Subject: RPs information in leaf-routers

From: Mikael Liljebladh <[email-masked]>
Date: Mon, 20 Sep 1999 16:01:09 +0200

Hi,

I wonder how much information about the RPs will be stored in the leaf
router.
How big is the hash table? is it number of RPs * number of groups?
How many RPs will be needed in a domain? is it depending of number of
groups or the size of the network?
Will all leaf routers have a complete knowledge of all RPs or only the
ones that is of interest for that leaf router.

Would appreciate any comments

Mikael

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From: [email-masked]
Date: Mon, 20 Sep 1999 08:31:20 -0700 (PDT)

> I wonder how much information about the RPs will be stored in the leaf

all PIM routers should have the same RPSet to run the hash algo
against.  

> How big is the hash table? is it number of RPs * number of groups?

It will probably be the # of group prefixes advertised, + 1 for every
C-RP that advertises that particular group prefix.  this will probably 
be pretty small.

> groups or the size of the network?

yes, and the level of redundancy your looking for.

> ones that is of interest for that leaf router.

all PIM routers should have the same RPSet during steady state, leaf
routers have no way of knowing a prori what local group interest will
be.

- rusty

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From: Dave Thaler <[email-masked]>
Date: Mon, 20 Sep 1999 11:52:41 -0700 (PDT)

> How big is the hash table? is it number of RPs * number of groups?

There is no hash table.  A hash function is used to compute the
RP for a group, and it is stored with the (*,G) entry.

> How many RPs will be needed in a domain? 

Two (for robustness) or more.

> is it depending of number of

Those who use MSDP typically want an RP per POP.
If you don't use MSDP, then the answer probably depends more on how 
much bandwidth/CPU overhead of register decapsulation each RP can
handle.

> ones that is of interest for that leaf router.

In PIM-SMv2, all routers have the list of all RPs in the domain.

-Dave