Re: [bess] Queries to authors of https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html

["Dikshit, Saumya" <[e-mail]>]

Just to elaborate further,
Below might be the scenario where both MAC aliasing (MAC routes) and IP-aliasing (for /32 host routes) is needed in mixed deployment of Symmetric IRB fabric.
Fabric may have mixed-bag of PEs, where-in, some of them have VRF-extended (/32 routes) while others have only subnet extended (MAC).

Regards,
Saumya.

From: BESS [mailto:[e-mail]] On Behalf Of Dikshit, Saumya
Sent: Tuesday, March 5, 2024 7:53 AM
To: Jorge Rabadan (Nokia) <jorge.rabadan=[e-mail]>; Allu, Ramaprasad <[e-mail]>; [e-mail]; [e-mail]
Cc: [e-mail]
Subject: Re: [bess] Queries to authors of https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html

Hi Jorge,

Is this the same RD for IP VRF (uniquely defined for IP-AD per EVI route), that should be leveraged for host routes in Route Type-2 and Prefix Routes in Route Type-5 ? Is that the safe assumption (as per rfc9135/9134) ?

In case yes, then If we have a unique RD for the IP-VRF, what RD should be used for the NLRI in the Route-Type-2 carrying MAC/IP for tied to MAC-VRF and IP-VRF ?  Should it be MAC-VRF RD or IP-VRF RD.

Regards,
Saumya.

From: BESS [mailto:[e-mail]] On Behalf Of Jorge Rabadan (Nokia)
Sent: Tuesday, March 5, 2024 1:57 AM
To: Allu, Ramaprasad <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>; Dikshit, Saumya <[e-mail]<mailto:[e-mail]>>
Subject: Re: [bess] Queries to authors of https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html<https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html>

Hi Ramaprasad,

About this:


“If MPLS label field is not considered for BGP route key, then BGP RIB will have only one route entry at any given point of time.

That is, IP A-D per EVI route overwrites Ethernet AD per EVI and vice-versa if same RD is used for IP-VRF and MAC-VRF.”

The Ethernet AD per EVI route and IP AD per EVI routes must use different RDs. It was sort of implicit, since the former one uses the RD of the MAC-VRF and the latter the RD of the IP-VRF, but we added this in rev 01 to make sure there is no misunderstanding:

          *  The Route-Distinguisher is for the corresponding IP-VRF.  The
            Route-Distinguisher allocated for the IP-VRF MUST be unique in the
            PE.

Hope it helps.

Thank you,
Jorge

From: Allu, Ramaprasad <[e-mail]<mailto:[e-mail]>>
Date: Sunday, March 3, 2024 at 10:04 PM
To: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, Dikshit, Saumya <[e-mail]<mailto:[e-mail]>>
Subject: Re: Queries to authors of https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html<https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html>
You don't often get email from [e-mail]<mailto:[e-mail]>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification>


CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information.


Hi Authors,

Gentle reminder.
Can you please take a look at it and respond to below query?

Thanks,
Ramaprasad
From: Allu, Ramaprasad <[e-mail]<mailto:[e-mail]>>
Date: Wednesday, 21 February 2024 at 5:40 PM
To: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>, Dikshit, Saumya <[e-mail]<mailto:[e-mail]>>
Subject: Queries to authors of https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html<https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html>
Hi Authors of draft https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html<https://www.ietf.org/archive/id/draft-ietf-bess-evpn-ip-aliasing-00.html>

I have a following query on the draft.  Please help with your response.


Context of section https://www.ietf.org/archive/id/draft-sajassi-bess-evpn-ip-aliasing-09.html#section-3.1<https://www.ietf.org/archive/id/draft-sajassi-bess-evpn-ip-aliasing-09.html#section-3.1>,

In the section, it is mentioned that the construction of the IP A-D per EVI route is same as that of the Ethernet A-D per EVI route. The NLRI consists of the following,

                +---------------------------------------+

                |  Route Distinguisher (RD) (8 octets)  |

                +---------------------------------------+

                |Ethernet Segment Identifier (10 octets)|

                +---------------------------------------+

                |  Ethernet Tag ID (4 octets)           |

                +---------------------------------------+

                |  MPLS Label (3 octets)                |

                +---------------------------------------+



And as per https://www.rfc-editor.org/rfc/rfc7432.html#section-7.1<https://www.rfc-editor.org/rfc/rfc7432.html#section-7.1>, “ for the purpose of BGP route key processing, only the Ethernet

   Segment Identifier and the Ethernet Tag ID are considered to be part

   of the prefix in the NLRI.  The MPLS Label field is to be treated as

   a route attribute as opposed to being part of the route”



If MPLS label field is not considered for BGP route key, then BGP RIB will have only one route entry at any given point of time.

That is, IP A-D per EVI route overwrites Ethernet AD per EVI and vice-versa if same RD is used for IP-VRF and MAC-VRF.



Is there any reason for explicit mention of not using MPLS label field as key for BGP route or not carrying two labels one for Ethernet A-D per EVI and another for IP-AD per VRF?

In this case, I see only MPLS Label (VNI in case of VXLAN) is the distinguisher if same RD is used for both IP-VRF and MAC-VRF.



And to keep two separate routes in BGP RIB, we need to use MPLS label also one of the keys in addition to RD, ESI and ETAG fields.

Or Carry both the labels and extended communities as part of single A-D per EVI route and store single route in the global BGP RIB.



Please let me know what you think.



Thanks,

Ramaprasad