Hi Jorge,
Lots of thanks for a prompt response.
I have explained my position with regard to IP Aliasing for RT-5 in
Interface-less IP-VRF-to-IP-VRF model in my previous email.
I only can add that the neither the metadata of the IP Aliasing draft nor its
text specify an update to RFC 9136.
Regards,
Sasha
From: Jorge Rabadan (Nokia) <jorge.raba...@nokia.com>
Sent: Monday, April 3, 2023 4:17 AM
To: Alexander Vainshtein <alexander.vainsht...@rbbn.com>;
draft-sajassi-bess-evpn-ip-aliasing.auth...@ietf.org
Cc: bess@ietf.org; Dmitry Valdman <dmitry.vald...@rbbn.com>; Nitsan Dolev
<nitsan.do...@rbbn.com>; Michael Gorokhovsky <michael.gorokhov...@rbbn.com>;
Ron Sdayoor <ron.sday...@rbbn.com>; Egon Haparnass <ehaparn...@rbbn.com>; Shell
Nakash <shell.nak...@rbbn.com>; Marina Fizgeer <marina.fizg...@rbbn.com>; Orly
Kariv <orly.ka...@rbbn.com>; Moti Morgenstern <moti.morgenst...@rbbn.com>;
Rotem Cohen <rotem.co...@rbbn.com>
Subject: [EXTERNAL] Re: Question and comments on the EVPN IP Aliasing draft
Hi Sasha,
Please see in-line with [jorge].
Thanks for the good questions/points.
Jorge
From: Alexander Vainshtein
<alexander.vainsht...@rbbn.com<mailto:alexander.vainsht...@rbbn.com>>
Date: Sunday, March 26, 2023 at 11:16 PM
To:
draft-sajassi-bess-evpn-ip-aliasing.auth...@ietf.org<mailto:draft-sajassi-bess-evpn-ip-aliasing.auth...@ietf.org>
<draft-sajassi-bess-evpn-ip-aliasing.auth...@ietf.org<mailto:draft-sajassi-bess-evpn-ip-aliasing.auth...@ietf.org>>
Cc: bess@ietf.org<mailto:bess@ietf.org> <bess@ietf.org<mailto:bess@ietf.org>>,
Dmitry Valdman <dmitry.vald...@rbbn.com<mailto:dmitry.vald...@rbbn.com>>,
Nitsan Dolev <nitsan.do...@rbbn.com<mailto:nitsan.do...@rbbn.com>>, Michael
Gorokhovsky
<michael.gorokhov...@rbbn.com<mailto:michael.gorokhov...@rbbn.com>>, Ron
Sdayoor <ron.sday...@rbbn.com<mailto:ron.sday...@rbbn.com>>, Egon Haparnass
<ehaparn...@rbbn.com<mailto:ehaparn...@rbbn.com>>, Shell Nakash
<shell.nak...@rbbn.com<mailto:shell.nak...@rbbn.com>>, Marina Fizgeer
<marina.fizg...@rbbn.com<mailto:marina.fizg...@rbbn.com>>, Orly Kariv
<orly.ka...@rbbn.com<mailto:orly.ka...@rbbn.com>>, Moti Morgenstern
<moti.morgenst...@rbbn.com<mailto:moti.morgenst...@rbbn.com>>, Rotem Cohen
<rotem.co...@rbbn.com<mailto:rotem.co...@rbbn.com>>
Subject: Question and comments on the EVPN IP Aliasing draft
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Hi all,
A few questions and comments on the EVPN IP Aliasing
draft<https://clicktime.symantec.com/15t5ei6Q21cWwECv3dXHo?h=hLCOzcf5t8oR3LIGwDra1wBHCN4UcxyL3SN_N-D7vPY=&u=https://datatracker.ietf.org/doc/html/draft-sajassi-bess-evpn-ip-aliasing-06>:
1. Section 3 of the draft states that a PE that is attached to a MH ES
shall advertise a set of IP per ES A-D routes, and Section 4.1 says that these
routes shall be tagged with Export RTs of all IP-VRFs attached to this MH ES.
The following is not mentioned:
a. Should the ESI Label Extended Community be attached to these routes?
My guess (FWIW) is that this is necessary, since this is the only way to let
the remote PEs to know the MH mode of the MH ES in question.
[jorge] correct
b. Assuming an affirmative answer to the previous question, what should
the ESI Label Extended Community attached to these routes carry in its Label
field? My guess (FWIW) is that his field is not relevant and should be set to
all zeroes.
[jorge] yes. We can add a sentence to that respect. The label field SHOULD be
set to 0 and MUST be ignored on reception.
2. Section 3 of the draft says that “a remote PE that receives an EVPN
MAC/IP Advertisement route or an IP Prefix route with a non-reserved ESI and
the RT of a particular IP-VRF SHOULD consider it reachable by every PE that has
advertised an IP A-D per ES and IP A-D per EVI route for that ESI and IP-VRF”:
a. Is the statement above applicable in the case of a MH ES in
Single-Active MH Mode? My guess is that it is only applicable to MH Es in
All-Active MH mode
[jorge] same as in rfc7432bis, both modes
i. If the answer to the previous question
is negative, should the PE that receives an EVPN Type 2 route for an IP→MAC
pair treat the IP address in this pair reachable only via he PE that has
advertised this route and treating other PEs as “backup PEs” (similar to what
is defined in Section 14.1.1 of RFC
7432<https://clicktime.symantec.com/15t5pNUxwEyhm7rm8kKb3?h=m9ESlNFEXlL5s4xyn-g6bmr0dWvx9li2FHAjKrC16c0=&u=https://www.rfc-editor.org/rfc/rfc7432.html%23section-14.1.1>)?
[jorge] yes, assuming that PE the has received the AD routes.
ii. The suggestion to attach the Layer 2
Attributes Extended Community to the per EVI IP A-D route in Section 3.1 of the
draft seems to support my guesses above
iii. I also think that if the MH ES in
Single-Active mode is attached o more than 2 PEs, the Layer 2 Attributes
Extended Community MUST be attached to EVPN per EVI IP A-D routes.
[jorge] at the moment the addition of the L2 Attr ext community is a SHOULD. I
have no problem in making it a MUST assuming my co-authors are ok.
3. I have to admit that I do not understand how IP Aliasing should work
for EVPN IP Prefix routes in the Interface-less IP-VRF-to-IP-VRF scenario
mentioned in Section 1.2 of he draft:
a. Table 1 in RFC
9136<https://clicktime.symantec.com/15t5jYHgUdJ7MB2qbBvSR?h=3pwOHmxhy4P_vmCrfN-Bzd29Fz_PC1o-KGYWe1eTTfY=&u=https://datatracker.ietf.org/doc/html/rfc9136%23fields_overlay_table>
states that a non-zero ESI value in the NLRI of IP Prefix routes is used as an
Overlay index for recursive resolution, while that the Label value in such a
NLRI is “Don’t Care”.
b. At the same time, section 4.1.1 of this RFC states that the ESI field
of the NLRI f these routes is set to all zeroes in the Interface-less
IP-VRF-to-IP-VRF scenario while the Label field in the NRLI of these routes
identifies the IP VRF in question.
c. Can you please explain how can, in this scenario, the receiving PE
associate received EVPN IP Prefix routes with a specific MH ES?
[jorge] section 1.2 illustrates an RFC9136 interface-less model since there is
no SBD. However, this draft modifies the interface-less model by using non-zero
ESI on the IP Prefix routes and a recursive resolution to A-D per ES/EVI routes.
Your timely feedback would be highly appreciated.
Regards, and lots of hanks in advance,
Sasha
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