Tony,

Please see in-line.
Thanks for your comments.

From: Antoni Przygienda 
<antoni.przygie...@ericsson.com<mailto:antoni.przygie...@ericsson.com>>
Date: Wednesday, January 14, 2015 at 5:40 PM
To: Jorge Rabadan 
<jorge.raba...@alcatel-lucent.com<mailto:jorge.raba...@alcatel-lucent.com>>, 
"Henderickx, Wim (Wim)" 
<wim.henderi...@alcatel-lucent.com<mailto:wim.henderi...@alcatel-lucent.com>>, 
"flo...@nuagenetworks.net<mailto:flo...@nuagenetworks.net>" 
<flo...@nuagenetworks.net<mailto:flo...@nuagenetworks.net>>, "Ali Sajassi 
(sajassi) (saja...@cisco.com<mailto:saja...@cisco.com>)" 
<saja...@cisco.com<mailto:saja...@cisco.com>>
Cc: "bess@ietf.org<mailto:bess@ietf.org>" <bess@ietf.org<mailto:bess@ietf.org>>
Subject: RE: Tunnel question for ESI next-hop in draft evpn prefix-advert

Jorge, reread the -03, don’t know how I ended up working off and commenting on 
-02, too many context changes here I guess. inline



What do you mean by “and the corresponding tunnel information” for ESI next-hop 
for type-5 in the vxLAN case?


a)      I don’t see how vxLAN will work with that since at least a Router MAC’s 
extended comm is needed in such a case, section 5.4 (4) describing how to 
derive the inner MAC is fuzzy, we cannot look-up the VRF ARP table since NVE2 
has no overlay IP address and ‘EVI-10 FDB table’ is something I don’t 
understand and I don’t think has been defined. The alleged M2 to be used does 
not exist in the figure at all.

We can clarify that section for sure. The idea is that the RT5 in this case 
requires a recursive lookup resolution to the information given by the RT1. The 
tunnel information (destination VTEP, VNI) comes from the RT1. In this use-case 
we want to direct the encapsulated frames to the owner of the active ESI. 
EVI-10 FDB should be replaced by MAC-VRF10 FDB in DCW1/2, we can fix that. In 
the MAC-VRF you could find M2 since it is associated to the ESI23 (NVE2/3 
advertise TS2/3 MACs with ESI23).

[Tony said]  the idea is completely clear to me (and commendable).  I got what 
you say but Figure 5 is missing M2 and M3 in it and maybe a sentence saying to 
be perfectly clear that NVE2 announces M2  type-2 (without IP address 
obviously).  The text still implies an impossible lookup to me. ARP table needs 
IP addresses for NVE2/NVE3, there is no such thing as ESI23<->M2 entry so it’s 
some kind of a completely new beast which I need to think through. I think 
calling it ‘ARP lookup or EVI-10 MACVRF’ is implying magic in this case.

[JORGE] that’s fair. Will clarify that after the call for adoption.

[Tony said]   yes, -03 clearly indicates that encapsualtion extcomm is on 
type-1 now as well. thanks.  However, I still think that


1.      we need M2 over NVE2 in the figure

2.      I would prefer the router MAC extcomm on type-1 in such case since the 
lookup ESI23 to M2 implies new magic not present in other drafts. Adding the 
router MAC extcomm would make it completely analogous to the inter-subnet draft 
cases IMO. And if the ESI to MAC lookup is desired, the example should at least 
describe that NVE2 is advertising an RT-2 with the M2 MAC.



[JORGE] will clarify the figure in the next rev. I’m ok to add the router’s mac 
ext-comm as I said in a separate thread. For the next rev, I will share a text 
with you and my co-authors and we can discuss it before publishing.






b)      the “tunnel information” provided by A-D route seems to imply ext-comm 
RFC5512 carried on A-D routes as well (original eVPN draft does not provision 
for carrying those ext-comms on type-1 unless I missed some other draft). How 
can we differentiate otherwise between MPLS and vxLAN tunneling? If that’s the 
intention, I think it has to be spelled out.

Definitively RFC5512 bgp encap ext community as per 
http://tools.ietf.org/html/draft-ietf-bess-evpn-overlay-00
[Tony said] ok, yes, but carrying 5512 on type-1 routes is a completely new 
concept I didn’t see in any other draft and I think that should be pointed out 
explicitly. Honestly, the resolve the problem above we may want to carry the 
Gateway MAC ExtComm as other VxLAN cases do. That would make things symmetric 
and resolve the ‘magic lookup’ I see here.

[JORGE] About the 5512 ext community, the above draft explicitly says that all 
the routes, including RT1 should carry the 5512 ext community with the right 
tunnel type. I don’t think it is required a new reference here since the 
evpn-overlay draft is referenced. However if you still think it is better to 
explicitly mention it, please suggest a text and we can add it.

[Tony said]  agreed, -03 is very clear now.


About adding the router’s MAC ext community to the RT5 in this use-case… do we 
need it assuming that the NVE is sending a RT2 with the MAC associated to the 
ESI?

[Tony said]  as above, I do not think it’s beneficial to add implications of a 
lookup from ESI to a valid MAC just for this specific case.

[JORGE] see above.

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