EIGRP stands for Enhanced Interior Gateway Routing Protocol with an AD = 90. The EIGRP is an advanced version of IGRP and is cisco proprietary. EIGRP uses a DUAL algorithm, and has a fast convergence, faster than OSPF. EIGRP supports VLSM because EIGRP update packets contain a prefix length for each network. This protocol sends multicasts packets to 224.0.0.10 for dynamic neigbor discovery and uses the IP protocol 88.
EIGRP activates by defaul equal-cost load sharing up to 4 paths, but can be configured to a maximum of 6 paths. The command is:
(config)#router eigrp
(config-router)#maximum-paths
The DUAL (Diffusing Update Algorithm) is an algorithm which calculates the successors (main routes) and the feasible successors (backup route). Therefore, should the successors fail, the feasible successor is instantly ready for use.
EIGRP has 3 tables which is the standard routing table, the EIGRP topology table and the neighbor table. The routing table contains primary routes (successors) only, while the EIGRP topology stores both the successors and the feasible successors. The neighbor table stores information about the EIGRP neigboring routers.
EIGRP's metric is calculated based on 5 k-weights which are in order bandwidth, delay, load, reliability and MTU. However, only bandwidth and delay is set active by default (set to 1) while all other is set inactive (set to 0). The bandwidth and delay can be configured with the command:
(config)#interface
(config-if)#bandwidth
(config-if)#delay
EIGRP has 5 different type of packets which are:
1. Hello packets that are used for neigbor discovery and maintain the connection with the neighbors. This data uses UDP packets and is therefore unreliable.
2. Acknowledgement packets that are used from the originating router to confirm the update received from the neigboring routers. This data uses also UDP packets and is therefore unreliable.
3. Query packets are sent when the router loses its successor route and does not have a feasible successor. This packet uses Reliable Transport Protocol (RTP) and is therefore reliable.
4. Reply packets that is used to response a query packet and can also mean that a new route is found to the destination router. This packet uses RTP and is therefore reliable.
5. Update packets that is sent and received to build a routing table or when a change in the network happens. If the latter happens, this packet will only send the changing routes instead of all the routes from the originating router, thus making EIGRP more resource effecient. This packet is send using unicast to the destination router and uses RTP protocol.
To see these number of packets sent or received use the #show ip eigrp traffic command.
-- 27 January 2011 --
EIGRP activates by defaul equal-cost load sharing up to 4 paths, but can be configured to a maximum of 6 paths. The command is:
(config)#router eigrp
(config-router)#maximum-paths
The DUAL (Diffusing Update Algorithm) is an algorithm which calculates the successors (main routes) and the feasible successors (backup route). Therefore, should the successors fail, the feasible successor is instantly ready for use.
EIGRP has 3 tables which is the standard routing table, the EIGRP topology table and the neighbor table. The routing table contains primary routes (successors) only, while the EIGRP topology stores both the successors and the feasible successors. The neighbor table stores information about the EIGRP neigboring routers.
EIGRP's metric is calculated based on 5 k-weights which are in order bandwidth, delay, load, reliability and MTU. However, only bandwidth and delay is set active by default (set to 1) while all other is set inactive (set to 0). The bandwidth and delay can be configured with the command:
(config)#interface
(config-if)#bandwidth
(config-if)#delay
EIGRP has 5 different type of packets which are:
1. Hello packets that are used for neigbor discovery and maintain the connection with the neighbors. This data uses UDP packets and is therefore unreliable.
2. Acknowledgement packets that are used from the originating router to confirm the update received from the neigboring routers. This data uses also UDP packets and is therefore unreliable.
3. Query packets are sent when the router loses its successor route and does not have a feasible successor. This packet uses Reliable Transport Protocol (RTP) and is therefore reliable.
4. Reply packets that is used to response a query packet and can also mean that a new route is found to the destination router. This packet uses RTP and is therefore reliable.
5. Update packets that is sent and received to build a routing table or when a change in the network happens. If the latter happens, this packet will only send the changing routes instead of all the routes from the originating router, thus making EIGRP more resource effecient. This packet is send using unicast to the destination router and uses RTP protocol.
To see these number of packets sent or received use the #show ip eigrp traffic command.
-- 27 January 2011 --
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