Re: V4 via V6 and IGP routing protocols

[Masataka Ohta <mohta () necom830 hpcl titech ac jp>]

Mark Tinka wrote:

> > MPLS with nested labels, which is claimed to scale because
> > nesting represents route hierarchy, just does not scale because
> > source hosts are required to provide nested labels, which
> > means the source hosts have the current most routing table at
> > destinations, which requires flat routing without hierarchy or on
> > demand, that is, flow driven, look up of detailed routing tables
> > of destinations at a distance.
>
> This detail is limited to PE devices (ingress/egress).

As it requires

>> flat routing without hierarchy or on
>> demand, that is, flow driven, look up of detailed routing tables
>> of destinations at a distance.

MPLS is just broken.

> You don't need to 
> carry a BGP table in the P devices (core), as only label swapping is 
> required.

So?

> Fair point, it is a little heavy for an edge box,

Requiring

>> flat routing without hierarchy

means it is fatally heavy for intermediate boxes.

>> or on
>> demand, that is, flow driven, look up of detailed routing tables
>> of destinations at a distance.

means it is fatally heavy for edge boxes.

> In the end, having a flat L2 domain was just simpler.

That's totally against the CATENET model. Why, do you think,
NHRP was abandoned?

> we've never ran into an issue carrying
> thousands of IS-IS IPv4/IPv6 routes this way.

Thousands of? Today with so powerful CPUs, that is a small
network. So?

                                                Masataka Ohta