Subject: [Pim] (no subject)

From: "Bakar" <[email-masked]>
Date: 14 Feb 2002 11:51:57 -0000

Hi,

If in a PIM-SM domain every router is configured with static RP set, and every router also learns RP set dynamically by BSR mechanism, routers in effect will have two RP sets. One dynamic and One static.

What should be search mode for a given G ? Is it like, 
search if we have matching G/M in dynamic first 
if not then lookup static set.

If that is so, lets say a longest match is available in static. 

To be more clear 
dynamic has => 245.0.0.0/8 = R1
and 
static has => 245.1.0.0/16 = R2

if we dont consult static also then we will end up sending join towards R1.

but instead we do like this,
do a longest match on static also we will send to R2

in the second approach static entry is rejected only if there is a clashing entry in static also. eg

dynamic has => 245.0.0.0/8 => R1 and 
static also has => 245.0.0.0/8 => R2

then in this case prefernce is given to dynamically learnt. 

I want to know how this is done in cisco / juniper. Will be very much helpfull if someone can share this knowledge.

thanx and regards,
Bakar

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---

From: "Shankar V" <[email-masked]>
Date: Fri, 15 Feb 2002 09:27:59 +0530

Hi Bakar,

If my understanding is correct, this needs to be the same in all
implementation
otherwise domain deploying different vendor machines will have different
views of
RP and will lead to chaos.

cisco's config manual says something like

"If a conflict exists between the RP configured with this command and one
learned by Auto-RP, the Auto-RP information is used, unless the override
keyword is configured."

in description of the cli command to configure static RP.

so it is clear that only on "conflict", we have the ambiguity to choose
which one, either dynamic / static entry. usually a policy can be configured
to dictate the preference to solve the ambiguity.

i guess by "conflict" we mean the case where 245.0.0.0/8 is both learnt
dynamically and statically configured.

I would call the other one to be "overlapping" i.e 245.0.0.0/8 and
245.1.0.0/16 are not conflicting and in my view,
for a G = 245.1.3.250 (say) the entry chosen would be the static one
245.1.0.0/16 => R2

for a G = 245.2.3.250 (say) the entry chosen would be the dynamic one
245.0.0.0/8 => R1

I hope my views are correct. Somebody correct me if am wrong.

regards,
shankar

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of Bakar
Sent: Thursday, February 14, 2002 5:22 PM
To: [email-masked]
Subject: [Pim] (no subject)

Hi,

If in a PIM-SM domain every router is configured with static RP set, and
every router also learns RP set dynamically by BSR mechanism, routers in
effect will have two RP sets. One dynamic and One static.

To be more clear

in the second approach static entry is rejected only if there is a clashing
entry in static also. eg

I want to know how this is done in cisco / juniper. Will be very much
helpfull if someone can share this knowledge.

thanx and regards,
Bakar

---

From: Yiqun Cai <[email-masked]>
Date: Thu, 14 Feb 2002 21:23:15 -0800 (PST)

> Importance: Normal

If "override" is configured, Cisco IOS will choose R2 as the RP for
245.1.3.250; otherwise, R1 is selected.  The prefix length is not
considered as a tie-breaker to decide between learned RP and
statically configured RP.

-- 
Yiqun