On Mar 21, 2012, at 4:57 PM, Christopher Morrow wrote:

> On Wed, Mar 21, 2012 at 3:19 PM, Eric Osterweil <[email protected]> 
> wrote:
> 
>> How about we turn this around with a simple question:
>> Suppose two different feasible paths are being evaluated for a single 
>> prefix/origin pair and one was delivered via a signed bgpsec update, and the 
>> other was delivered via an unsigned update.  What 
>> annotations/influencers/considerations/etc. does the bgpsec design suggest 
>> when the router is making its path selection between these two?
>> 
> 
> ideall, I think, the process is something like:
>  1) first path gets evaluated, is it 'good' (next-hop reachable, not
> discarded by prefix-list/etc)
>  2) second path gets evaluated, is it 'good' (same as above +
> origin-validate + path-validation)
> 
> If both 1 and 2 come out 'ok', assume each path was received from a
> different peer on the same device:
>  1) 1 - 2 - 701 - you
>  2) 1 - 3 - 7018 - you
> 
> If you decide that your network's policy is 'prefer signed and valid
> over unsigned' paths, you'd pick #2. It could be that your method of
> doing this is saying:
>  route-map inbound-bgp permit 10
>    if route-signed and verified
>    set localpref 100
> 
> Which ideally would let localpref on the #1 route stay normal == 80
> and magically you'd just use the 'right' (from your perspective) path.
> (signed and verified).
> 
> of course, in the beginning of this you may choose a more conservative:
>   route-map inbound-bgp permit 10
>      if route-signed and verified
>        set community you:verified
> 
> so you could measure the deployment state of your customers + 
> rest-o-interwebs.
> 
> In the end, I think 'bgpsec suggests' that the operator would make
> some decision... ideally the same decision across the network.
> 
> does that make sense? (the policy is deliberately short and simple,
> obviously real policy is longer/stranger, but the end result is the
> same)

Indeed, this makes sense, thanks for the detailed response.  However, this also 
illustrates an evolution of semantics under non-attack circumstances. :)

Eric

_______________________________________________
sidr mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/sidr

Reply via email to