Re: rtg-cfg hierachy (PLEASE REPLY TO THIS ONE WITH THE CORRECT MAIL ALIASES)

[Ladislav Lhotka <[e-mail]>]

Hi Thomas,

I apologize for a late response, I was on holiday last week.

Thomas Morin <[e-mail]> writes:

> Hi Acee, Lada,
>
> It seems that my comment that you quote was more related to filters than 
> to routing tables, and indeed, *filters* were moved from "router" to 
> "global" in revision -03 that followed my review.

Right, but each filter could then be specified for either
"connected-routing-table" or "recipient-routing-table", and if the
'remote' routing table is in a different routing instance, it IMO makes
more sense to have routing tables (RIBs) as global objects
accessible to all routing instances.

In fact, even if RIBs are routing-instance specific, it will still be
possible to access a RIB in a foreign routing instance, it will just be
more laborious - one will have to specify the target routing instance &
RIB. Also, names of RIBs will no more be unique system-wide.

>
> Additionally, Lada, you say that based on my comments "in rev. -03 the 
> list of RIBs (then called "routing-table") was the moved out of the 
> routing instance (then called "router") and became global.". But if I 
> look at -03, "routing-table" is still a child of "router".  The change 
> to make "routing-table" global was made in -05.
>
> I guess you need to find out what was the motivation for the change in 
> -05, a few months after my initial comments were address.

Yes, you are right, it seems the immediate motivation for this change
was this review by Martin Bjorklund:

http://www.ietf.org/mail-archive/web/netmod/current/msg06962.html

Thanks, Lada

>
> Best,
>
> -Thomas
>
>
>
>
>
> 2015-02-13, Acee Lindem (acee):
>>
>> Hi Lada, Thomas,
>>
>> On 2/13/15, 5:10 AM, "Ladislav Lhotka" <[e-mail]> wrote:
>>
>>> Hi,
>>>
>>> "Acee Lindem (acee)" <[e-mail]> writes:
>>>
>>>> Hi Thomas,
>>>>
>>>> It is my understanding that the RIBs were moved out of the
>>>> routing-instance in response to your comment that a RIB would need to be
>>>> attached to multiple routing instances. I don¹t agree with this
>>>> model. I
>>>
>>> Acee refers to this comment that Thomas made in his review of
>>> draft-ietf-netmod-routing-cfg-02 on 2012-03-23:
>>>
>>> "Allowing multiple "routers" is a good starting point for using these
>>> specs in the context of RFC4364 (MPLS/BGP IP VPNs). However, if I
>>> understand correctly Yang syntax, the way the filters are defined would
>>> not work in the context of RFC4364, where a BGP routing instance in the
>>> master "router" exports selected routes in each of the routing table of
>>> each VPN (VRF).  The VRF also export routes to the master instance."
>>>
>>> And indeed, in rev. -03 the list of RIBs (then called "routing-table")
>>> was the moved out of the routing instance (then called "router") and
>>> became global.
>>
>> Then do you agree to move the RIBs back into the routing-instance? Both
>> the BGP YANG drafts model L3VPN definitions under the corresponding
>> address family in BGP.
>>
>> http://www.ietf.org/id/draft-shaikh-idr-bgp-model-00.txt
>> http://www.ietf.org/id/draft-zhdankin-idr-bgp-cfg-00.txt
>>
>> Thanks,
>> Acee
>>
>>
>>
>>>
>>> Lada
>>>
>>>> believe that a routing instance implies a VRF, virtual router or
>>>> something
>>>> in between and that a RIB should be associated with one and only one
>>>> routing instance. Additionally, I feel that RIBs are basically passive
>>>> entities with respect to import/export of routes between RIBs in the
>>>> same
>>>> or other routing-instances. Rather, all import/export is under the
>>>> control
>>>> of a routing-protocol. For example, this would be handled by a BGP
>>>> routing-protocol instance for L3VPNs.
>>>>
>>>> I¹d like to get the opinions of others on this fundamental aspect of the
>>>> rtg-cfg model.
>>>>
>>>> Thanks,
>>>> Acee
>>>>
>>>>
>>>
>>> --
>>> Ladislav Lhotka, CZ.NIC Labs
>>> PGP Key ID: E74E8C0C
>>
>>
>>
>

-- 
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C