Weiguo,

Your proposal introduces a control plane processing load that is O(#EVIs * PEs) 
per DF election and given that there can be 4K EVIs per ES, this looks like a 
*substantial* load.  Furthermore,
you can't  use the ES route to co-ordinate DF election because you would need 
to carry your new extended community for each EVI and they would not all fit.  
You also can't use the Per EVI Ethernet AD route because that is processed by 
all PEs in the EVI.

I think that from a practical perspective the new DF election proposed in 
Satya's draft is sufficiently stable that it renders your draft moot, even if 
it could be made to work.
Yours Irrespectively,

John

From: BESS [mailto:[email protected]] On Behalf Of Haoweiguo
Sent: Wednesday, March 25, 2015 5:34 PM
To: Ali Sajassi (sajassi); [email protected]
Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on Paxos algorithm


Hi Ali,

Thanks for your information. I scanned through this draft, it really introduces 
inter-chassis message for DF election handshaking, the requirements in this 
draft is to eliminate transiet Loop and traffic duplication. Current EVPN DF 
election mechanism already eliminated loop and traffic duplication by 
configuring long reception timer on each multi-homed PE, but up to reception 
timer traffic disruption issue still exist. EVPN for DCI is an important use 
case for EVPN, up to reception timer traffic disruption can't be tolerated for 
service providers, it should be improved.

Also for accuracy, i think handshaking state machine on each multi-homed PE is 
also needed. From solution perspective, in my draft, no inter-chassis message 
is introduced, only one new extended community is introduced, i think the 
process is comparatively simple than your following draft.



Current EVPN DF election has some drawbacks, so there are three new drafts 
about DF election emerged. I think BESS WG can consider these three drafts in 
global view,  a single,comprehensive new DF election draft is hoped.



thanks.



Thanks,

weiguo

________________________________
From: BESS [[email protected]] on behalf of Ali Sajassi (sajassi) 
[[email protected]]
Sent: Thursday, March 26, 2015 0:21
To: [email protected]<mailto:[email protected]>
Subject: [bess] Handshaking among PEs in an EVPN ES based on Paxos algorithm

FYI- First published July 4, 2011

https://datatracker.ietf.org/doc/draft-sajassi-l2vpn-evpn-segment-route/


-Ali
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