Re: [Srcomp] Section 2.3 Paragraph C.1

[Ron Bonica <[e-mail]>]

There is a difference between this use case and the one in Appendix B of the CRH draft. In this use case, there are three CRH-capable nodes in the picture. D1B1 only needs to maintain enough state to get the packet to DnB1. DnB1 maintains the state require to get the packet to Dest.

In Appendix B of the CRH draft, there are only two CRH-capable nodes in the picture. So, one has to maintain enough state to get all the way to the other.

                                                                                           Ron




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From: Darren Dukes (ddukes) <ddukes=[e-mail]>
Sent: Friday, June 11, 2021 4:33 PM
To: Ron Bonica <[e-mail]>; [e-mail]
Subject: Re: Section 2.3 Paragraph C.1

[External Email. Be cautious of content]

This is not what Appendix B of CRH draft says.  It says to instantiate state for every endpoint D1-DN at P.  Recall the destination is not a remote border node but a remote PE or segment in a remote SR sub-domain.


On 2021-06-11, 4:11 PM, "Srcomp" <[e-mail]<mailto:[e-mail]>> wrote:

Darren,

I think that Section 2.3 Paragraph C1 has a bug in it.

Assume that we have 11 domains, D1 through D11. Each domain has two border routers, B1 and B2. The B1 router in Domain D1 is connected to the B1 router in all of the other domains (10 connections). Likewise, the B2 router in Domain D1 is connected to all of the B2 routers in the other domains (another 10 connections).

The border routers in Domain D1 maintains state for:


-          All of the routers in D1 (N = 1000)

-          All of the border routers in Domains D2 through D11 (N = 20)

With only that amount of state, any node in Domain D1 can reach any destination in Dn using either of the following paths:


-          D1B1, DnB1, Dest

-          D1B2, DnB2, Dest

D1B1 doesn't need to maintains state for dest, because DnB1 does.

So, C1 should read:

OLD>
a CFIB entry per unique endpoint (N*D*I), assuming IP flex  algo is not implemented on non-CRH domain (I=1), plus inter- domain adjacency (2) (N*D*I+2=10002) *RON-REVIEW*
<OLD
NEW>
a CFIB entry per CRH node per IGP algorithm for local and remote  prefix segments (N*I=2000) plus a CFIB entry per local adjacency segment (A=100) plus a CFIB entry per connected remote border router (20)
<NEW

So, the value of C.1 should 2102, not 10002.

                                                                                                    Ron





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