# RIP & EIGRP ### RIP RIP (Routing Information Protocol) uses hop count as its metric. The maximum hop count is 15. It is not usually used in real networks. It has three versions: * RIPv1 and RIPv2 - used for IPv4 * RIPng (RIP Next Generation) - used for IPv6 It uses two message types: * Request - to ask neighbours to send their routing table * Response - to send the local router's routing table to neighbouring routers By default, routing tables are shared every 30 seconds. #### Versions RIPv1: * only advertises classful addresses * doesn't include subnet mask information * doesn't support VLSM, CIDR * messages are broadcast to `255.255.255.255` RIPv2: * supports VLSM, CIDR * includes subnet mask information * messages are multicast to `224.0.0.9` #### Configuration First, enter the RIP config mode, using the command `router rip` from the global config mode. Choose a version with the command `version` followed by the version number. To disable classful networking logic use the command `no auto-summary`. Then you have to use the `network` command. The `network` command tells the router to: * look for an interface with an IP address that is in the specified range * activate RIP on the interfaces that fall in the range * form adjacencies with connected RIP neighbours * advertise the network prefix of the interface If there are no RIP neighbours connected to the interface, the interface should be configured as a passive interface so that the router doesn't send RIP advertisements out of the interface. To do so, use the command `passive interface` followed by the interface number. The command is entered from the RIP config mode. To advertise the default route via RIP, use the command `default-information originate`. To check the information on the routing protocol being used, enter the command `show ip protocols` from the privileged EXEC mode. ### EIGRP EIGRP (Enhanced Interior Gateway Routing Protocol) is a Cisco proprietary protocol that is considered an advanced distance vector routing protocol. It is much faster than RIP and doesn't have a 15 hop-count limit. It sends messages using a multicast address `224.0.0.10`. By default, it load-balances like RIP over 4 paths but it is the only IGP that can perform unequal-cost load-balancing. #### Configuration To enter the EIGRP config mode, use the command `router eigrp` followed by the AS number. The AS (Autonomous System) number must match between the routers to form an adjacency. Auto-summary and passive-interface configurations are the same as in RIP. The `network` command assumes a classful address if the network mask is not specified. EIGRP uses a wildcard mask instead of a regular subnet mask. A wildcard mask is just an inverted subnet mask. All `1`s in the subnet mask are `0` (zero) in the equivalent wildcard mask and vice versa. {% file src="" %} {% file src="" %} {% file src="" %} {% embed url="" %}