[MLB-WIRELESS] Combining 2 internet conenctions.

[Tim Hogard]

> 
> On Mon, 17 May 2004, Tim Hogard wrote:
> 
> > Of course if the APNIC got its act together and started assigning joint
> > IP address space, then we could do proper dual homing but I don't
> > see that ever happening.
> 
> Last time I checked the *smallest* allocation that APNIC would grant was a
> /19, which is 8192 IPs. You also need to justify your usage of these IPs
> with a plan showing how they will be used now, and in the future.
Thats correct.
What they should do is tell Telstra that they aren't getting any
new address space unless they share it.  So then they allocate a 
/19 that is dual routeable to both Telstra and Optus and another
one that is dual routeable to Telstra and Comendico.  Then when
you ask Telstra for IP addresses, they ask "Will you be dual homed?"
and give you address space that is shared with another carrier.

Of course the /19 is also a result of past limits of cisco routers.
I still don't know why they never did it right.  From a multi-homed
routers point of view addresses fit into a very few classes and you
can treat the entire world as /24 with more than 8 interfaces in 8
mbytes of ram.  In most cases, the routes are static or need to be
recomputed when an link goes down and only in thouse cases.  Even
years ago 8 mb of cache memory could make most routing decision in
about 2 ns with a background task rebuilding the bit map in almost
real time and no one would notice and there would be less route
flapping than current system.

> IP address space is precious, and global routing tables are growing
> larger... there's no way that end users will ever be assigned IPv4
> portable IPs again! I'm lucky that I have a "legacy"  /24 (256 IPs) from
> 1996 when they were easy to get. A /24 is the smallest practical address
> space that you can dual-home on the net, and even then routing may not
> always work as you expect.
Route tables are increasing because the number of people who need
to have several upstreams is increasing.  It doesn't matter if
they they are /17 or /28, the route table size is realted to the
number of groups that do multi-homing correctly.

> IPv6 is probably another matter entirely... :)
Nothing like increasing the data the router needs to hold by
a factor of 8x when the problem they were tring to solve was
memory footprint.

-tim
http://web.abnormal.com

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