[Idr] Shortest Path Routing Extensions for BGP Protocol

[Robert Raszuk <[e-mail]>]

Hi,

I have reviewed your proposal.

Turning path vector or distance vector protocol into link state carrier is
no doubt a bold idea :).

Effectively what you are proposing is to use BGP TCP sessions to propagate
link state database creating first "link vector protocol" !

For start I have few questions:

Q1:

RFC7752 has gone via lot of efforts (especially sections 3.2 and up) to
include number of OSPF or ISIS specific encodings. In your proposal you
mentioned OSPF twice and not even once ISIS. Does it mean that you are not
going to use all encoding for specific IGPs as defined in RFC7752 ?

Q2:

Who creates and maintains LSDB in each BGP speaker ? Are you planning to
run OSPF and or ISIS except disable it to establish any adjaciencies ?

Q3:

Currently there are already to models to build DCs with BGP ... one uses
BGP to create only lean underlay the other is to use BGP for both underlay
and tenants (example project Calico for the latter). With that scale wise I
think your proposal will work great for the former. However I do have
concerns about using your model for the latter where say 10,000 or 100,000
/32s or /128s from each VMs are injected and you need to construct SPT with
all of those.

Q4:

Related to Q3 in your model and say flat DC routing each compute node other
then just injecting 10s of /32s and being "done" now becomes an IGP node.
Since your document explicitely targets Massively Scaled Data Centers
(MSDCs) I am concerned that having 100,000+ IGP nodes and in many case much
more is not the best idea.

Q5:

Have you considered just proposing an OSPF route reflector instead without
stuffing BGP into the mix ? As some of you perhaps remember the work on
this started around year 2000 to optimize PE-CE CSC deployments :) It seems
to me very reusable for this goal.

Best regards,
Robert.