Question 1

A network is usually said to be converged when all the routers know a loop-free path to get to all other networks.

Accepted Answer

A network is considered converged when all routers within the network have complete and accurate information about the entire network topology, allowing them to route packets through loop-free paths to every other network or destination.

Question 2

When a packet is fragmented, all fragments are given different TTL values.

Accepted Answer

All fragments of a packet retain the original packet's TTL value; they do not receive different TTL values.

Question 3

Which of the following can summarize routing information before sending link-state packets to other networks?

Accepted Answer

Area border routers (ABRs) summarize routing information from one area to another in OSPF, reducing the amount of routing information that needs to be propagated between areas.

Question 4

What do routers use in order to connect autonomous systems (ASs)?

Accepted Answer

Routers use exterior gateway protocols (EGPs) to connect different autonomous systems (ASs). EGPs are designed to exchange routing information between ASs, allowing them to route traffic efficiently across the internet.

Question 5

Which of the following occurs on a network when ICMP is turned off and a router discards packets without sending any notification about its actions?

Accepted Answer

When ICMP is turned off and a router discards packets without sending any notification, it creates a situation known as a "black hole" in networking. This is because the data packets are dropped silently, making it difficult for the source to determine what happened to the packets or to find an alternative route.

Question 6

ARP is used to obtain the hardware address of the destination IP hosts.

Accepted Answer

ARP (Address Resolution Protocol) is used to map an IP address to its corresponding physical network (hardware) address in a local area network.

Question 7

What type of routing protocol uses information about the distances between networks rather than the amount of time it takes for traffic to make its way from the source network to the destination network?

Accepted Answer

Distance vector routing protocols use information about the distances between networks to determine the best path for data to travel from source to destination. They do not consider the time it takes for traffic to travel.

Question 8

Which of the following prevents a router from advertising a network on the same interface from which it learned that network?

Accepted Answer

Split horizon is a method used in routing to prevent routing loops by prohibiting a router from advertising a route back onto the interface from which it was learned.

Question 9

If a packet with TTL=1 arrives at a router, the router must discard the packet because it cannot decrement the TTL to 0 and forward the packet.

Accepted Answer

When a packet with TTL (Time To Live) = 1 arrives at a router, the router decrements the TTL to 0 and, according to the TTL mechanism, must discard the packet because a packet with TTL=0 cannot be forwarded. This mechanism prevents packets from looping indefinitely in the network.

Question 10

Routed protocols are Layer 1 protocols that are used to get packets through an internetwork.
Indicate the answer choice that best completes the statement or answers the question.

Accepted Answer

Routed protocols are Layer 3 protocols that determine the path for sending packets across a network. Layer 1 protocols deal with the physical layer, such as cabling and electrical signals.

Question 11

Which of the following do routers use to select a routing path when there are multiple paths available?

Accepted Answer

Routers use the Type of Service (ToS) field in the IP header to determine the priority of each packet and select the most appropriate routing path based on the desired quality of service.

Question 12

Which of the following is a method that allows an IP host to use a simplified subnetting design?

Accepted Answer

Proxy ARP allows an IP host to interact with devices on a different subnet as if they were on the same subnet, simplifying subnetting design by reducing the need for multiple IP configurations and routing.

Question 13

What is the recommended starting TTL value?

Accepted Answer

The recommended starting TTL (Time to Live) value for packets in many operating systems is 64.

Question 14

In a RIPv2 packet, which field contains a plain text password?

Accepted Answer

The Authentication field in a RIPv2 packet is used to contain a plain text password when simple password authentication is enabled. This is part of the protocol's effort to provide basic security measures.

Question 15

Two examples of routing protocols that support multiple types of services are OSPF and which of the following?

Accepted Answer

Border Gateway Protocol (BGP) supports multiple types of services, similar to OSPF, by allowing for different routing policies and paths based on various criteria, making it suitable for the internet's complex, heterogeneous environment.

Question 16

What is required to get the packet from one IP host to another IP host on a single network?

Accepted Answer

To get a packet from one IP host to another IP host on a single network, the hardware address (also known as the MAC address) is required. This address ensures that the packet reaches the correct device on a local network segment.

Question 17

What does a router use to determine which packet to send when several packets are queued for transmission from a single-output interface?

Accepted Answer

Routers can use precedence levels assigned to packets to determine their transmission order when multiple packets are queued for transmission from a single-output interface. This helps in managing traffic by prioritizing certain packets over others based on their importance or urgency.

Question 18

IP fragmentation enables a larger packet to be automatically fragmented into smaller packets to cross a link that supports a smaller MTU. Which of the following devices performs this fragmentation?

Accepted Answer

Routers are responsible for IP fragmentation when a packet needs to traverse a network segment with a smaller Maximum Transmission Unit (MTU) than the original packet size. They break down the packets into smaller units to ensure they can be transmitted across the network segment and then reassembled at the destination.

Question 19

All IPv4 packets have a predefined lifetime indicated in which field?

Accepted Answer

The Time To Live (TTL) field in IPv4 packets indicates the packet's lifetime, determining how many hops (routers) the packet can pass through before it is discarded. This prevents packets from circulating indefinitely on the network.

Question 20

Which of the following terms best describes a compilation of information about all the networks that the router can reach?

Accepted Answer

A routing table is a data table stored in a router or a networked computer that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes. It is a critical component for a router to decide the best path to forward packets.

Quiz 4: Data Link and Network Layer Protocols in Tcp/Ip