bird: show route behaviour

Dan Rimal danrimal at gmail.com
Mon Feb 25 09:01:36 CET 2013


I agree with Hans. I think bird should use table defined within each 
protocol or use master if table isn't defined. But i don't know, if 
other part of bird will not be affected (in negative point of view) by 
this behaviour.

I will try patch this evenging, thank you for it.

Dan


On 02/24/2013 07:40 PM, Ondrej Filip wrote:
> On 24.2.2013 19:35, Hans van Kranenburg wrote:
>>> yes, because 'table master' is default. I produced a simple patch
>>> (attached) against the current git repository, but it should work
>>> against 1.3.9.  However I am not 100% sure whether to submit this into
>>> the main branch or rather just document that 'table master' is
>>> default. I will discuss it with my teammates. And of course, your
>>> comments are welcome.
>> How should the output of the following command in Dans example be
>> interpreted?
>>
>> bird> show route export nix1_nix
>> 4.4.4.0/24         via 172.17.1.1 on eth0 [s_master 00:29] * (200)
>> 5.5.5.0/24         via 172.17.1.1 on eth0 [s_nix 00:29] * (200)
>> 6.6.6.0/24         via 172.17.1.1 on eth0 [s_tranzit 00:29] * (200)
>>
>> I guess it should be done like: "these are the routes that could
>> possibly be exported from table master via table t_nix to nix1_nix if
>> none of them were being filtered"? This does not make any sense to me as
>> default output.
> No, that are routes from master table that could be exported to
> protocol nix1_nix filtered by import protocol. But anyway.
>
>> The config Dan is showing explicitely has an import none from master to
>> t_nix, so when being busy to debug route information at the nix1_nix
>> proto, after filtering all those routes from t_nix to nix1_nix (possibly
>> to isolate the test case while tracking down a problem) this looks very
>> confusing.
>>
>> I'm always a fan of defaults that match how (new) people would use the
>> software intuitively, and here's how I would intuitively think:
>>
>> One of the first pages you read when starting with bird is this one:
>>
>> http://bird.network.cz/?get_doc&f=bird-2.html
>>
>> "Each protocol is connected to a routing table through two filters which
>> can accept, reject and modify the routes. An export filter checks routes
>> passed from the routing table to the protocol, an import filter checks
>> routes in the opposite direction."
>>
>> This makes me think by default that show route export <protocol> would
>> show me information about what is actually going in in <protocol> right
>> now by default, related to its own connected bird table.
>>
> OK. I understand your point.
>
> 			Ondrej
>
>




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