[RRG] Re: map change due to a path failure?

["William Herrin" <bill@herrin.us>]

On Mon, Mar 24, 2008 at 7:48 PM, Brian E Carpenter
<brian.e.carpenter@gmail.com> wrote:
> On 2008-03-23 09:50, William Herrin wrote:
>  > 2a. What's the maximum acceptable time in which one EID may be
>  > inaccessible to another because of a map change due to a path failure?
>
>  That seems to assume that a failure will produce a map change.
>  I expect a failure to produce a change in the routing tables,
>  but why should a (temporary) failure produce any change
>  in the map? I would expect this would cause the routing
>  algorithm to be told about the failure and to find an alternative
>  path involving the same or an alternative map entry.

Hi Brian,

I suppose that depends on how you split the duties between routing and
mapping. With TRRP, path failures between the endpoint and a little
ways upstream of the ETR will be handled by a map change (expressing
which ETRs are currently able to natively reach the endpoint) while
most path failures between the ITR and ETR will be handled by a BGP
route change. In both cases, the question which matters is: how long
does it take to detect the failure and restore service?

Lets rephrase the question so that it's agnostic on the map/route issue:

2a. What's the maximum acceptable time in which one EID may be
inaccessible to another during change propagation due to a path
failure?

Regards,
Bill Herrin



-- 
William D. Herrin herrin@dirtside.com bill@herrin.us
Web: <http://bill.herrin.us/>

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