Re: [Idr] WKLC transitivity considerations (was Re: Adoption call for draft-heitz-idr-wklc-02 (3/9 to 3/23))

[Ben Maddison <[e-mail]>]

Hi Jakob,

On 03/20, Jakob Heitz (jheitz) wrote:
> A local configuration is required to make an eBGP session NOT
> an administration boundary. This configuration should be
> applied at both the sender and at the receiver.
> Without configuration, every eBGP session is also treated
> as an administration boundary.
> 
I fear this may end up being a bit too binary.
Depending on the semantics that end up in WKLCs, a pair of operators may
need to treat a session as a boundary with respect to WKLC-A, but not
with respect to WKLC-B.
Without knowing exactly what semantics may be defined in the future,
it's rather hard to know whether this will be important or not.

> An iBGP session is no boundary.
> 
CE-PE via iBGP in an IP-VPN?
This probably needs to be a configurable default too.

> The transitivity bits should not be used for LC matching if the LC begins
> with the WLC distinguisher bits 111101.
> Such LCs should not exist in the public internet, because ASNs beginning
> with those bits have not been assigned.
> 
Has the assumption that these don't exist in the wild wild DFZ been
checked?

One of the motivations for the shape of LCs was to give operators an
alternative to defining semantics in private/unallocated ASN namespaces,
so these *shouldn't* have appeared.
But I wouldn't put money on the fact that some bright spark hasn't gone
and polluted this range already.

Cheers,

Ben