ccna 200 301 syllabus of upsc pdf material

ccna 200 301 syllabus of upsc pdf material.6.1.3 RIP Timers***RIP uses 4 different types of timers to manage its performance. Using the "showipprotocolsw command on a router running the RIP protocol shows the following.Routing Protocol is HripMIncomingupdate filter listfor all interfaces is not setSending updates every30 seconds, next due in 0 seconds Invalidafter 180 seconds, hold down180, flushedafter 240(1) Routing update timer: Used to set the interval for periodic routing updates, the default is 30 seconds. In the above output, ^Sending updatesevery30seconds" refers to the routing update timer, where every 30 seconds the router will make a complete copy of its entire routing table to the neighboring routers, even if the topology of this router has not changed.(2) Route Invalidation Timer: The amount of time a router needs to wait before it determines a route to be invalid, the default is 180 seconds. In the above output, "Invalid after 180seconds,, refers to the invalidation timer° If the router does not receive an update message about a route within this period, it will consider the route invalid. When this happens, the router will send an update message to all its neighboring routers to inform them that this route is no longer valid.(3) suppression timer (holddown time):Used to set the time for which routing information is suppressed. When an update packet indicating that a route is unreachable is received, the router will enter holddowntime, which is also 180 seconds by default, i.e. "holddown180" in the above output. See Section 5.5.4 in Chapter 5 for more information on suppression timers.(4) Route refresh timer: Used to set the interval for a route to become invalid and remove it from the routing table, the default is 240 seconds, i.e. flushedafter240" in the output above. Before removing it from the routing table, the router informs its neighbors that the route is about to die out. The value of the route expiration timer must be less than the value of the route refresh timer, which provides enough time for the router to inform its neighbors about this invalid route before the local routing table is updated.The four timers above can be understood in this way, without considering the use of any distance vectoring protocol to prevent routing loops. In conjunction with Figure 5-5-1, by default RIP sends routing updates every 30 seconds. If a topology change occurs, in this case network 1 on router A is invalidated and the update packet sent from router A to router B no longer contains network 1, the route invalidation timer, route suppression timer, and route refresh timer start simultaneously, and for six consecutive update cycles, router B does not receive Router B does not receive information about network 1 from router A. Router B considers network 1 to be invalid. The route failure timer is used here, and before the route failure, if Router B receives a packet addressed to Network 1, Router B is sending a packet to Router