Hi Jorge and Vinayak,
I don't understand this use case of RFC9136 very well either,
because when a BD of VLAN-aware bundle EVI is used in Bump-in-the-wire use case,
I don't sure how the IP prefixes routes are recursively rosolved.
I hope to share my understandings to help to make this use case more clear.
When an IP Prefix route is advertised in the context of a VLAN-aware BD, and
the IP Prefix route would be using a non-zero Ethernet Tag ID,
The overlay index of the IP prefix route should be considered to be the <ESI,
Ethernet Tag ID> or just the ESI?
In section 3 of RFC9136, I see that only the ESI is considered to be the
overlay index.
Thanks,
Yubao
On Fri, 3 Dec 2021 17:03:48 +0000
"Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.raba...@nokia.com> wrote:
> Hi again,
>
> John pointed to me that there are some cases where a non-zero Ethernet Tag ID
> on the IP Prefix route may be used in RFC9136.
>
> In the RFC9136 IP-VRF-to-IP-VRF use cases, the Ethernet Tag ID is always
> zero, since the IP Prefix route is advertised in the context of the IP-VRF.
> However it is true that RFC9136 also discusses some use-cases where the IP
> Prefix route is advertised in the context of a BD, in which case, if the BD
> belongs to a VLAN-aware bundle EVI, the IP Prefix routes would be using a
> non-zero Ethernet Tag ID.
>
> I overlooked that when I replied first.
> Thanks John.
>
> Jorge
>
> From: Rabadan, Jorge (Nokia - US/Mountain View) <jorge.raba...@nokia.com>
> Date: Thursday, December 2, 2021 at 6:00 PM
> To: Joshi, Vinayak <vinayak.jo...@hpe.com>, bess@ietf.org <bess@ietf.org>
> Subject: Re: Query about Ethernet Tag Id for TYpe-5 routes (RFC 9136)
> Hi Vinayak,
>
> RFC9136 does not have any use case for the use of a non-zero ethernet tag id.
> The IP Prefix route includes the ethernet tag id as part of the key for
> consistency with the rest of the EVPN service routes, for future use.
>
> Thanks.
> Jorge
>
> From: BESS <bess-boun...@ietf.org> on behalf of Joshi, Vinayak
> <vinayak.jo...@hpe.com>
> Date: Thursday, December 2, 2021 at 7:33 AM
> To: bess@ietf.org <bess@ietf.org>
> Subject: [bess] Query about Ethernet Tag Id for TYpe-5 routes (RFC 9136)
> Hi all,
>
> RFC 9136 says the following (Section 3.1)
>
>
> “ The RD, Ethernet Tag ID, IP prefix length, and IP prefix are part of
> the route key used by BGP to compare routes. The rest of the fields
> are not part of the route key.
>
> With VLAN Aware Bundling the Eth Tag ID acts as a distinguisher for the
> routes while importing into L2-VRF.
> But for L3 prefix routes what is the use case for setting the Ether Tag ID to
> any non-zero value?
>
> Thanks in advance,
> Vinayak
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