Archive - 2014

1: Is EIGRP a distance vector or a link state routing protocol?

*** EIGRP is a Hybrid routing protocol,it have features of both distance vector
and link state routing protocol.

2: What is the maximum configured bandwidth EIGRP will use on a link?
Can this percentage be changed?

*** By default, EIGRP uses no more than 50% of the link’s bandwidth, based on
the bandwidth configured on the router’s interface. This percentage to be
changed with the command ip bandwidth-percent eigrp.

3: How do EIGRP and IGRP differ in the way they calculate the composite
metric?

*** EIGRP and IGRP use the same formula to calculate their composite metrics, but EIGRP scales the metric by a factor of 256.

4: In the context of EIGRP, what does the term reliable delivery mean?
Which two methods ensure reliable delivery of EIGRP packets?

*** Reliable delivery means EIGRP packets are guaranteed to be delivered, and
they are delivered in order. RTP uses a reliable multicast, in which received
packets are acknowledged, to guarantee delivery; sequence numbers are used
to ensure that they are delivered in order.

5: Which mechanism ensures that a router is accepting the most recent
route entry?

*** Sequence numbers ensure that a router is receiving the most recent route
entry.

6: What is the multicast IP address used by EIGRP?

*** EIGRP uses the multicast address 224.0.0.10.

7: At what interval, by default, are EIGRP Hello packets sent?

*** The default EIGRP Hello interval is 5 seconds, except on some slow-speed
(T1 and below) interfaces, where the default is 60 seconds.

8: What is the default hold time?

*** The EIGRP default hold time is three times the Hello interval.

9: What is the difference between the neighbor table and the topology
table?

*** The neighbor table stores information about EIGRP-speaking neighbors; the
topology table lists all known routes that have feasible successors.

10: What is the feasibility condition?

*** The feasibility condition is the rule by which feasible successors are chosen
for a destination. The feasibility condition is satisfied if a neighbor’s advertised
distance to a destination is lower than the receiving router’s feasible distance to
the destination. In other words, a router’s neighbor meets the feasibility condition
if the neighbor is metrically closer to the destination than the router. Another way
to describe this is that the neighbor is “downstream” relative to the destination

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1: What information must be stored in the route table?

* At a minimum, each entry of the routing table must include a destination
address and the address of a next-hop router or an indication that the destination
address is directly connected.

2: What does it mean when a route table says that an address is variably

subnetted?

**Variably subnetted means that the router knows of more than one subnet mask
for subnets of the same major IP address.

3: What are discontiguous subnets?

** Discontiguous subnets are two or more subnets of a major IP network address
that are separated by a different major IP address.

4: What command is used to examine the route table in a Cisco router?

** show ip route is used to examine the routing table of a Cisco router.

5: What are the two bracketed numbers associated with the non-directly
connected routes in the route table?

**The first bracketed number is the administrative distance of the routing protocol
by which the route was learned. The second number is the metric of the route.

6: When static routes are configured to reference an exit interface instead
of a next-hop address, in what way will the route table be different?

**When a static route is configured to reference an exit interface instead of a
next-hop address, the destination address will be entered into the routing table
as directly connected.

7: What is a summary route? In the context of static routing, how are
summary routes useful?

**A summary route is a single route entry that points to multiple subnets or major
IP addresses. In the context of static routes, summary routes can reduce the
number of static routes that must be configured.

8: What is an administrative distance?

**An administrative distance is a rating of preference for a routing protocol or a
static route. Every routing protocol and every static route has an administrative
distance associated with it. When a router learns of a destination via more than
one routing protocol or static route, it will use the route with the lowest
administrative distance.

9: What is a floating static route?

** A floating static route is an alternative route to a destination. The
administrative distance is set high enough that the floating static route is used
only if a more-preferred route becomes unavailable.

10: What is the difference between equal-cost and unequal-cost load
sharing?

**Equal-cost load sharing distributes traffic equally among multiple paths with
equal metrics. Unequal-cost load sharing distributes packets among multiple
paths with different metrics. The traffic will be distributed inversely proportional to
the cost of the routes

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