North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: router startup behavior
> > Just guessing - you're seeing these events between midnight > > and 5 am? > > Hm, couldn't reist this one: "which time zone"? > > Just hinting that even though it's that time interval in the US, local > time is different in other places around the world, so if this is > causing disturbance, others are probably being hit in their working > hours. Heh, the "perpetual global maintenance window syndrome", eh? A very useful concept... > Besides, I was under the impression that to activate a new outbound > roting policy on a Cisco, you could just modify / replace it, but that > you would still have to do > > router#clear ip bgp xxx soft out > > to activate it. This means that the policy for an existing peer can > be modified without having to remove the peering and reenable it > shortly thereafter (something which would cause needless route > flapping). Somewhat true. The new policy would not be applied to routes that were already in the table, but would be applied to any adds/withdrawals that occur once the policy changes are placed in the configuration. This fact has a synergistic effect when you're making changes that affect lots of sessions. So a policy change made a significant time before a clear or soft clear could in fact result in flaps. Also consider: there are a lot of routers using traditional ACL's in their policies (as opposed to things like prefix-lists which have more granular editing features) which would necessitate removing the ACL completely and rewriting it with updated lines. Due to the above, a potential for leaks exists unless the session is either shutdown or deleted while acl's are being modified. If the sequence of events in a configuration script is not well thought out, the result could be what Ratul has observed in his study. > > Regards, > > - H�vard >
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