving space, so we ended up
staying with the VXR platform even with the NPE-300.  The eval 7301
was in production use for several months and was completely
trouble-free, so I agree with Woody's assessment that these are nice
boxes.

Regardless of what your users' usage is like, you're going to have an
awfully tough time going over 20000 users on one box because of the
IDB limit that Cisco imposes in their software for that platform.

                                        ---Rob