Testout 2.6 Data Communications

2. Workstation2 needs to send data to Workstation3. It sends out and ARP request for the address of the default gateway. Which of the following are true of this request? (2)

>The switch sends the ARP request to Workstation1 and the router >Only the router will respond with an address of 000b5f2a2222

4. A host wants to send a message to another host with the IP address 115.99.80.157. The host does not know the hardware address of the destination device. Which protocol can be used to discover the MAC address? ARP

ARP (NOT ICMP, DNS, BOOTP, IGMP, DHCP)

1. That role does ARP play in the routing process?

If a router does not know a destination device's MAC address, it sends an ARP broadcast containing the IP address and requesting the MAC address

10. Workstation2 needs to send data to Workstation3. Identify the Layer 2 and Layer 3 address used by Workstation2 to send the data by dragging corresponding address from list on left to location on right.

Layer 2 source address > 080046987654 Layer 3 source address > 192.168.10.12 Layer 2 destination address > 000b5f2a2222 Layer 3 destination address > 192.168.11.11 >The source layer 2 address is its own MAC address >The source layer 3 address is its own IP address >The destination layer 2 address is the MAC address of the default gateway router. The MAC address is the address of the interface connected to the same subnet as Workstation2 >The destination layer 3 address is the IP address of the destination device (Workstation3)

3. Routing data between computers on a network requires several mappings between different addresses. Which of the following statements is true?

Routers us ARP to resolve known IP addresses into MAC addresses by broadcasting requests to the network.

9. You have several hosts, a switch, and a router as shown in the image. Workstation2 sends an IP packet to Workstation3. Which default gateway address is used by Workstation2? 192.168.10.1

The default gateway for Workstation2 is the logical address of the network's interface on the router. (The packet travels to the IP address of the router that exists in its network--not the network that Workstation3 is on)

7. You have several hosts, a switch and a router as shown in the image. Worstation1 sends and IP packet to Workstation3. When the packet reaches Workstation3, which source addresses are in the frame and packet? The MAC address of the router on the side of Workstation3: 00b5f2a2223. The IP address of Workstation1: 192.168.10.11

The MAC address of the default gateway for Workstation 3 will be the source of the frame (this is the network interface of the router closest to the destination device). The source IP address will be the IP address of Workstation1. Source and destination IP addresses do not change. The MAC address of Workstation1 is on a different network than Workstation3, so Workstation1 had to send the packet to its default gateway (the router) and rely on the router to forward the packet to Workstation3. The switches MAC address is never placed in the Ethernet header of a packet unless the packet originates from the switch.

8. You have several hosts, a switch and a router as shown in the image. Workstation3 sends an IP packet to Workstation1. The packet is received by the CIsco 2600 router as shown. When the packet leaves the router, which source and destination IP addresses will be contained in the IP packet? Destination IP address = 192.168.10.11 (Workstation1) Source IP address = 192.168.11.11 (Workstation3)

The destination IP address and source IP address do not change as a packet travels through an internetwork.

11. Workstation 3 has started communicating with Workstation2. It sends a frame to the default gateway. Identify the Layer 2 and Layer 3 address used by the Cisco 2600 router to forward the data to Workstation by dragging the corresponding address from the list on the left to its location on the right.

The router is the default gateway. When it receives from Workstation3, it examines the Layer 3 address in the packet to locate the destination device. It then creates a new frame and modifies the source and destination Layer 2 addresses (MAC addresses) as follows: >Layer 2 source address is its own MAC address on the same segment as as the destination device: 000b5f2a2222 >Layer 3 destination address is the MAC addresses of the destination device: 080046987654 The source and destination Layer 3 addresses (IP addresses) do not change: >The source IP address is the IP address of Workstation3: 192.168.11.11 >The destination IP address is the IP address of Workstation2: 192.168.10.12

5. You have several hosts, a switch and a router as shown in the image (in 240 on harddrive). Workstation1 sends and IP packet containing a text document to Workstation2. Which destination address does Workstation1 put in the Ethernet frame header of the packet containing the text document? 080046987654

Workstation1 and Workstation2 are on the same network, so the destination MAC address is used in the ethernet frame to send the packet. 198.162.10.1 and 192.168.10.12 are both logical addresses. When both the sending and destination devices are on the same network, the packet is forwarded directly to the MAC address of the destination device not the logical address. The address 000b5f2a5111 is the MAC address of the switch. The packet is addressed to the workstation, not the switch.

6. You have several hosts, a switch and a router as shown in the image. Workstation1 sends and IP packet containing a photograph to Workstation3. Which destination MAC address does Workstation1 use? 000b5f2a2222

Workstation1 and Workstation3 are on different networks, so the frame containing the packet must be sent to the MAC address of the default gateway which will forward the frame to the destination device's MAC address. The MAC address of the default gateway that is used will be the address on the same network as the sending computer. The address 080046982365 is the MAC address of Workstation3. The destination router, not Workstation1, will place this MAC address in the ethernet header of the frame containing the packet. The switch MAC address is not used as a destination address unless the frame is sent to the switch itself.