Re: [pim] DR priority adjustment automatically according to the status of the tracked interfaces

[Su Haiyang <suhaiyang at huawei.com>]

Hi,
  I don't think that it is necessary for a DR to track 
it's upstream link to a source or RP, since IGP would care it for PIM. When
a router's link to a source or RP is down, IGP would converge to another
link to reach the source or RP. If there is no other link to source or RP,
IGP may be fail to find a new route. But isn't that be a poor topology?
Regards
Su Haiyang

-----Original Message-----
From: pim-bounces at ietf.org [mailto:pim-bounces at ietf.org] On Behalf Of Xu
Xiaohu
Sent: Wednesday, August 05, 2009 11:00 AM
To: pim at ietf.org
Subject: [pim] DR priority adjustment automatically according to the status
of the tracked interfaces

Hi all,

In the following PIM-SM (or SSM) scenario, R!, R2 and Client are located
with the same LAN. R1 is elected as the DR for that LAN. Now R1's uplink to
the PIM-SM Network  is down, as long as R1 still acts as the DR, the
multicast stream will be broken soon or later. 

             |
             |   +-----+    +------------------+
             +---+ R1  +----+                  |
             |   +-----+    |                  |
 +-------+   |              |                  |  +-------+
 |Client +---+              | PIM-SM Network   +--+Source |
 +-------+   |              |                  |  +-------+
             |   +-----+    |                  |
             +---+ R2  +----+                  |
             |   +-----+    +------------------+
             |

I wonder whether it is suitable for the DR (e.g., R1 in the above figure) to
track the upstream link, and once the tracked link is down, its DR priority
is reduced automatically so as to cease the DR role. Of couse, this
mechanism is also suitable for the scenario where the Multicast Souce is
connected to more than one PIM routers via LAN.

Any comment? Or whether some vendor has already implement this feature?

Xiaohu


_______________________________________________
pim mailing list
pim at ietf.org
https://www.ietf.org/mailman/listinfo/pim