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Community Member

DLSW peer limitation


Is there any limitation on 3662 routers regarding dlsw peer , according to my understanding we can have 250 to 300 peer per router.

please advice



Re: DLSW peer limitation

No hard and fast limitation. Its a function of memory. Your understanding is corrcect if you have the memory

Community Member

Re: DLSW peer limitation

It's been a while since I've done DLSw, but the last network I was involved in had roughly 200 DLSw-TCP peers distributed across two 7206VXRs with NPE-300s. Typically, each DLSw peer had a single LLC circuit associated with it that was handling traffic for a host connect terminal or a printer. The NPE-300's would run at a sustained 60-70% or higher (at the time, the NPE-300 was the fastest CPU without moving to a 7500).

The 3662 is a 225 MHz based CPU while the NPE-300 is, well, 300 MHz. The newer NPEs for the 7200 series are faster, with the new NPE-G1 looking quite nice at 700 MHz. Of course, as with all things Cisco, the processors don't necessary scale evenly based on MHz due to CPU architecture differences and with new hardware comes eclectic versions of software usually hot from the hands of Cisco DEs and not always ready for enterprise production use.

In order to mitigate the CPU load, you could switch to DLSw-FST, however, your LLC sessions could be become susceptible to T1 timers popping due to out-of-order packets if there is any redundancy in your network design and significant latency in re-assembling those packets for final delivery.

Memory is also a concern. Floating on CCO, there is a nice DLSw document that has the formulas for computing the memory requirements on a per-peer basis. As with all things computer-related, generally more memory is better.

Anyway, this isn't a direct answer to your original question, however, it might serve as a foundation for your continued research.


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