Which of the following are characteristics of Enhanced Interior Gateway Routing Protocol (EIGRP)? (Choose all that apply.)
A. Requires a hierarchical physical topology
B. Does not require a hierarchical physical topology
C. Uses Diffusing Update Algorithm (DUAL) to provide loop prevention
D. Uses Bellman-Ford algorithm to provide loop prevention
E. Supports Message-Digest Algorithm 5 (MD5) authentication
F. Does not support Message-Digest Algorithm 5 (MD5) authentication
G. Can differentiate between internal and external routes
H. Uses a 32-bit metric
Correct Answer: B, C, E, G, H
Explanation:
EIGRP does not require a hierarchical physical topology. It uses Diffusing Update Algorithm (DUAL) to provide loop prevention, and it supports Message-Digest Algorithm 5 (MD5) authentication. It can differentiate between internal and external routes, and uses a 32-bit metric.
EIGRP is a classless protocol that allows the use of variable length subnet masks (VLSM) and supports classless interdomain routing (CIDR) for allocation of IP addresses. The following are characteristics of EIGRP:
– Supports large networks due to high scalability
– Provides fast convergence using the Diffusing Update Algorithm (DUAL) Performs equal and unequal load balancing by default
– Supports variable length subnet masks (VLSM) and classless interdomain routing (CIDR)
– Is a hybrid routing protocol (distance-vector protocol) that also provides link-state protocol characteristics Is a classless protocol
– Sends partial route updates only when there are changes, reducing bandwidth usage for routing updates
– Has an administrative distance of 90 for EIGRP internal routes, 170 for EIGRP external routes, and 5 for EIGRP summary routes Is used only with Cisco platforms
– Provides support for IP IPX and AppleTalk protocols Can differentiate between internal and external routes Uses a 32-bit metric
EIGRP can load-balance up to four unequal cost paths. To do so, use the variance n command to instruct the router to include routes with a metric of less than n times the minimum metric route for that destination. The variable n can take a value between 1 and 128. The default is 1, which means equal cost load balancing.
The option stating that EIGRP requires a hierarchical physical topology is incorrect because EIGRP does not require or support a hierarchical routing topology. The option stating that EIGRP uses Bellman-Ford algorithm to provide loop prevention is incorrect. EIGRP uses DUAL to provide loop prevention.