Hi Jorge,

Yes, EVPN has evolved over many years and that’s why it has such a big traction 
in industry (thanks to your contributions and many others) and we have always 
been open to improvements (mostly driven by our customers) and evaluated them 
objectively. So, if there is any suggestion wrt to Anycast ID, we can 
definitely evaluate it based on what use cases it covers, All-active mode (both 
equal and unequal LB), failure scenarios, convergence, impact to underlay and 
overlay protocols, as well as applicability to different encapsulations to name 
a few.

Cheers,
Ali

From: "Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.raba...@nokia.com>
Date: Friday, November 20, 2020 at 12:26 PM
To: Cisco Employee <saja...@cisco.com>, "Jeffrey (Zhaohui) Zhang" 
<zzh...@juniper.net>, Sami Boutros <boutros.s...@gmail.com>
Cc: "bess@ietf.org" <bess@ietf.org>
Subject: Re: [bess] comments on draft-boutros-bess-elan-services-over-sr

Hi Ali,

Yes, I understand it has pros and cons. What I meant is that, if using anycast 
SID in EVPN satisfies Sami’s requirements (or most), there is no need to add a 
completely new technology that needs to reinvent how to do all services (elan, 
eline, etree, L3, mcast, etc) and relies on data-plane mac-learning - we can 
apply anycast SIDs to existing EVPN.

Thanks.
Jorge

From: Ali Sajassi (sajassi) <saja...@cisco.com>
Date: Friday, November 20, 2020 at 7:21 PM
To: Rabadan, Jorge (Nokia - US/Mountain View) <jorge.raba...@nokia.com>, 
Jeffrey (Zhaohui) Zhang <zzh...@juniper.net>, Sami Boutros 
<boutros.s...@gmail.com>
Cc: bess@ietf.org <bess@ietf.org>
Subject: Re: [bess] comments on draft-boutros-bess-elan-services-over-sr
Hi Jorge,

<snip>
Agreed, any technology can use any cast SID.
[jorge] if you want to specify an anycast SID solution for EVPN as an 
alternative to aliasing, since it may have its merits, I’ll be glad to 
investigate it with you and help. However data plane-learning sounds a step 
back to me.
<end of snip>

I looked at this long time ago and it had some issues. For example, if you pass 
the anycast ID in underlay, then the load balancing is dictated by your 
underlay topology instead of the actual link BW of MCLAG. If you try to get 
fancier and distribute link bw info in the underlay (IGP), then you are 
burdening the underly protocol with overlay info.  And finally if you 
distribute it in the overlay (e.g., BGP), it becomes very similar to what we do 
currently.

BTW, Aliasing feature in EVPN is not mandatory but rather optional as you know.

Cheers,
Ali



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