at&t ccna jobs

at&t ccna jobs.EIGRP uses Hello to maintain neighbor stateEIGRP does not send full or partial update messages based on timers, so EIGRP cannot rely on update messages to monitor the state of EIGRP neighbors. Therefore, using the same basic concept as OSPF, EIGRP defines a Hello message. This EIGRP Hello message and protocol defines that each router should periodically send a HeDo message on each interface so that all EIGRP routers knowThe router is still working. Figure 9-8 shows this concept.Routers use their own separate Hello interval (which defines the time period of each EIGRP Hello). For example, routers Rl and R2 do not send Hello messages at the same time. Routers must also receive Hello messages from neighboring routers at a certain interval (called the "hold interval"), set by default to four times the Hello interval.For example, imagine that Rl and R2 both use the default 5 or 15 as their Hello interval and hold interval. Under normal circumstances, R1 receives Hello messages from R2 every 5 seconds, which is right within R1's hold interval (15 seconds), otherwise R1 would conclude that R2 has stopped working. If R2 does fail, R2 will no longer send Hello messages. and R1 does not receive a Hello message from R2 after 15 seconds. then R1 is able to choose not to use R1 as the new router for the next hop.EIGRP does not require two adjacent routers to use the same Hello and hold interval, but it does work to use the same Hello and hold interval on all routers. Unfortunately, the flexibility of using different settings on adjacent routers can cause the adjacent routers to work improperly if the Hell. and hold intervals are not chosen properly. For example, if R2 sets its Hello/Hold interval period to 30 seconds/60 seconds respectively, and R1 maintains its 5-second/15-second Hello/Hold interval, then R1 periodically determines that R2 is not working properly.R2 only sends Hello messages every 30 seconds, but R1 expects to receive one every 15-second Hold interval. Overview of Internal Routing Protocol FeaturesTable 9-3 summarizes the features discussed in this chapter, such as RIP2, EIGRP, and OSPFv2 Later in the table, the second major section of this chaptersection-which dives into the details of EIGRP step-by-step-is about to begin.Table 9-3 Internal IP Routing Protocol ComparisonFunction RIP-2 EIGRP OSPFV2