[cisco-bba] Using more than one IP Local Pool

[Krzysztof Adamski]

On Wed, 2017-07-05 at 08:23 +0100, James Bensley wrote:
> On 4 July 2017 at 22:41, Juergen Marenda <cnsp at marenda.net> wrote:
> >> You don't need to have a contiguous IP block in an IP Pool. You can simply
> >> do something like this:
> >>
> >> TestBNG(config)# ip local pool dynamic-dsl 192.168.0.0 192.168.255.255
> >> TestBNG(config)# ip local pool dynamic-dsl 172.16.0.0 172.31.255.255
> >> TestBNG(config)# ip local pool dynamic-dsl 10.0.0.0 10.255.255.255
> >
> > Remember that there exists an special IPv4 Address-range for "Carrier Grade
> > NAT".
> >
> > Why not assign fixed (real) IPv4/32 for each dial-up account ?
> >
> > Just my 0.01 $
> >
> > Juergen.
> 
> We use static IPs for all xDSL customers/sites, one problem we have
> from this is that each LNS (depending on which one the customer
> connects to) is announcing loads of /32's into our iBGP that aren't
> aggregatable/summary routes, which they would be if we had a unique
> pool per LNS. We have thousands of extra routes in our iBGP because of
> this, it's not a major issues but still not ideal.
> 
> Cheers,
> James.

You can have each LNS aggregate part of the address space, then when a
customer with IP that matches the aggregate lands on this LNS
customers /32 won't be advertised, but when the customer lands on a
different LNS /32 will go into your iBGP. Depending on luck you could
cut in half the number of /32 in your iBGP.