Hi Rostam, 1. Does the RIP updates timers work is series? i.e after one elapses the other starts? Nope it is a continuous timer, so a flush would occur after 240 seconds total.
With RIP you have the following timers: Update: how often to send updates in seconds, by default 30 seconds Invalid: how long does the router wait before it considers the route invalid, and places the route into hold down Hold Down: How long does the router not believe any equal or less impressive (worse) route updates for routes that are in hold down, this timer is Cisco proprietary Flush: how long since the last valid update, until the route is killed. So really your default timers are: 30 seconds for updates, 180 seconds for invalid/hold, and 240 for flush. The reason that hold & invalid run at the same time is because Hold is a Cisco proprietary timer they added in to help guard against routing loops during the convergence process, so it makes sense that it runs the same time that the route is marked as down. Hope that helps Cheers, Donald Robb Productive Networks / Network Consultant ______________________________________________________________ CCIE Written, CCIP, CCSP, CCDP, CCNP, CCNA: Voice, JNCIP, SCP, MCSA 2003, Security+, CCSE.R65, PACE Experts-Exchange: Guru R&S -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Rostam Sohrab Sent: January-19-12 4:56 AM To: [email protected] Subject: [OSL | CCIE_RS] Correct Understanding the RIP timers! I have a little confusion in the understanding of RIP timers. First the basics... update timer is 30 secs --> Invalid timers should be 3 times of update i.e 90secs but the default is 180secs --> Holddown timers should be 3 times of update i.e, 90secs but the default is 180secs --> Flush timer, default is 240 secs. Now there are three parts to my question... The first question might sound silly but for the sake of a clear understanding I'll write it. 1. Does the RIP updates timers work is series? i.e after one elapses the other starts? ex: once U-30sec is over --> Invalid starts and runs for 180 secs --> Holddown starts and runs for another 180secs --> And finally flush timer starts and runs for 240secs. Here the total time would be 30+180+180+240=630secs until a route is flushed out which is looking quite unreasonable! 2. Does the Invalid, Holddown & flush timers work is parallel? ex: once U-30sec is over -> Invalid, Holddown runs for 180secs along with the flushtimer which runs for 240secs? Here the total time would be 30+240=270secs until a route is flushed out which looks very much acceptable. 3. And why does the Invalid & Holddown timers run in parallel, if all they do? Because at the end of these two timers (IT & HDT) it would take another 60secs for flush timer to flush out the route, which means that all the timers IT/HDT/FT are kicking off at the same time immediately after update timer expires! I think I'm just complicating what is supposed to be a simple understanding!!! -RS _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
