Maximum DLSw+ Remote Peers

[ayaz.akhtar]

Is there a limit on the number of DLSw+ remote peers that can be terminated on the same router?

Would it be OK to terminate approx. 800 DLSw+ remote peers on a Cisco 2612 router with 64MB DRAM and 16MB Flash?

Are there any relevant URLs that discuss limitations of DLSw+?

Thanks for your help.

[mbinzer]

Hi,

sorry there is no simple yes or no answer to this question.

It really depends on how much traffic you are trying to push through that router, not how many peers and circuits you have up at any given point.

In other words. You can have a router with 1 dlsw peer and 1 dlsw circuit running at 85% cpu and the same router with 50 peers and 100 circuits running at 45% cpu load.

The question is how much traffic on average doe your end systems generate? Below URL gives you an overview of cpu load versus frames/second to get an idea what type of router you would need for your environment.

http://cco/en/US/netsol/ns340/ns394/ns74/ns144/networking_solutions_white_paper09186a008007ce75.shtml

The only other considerations are:

1. If you terminate 800 dlsw peers you need to maintain 800 tcp sessions which has a certain overhead on its own. However if you loose your WAN connection or if the router is rebooted all connections could potentialy come in at once and try to bring up the tcp peer and also try to start dlsw circuits. Your router must be capable of handling this load, not only the steady load on average when all connections are up.

2. How large of a fault domain do you want to allow?

If one router with 800 peers fails you loose all of its 800 connections, obviousley. If you split them over 2 routers with 400 connections each than you only loose half of them when one router goes down.

thanks...

Matthias

[ridavidson]

I use 4700M's to terminate 300 DLSW peers. He's got an R4700 running at 133Mhz. I've got 900 peers total and use 3 4700Ms to terminate all the DLSW peers. These routers do nothing but terminate DLSW.

Another concern will be whether or not your're doing SRTLB on the DLSW router. I've got Token Ring interfaces on them, so I'm just doing SRB. I believe SRB and SRTLB are both process switched, but SRB will require less CPU. You can only do SRB if you've got TR interfaces.

4700M vs 2610 performance

4700M 2610

Process Switching 6-7Kpps ???

Fast Switching 50-55Kpps 15Kpps

CPU R4600 133Mhz MPC860 40Mhz

Couldn't find details on process switching performance on the 2610. Like Matthias said, it all depends on the amount of traffic you want to push. Unless you've got an extremely small amount of DLSW traffic, I wouldn't even consider the 2610. If it were up to me, I'd be look at distributing the peers across two 3725s.

If DLSW is servicing a mission critical appl, I'd be loading them up on DRAM (i.e. max amount supported).

I fixing to replace 2 4700Ms doing BSTUN termination for 900 Bisync debices. I'll be using 3 3745s w/ 256MB DRAM to terminate the peers. The 3745 has 3 to 4 times the performance of the 4700M. In reality, I'd could probably get by w/ a single 3745. I'm using 3 to limit the fault domain. I'm loading them w/ max amount of DRAM because it's a miniscule cost compared to not having DRAM available.