[mpls] Some thoughts on BoS and ACH. U

[Loa Andersson <[e-mail]>]

Kireeti, Tarek, et.al. 

I’m not really done digesting your draft and slides. 

One corner stone in MPLS has been that there is no semantics to the bits in the 20 bit label value. 

I’m not sure I want to change that, but would be prepared to discuss. 

You say that TC field and TTL is not acted upon other than for the top label. Doesn’t RFC 3443 do that?

All,

One other thing that is that I see a number of new solutions, that if they are all progressed will create a very complicated set of interdependencies. 

I would like to see one method to find multiple ACH’s after the BoS. 

My straw man. 

What if?

We create a two new FECs.  

That first FEC says
- use this label for FIB LOOK-up
- this is for end node processing
- be aware that there is a special ACH after the BoS. 

The second FEC says
- use this label for the FIB look-up
- this is for hop by hop processing
- be aware that there is a special ACH after the BoS

The Special ACH would give you the number of ACH’es after the BoS and their length, in the order you’d find them, including the Special ACH itself. 

The old methods to find one ACH after the BoS would work, since they are not using the new FEC. And could gradually fade out. 

/Loa

Sent from my iPhone