Cell Relay Archive

["Rick & Robin Stanback" <rstanbac@ix.netcom.com>]

This is the way I understand it works,

When a SVC is setup in a PNNI peer group the first switch will establish the
source route path to the destination or the border switch for the next PNNI
peer group.  This source routing is call the DTL,designated transit list.
There is unique DTL for each PNNI peer group that the call must transit.  If
the SVC is blocked the call will crankback to the originator of the DTL with
information about the problem and a new DTL will be generated.  If the
crankback makes it all the way to the originator of the call the crankback
is translated into a REJECT and the user must start again.

Daniel J. Wentzel wrote in message
<1dhoh2i.15zisiksjhd8N@up18.ro.evosys.net>...
>Hello All,
>
>     Another question for you- while trying to explain the basics of
>PNNI I was asked about crankback.  I've looked in all of my books on the
>subject and none of them even mention it.  The specific question is, if
>there is a link failure within an ATM network creating a crankback
>situation, what switch is now going to perform the routing decision
>across the peer group for the connection?  The original ingress switch,
>or the switch which encountered the link failure?  (or, vendor dependent
>:)  )
>
>TIA,
>
>DJW
>
>REMOVE NOJUNK from the end of the e-mail address for proper delivery.