4_Static Routing

Question 1

Explain the role of a routing table in a router.

Answer 1

A routing table is used by a router to store information about which network is reachable via which network interface. When a packet needs to be forwarded, the router consults the routing table to decide the appropriate network interface to route the packet.

Question 2

Describe the routing process for a packet from the source host to a destination host located on a different network.

Answer 2

When a packet is sent to a host on a different network, it is forwarded to the default gateway of the source network. The router uses its routing table to determine the next hop and the appropriate interface. The packet is encapsulated in a layer 2 frame with updated MAC addresses for each hop until it reaches the destination network.

Question 3

What is a default static route, and why is it used?

Answer 3

A default static route is a route that matches all packets (with destination 0.0.0.0/0). It is used to specify a gateway of last resort, where packets are forwarded if no specific route to the destination exists in the routing table.

Question 4

Compare the advantages and disadvantages of static routing.

Answer 4

Advantages:

Enhanced security as routes are not advertised over the network.
Reduced bandwidth usage since no communication is required to maintain the routes.
Predictable paths are used for data transmission.
Disadvantages:
Time-consuming initial configuration and maintenance.
High risk of configuration errors in large networks.
Does not scale well with growing networks.
Requires complete knowledge of the network for proper implementation

Question 5

Define a “floating static route” and explain its purpose

Answer 5

A floating static route is a backup route configured with a higher administrative distance than the primary route. It is used as a fallback path if the primary route fails.

Question 6

What are the three types of static routes based on how the next hop is identified?

Answer 6

Next-hop route: Only the next-hop IP address is specified.

Directly connected static route: Only the router exit interface is specified.

Fully specified static route: Both the next-hop IP address and exit interface are specified.

Question 7

Under what circumstances is static routing most suitable?

Answer 7

Static routing is suitable for:

Small networks with minimal expected growth.

Routing to and from stub networks, where only one path exists for data to enter or exit.

Scenarios requiring a default route to represent a path for unmatched destinations.

Question 8

How do routers handle packets when no route is found in the routing table?

Answer 8

If no route is found in the routing table and no default route is configured, the router will drop the packet. If a default route exists, the packet is forwarded to the specified gateway.