From: Aidan Marks (amarks@cisco.com)
Date: Thu Dec 19 2002 - 08:04:21 GMT-3
The passive state is stored on the IDB and each protocol, where necessary
checks this state, e.g. the ospf hello function before doing anything.
It is fairly simple.
At 08:14 PM 19/12/2002, tan wrote:
> > Ah, but it *is* routing-protocol specific. Just because the syntax is
> > similar between different protocols doesn't mean that the
> > internals are
> > identical. Link-state and distance-vector routing protocols behave
> > differently,
>
>Entering a command under the protocol within the running config is indeed a
>good ascertation that the process is protocol internal, but does not
>necessarily mean the background logic used by each protocol in how it deals
>with passive-interface isn't similar. Especially if there is a historical
>precedent for how the command was first implemented, then copied over the
>years with new protocols.
>
>Most books only go as far as to say
>"routing updates not sent"
>"hellos not sent"
>"no adjacencies, so no routing updates"
>
>Now look at this surmise...
>-passive interface kills packets destined for 255.255.255.255 and sourced
>from this router.
>
>Could not some variation on this with a little thought satisfy all results
>seen in each protocol?
>
>However, you are probably right in the end. Each protocol most likely has a
>unique logical flowchart, and it is probably not as simple as an internal
>ACL. Well, heck maybe it is simple, but the answer is probably too deep in
>IOS code.
>
>Thanks
>.
.
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