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

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 characteristicsIs 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.
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization,
redistribution, stub)

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