Re: [OSPF] Benoit Claise's Discuss on draft-ietf-ospf-ospfv3-autoconfig-13: (with DISCUSS)

["Acee Lindem (acee)" <[e-mail]>]

Hi Benoit, 

On 2/5/15, 8:31 AM, "Benoit Claise (bclaise)" <[e-mail]> wrote:

>Benoit Claise has entered the following ballot position for
>draft-ietf-ospf-ospfv3-autoconfig-13: Discuss
>
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>----------------------------------------------------------------------
>DISCUSS:
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>   4.  OSPFv3 interfaces MAY use an arbitrary HelloInterval and
>       RouterDeadInterval as specified in Section 3.
>
>Hopefully, an easy DISCUSS.
>>From a management point of view, we must be able to determine if a router
>or interfaces within a router are OSPF-autoconfigured.
>If I'm not mistaken, you miss, in the management considerations section,
>something like this: The OSPFv3 routers MUST flag the interfaces
>supporting this specification.

I will add:

   OSPFv3 Routers supporting this specification MUST augment mechanisms
   for displaying or otherwise conveying OSPFv3 operational state to
   indicate whether or not the OSPFv3 router was autoconfigured and
   whether or not its OSPFv3 interfaces have been auto-configured.


Additionally, we will consider adding a feature to the OSPF YANG model for
auto-configuration.


> 
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>Background: I recall one particular tool in the past that would check the
>different router configs and flag the HelloInterval and
>RouterDeadInterval
> mismatched values for adjacent routers. This would be equivalent to the
>following debug:
>OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
>OSPF: Mismatched hello parameters from 192.168.0.2
>OSPF: Dead R 40 C 60, Hello R 10 C 15  Mask R 255.255.255.252 C
>255.255.255.252
>
>In case of OSPF auto-config, this check doesn't make any sense.

This looks like debug messages from a router. Perhaps, this tool simply
snoops on OSPF networks and does analysis. Since there is nothing in the
packet to indicate auto configuration, there is no way to detect this
simply by sniffing. There was a proposal to provide an indicate but it was
more complex and offered little additional functionality. Unfortunately,
we cannot use 0 for hello-interval since this is used for a proprietary
sub-second hello extension implemented by many vendors.

Thanks,
Acee 


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