ROUTING WITH EIGRP ON THE ASA
The Enhanced Interior Gateway Routing Protocol (EIGRP) uses a complex routing metric that is based on a combination of delay, bandwidth, reliability, load, and MTU. EIGRP combines the advantages of link-state and distance-vector routing protocols, making it a hybrid of both methods.
EIGRP uses a neighbor discovery mechanism that works by sending hello messages to directly connected neighboring routers. Neighbors can be dynamically discovered or statically configured. All EIGRP messages, including the hello protocol, are sent as multicast packets to address 188.8.131.52, the “all EIGRP routers” address, using IP protocol 88.
EIGRP supports variable-length subnet masks (VLSM) and route summarization, providing plenty of flexibility in its routing information. It also uses the Diffusing Update Algorithm (DUAL) to compute and maintain routing information from all of its neighbors.
Our demonstration example uses the same network topology as the one we used in the RIPv2 routing protocol. The ASA is going to advertise the network 172.16.0.0/24, 10.0.0.0/24, 192.168.10.0/24 and 184.108.40.206/24 using the EIGRP routing protocol. At the same time the MOIGETECH-INSIDE-ROUTER is going to advertise 10.0.10.0/24, 10.0.20.0/24, 10.0.30.0/24, 10.0.40.0/24 and 192.168.10.0/24 using EIGRP routing protocol. The network topology is shown below.
EIGRP NETWORK TOPOLOGY
The following diagram shows that the ASA has learned EIGRP routes from the MOIGETECH-INSIDE-ROUTER as shown in the figure below.
The following figure shows the MOIGETECH-INSIDE-ROUTER having learned routes using the EIGRP routing protocol from the ASA firewall as show in the diagram below.