From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Jul 30 2003 - 16:48:36 GMT-3
Tomasz,
IS-IS, like OSPF, uses periodic hello messages to establish and
maintain an active neighbor adjacency. Unlike OSPF, however, IS-IS has
no built in method to manage on demand circuits. Therefore, if
IS-IS hello packets (protocol CLNS_IS) are listed as interesting
traffic, the DDR link will remain up indefinitely.
Since there are no built in DDR management mechanisms for IS-IS,
we must use some other protocol independent methods. These methods
include dialer-watch and backup interface.
With dialer-watch, the watch-list *is* the interesting traffic,
therefore there is no need to specify CLNS_IS as interesting. With
backup interface on the other hand, CLNS_IS should be specified as
interesting traffic if you want IS-IS hellos to initiate a call once the
interface in question comes out of standby. Keep in mind that backup
interface does not initiate a DDR call, it simply takes the interface
out of standby mode once the primary interface is down.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Cell: 708-362-1418
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Tomasz Szymanski
> Sent: Wednesday, July 30, 2003 1:16 PM
> To: ccielab@groupstudy.com
> Subject: ISIS on Frame-Relay and DDR (IPexpert lab 26)
>
> Hello group,
>
> I have touched the problem of ISIS running on frame relay network I'd
> like to share with you.
>
> When configuring ISIS on point-to-point subinterfaces there is no
> additional configuration needed (besides "ip router isis"). When you
> configure ISIS on multipoint subinterfaces (what is not a recommended
> solution but exam is not real life) you have to configure "fram relay
> map clns" to make ISIS work. That's because LAN LSPs are sent over
> multipoint interfaces.
>
> When configuring ISIS over DDR there is also a need for mapping clns
to
> dialstring.
>
> Does someone know a document that describes how to configure ISIS on
ATM
> point-to-point and multipoint interfaces?
>
> What are preferred methods for backup on ISDN in networks using ISIS
> (dialer watch is one of them but is it preferred)?
>
> TS
>
>
>
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