Re: [Rtg-yang-coord] issue :R03: assignment of interfaces to routing instances

Hi Xufeng,

> On 13 Jan 2015, at 16:11, Xufeng Liu <xufeng.liu@ericsson.com> wrote:
> 
> For the routing-instance to interface relationship, I support the aggregation (or containment) relationship, which means:
> 1. We can easily navigate to interfaces from a routing-instance.
> 2. The key attributes in interfaces are unique within the scope of a routing-instance.
> 
> The current leafref in routing-instance is not sufficient for the above requirements. The uniqueness of interface name within the scope of a routing-instance is not supported.

The data model aims to support different types of routing instances, and it is conceivable that for some types an interface might be allowed to be assigned to more than one routing instance.

However, the draft also says (last paragraph in sec. 5.1) that additional constraints like this uniqueness requirement can be added for a specific routing-instance type.

> 
> My proposal is:
> 1. Keep the current leafref in routing-instance.

OK.

> 2. Add an attribute routing-instance-ref (type leafref) in interface to point to the name attribute (key) of routing-instance.

This is IMO a good idea, we would then have links in both directions.

> 3. Make the new routing-instance-ref added above to be part of the key, i.e. create a composite key <name, routing-instance-ref> for interface.

This is not possible because:

- the key of the if:interface list cannot be extended by additional components;

- if:interface is a flat list that contains interfaces of all layers, but an assignment to a routing-instance makes sense only for L3 interfaces;

- YANG module ietf-interfaces is intended for all kinds of devices, including those that don’t implement ietf-routing.

Thanks, Lada

> 
> Thanks,
> 
> - Xufeng
> 
>> -----Original Message-----
>> From: Rtg-yang-coord [mailto:rtg-yang-coord-bounces@ietf.org] On Behalf Of
>> Ladislav Lhotka
>> Sent: Tuesday, January 13, 2015 4:32 AM
>> To: Acee Lindem (acee)
>> Cc: rtg-yang-coord@ietf.org
>> Subject: Re: [Rtg-yang-coord] issue :R03: assignment of interfaces to routing
>> instances
>> 
>> 
>>> On 13 Jan 2015, at 02:11, Acee Lindem (acee) <acee@cisco.com> wrote:
>>> 
>>> Hi,
>>> 
>>> Lada and I have been discussing this issue for some time and were
>>> hoping for some comments from the routing community. The question is
>>> basically whether to have a list of interfaces in routing-instance
>>> that reference the RFC 7223 interfaces:
>>> 
>>>       container interfaces {
>>>          description
>>>            "Configuration of the routing instance's interfaces.";
>>>          list interface {
>>>            key "name";
>>>            description
>>>              "List of network layer interfaces assigned to the routing
>>>               instance.";
>>>            leaf name {
>>>              type if:interface-ref;
>>>              description
>>>                "A reference to the name of a configured network layer
>>>                 interface.";
>>>            }
>>>          }
>>>        }
>>> 
>>> 
>>> 
>>> Or to augment the RFC 7223 interfaces to point to the routing-instance.
>> 
>> Please see also my earlier mail:
>> 
>> http://www.ietf.org/mail-archive/web/rtg-yang-coord/current/msg00131.html
>> 
>> Thanks, Lada
>> 
>>> 
>>> 
>>> Thanks,
>>> Acee
>>> 
>>> On 11/25/14, 8:16 AM, "Ladislav Lhotka" <lhotka@nic.cz> wrote:
>>> 
>>>> Hi,
>>>> 
>>>> this issue refers the YANG module "ietf-routing" contained in
>>>> 
>>>> http://tools.ietf.org/html/draft-ietf-netmod-routing-cfg-16
>>>> 
>>>> Please indicate your preference or add comments.
>>>> 
>>>> ***** :R03: assignment of interfaces to routing instances
>>>>    In -16 it is done by including a network-layer interface in the
>>>>    list rt:interface under rt:routing-instance. An advantage of
>>>>    this organization is that the rt:interface list should contain
>>>>    only network layer interfaces for which the assignment makes
>>>>    sense. A drawback is that the assignment is detached from the
>>>>    specification of IP addresses in if:interface.
>>>> 
>>>> ****** Solution R03-1
>>>>     No change.
>>>> 
>>>> ****** Solution R03-2
>>>>     Do the assignment of an interface to a routing instance inside
>>>>     the if:interface entry.
>>>> 
>>>> --
>>>> Ladislav Lhotka, CZ.NIC Labs
>>>> PGP Key ID: E74E8C0C
>>>> 
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>>> 
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>> 
>> --
>> Ladislav Lhotka, CZ.NIC Labs
>> PGP Key ID: E74E8C0C
>> 
>> 
>> 
>> 
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--
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C