CompTIA Network+ - Section 2.2

Question 1

What do routers use to dynamically keep their routing tables up to date with information from the surrounding network?

Answer 1

Dynamic Routing Protocols

Question 2

What do routers use to determine the best path a packet should travel to get to it’s destination?

Answer 2

Routing Tables

Question 3

What is the main difference between different types of Dynamic Routing Protocol?

Answer 3

They each have their own way of determining how routing tables are setup and what the best route between point A and point B is

Question 4

What Dynamic Routing Protocol should we use?

Answer 4

This answer is different for each situation and depends on a number of criteria

• How does the protocol define the ‘Route’?
• How does the protocol determine what the best path is?
• How does the protocol handle recover after a change in the network occurs?
• Does the protocol use standard or proprietary?

Question 5

What is Distance-Vector Routing Protocol?

Answer 5

This is a routing protocol that determines the best route by how far away a connection is. (How many hops away is the destination network?)

Question 6

How are mose Distance-Vector Routing Protocol configured?

Answer 6

Most times, it’s as simple as enabling the option in the router and it automatically working with very little configuration required.

Question 7

Are Distance-Vector Routing Protocols best used with small or large networks?

Answer 7

They are good for smaller networks but don’t typically scale well with large networks of hundreds of thousands of routers.

Question 8

What are a few examples of Distance-Vector Routing Protocols?

Answer 8

Standard = RIP (Routing Information Protocol)

Proprietary to Cisco = EIGRP (Enhanced Interior Gateway Routing Protocol)

Question 9

Using this image, determine which route the Distance-Vector Routing Protocol would take.

Answer 9

It would take the route with the least amount of hops. Even if this route is not the fastest.

Question 10

What is Link-State Routing Protocol?

Answer 10

This is a routing protocol that determines the best route by using multiple metrics including determining which path is the actual fastest in terms of speed.

Question 11

Are Link-State Routing Protocols best used with small or large networks?

Answer 11

They are very scalable so they are most often used in large networks.

Question 12

Using this image, determine which route the Link-State Routing Protocol would take.

Answer 12

It would take the route with the fastest possible option. Even if this route has more hops compared to other routes.

Question 13

What is a Hybrid Routing Protocol?

Answer 13

This is a Routing Protocol that combines the benefits of both Link-State and Distance-Vector Protocols.

Question 14

What is an example of a Hybrid Routing Protocol?

Answer 14

BGP (Border Gateway Protocol) which determines routes based on paths, network policies, and other configured rule sets.

Question 15

When traffic is sent across the internet, the packet stops at every router along the way asking for direction. What does the router use to give those packets directions to the next location it needs?

Answer 15

The routers use paths contained inside their routing tables to tell the packet where it will be sent next.

Question 16

What devices need a routing table?

Answer 16

Any device that needs to make a decision on where packet traffic is going (Routers, Workstations, and Other Devices)

Question 17

What is a ‘Hop’?

Answer 17

The term used to describe when a packet jumps from one router to the next.

It hops from router A to router B.

Question 18

What does the ‘Next Hop’ refer to?

Answer 18

It refers to the destination address of the gateway (Destination Router / Destination Gateway)

Question 19

Have multiple routers and configurations can lead to a loop in the network that the packet circles endlessly. How are we able to solve this issue?

Answer 19

IPv4 uses ‘Time to Live’ and IPv6 uses ‘Hop Limit’

Question 20

What is IPv4’s ‘Time to Live’?

Answer 20

This is a mechanism used in IPv4 that prevents routing loops by counts the number of times a packet hits a router.

Every time the packet hits the same router the counter is reduced by 1

Once the counter hits 0 the packet is discarded by the router.

Question 21

What is IPv6 ‘Hop Limit’?

Answer 21

This is a mechanism used in IPv6 that prevents routing loops by counts the number of times a packet hops around between the same routers.

After a number of hops the packet is eventual discarded, stopping the loop.

Question 22

What are the two ways routers can be configured to determine routes for packets?

Answer 22

They can be configured Dynamically or Manually.

If it’s dynamic, it will choose the best path itself.

If it’s Manual, we will tell it the best path it must choose.

Question 23

What is a default route?

Answer 23

This is a ‘last choice’ route inside of the routing table that is used when nothing in the routing table matches the destination that the packet is trying to arrive at.

Instead of dropping the packet, we would send it to the default route.

Question 24

How are routing metrics determined by each Dynamic Routing Protocol?

Answer 24

Each metric is determined differently.

RIPv2 metrics aren’t useful to OSPF or EIGRP.

Question 25

Why are routing metrics useful?

Answer 25

They are useful when we run into uses of redundant routes where we have multiple ways to get from point A to point B

Question 26

Generally speaking, which metric is the best choice? 1 or 2?

Answer 26

Metric 1 would be better than Metric 2.

Lower values are often the best choice

Question 27

What does ‘Destination’ refer to?

Answer 27

The address of the network that the packet is heading to

Question 28

What does ‘Gateway’ refer to?

Answer 28

The next hop (or next router)

Question 29

What does ‘Interface’ refer to?

Answer 29

On-board connection that the packet will travel out of

Question 30

How would we determine if the router circled in green is going to the correct ‘Next Hop’ in this image?

Answer 30

We would need to call the ISP because we won’t be able to gather that information as it’s on their side of the network.

Question 31

Networks have multiple routers that each could be using a different type of multiple dynamic routing protocols to build their routing tables.

One router on the inside of your network might be using OSPF and on the ISP side of the network their router could be using BGP. How do we get around this issue?

Answer 31

We would use a Administrative distance.

Question 32

What is administrative distance?

Answer 32

It’s a table used by the router to determine what routing protocol has priority over another.

The lower the value the higher the priority

Question 33

How do we determine the priority of different applications used by companies?(VoIP, Streaming, Interactive communication to a database, and so on)

Answer 33

This is different for every company and depends solely on what the organization is trying to accomplish.

Example of priority

1. A company needs to focus more on phone calls so we priorities VoIP
2. Company wants us to focus more on interactive communication to a database over everything else

Question 34

What is traffic shaping?

Answer 34

A method for prioritizing traffic on a network that allows you to set priorities for different applications based on different variables.

Question 35

What is another name for traffic shaping?

Answer 35

Packet Shaping

Question 36

What does ‘Managing the QoS’ stand for?

Answer 36

It refers to managing traffic shaping and can be configured inside of an OS, router, switch, firewall, or similar devices with the feature.