ccna interview questions and answers

Part - 42 CCNA Interview Questions and Answers

216 Ping uses which Internet layer protocol?

A.) RARP

B.) ICMP

C.) ARP

D.) FTP

Ans B

Internet Control Message Protocol - ICMP is a management protocol and messaging service provider for IP. Its messages are carried as IP datagrams. ICMP is used in the following events: Destination Unreachable - If a router cannot send an IP packet any further, it uses an ICMP echo to send a message back to the sender notifying it that the remote node is unreachable.
Buffer Full - If a routers memory buffer is full ICMP will send out a message to the originator. Hops - Each IP datagram is assigned a path. This consists of hops. If it goes through the maximum number of hops, the packet is discarded and the discarding router sends an ICMP echo to the host. Ping - Ping use ICMP echo message to check connectivity.

217 Which is true regarding store-and-forward switching method?

A.) Latency varies depending on frame-length

B.) Latency is constant

C.) It is default for all Cisco switches

D.) It only reads the destination hardware address before forwarding the frame

Ans A

Store-and-Forward switching copies the entire frame into its buffer and computes the CRC. If a CRC error is detected, the frame is discarded, or if the frame is a runt (less than 64 bytes including the CRC) or a giant (more than 1518 bytes including the CRC). The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then forwarded to the outgoing interface. Cisco Catalyst 5000 switches uses the Store-and-Forward method. The problem with Store-and-Forward switching is latency is increased. Latency also varies with the size of the frame. The larger the frame, the more latency associated. This of course is due to the fact that the entire frame is copied into its buffer before being forwarded.

218 Which three of the following are true statements about connection-oriented sessions?

A.) The segments delivered are acknowledged back to the sender upon their reception

B.) Any segments not acknowledged the are retransmitted by the receiver

C.) A manageable data flow is maintained in order to avoid congestion, overloading and loss of any data

D.) Segments are sequenced back into their proper order upon arrival at their destination

Ans A C D

Connection-oriented services are useful for transmitting data from applications that are intolerant of delays and packet re-sequencing. FTP and Telnet applications are based on connection-oriented services as well as some voice and video programs. Any segment that is not acknowledged by the received is retransmitted by the sender.

219 What does a metric of 16 hops represent when using RIP?

A.) Number of hops to the destination

B.) Destination unreachable

C.) Number of routers

D.) Bandwidth

Ans B Routing Information Protocol (RIP) is a distance vector routing protocol that used hop count as its metric. The maximum hop count is 15, 16 hops is considered unreachable. RIP updates are broadcast every 30 seconds by default. RIP has an administrative distance of 120.

220 You need to come up with a TCP/IP addressing scheme for your company. Which two factors must you consider when you define the subnet mask for the network?

A.) The location of DHCP servers

B.) The volume of traffic on each subnet

C.) The number of subnets on the network

D.) The location of the default gateway

E.) The number of host IDs on each subnet

Ans C E

When determining which subnet mask to use, you must determine how many hosts and how many subnets are required.