Hi John,
Firstly I wouldn't even bother looking at the 2851 or 3845 now - these
are the first generation of ISR's and have been superseeded by the ISR
G2's (2951, 3925 etc). You'll get perhaps 2-3x the performance of a
2851 out of a 2951 for much the same money, as well as being able to
take advantage of future software updates, as it looks like there will
be no more T releases for the ISR G1's. Not that you would want to run
T releases, but the pattern of recent software from Cisco suggests that
we're not going to see all that many more major releases and hence new
features for the first generation ISR G1's going forward.
Refer:
http://www.cisco.com/web/partners/downloads/765/tools/quickreference/routerperformance.pdf
http://www.cisco.com/en/US/prod/collateral/routers/ps5853/qa_c67-631674_ps5854_Products_End-of-Life_Notice.html
Q. What IOS releases will be supported on the Cisco Integrated Services
Router 1800, 2800, and 3800 Series until End of Software maintenance period?
A. IOS release 15.1(4)M will be the long term IOS release supported on
the 1800, 2800, and 3800 Series through the end of software maintenance.
Software maintenance on 15.1(4)M will be offered until Nov. 1, 2014.
I also wouldn't go with the 7200s unless you are purchasing second hand
- but even then a higher end ISR G2 will likely perform better anyway
depending on your budget. It's all about the ASR's now and the 7200s
are somewhat on the way out (although still very handy to have).
Refer:
http://www.cisco.com/en/US/prod/collateral/routers/ps341/end_of_life_c51-681414.html
Now in terms of practical experience, I have a couple of older 2851s
maxed out with DRAM taking full BGP tables, some MPLS and terminating
some DSL services at small POPs, and they cope just fine. Featurewise
you will want an ADVIPSERVICES license, but yes the 2800s will happily
terminate sessions and do all these things without much trouble. They
will of course become CPU bound if you have a lot of BGP changes but
normal Internet feeds aren't going to cause a problem - just be prepared
for them to get hammered for a few minutes when BGP first connects to
your upstream and 400k prefixes come pouring down.
100 xDSL tails should be fine on a 2951 unless you have very demanding
users. Anything you can of course offload to a Layer 3 switch at your
POP you should though as these routers are all (largely) software based
and thus the more load then the more CPU you'll burn up. So any routing
you can do on a L3 switch at your POP you should.
When things grow you can just upscale with a new ISR G2 or another IOS
based device and pretty much keep the config as-is when you move it
across. Heck for the price of them nowadays you could just about fit
out two of them in your POP and have a hot spare for a fairly reasonable
sum.
Regardless of what you put in, keep an eye on the CPU load, upgrade if
it starts getting high and you should be fine.
Reuben
On 13/01/2012 3:07 PM, John Elliot wrote:
Thanks Hotmail - Ill resend to accommodate the (lack of)
formatting..
Have a potential new pop that we are looking to terminate dsl
tails(+MPLS,MPBGP, single Inet(full table), and some ethernet tails)
- Have some space restrictions(RU)
Looking for some "real life" experience with the following
platforms(Or alternatives?) on how many dsl tails they can support:
2851 - Cisco stated performance: 220,00PPS (2RU)
2951 - Cisco stated performance: 580,000PPS (2RU) but assume quite
$$?
3845 - Cisco stated performance: 500,00PPS (3RU?)
3925 - Cisco stated performance: 833,000PPS(3RU?) but assume quite
$$?
(NB would max out the ram on them for the bgp table)
Initially we are looking at ~100 dsl tails, with growth to 150 in
6months....are we better off looking at the old faithful 7200?
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