From: Andrew Lissitz \(alissitz\) (alissitz@cisco.com)
Date: Tue Dec 06 2005 - 14:47:29 GMT-3
I think the best way to answer this is with 2 to 3 routers. Do debugs
on the routers for BSR and PIM information. Keep this setup simple and
configure the candidate RP and candidate BSR on separate routers.
When the BSR no longer receives any messages from any routers wanting to
be the RP, you will see some changes. The BSR can not tell other
routers about the RP if it does not know about the RP itself.
When the BSR receives messages from RPs you will also see some
interesting activities. When other routers receive this BSR information
... you will see this in your debugs and show commands.
Your answer; yes without a RP, multicast will attempt to run as dense
mode. If dense mode is allowed to run over your interfaces then
multicast traffic will run in this manner.
I think a better question to ask or eventually investigate is: How many
ways can I configure multicast to keep it from falling back into dense
mode? There is more than one way to do this ;-)
________________________________
From: Anderson Nery Vilas Boas [mailto:andervb@yahoo.dk]
Sent: Tuesday, December 06, 2005 12:36 PM
To: Andrew Lissitz (alissitz); ccielab@groupstudy.com
Subject: SV: RE: Sparse-dense.
Almost , Just give me one more light ,
The router who has ip pim bsr candidate configured on an interface and
do not receive anymore candidates . Does it change to dense mode , and
the network continue working for the old groups?
I will undestand : yes it will continue working by what you wrote
"Dense mode is 'flood and prune'. In other words, dense mode assumes all
interfaces are interested in this multicast traffic unless the router
receives a prune message on that interface."
ok?
thanks again.
"Andrew Lissitz (alissitz)" <alissitz@cisco.com> skrev:
When there is no RP, the default behavior for the router is to
'fallback' to dense mode.
Dense mode is 'flood and prune'. In other words, dense mode
assumes all
interfaces are interested in this multicast traffic unless the
router
receives a prune message on that interface.
There is no RP in dense mode, so if the RP goes away, or the
routers can
not reach the RP ... The default behavior is to become dense
mode.
By configuring the interface as sparse-dense mode, you are
allowing this
interface to be either sparse or dense.
Since BSR uses pim for its advertisements you can configure the
interface to be sparse-mode only. If an interface is sparse-mode
only
... It can not operate in dense mode.
Does this answer your questions?
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf Of
andervb@yahoo.dk
Sent: Tuesday, December 06, 2005 12:00 PM
To: ccielab@groupstudy.com
Subject: Sparse-dense.
If I cofigure Router(config-if)# ip pim sparse-dense-mode
and BSR for the RP definition .
If the router announces as the RP for group 224.0.0.0
7.255.255.255 is
down , there is no backup:
Is the bsr will stop working?
Are the other routers will learn the the 224.0.0 7.255.255.255
dynamically as dense mode ?
regards,
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