From: Jeff Lodwick (climberartist@xxxxxxxxxxx)
Date: Sat Feb 09 2002 - 14:01:57 GMT-3
Mamoor,
Tear down means that the router disconnects the connection that it has.
2065 specifies the TCP port for high prioritized DLSW traffic and is usually
mentioned when used for ISDN dial-on-demand routing to bring up the line for
DLSW traffic. The following commands configure DLSW prioritization "dlsw
peer-on-demand-defaults tcp [priority]" and "dlsw remote-peer tcp
[priority]". The following links show more on DLSW prioritization:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios112/112cg_cr/8rbook
/8rdlsw.htm
http://www.cisco.com/warp/public/697/dlsw_backup_peer.html
http://www.cisco.com/warp/public/697/dlswdodisdn.html
The local port 2065 was referred in the link you have below because they
were actually specifying the port DLSW uses when it tears down or
disconnects the DLSW connection to be more specific. They could have also
just said "the DLSw with the higher IP address must tear down the TCP
connections" but they were just being more specific.
In the example of DLSW and NAT you have below this is a known problem with
DLSW and NAT. The way DLSW works is it "tears down" or disconnects the
connection of the router that has the highest IP address. This is always
fine when not using NAT because there is always going to be an IP address
that is higher. The problem with NAT and DLSW is that the addresses the
router that is running NAT compares is it's "NAT" address and the remote
routers "public" address. When the NAT address is higher then the remote
sides public address the router thinks it needs to tear down (disconnect)
it's DLSW connection because of the way DLSW works. This is fine except for
the case where the "public address" the router running NAT has is LOWER then
the remote routers "public address". In this situation the remote router
thinks it has the higher IP address and also tears down (disconnects) the
DLSW connection resulting in a disconnected DLSW connection. The fix to
this is changing the address of the router running NAT to translate the
private address to a HIGHER public address then the public address of the
remote router. Hope this helps.
Jeff Lodwick CCNP/MCSE
WorldCom
>From: "Ahmed Mamoor Amimi" <mamoor@ieee.org>
>Reply-To: "Ahmed Mamoor Amimi" <mamoor@ieee.org>
>To: <ccielab@groupstudy.com>
>Subject: wat does tear down mean
>Date: Sat, 9 Feb 2002 20:16:20 +0500
>
>i was looking at the page:
>http://www.cisco.com/warp/public/697/6.html
>
>it was saying something about tear down in DLSW when in nat....
>can someone explain me what does tearing down the connection to local port
>xxxx.
>
>-Mamoor
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