Hi Mahesh, Benoit, Draft Authors,

In terms of a layer-2 ACL, I’d want to be able to match ether-type against any 
2-octet number. Hence, I think a string is a very poor choice here.

In support of the above statement, one only needs to look at the existing IEEE 
registry for ether type.

https://regauth.standards.ieee.org/standards-ra-web/pub/view.html#registries

There are about 3700+ registered ether-types and most of them are private. This 
is hardly something that we’d want to represent as a YANG enum or even a set of 
identities.

However, if we are talking about future YANG enhancements, it would be nice to 
have an identity that could reference a YANG type as a base rather than another 
identify. That way the base type could be uint16 or some other 2-octet type and 
well-known ether-types could be represented by YANG identities referencing the 
base identity of type unit16.

Thanks,
Acee

From: netmod <netmod-boun...@ietf.org<mailto:netmod-boun...@ietf.org>> on 
behalf of Mahesh Jethanandani 
<mjethanand...@gmail.com<mailto:mjethanand...@gmail.com>>
Date: Tuesday, July 11, 2017 at 11:55 AM
To: "Benoit Claise (bclaise)" <bcla...@cisco.com<mailto:bcla...@cisco.com>>
Cc: Marc Holness <mholn...@ciena.com<mailto:mholn...@ciena.com>>, Glenn Parsons 
<glenn.pars...@ericsson.com<mailto:glenn.pars...@ericsson.com>>, NetMod WG 
<netmod@ietf.org<mailto:netmod@ietf.org>>
Subject: Re: [netmod] draft-ietf-netmod-acl-model-11 issue #3

Benoit,

Precisely. I did start in yangcatalog.com<http://yangcatalog.com> with the 
search for ether-type and found that it was defined as a string. It was helpful 
to get rid of the duplicate definition we had in the ACL draft. But that raised 
the question of whether it should be defined as a string, when ether-types are 
well known types.

Is there a IETF-IEEE co-ordination meeting planned in Prague?

On Jul 11, 2017, at 3:25 AM, Benoit Claise 
<bcla...@cisco.com<mailto:bcla...@cisco.com>> wrote:

Hi,

In order to look at what has been done already, the advice is to look at YANG 
search<https://www.yangcatalog.org/yang-search/yang-search.php>.
I searched on "ether.type" with the regex flag.
<gidfollnniceccif.png> Don't pay attention to the last entry, this will be 
fixed.

However, specifically pay attention to the second entry, the IEEE one.
It points to 
https://www.yangcatalog.org/yang-search/show_node.php?module=ieee802-dot1q-types&path=%2Fdot1q-types%3Aether-type&revision=2016-09-22

Regards, Benoit
Created issue #3 in github<https://github.com/netmod-wg/acl-model/issues/3> as 
"The model defines 'ether-type' node as a string.” with the following 
description.


The model defines 'ether-type' node as a string. Ideally, this should be a well 
defined list of all Ethernet Types assigned by IEEE. This requires 
collaborating with IEEE.

One suggestion was to define ether-type as identities. That works for when the 
identities themselves are distributed and need to be made extensible.

But Ethernet Types are doled out in IEEE by Registration Authority Committee 
(RAC), so they could choose to centrally define it as an enum and give each hex 
string a name that could be used by models. If a user wants to configure a 
particular ether-type, the server must import a version of the IEEE 8021q model 
that has that enumeration.

Alternatively, as @mbj4668<https://github.com/mbj4668> has suggested, it could 
also be a typedef like this:

    typedef ether-type {
      type union {
        type ieee-ether-type:ether-type-enum;
        type uint16; // or a hex-based number
      }
    }


Finally, the suggestion is to have ether-type defined as a number (or hex 
based). This is flexible, but requires users/operators to read and write 
numbers which are harder to remember than symbolic names.

My personal preference would be for IEEE to define and publish the YANG model 
with the definitions.

Mahesh Jethanandani
mjethanand...@gmail.com<mailto:mjethanand...@gmail.com>






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