Chapter 5 - OSI Network Layer

How many bits are in an IPv4 address?

32. There are four octets (8 bits each) in an IPv4 address.

Which of the following are true about network layer encapsulation? ( Choose two) a. it adds a header to a segment b. it can happen many times on the path to the destination host c. It is performed by the last router on the path d. both source and destination IP addresses are added e. it coverts transport layer information into a frame

A & D. Network layer encapsulation adds a header to a segment and adds both source and destination IP addresses. Network layer encapsulation happens only on the original host; other devices can read data, but when they do no remove or alter it until the destination network is reached. The network layer converts transport layer segments into packets.

Select three pieces of information about a route that a routing table contains. a. next - hop b. source address c. metric d. destination network address e. last hop f. default gateway

A, C & D. A routing table contains the next - hop, metric and destination network address. Routers do not need the source address, last hop or default gateway to find a path to a network.

What kinds of problems are caused by excessive broadcast traffic on a network segment? (Choose three) a. consumes network bandwidth b. increases overhead on network c. requires complex address schemes d. interrupts other host functions e. divides networks based on ownership f. advanced hardware required

A,B & D. Reduced network bandwidths, increased overhead, and reduced host functions and three potential results of excessive broadcasts. The other answers can be part of a solution to the problem of excessive broadcasts.

Which protocol provides connectionless network layer services? a. IP b. TCP c. UDP d. OSI

A. IP provides connectionless network layer services. TCP is connection oriented. UDP is connectionless, but it works at the transport layer.

Which of the following are true about TCP and IP? (Choose two) a. TCP is connectionless and IP is connection oriented b. TCP is reliable and IP is unreliable c. IP is connectionless and TCP is connection oriented d. TCP is unreliable and IP id reliable e. IP operates at the transport layer

B & C. TCP is reliable and connection oriented. IP is unreliable and connectionless. IP operates at the network layer.

Which of the following are true about IP? (Choose two) a. IP stands for International Protocol b. It is the most common network layer protocol c. It analyses presentation layer data d. it operates at OSI layer 2 e. it encapsulates transport layer segments

B & E. IP stands for the Internet Protocol, which operates at OSI Layer 3 (the network layer). IP encapsulates transport layer segments. IP does not look inside the upper-level PDU, so it has no knowledge of the presentation layer data.

Why is IP "media dependent"? a. it encapsulated Layer 1 instructions b. it works the same on all layer 1 media c. it carries both video and voice data d. it works without Layer 1 media

B. IP encapsulates OSI Layer 4 data. IP can carry voice, video and other types of data, but "media independent" refers to the OSI Layer 1 medium that carries the data across the networks. IP, or any other communication, can occur without a physical (OSI Layer 1) medium.

Which of the following are not functions of the network layer? (Choose two) a. routing b. addressing packets with an IP address c. delivery reliability d. application data analysis e. encapsulation f. decapsulation

C & D. Delivery reliability is a transport layer concern. Application data analysis is a concern of the presentation layer.. Routing, addressing packets with an IP address, encapsulation and decapsulation are function of the network layer.

Which of the following are true about static and dynamic routing? (Choose two). a. static routing requires a routing protocol such as RIP b. a default rout is a dynamic route c. dynamic routing adds packet processing overhead d. administrative overhead is reduced with static routing e. routers can use static and dynamic routing stimulataneously

C & E. Dynamic routing adds packet - processing overhead and routers can use static and dynamic routing simultaneously. Static routing doe snot require a routing protocol. A default route is an example of a static route. Because static routes must be manually configured and updated, they add the administrative overhead.

Which of the following is true about IP? a. It is connection oriented b. it uses application data to determine the best path c it Is used by both routers and hosts d. it is reliable

C. Routers and hosts use IP. B is incorrect because IP uses addressing information in the header to determine the best path for a packet. D is incorrect because IP is a "best effort" unreliable protocol.

What is the name of the process of removing the OSI layer 2 information from an IP packet?

Decapsulation.

What are three key factors to consider when growing hosts into a common network?

Purpose, ownership and geographic location are three key ways to device a network.

TCP is a ......... layer protocol.

Transport

What two commands can be used to view a host's routing table?

netstat -r and route print