Re: [Idr] I-D Action: draft-ietf-idr-bgp-model-17.txt

[Maria Matejka <[e-mail]>]

Hello!

I'm reiterating BIRD's issues with the BGP YANG model, like those sent 
here: https://mailarchive.ietf.org/arch/msg/idr/3rVyYyqVHIy9lMk12CPobFJ3CSo/

Shortly:

1. Indexing BGP neighbors by their IP addresses is broken for routers 
handling multiple VRF's on legacy IPv4. Our suggestion is this:

[page 26] in `list neighbor` exchange `key "remote-address"` for `key 
"name"` and add `leaf name { type string; description "Name of this 
neighbor entry."; }`

This allows for BIRD to key configured neighbors by their names (which 
is what we do) and everybody else can simply put the IP address in the 
"name" field as well. (It's a string type anyway.)

2. Regex on pages 112-113 representing `bgp-large-community-type` 
doesn't match `4199999999:0:0` which is an obvious bug. Our suggestion 
is to make it a container:

container bgp-large-community {
   leaf asn { type uint32; }
   leaf data1 { type uint32; }
   leaf data2 { type uint32; }
}

This also aligns better with RFC 8092 where the large community is 
defined as a block of three uint32 values.

3. The same regex bug occurs e.g. on page 116 in `route-origin` pattern. 
Our suggestion is to make the bgp-ext-community just a simple uint64 type.

4. Another regex bug occurs on page 112 in `bgp-comunity-type` (sorry 
for jumping backwards, just spotted it) which incorrectly matches 
`66444:0`. Our suggestion is to keep it simple with uint32 type only.

5. There is a completely big separate topic about the policy definitions 
but we're now tending to simply deviate from YANG in this completely and 
write our own YANG describing our filtering language as it may be much 
easier than trying to find a common ground.

This is _not_ an exhaustive list of our issues with the draft, I haven't 
completed its analysis yet.

Thank you for considering our issues.
Maria

On 7/5/23 20:45, Mahesh Jethanandani wrote:
> This version of the model addresses some of the comments that were 
> received as part of LC.
>
> For issues with this version of the draft, please feel free to discuss 
> them here, open issues or contribute via a PR at:
>
> https://github.com/mjethanandani/ietf-bgp-yang
>
> Thanks.
>
>> On Jul 5, 2023, at 11:28 AM, [e-mail] wrote:
>>
>>
>> A New Internet-Draft is available from the on-line Internet-Drafts
>> directories. This Internet-Draft is a work item of the Inter-Domain 
>> Routing
>> (IDR) WG of the IETF.
>>
>>   Title           : YANG Model for Border Gateway Protocol (BGP-4)
>>   Authors         : Mahesh Jethanandani
>>                     Keyur Patel
>>                     Susan Hares
>>                     Jeffrey Haas
>>   Filename        : draft-ietf-idr-bgp-model-17.txt
>>   Pages           : 225
>>   Date            : 2023-07-05
>>
>> Abstract:
>>   This document defines a YANG data model for configuring and managing
>>   BGP, including protocol, policy, and operational aspects, such as
>>   RIB, based on data center, carrier, and content provider operational
>>   requirements.
>>
>> The IETF datatracker status page for this Internet-Draft is:
>> https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-model/
>>
>> There is also an htmlized version available at:
>> https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-model-17
>>
>> A diff from the previous version is available at:
>> https://author-tools.ietf.org/iddiff?url2=draft-ietf-idr-bgp-model-17
>>
>> Internet-Drafts are also available by rsync at 
>> rsync.ietf.org::internet-drafts
>>
>>
>
>
> Mahesh Jethanandani
> [e-mail]
>
>
>
>
>
>
>
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-- 
Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.