hi all,
i want to know where is the subnet prefix length for ipv6 or
ipv4 stored .... i mean to say wheather its stored in the routing
tables or in the ip header( in destnation or source address )
Regards,
uday

In article <1178682481.883950.56810@y5g2000hsa.googlegroups.c om>,
uday <udaykumar84@gmail.com> wrote:

> hi all,
> i want to know where is the subnet prefix length for ipv6 or
> ipv4 stored .... i mean to say wheather its stored in the routing
> tables or in the ip header( in destnation or source address )
> Regards,
> uday

There's no place in the IP header for this information. It also doesn't
make sense there -- the prefix length may be different for different
routers, because of aggregation. Prefix lengths are used in routing
protocols and routing tables, they're not associated with addresses
globally.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

On May 9, 9:30 am, Barry Margolin <bar...@alum.mit.edu> wrote:
> In article <1178682481.883950.56...@y5g2000hsa.googlegroups.c om>,
>
> uday <udaykuma...@gmail.com> wrote:
> > hi all,
> > i want to know where is the subnet prefix length for ipv6 or
> > ipv4 stored .... i mean to say wheather its stored in the routing
> > tables or in the ip header( in destnation or source address )
> > Regards,
> > uday
>
> There's no place in the IP header for this information. It also doesn't
> make sense there -- the prefix length may be different for different
> routers, because of aggregation. Prefix lengths are used in routing
> protocols and routing tables, they're not associated with addresses
> globally.
>
> --
> Barry Margolin, bar...@alum.mit.edu
> Arlington, MA
> *** PLEASE post questions in newsgroups, not directly to me ***
> *** PLEASE don't copy me on replies, I'll read them in the group ***

ok thanks .
but how can i identify from an ip packet weather its a unicast address
or anycast address in ipv6 ??
i need to identify form the ip header weather its
1) unicast
2) anycast
3) multicast------- for multicast we can identify from the first 8
bits .. it will be always be FF
but for others 2 how can we identify from ip header ???

Regards,
uday

On Tue, 2007-05-08 at 22:28 -0700, uday wrote:
> but how can i identify from an ip packet weather its a unicast address
> or anycast address in ipv6 ??

"Anycast addresses are taken from the unicast address space, and are not
syntactically distinguishable from unicast addresses."

http://www.iana.org/assignments/ipv6-anycast-addresses