Re: [pim] pim querry related with secondary address and domain wide address

[Bill Atwood <bill at cse.concordia.ca>]

Bhavin,

For each interface, the router must choose one address, which will be
its primary address _for_that_interface_.  This address can be a
link-local address, since it will be used only for "link-local" messages
in PIM (hello, join/prune, assert).  (Link-local addresses are
well-defined for IPv6; for IPv4 the address is likely to be more widely
addressable.)

Suppose, as you suggest below, that I1 chooses A1 as its primary
address, and I2 through I8 choose A2 through A8, respectively.  Then
I1's primary address is A1, and the secondary addresses that it can
advertise are A2 through A8.  I2's primary address is A2, and the
secondary addresses that it may advertise are A1, and A3 through A8.

When sending a Hello, the primary address of that interface will be used
as the source address for link-local packets from that interface; the
secondary addresses (i.e., the other possible addresses that can be
associated with this router) may be announced using the Address List
option for PIM, for the reasons outlined in the expired Internet Draft
that was indicated in Jayanth's email to this list earlier today.

For those PIM packets that are sent to a (typically non-local) unicast
address, the source address must be domain-addressable, since it must be
possible for the recipient to reply to it.  Note that this address is
domain-addressable, and not necessarily globally-addressable, since
PIM-SM is a single-domain protocol.

  Bill

bhavin81 at iitb.ac.in wrote:
> Hello Friends,
>
>    I have got some querry related with secondary addresses and
> domai-wide address of router. Let me tell you what is going on
> in my mind:
>  (a) Let's say we are configuring a routre with 8 or n ports. Then what
> do we do:
> (i) for each port we assign some ip address. It can be different on
> each port if each port of router is connected to different networks.
> (II) In that case maximum addresses possible are n which correspond
> to no. of ports of the router.
>
>    Then what is all about primary and secondary addresses.
> Domain wide addresses are mentioned on page no. 107 of RFC 4601.
> ("The source address used for unicast messages is a domain-wide reachable
> address; the source address used for multicast messages is the link-local
> address of the interface on which the message is being sent.").
>
> Regards,
> Bhavin,
> Networking Student.
>
>
>
> _______________________________________________
> pim mailing list
> pim at ietf.org
> https://www.ietf.org/mailman/listinfo/pim
>   

-- 

Dr. J.W. Atwood, Eng.             tel:   +1 (514) 848-2424 x3046
Distinguished Professor Emeritus  fax:   +1 (514) 848-2830
Department of Computer Science
   and Software Engineering
Concordia University EV 3.185     email: bill at cse.concordia.ca
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