SEMESTER 2 Chapter 4
Distance Vector Routing Protocols
What are the three distance vector routing protocols?
RIP, IGRP, and EIGRP.
What are the key characteristics of RIP?
Hop count is used as the metric for path selection.
If the hop
count for a network is greater than 15, RIP cannot supply a route to that
Routing updates are broadcast or multicast every 30 seconds, by default.
What are the key characteristics of IGRP?
Bandwidth, delay, load and reliability are used to creat
e a composite metric.
Routing updates are broadcast every 90 seconds, by default.
IGRP is the predecessor of EIGRP and is now obsolete.
What are the key characteristics of EIGRP?
It can perform unequal cost load balancing.
It uses Diffusing Update Alg
orithm (DUAL) to calculate the shortest path.
There are no periodic updates as with RIP and IGRP. Routing updates are sent only
when there is a change in the topology.
How are distance vector routes advertised?
Periodic Updates are sent at regular
intervals (30 seconds for RIP and 90 seconds
Does a router in a distance vector network have knowledge of the entire path to a
What are the 2 things a distance vector router knows?
The direction or interface in which p
ackets should be forwarded and
The distance or how far it is to the destination network
What are the two reasons sending an entire routing table in an update inefficient?
updates not only consume bandwidth but also consume router CPU resources to
process the updates.
What is the periodic update time for RIP?
What is the periodic update time for IGRP?
What is the address for broadcast updates?
What is the algorithm used for?
calculate the best paths
and then send that information to the neighbors.
What processes does the routing protocol define?
Mechanism for sending and receiving routing information.
Mechanism for calculating the best paths and installing routes in the routing table.
r detecting and reacting to topology changes.
Define Time to Convergence.
Time to convergence defines how quickly the routers in the network topology share
routing information and reach a state of consistent knowledge.
ility defines how large a network can become based on the routing protocol
that is deployed.
Define Classless (Use of VLSM) or Classful.
Classless routing protocols include the subnet mask in the updates
Define Resource Usage.
Resource usage includes t
he requirements of a routing protocol such as memory
space, CPU utilization, and link bandwidth utilization
Define Implementation and Maintenance
Implementation and maintenance describes the level of knowledge that is required
for a network administrator
to implement and maintain the network based on the
routing protocol deployed.
List the advantages for distance vector protocols.
They are simple to implement and maintain.
They have low resource requirements
List the disadvantages for distance vector
Slow to converge, limited scalability and routing looops
Definitely practice the exercise at the right. It will help you remember each protocol.
What are the routes that router will initially discover after booting?
ompleting the initial discovery what does the router start to do?
What does the initial exchange of routing information contain?
What does the router do with the information that is not contained in its routing
After the first exchan
ge of routing updates what has been added to each routing
What is convergence?
What is slit horizon?
The amount of time it takes for a network to converge is directly proportional to
The speed of achieving
convergence consists of what two things?
What are the two reasons routers exchange routing updates?
What is the period update time for RIP?
What are the four reasons listed for topology changes?
What are the three additional timers
If an update has not been received to refresh an existing route after 180 seconds,
what happens to that route in the routing table?
What happens to the route after 240 seconds have elapsed?
What does a holddown timer do?
What are the two comm
ands that will show the timers?
Define bounded update.
What are characteristic of EIGRP updates?
What is a triggered update?
What are the three reasons to send a triggered update?
What are the two problems with triggered updates?
What is it called when all the routers send updates at the same time on a network
with a hub at the center?
It this a problem on a switched network?
What is a routing loop?
What are some reasons for routing loops?
What mechanism i
s built into IP to overcome routing loops?
What conditions can be created because of routing loops?
What are some of the mechanisms used to avoid routing loops?
What is count to infinity?
What is infinity defined by?
What is infin
ity for RIP?
What is it called when a route goes up, then down, then up etc.?
What are holddown timers used for?
Describe the process of how a holddown timer works.
What is the split horizon rule?
What is route poisoning?
What is split horizon with poison reverse?
What is time
What happens when a packet’s TTL reaches 0?
What are the factors that affect the distance vector protocol you choose?
What are the features of RIP?
eatures were introduced with RIPv2?
What are the features of EIGRP?
What are the advantages of EIGRP?