Re: [Idr] [bess] Type 1 RD for Pure IPv6 network -- EVPN

Why preclude RFC 6286 ?

Regards,
Jakob.

From: Idr <idr-bounces@ietf.org> On Behalf Of Muthu Arul Mozhi Perumal
Sent: Tuesday, February 2, 2021 9:21 PM
To: Gyan Mishra <hayabusagsm@gmail.com>
Cc: TULASI RAM REDDY <tulasiramireddy@gmail.com>; bess@ietf.org; idr@ietf.org
Subject: Re: [Idr] [bess] Type 1 RD for Pure IPv6 network -- EVPN

Hi Gyan,

Please see inline..
Regards,
Muthu

On Sat, Jan 30, 2021 at 3:26 AM Gyan Mishra <hayabusagsm@gmail.com<mailto:hayabusagsm@gmail.com>> wrote:
Muthu

How does RFa. 6286 AS wide BGP identifier change the BGP path selection process when all attributes are equal and ‘bestpath compare-routerid” is uses so the valid/best path is deterministic and oldest versus newest default.
The AS wide BGP identifier shouldn't change the BGP path selection process in this case, since you compare by converting them to host byte order and treating them as 4-octet unsigned integers as per RFC4271.

I believe the BGP Identifier just as with OSPF or ISIS does not have to be routable, so in an IPv6 only network precluding RFC 6286 I believe could you still use a 4 octet IP address as the router-id.

Right. However, if we preclude RFC6286, then the BGP identifier needs to be a valid unicast host IPv4 address (for e.g. can't be a multicast address):

<snip RFC4271>
   Syntactic correctness means that the BGP Identifier field represents
   a valid unicast IP host address.
</snip>

This question comes up a lot these days as operations migrate to some flavor of IPv6 only core MPLS LDPv6, SR-MPLSv6, SRv6.

Thanks

Gyan
On Wed, Jan 27, 2021 at 5:45 AM Muthu Arul Mozhi Perumal <muthu.arul@gmail.com<mailto:muthu.arul@gmail.com>> wrote:
Hi Tulasi,

In pure IPv6 networks, I think using the BGP identifier in place of the IP address part in the type 1 RD should suffice for all practical purposes. The only catch is, if it is an AS-wide unique BGP identifier [RFC6286], then it is not an IP address 'per se'. But, I think it makes no difference from an interoperability standpoint..
Perhaps, in line with RFC6286, we should redefine the IP address part of the type 1 RD as just a 4-octet, unsigned, non-zero integer..
Regards,
Muthu

On Fri, Jan 22, 2021 at 11:31 AM TULASI RAM REDDY <tulasiramireddy@gmail.com<mailto:tulasiramireddy@gmail.com>> wrote:
Hi All,

In a pure IPv6 network, how do one expect to construct the Type 1 RD.
As per EVPN RFC 7432 for EAD per ES, it should be Type 1 RD, but if the loopback address is only IPv6 then what is the expectation here?
Should we use BGP router ID(32bit) here?

From RFC7432: EVPN
8.2.1<https://tools.ietf.org/html/rfc7432#section-8.2.1>.  Constructing Ethernet A-D per Ethernet Segment Route

   The Route Distinguisher (RD) MUST be a Type 1 RD [RFC4364<https://tools.ietf.org/html/rfc4364>].  The

   value field comprises an IP address of the PE (typically, the

   loopback address) followed by a number unique to the PE.

Thanks,
TULASI RAMI REDDY N
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