Which layer of the OSI model controls the reliability of communications between network devices using flow control,
Sequencing and acknowledgments? A. Physical
Answer C Explanation
Which statements are true regarding ICMP packets? (Choose two.) A. They acknowledge receipt of TCP segments.
B. They guarantee datagrams delivery.
C. TRACERT uses ICMP packets.
D. They are encapsulated within IP datagramsâ. E. They are encapsulated within UDP datagramsâ.
Answer C, D Explanation
Ping may be used to find out whether the local machines are connected to the network or whether a remote site is reachable. This tool is a common network tool for determining the network connectivity, which uses ICMP protocol instead of TCP/IP and UDP/IP. This protocol is usually associated with the network management tools, which provide network information to network administrators, such as ping and traceroute (the later also uses the UDP/IP protocol). ICMP is quite different from the TCP/IP and UDP/IP protocols. No source and destination ports are included in its packets. Therefore, usual packet- faltering rules for TCP/IP and UDP/IP are not applicable. Fortunately, a special "signature" known as the packetâs Message type is included for denoting the purposes of the ICMP packet. Most commonly used
message types are namely, 0, 3, 4, 5, 8, 11, and 12 which represent echo reply, destination unreachable, source quench, redirect, echo request, time exceeded, and parameter problem respectively.
In the ping service, after receiving the ICMP "echo request" packet from the source location, the destination
which statements accurately describe CDP? (Choose three.) A. CDP is an IEEE standard protocol.
B. CDP is a Cisco proprietary protocol.
C. CDP is a datalink layer protocol.
D. CDP is a network layer protocol.
E. CDP can discover directly connected neighboring Cisco devices. F. CDP can discover Cisco devices that are not directly connected. Answer: B, C, E
Explanation: CDP. (Cisco Discovery Protocol) is a proprietary protocol designed by Cisco to help administrators Collect information about both locally attached and remote devices. By using CDP, you can gather hardware and protocol information about neighbor devices containing useful info for troubleshooting and documenting the network.
How does a switch differ from a hub?
A. A switch does not induce any latency into the frame transfer time. B. A switch tracks MAC addresses of directly-connected devices.
C. A switch operates at a lower, more efficient layer of the OSI model. D. A switch decreases the number of broadcast domains.
E. A switch decreases the number of Collision domains.
Some of the features and functions of a switch include:
A switch is essentially a fast, multi-port bridge, which can contain dozens of ports. Rather than creating two collision domains, each port creates its own collision domain. In a network of twenty nodes, twenty Collision domains exist if each node is plugged into its own switch port.
If an uplinkport is included, one switch Creates twenty-one single-node Collision domains.
A switch dynamically builds and maintains a Content-Addressable Memory (CAM) table, holding all of the necessary MAC information for each port.
For a detailed description of how switches operate, and their key differences to hubs, see the reference link below.
Which OSI layer header contains the address of a destination host that is on another network? A. application
D.network E. data link F. physical Answer: D
Explanation: Only network address contains this information. To transmit the packets the sender uses network address and datalink address. But the layer 2 address represents just the address of the next hop device on the way to the sender. It is changed on each hop. Network address remains the same.
Refer to the exhibit.
If the hubs in the graphic were replaced by switches, what would be virtually eliminated? A. broadcast domains
B. repeater domains
C. Ethernet Collisions
D. signal amplification E. Ethernet broadcasts Answer: C Explanation:
Modern wired networks use a network switch to eliminate collisions. By connecting each device directly to a port on the switch, either each port on a switch becomes its own Collision domain (in the case of half duplex links) or the possibility of Collisions is eliminated entirely in the case of full duplex links.
Refer to the exhibit.
If host A sends an IP packet to host B, what will the source physical address be in the frame when it reaches host B?
C. A1nA1nA1nA1nA1nA1 D. B2nB2nB2nB2nB2nB2 E. C3nC3nC3nC3nC3nC3 F. D4nD4nD4nD4nD4nD4 Answer: E
When packets transfer from one host to another across a routed segment, the source IP address always remains the same source IP address, and the source physical (MAC) address will be the existing routerâs interface address. Similarly, the destination IP address always remains the same and the destination physical (MAC) address is the destination routerâs interface address.
Refer to the exhibit.
Host is transferring a file to the FTP server. Point A represents the frame as it iOS toward the Toronto router. What will the Layer 2 destination address be at this point?
A. abcd.1123.0045 B. 192.168.7.17
C. aabb.5555.2222 D. 192.168.1.1
Answer E Explanation
For packets destined to a host on another IP network, the destination MAC address will be the LAN interface of the router. Since the FTP server lies on a different network, the host will know to send the frame to its default gateway, which is Toronto.