1.
In an IPv4
environment, what information is used by the router to forward data
packets from one interface of a router to another?
Correct Answer
A. Destination network address
Explanation
In an IPv4 environment, routers use the destination network address to forward data packets from one interface to another. The destination network address helps the router determine the next hop or interface to send the packet to in order to reach its intended destination. The source network address and source MAC address are used for routing decisions and addressing purposes within the local network, but they are not directly used by the router to forward packets between different interfaces. The well-known port destination address is not relevant to the forwarding process and is used for identifying specific applications or services within a network.
2.
What information is added during encapsulation at OSI Layer 3?
Correct Answer
D. Source and destination IP address
Explanation
During encapsulation at OSI Layer 3, the information that is added includes the source and destination IP address. This is because Layer 3, also known as the Network layer, is responsible for routing and addressing in a network. The IP address is used to identify the source and destination of the data packets being transmitted over the network.
3.
In a connectionless system, which of the following is correct?
Correct Answer
B. The destination is not contacted before a packet is sent.
Explanation
In a connectionless system, the destination is not contacted before a packet is sent. In connectionless communication, each packet is treated independently and does not require prior setup or communication with the destination. The sender simply sends the packet to the network, and it is responsible for routing and delivering the packet to the destination. There is no need for a handshake or acknowledgment from the destination before sending the packet.
4.
Which IP packet field will prevent endless loops?
Correct Answer
D. Time-to-live
Explanation
The time-to-live field in an IP packet determines the maximum number of hops or routers that the packet can pass through before it is discarded. This prevents endless loops by ensuring that the packet is not continuously forwarded in a loop between routers. Once the time-to-live value reaches zero, the packet is dropped, preventing it from circulating indefinitely. Therefore, the time-to-live field is essential in preventing endless loops in IP packets.
5.
Which portion of the network layer address does a router use to forward packets?
Correct Answer
C. Network portion
Explanation
A router uses the network portion of the network layer address to forward packets. The network portion identifies the network to which the router is connected. By examining this portion of the address, the router can determine the appropriate path for the packet to reach its destination within the network. The host portion, broadcast address, and gateway address are not used for forwarding packets in the network layer.
6.
If the default gateway is configured incorrectly on the host, what is the impact on communications?
Correct Answer
B. The host can communicate with other hosts on the local network, but is unable to communicate with hosts on remote networks.
Explanation
If the default gateway is configured incorrectly on the host, it means that the host does not have the correct information about how to reach hosts on remote networks. As a result, the host can still communicate with other hosts on the local network because they are within the same network and do not require the default gateway. However, when the host tries to communicate with hosts on remote networks, it will not be able to find the correct path and the communication will fail.
7.
What is the purpose of a default gateway?
Correct Answer
E. Identifies the device that allows local network computers to communicate with devices on other networks
Explanation
The purpose of a default gateway is to identify the device that allows local network computers to communicate with devices on other networks. The default gateway acts as a bridge between the local network and external networks, forwarding network traffic between them. It is responsible for routing data packets to the appropriate destination outside of the local network. Without a default gateway, computers on a local network would not be able to access resources or communicate with devices on other networks.
8.
What type of routing uses information that is manually entered into the routing table?
Correct Answer
C. Static
Explanation
Static routing is a type of routing that uses manually entered information in the routing table. In static routing, network administrators manually configure the routes in the routing table, specifying the destination network and the next hop to reach that network. This type of routing is useful in small networks or in situations where the network topology is stable and changes infrequently. Unlike dynamic routing, static routing does not rely on protocols to automatically update the routing table based on network changes.
9.
When the destination network is not
listed in the routing table of a Cisco router, what are two possible
actions that the router might take? (Choose two.)
Correct Answer(s)
B. The router discards the packet.
E. The router forwards the packet out the interface indicated by the default route entry.
Explanation
When the destination network is not listed in the routing table of a Cisco router, the router can take two possible actions. First, it can discard the packet because it does not have a route to the destination network. Second, it can forward the packet out the interface indicated by the default route entry. The default route acts as a "catch-all" route, directing traffic to a specific interface when there is no specific route for the destination network.
10.
What are the key factors to consider when grouping hosts into a common network? (Choose three.)
Correct Answer(s)
B. Purpose
D. Ownership
E. GeograpHic location
Explanation
When grouping hosts into a common network, it is important to consider the purpose of the network, as different networks may have different requirements and configurations based on their intended use. Ownership is also a key factor to consider, as different owners may have different security and access requirements for the network. Geographic location is another important factor, as networks in different locations may have different connectivity options and latency considerations.
11.
What is a component of a routing table entry?
Correct Answer
D. The next-hop address
Explanation
A component of a routing table entry is the next-hop address. The next-hop address refers to the IP address of the next router or network device that the packet needs to be forwarded to in order to reach its destination. It is used to determine the best path for forwarding the packet to the intended destination. The next-hop address is an important element in the routing process as it helps in determining the optimal route for data transmission.
12.
Which intermediary devices could be used to implement security between networks? (Choose two.)
Correct Answer(s)
A. Router
D. Firewall
Explanation
Routers and firewalls are the two intermediary devices that can be used to implement security between networks. A router is responsible for routing network traffic between different networks and can be configured to filter and block certain types of traffic, providing a level of security. Firewalls, on the other hand, are dedicated security devices that monitor and control incoming and outgoing network traffic based on predefined security rules. They act as a barrier between networks, filtering out unauthorized access and protecting against potential threats.
13.
What are three common problems with a large network? (Choose three.)
Correct Answer(s)
B. Performance degradation
C. Security issues
E. Host identification
Explanation
A large network can face several common problems. Performance degradation can occur due to increased traffic and congestion on the network, leading to slower response times and decreased efficiency. Security issues are also common in large networks, as they are more susceptible to unauthorized access, data breaches, and malware attacks. Host identification can be challenging in a large network, making it difficult to track and manage individual devices and their activities. These three problems can significantly impact the functionality, reliability, and security of a large network.
14.
What statement describes the purpose of a default route?
Correct Answer
D. A host uses a default route to transfer data to a host outside the local network when no other route to the destination exists.
Explanation
A default route is used by a host to transfer data to a host outside the local network when there are no other specific routes available for the destination. It acts as a "catch-all" route, directing traffic to a default gateway or router that can handle the data transfer to external networks. This allows the host to send data to destinations that are not part of its directly connected networks.
15.
Which three statements are true about routes and their use? (Choose three.)
Correct Answer(s)
B. If the destination network is directly connected, the router forwards the packet to the destination host.
D. If no route exists for the destination network and a default route is present, the packet is forwarded to the next-hop router.
E. If the originating host has a default gateway configured, the packet for a remote network can be forwarded using that route.
Explanation
If the destination network is directly connected, the router forwards the packet to the destination host: This means that if the destination network is directly connected to the router, it can send the packet directly to the destination host without needing to go through any other routers.If no route exists for the destination network and a default route is present, the packet is forwarded to the next-hop router: This means that if there is no specific route available for the destination network, the router will use a default route to forward the packet to the next-hop router, which will then attempt to find a route to the destination network.If the originating host has a default gateway configured, the packet for a remote network can be forwarded using that route: This means that if the originating host has a default gateway configured, it can use that route to forward packets to remote networks that are not directly connected.
16.
What are three common problems with a large network? (Choose three.)What two characteristics are commonly associated with dynamic routing protocols? (Choose two.)
Correct Answer(s)
B. Provide routers with up-to-date routing tables
D. Consume bandwidth to exchange route information
Explanation
Dynamic routing protocols provide routers with up-to-date routing tables by exchanging route information with other routers in the network. This allows routers to learn about network changes and adjust their routing tables accordingly. However, this constant exchange of route information consumes bandwidth, as routers need to send and receive updates. Therefore, the two characteristics commonly associated with dynamic routing protocols are providing routers with up-to-date routing tables and consuming bandwidth to exchange route information.