Stop thinkking subnets, start thinking in CIDR terms. It should
theoretically be possible to aggregate with up to a /0 (0.0.0.0/0 -
everything!).
However, if we look at usable address space, besides /0, some of the
smallest prefixes are not practical:-
0.0.0.0/1 = 0.0.0.0 - 127.255.255.255 (includes the 0.0.0.0 and 127.0.0.0
address space that is reserved for the all networks and loopback)
0.0.0.0/2 = 0.0.0.0 - 63.255.255.255 (includes the 0.0.0.0)
64.0.0.0/2 = 64.0.0.0 - 127.255.255.255 (includes the 127.0.0.0)
Starting from a /3 you can actually get usable aggredated address space:-
32.0.0.0/3 = 32.0.0.0 - 63.255.255.255
However, I doubt if any single AS has been given more than a Class A... so
the use of a prefix smaller than /8 is probably rare/unheard of in
practice... but theoretically should work with any classless IP routing
protocol.
Regards,
Adrian
""Cthulu, CCIE Candidate"" <[EMAIL PROTECTED]> wrote in message
8p3k0e$ik7$[EMAIL PROTECTED]">news:8p3k0e$ik7$[EMAIL PROTECTED]...
> Hi, all,
>
> I wanted to stimulate some discussion on subnetting here. I was playing
> around with subnetting today (I was not trying to solve any problem in
> particular). Anyways, on a router interface, I entered:
>
>
> ip address 192.0.0.1 128.0.0.0
>
>
> The router happily took it. I could ping the interface...scarey! I am
well
> aware that in the real world, we start things with a 255 on that first
> octet. But for discussion purposes...
>
>
> why shouldn't I do this (see below): Granted, classful routing protocols
> such as RIP V1 would probably sicken and be unable to handle something
like
> this, but what of EIGRP and OSPF? IS-IS? Something like this would be
good
> for aggregation purposes (BGP)??
>
>
> Technically, doing the straight math, we have two subnets containing all
the
> host addresses in the free world!!! Wowza! ("Bob, we just lost
Wichita!")
>
> 0.0.0.0 to 127.255.255.255 (subnet number and its associated broadcast
> address, first host address would be 0.0.0.1)
> 128.0.0.0 to 255.255.255.255 (subnet number and its associated broadcast
> address, first host address would be 128.0.0.1)
>
>
> Would be interesting to hear some theories and feedback....
>
> Flames to: [EMAIL PROTECTED]
>
>
> Charles
>
>
>
>
>
>
>
>
>
> ___________________________________
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