Re: Address allocation

[Marshall Eubanks <tme@21rst-century.com>]

Hello Ali;

Ali Boudani wrote:
> 
> I didnt understand the issue aof address allocation in ssm.?
> we have a source S and a receiver say R want to recieve informations
> from S.
> So in that case R should inform its DR by using IGMPv3.
> How R knows that he is a member of a group G and how is G is allocated?

R knows he is a member of the group because he joined it ? If you
are asking "how does R know that a group exists to be joined ?",
this is done "out of band" - that is, you will know about SSM groups
because you have been informed about them in some other fashion, such
as by clicking on a button on a web page, or in an e-mail, etc., etc.

The address G is allocated by the source. There are basically no
restrictions on G, except that it has to be kept in the 232/8 
address range (for multicasts to the general Internet) and,
if you are sourcing more than one group from the same IP address, S,
you have to give them unique group  addresses, G.

Also, from
http://www.ietf.org/internet-drafts/draft-holbrook-ssm-arch-02.txt

The network service
identified by (S,G), for SSM address G and source host address S, is
referred to as a "channel."  

So the use of "Group" is considered obsolete !

Again, from the above draft :

The following table summarizes the terminology:

  Service Model:        Any-Source          Source-Specific
  Network Abstraction:  group               channel
  Identifier:           G                   S,G
  Receiver Operations:  join, leave         subscribe, unsubscribe

(Personally, I regard unnecessary changes in widely used terminology to be
unwise, but the rough consensus seems to have gone otherwise.)

> is the address g is allocated by the application ??
> 
> I just want to know the complete process because it is not clear in the
> drafts.
> thanx


                                   Regards
                                   Marshall Eubanks

  
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