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Number of DLSW TCP Peers supported on a 1721 Router


I have a Cisco 1721 Router which I use as central side DLSW Peer Router. We use TCP. We now have 15 DLSW TCP Remote Peers active. Peer Number 16 doesn't come up. CPU Load is 5 %, memory is almost emty. SW ist 12.3(6). Because it is already in production we could not try to shut one activ peer down, to see, if the other one comes up.

Has anybody experience with the number of DLSW TCP Peers on a 1721. Is there a limit comming from the IDBs Interface descripter blocks) or something like that?



Cisco Employee

Re: Number of DLSW TCP Peers supported on a 1721 Router


under normal conditions there is no limit for the number of dlsw peers. We have routers running with a couple of dozen peers, or even a few hundert.

What you might want to double check is that the aux port is not using port 2065 aswell as dlsw.

You can do a show line and see what line numbers you are seeing.

We had problems in the past with that, it should be fixed but i could not find any particular ddts numbers. Only very old ones.

when you do a show line and you see something like this:

kiekeboe#sh line

Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int

* 0 CTY - - - - - 0 0 0/0 -

65 AUX 9600/9600 - - - - - 0 0 0/0 -

66 VTY - - - - - 0 0 0/0 -

67 VTY - - - - - 0 0 0/0 -

68 VTY - - - - - 0 0 0/0 -

69 VTY - - - - - 0 0 0/0 -

70 VTY - - - - - 0 0 0/0 -

note the AUX port is using 65 which translates to port 2065, the same as dlsw. You see this on platforms which have the ability to become a terminal server/access router.

In that case you might try to configure on the aux port.

line aux 0

transport input none

and see if this makes any difference.

If you try anything like this do it after hours to make sure you dont impact existing peers and circuits.

If this above is not true, you need to investigate what the difference is between the connections working and the new one not working. I.e. what wide area is used, mpls instead of frame .....

The CE showed me the debugging of your case today and we see that the central router is refusing the connection. So the question is why is the central router refusing the tcp connection?



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