ACSP Routing Protocols & IP Addressing — Questions and Answers

Question 1: What is the function of the routing table?

Forwarding packets to the destination
Storing IP addresses
Determining network topology
Routing data between VLANs

The routing table is a crucial component within a router or Layer 3 switch, containing information about network destinations and how to reach them. Its primary function is to store routes to various network segments, including the next-hop IP address and the outgoing interface. This information allows the router to make intelligent decisions about forwarding IP packets to their correct destination across different networks.

Question 2: Which routing protocol is used for dynamic routing in small to medium-sized networks?

OSPF
RIP
BGP
EIGRP

RIP (Routing Information Protocol) is a distance-vector routing protocol commonly used for dynamic routing in small to medium-sized networks. It is known for its simplicity and ease of configuration, using hop count as its metric to find the best path. While less scalable than protocols like OSPF or EIGRP, RIP's straightforward nature makes it suitable for less complex network environments.

Question 3: What does an IP address of 192.168.1.1/24 represent?

Private IP address with a /32 subnet
Public IP address
Private IP address with a /24 subnet
Public IP address with a /24 subnet

The IP address 192.168.1.1 falls within the 192.168.0.0/16 range, which is reserved for private IP addresses as defined by RFC 1918. The /24 notation, also known as CIDR (Classless Inter-Domain Routing), specifies that the first 24 bits of the IP address represent the network portion. This means the subnet mask is 255.255.255.0, defining a network with 254 usable host addresses.

Question 4: What is the main role of OSPF in a network?

Path selection
Network address translation
IP address assignment
Packet encryption

The main role of OSPF (Open Shortest Path First) in a network is efficient path selection. As a link-state routing protocol, OSPF builds a complete topology map of the network and uses Dijkstra's algorithm to calculate the shortest path to each destination based on a cost metric. This enables routers to make optimal forwarding decisions and quickly adapt to network changes.

Question 5: What is the purpose of NAT in networking?

Providing security
Mapping private IP addresses to public IPs
Encrypting traffic
Forwarding routing information

The purpose of NAT (Network Address Translation) in networking is to map private IP addresses used within a local network to one or more public IP addresses. This allows multiple devices on a private network to share a single public IP address when accessing the internet, conserving public IP addresses. NAT also provides a basic level of security by hiding the internal network's structure from external networks.

Question 6: Which command displays the routing table on a Cisco router?

show interfaces
show ip route
ping
traceroute

On a Cisco router, the `show ip route` command is used to display the IP routing table. This command provides detailed information about all known routes, including directly connected networks, static routes, and dynamically learned routes via routing protocols. It shows the destination network, the administrative distance, the metric, the next-hop IP address, and the outgoing interface for each route.

Question 7: What is the primary difference between RIP and OSPF?

RIP is faster
OSPF uses less bandwidth
OSPF uses link-state while RIP uses distance-vector
RIP supports more routers

RIP (Routing Information Protocol) is a distance-vector protocol, meaning routers share their entire routing tables with neighbors, and routes are chosen based on hop count. OSPF (Open Shortest Path First) is a link-state protocol, where routers build a complete map of the network topology and calculate the shortest path using an algorithm like Dijkstra's. This fundamental difference allows OSPF to converge faster and scale better in larger, more complex networks compared to RIP.

Question 8: Which IP addressing class does the IP address 192.168.5.100 belong to?

Class A
Class B
Class C
Class D

IP addressing classes are determined by the value of the first octet of the IP address. An IP address starting with 192 (specifically 192-223) falls within the Class C range. Class C addresses are typically used for smaller networks, allowing for many networks with fewer hosts per network.

Question 9: What is an example of a private IP address?

8.8.8.8
10.0.0.1
172.16.254.1
192.168.1.1

Private IP addresses are reserved ranges that are not routable on the public internet, used for internal networks. The 192.168.0.0/16 range (192.168.0.0 to 192.168.255.255) is one of the three designated private IP address ranges. Therefore, 192.168.1.1 is a classic example of a private IP address, commonly used as a default gateway for home and small office networks.

ACSP Routing Protocols & IP Addressing

What is the function of the routing table?