Re: Address allocation

[Ali Boudani <aboudani@irisa.fr>]

Hello,
If all sources use the same G , there is no meaning of multicast group.
because S1 ....Sn can use the same address G and in that case all the
multicast world is using the same address G. So we can maybe just assign or
allocate a single multicast address to all the multicast recievers in the
internet and use the S just to differciate between them.
Isnt true??
Ali

Marshall Eubanks wrote:

> 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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