DLSw+ over ISDN DDR

ayaz.akhtar · ‎07-10-2003

I have the following config on my client router:

dlsw remote-peer 0 tcp 10.10.220.1 lf 1500 keepalive 0 timeout 90 dynamic dmac-output-list 700

The config on the central router is as follows:

dlsw remote-peer 0 tcp 10.10.84.250 lf 1500 keepalive 0 timeout 90 dynamic

The problem is that the central router is bring up the ISDN line throughout the night to establish a DLSw+ peer with the client router although there is no traffic to send.

What could be causing this…???

My understanding, based on the details given on CCO, is that the DYNAMIC keyword prevents the peer connection from being brought up automatically – only when a circuit tries to connect, DDR dialing is initiated and the peer comes up.

Does this mean that we have a device on our central network that tries to establish a circuit with a device on the client network throughout the night?

What would be the best method for troubleshooting this problem?

Thanks in advance for your help.

dixho · ‎07-10-2003

I do not have enough information to tell you the root cause. I am guessing that the central router receives LLC1 traffic. Thus, it brings up the DLSw peer connection. If you only want to transpot SNA traffic over DLSw, you can define "dlsw icanreach sap 4" on the client router. If that does not fix the problem, please take a sniffer trace to capture the DLSw traffic (i.e. any ip path between the central router and client router)

ayaz.akhtar · ‎07-14-2003

As a further test, I have setup a Cisco 2600 router on ISDN and set the config the same as a client router. I have assigned the client test router an IP range that is free but also has a DLSw+ peer setup on the central router.

To prove that the central router is bringing the ISDN line up to establish the DLSw+ peer to the client test router, I have setup a private Dialer interface on our central router just for this client test router and then assigned an outbound access list to the interface.

The access list is set to block any netbios traffic as well as blocking DLSw+ traffic on port 2065 and allowing any other traffic to get to the central site if it needs to. The results of the access list are shown below and I can clearly see that the DLSw+ peer port 2065 is trying to communicate with the site. (No DLSw+ peer config is on the client test router, so the central router is forcing communication).

deny udp any eq netbios-dgm any

deny udp any eq netbios-ns any

deny udp any eq netbios-ss any

deny tcp any any eq 139

deny tcp any any eq 445

deny tcp any eq 2065 any (90 matches)

permit ip any any

If I remove the IP route for the client test router from the central router, then the central router will sit there and will not bring up the ISDN line at all.

What could be causing the central router to bring up the ISDN line to establish the DLSw+ peer to the client router, although the client router has no DLSw+ config???