Chapter 1: Routing Concepts

PC A is connected to switch S1, which in turn is connected to router R1. Router R1 is connected to a cloud, and the cloud is connected to Server B. At one side of the PC is a label with the following information: PC A MAC address: 00-0B-85-7F-47-00 IPv4 address: 192.168.10.10At one side of the switch is a label with the following information: S1 MAC address: 00-0B-85-D0-BB-F7 IPv4 address: 192.168.11.1At one side of the router is a label with the following information: R1 MAC address: 00-0B-85-7F-86-B0 IPv4 address: 192.168.10.1At one side of the server is a label with the following information: SERVER B MAC address: 00-0B-85-7F-0A-0B IPv4 address: 192.168.12.16 Refer to the exhibit. PC A sends a request to Server B. What IPv4 address is used in the destination field in the packet as the packet leaves PC A? > 192.168.10.10 > 192.168.11.1 > 192.168.10.1 > 192.168.12.16

> 192.168.12.16*

What are two functions of a router? (Choose two.) > A router connects multiple IP networks > It controls the flow of data via the use of Layer 2 addresses > It determines the best path to send packets > It provides segmentation at Layer 2 > It builds a routing table based on ARP requests

> A router connects multiple IP networks* > It determines the best path to send packets* (Routers connect multiple networks, determine the best path to send packets, and forward packets based on a destination IP address.)

Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.) > Administrative distance refers to the trustworthiness of a particular route* > A router first installs routes with higher administrative distances > The value of the administrative distance cannot be altered by the network administrator > Routes with the smallest metric to a destination indicate the best path* > The metric is always determined based on hop count > The metric varies depending on which Layer 3 protocol is being routed

> Administrative distance refers to the trustworthiness of a particular route* > Routes with the smallest metric to a destination indicate the best path*

Which packet-forwarding method does a router use to make switching decisions when it is using a forwarding information base and an adjacency table? > fast switching > Cisco Express Forwarding > process switching > flow process

> Cisco Express Forwarding* (Cisco Express Forwarding (CEF) is the fastest and preferred switching method. It uses a FIB and an adjacency table to perform the task of packet switching. These data structures change with the topology.)

In order for packets to be sent to a remote destination, what three pieces of information must be configured on a host? (Choose three.) > hostname > IP address > subnet mask > default gateway > DNS server address > DHCP server address

> IP address* > subnet mask* > default gateway*

What two pieces of information are displayed in the output of the show ip interface brief command? (Choose two.) > IP addresses > MAC addresses > Layer 1 statuses > next-hop addresses > interface descriptions > speed and duplex settings

> IP addresses* > Layer 1 statuses* (The command show ip interface brief shows the IP address of each interface, as well as the operational status of the interfaces at both Layer 1 and Layer 2.)

Server B is connected to switch S1, which in turn is connected to router R1. Router R1 is connected to a cloud, and the cloud is connected to PC A. At one side of the server is a label with the following information: SERVER B MAC address: 00-0B-85-7F-0A-0B IPv4 address: 192.168.10.16At one side of the switch is a label with the following information: S1 MAC address: 00-0B-85-D0-BB-F7 IPv4 address: 192.168.11.1At one side of the router is a label with the following information: R1 MAC address: 00-0B-85-7F-86-B0 IPv4 address: 192.168.10.1At one side of the PC is a label with the following information: PC A MAC address: 00-0B-85-7F-47-00 IPv4 address: 192.168.12.10 Refer to the exhibit. What does R1 use as the MAC address of the destination when constructing the frame that will go from R1 to Server B? > If the destination MAC address that corresponds to the IPv4 address is not in the ARP cache, R1 sends an ARP request > The packet is encapsulated into a PPP frame, and R1 adds the PPP destination address to the frame > R1 uses the destination MAC address of S1 > R1 leaves the field blank and forwards the data to the PC

> If the destination MAC address that corresponds to the IPv4 address is not in the ARP cache, R1 sends an ARP request*

What is a characteristic of an IPv4 loopback interface on a Cisco IOS router?​ > The no shutdown command is required to place this interface in an UP state > It is a logical interface internal to the router > Only one loopback interface can be enabled on a router > It is assigned to a physical port and can be connected to other devices

> It is a logical interface internal to the router*

Consider the following routing table entry for R1: D 10.1.1.0/24 [90/2170112] via 209.165.200.226, 00:00:05, Serial0/0/0 What is the significance of the Serial0/0/0? > It is the interface on R1 used to send data that is destined for 10.1.1.0/24 > It is the R1 interface through which the EIGRP update was learned. > It is the interface on the final destination router that is directly connected to the 10.1.1.0/24 network. > It is the interface on the next-hop router when the destination IP address is on the 10.1.1.0/24 network.

> It is the interface on R1 used to send data that is destined for 10.1.1.0/24*

A network administrator enters the command copy running-config startup-config. Which type of memory will the startup configuration be placed into? > flash > RAM > NVRAM > ROM

> NVRAM* (A router contains four types of memory: RAM - volatile memory used to store the running IOS, running configuration file, routing table, ARP table, as well as serve as a packet buffer ROM - nonvolatile memory used to hold a limited version of the IOS, bootup instructions, and basic diagnostic software NVRAM - nonvolatile memory used to hold the startup configuration file Flash - nonvolatile memory used to hold the IOS and other system files)

The exhibit contains CLI output that says: R1# show ipv6 route C 2001:DB8:ACAD:2::/64 [0/0] via ::, FastEthernet0/0 L 2001:DB8:ACAD:2::54/128 [0/0] via ::, FastEthernet0/0 C 2001:DB8:ACAD:A::/64 [0/0] via ::, FastEthernet0/1 L 2001:DB8:ACAD:A::12/128 [0/0] via ::, FastEthernet0/1 L FF00::/8 [0/0] via ::, Null0 R1# Refer to the exhibit. A network administrator issues the show ipv6 route command on R1. What two conclusions can be drawn from the routing table? (Choose two.) > R1 does not know a route to any remote networks > The network FF00::/8 is installed through a static route command > The interface Fa0/1 is configured with IPv6 address 2001:DB8:ACAD:A::12 > Packets that are destined for the network 2001:DB8:ACAD:2::/64 will be forwarded through Fa0/1 > Packets that are destined for the network 2001:DB8:ACAD:2::54/128 will be forwarded through Fa0/0

> R1 does not know a route to any remote networks* > The interface Fa0/1 is configured with IPv6 address 2001:DB8:ACAD:A::12*

Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.) > Administrative distance refers to the trustworthiness of a particular route* > A router first installs routes with higher administrative distances > The value of the administrative distance can not be altered by the network administrator > Routes with the smallest metric to a destination indicate the best path > The metric is always determined based on hop count > The metric varies depending which Layer 3 protocol is being routed

> Routes with the smallest metric to a destination indicate the best path*

he exhibit shows the following router output: The gateway of last resort is 209.165.200.226 to network 0.0.0.0 S* 0.0.0.0/0 [1/0] via 209.165.200.226 192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.10.0/24 is directly connected, GigabitEthernet0/0 L 192.168.10.1/32 is directly connected, GigabitEthernet0/0 192.168.11.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.11.0/24 is directly connected, GigabitEthernet0/1 L 192.168.11.1/32 is directly connected, GigabitEthernet0/1 209.165.200.0/24 is variably subnetted, 2 subnets, 2 masks C 209.165.200.224/30 is directly connected, Serial0/0/0 L 209.165.200.225/32 is directly connected, Serial0/0/0 Refer to the exhibit. What will the router do with a packet that has a destination IP address of 192.168.12.227? > Drop the packet > Send the packet out the Serial0/0/0 interface > Send the packet out the GigabitEthernet0/0 interface > Send the packet out the GigabitEthernet0/1 interface

> Send the packet out the Serial0/0/0 interface*

A network administrator configures the interface fa0/0 on the router R1 with the command ip address 172.16.1.254 255.255.255.0. However, when the administrator issues the command show ip route, the routing table does not show the directly connected network. What is the possible cause of the problem? > The interface fa0/0 has not been activated > The configuration needs to be saved first. > No packets with a destination network of 172.16.1.0 have been sent to R1. > The subnet mask is incorrect for the IPv4 address.

> The interface fa0/0 has not been activated* (A directly connected network will be added to the routing table when these three conditions are met: (1) the interface is configured with a valid IP address; (2) it is activated with no shutdown command; and (3) it receives a carrier signal from another device that is connected to the interface. An incorrect subnet mask for an IPv4 address will not prevent its appearance in the routing table, although the error may prevent successful communications)

What are two common types of static routes in routing tables? (Choose two) > a default static route > a built-in static route by IOS > a static route to a specific network > a static route shared between two neighboring routers > a static route converted from a route that is learned through a dynamic routing protocol

> a default static route* > a static route to a specific network*

What route would have the lowest administrative distance? > a directly connected network > a static route > a route received through the EIGRP routing protocol > a route received through the OSPF routing protocol

> a directly connected network*

Which two parameters are used by EIGRP as metrics to select the best path to reach a network? (Choose two.)​ > hop count > bandwidth > jitter > resiliency > delay > confidentiality

> bandwidth* > delay* (EIGRP uses bandwidth, delay, load, and reliability as metrics for selecting the best path to reach a network.​)

When a router receives a packet, what information must be examined in order for the packet to be forwarded to a remote destination? > destination MAC address > destination IP address > source IP address > source MAC address

> destination IP address*

Which two items are used by a host device when performing an ANDing operation to determine if a destination address is on the same local network? (Choose two.) > destination IP address > destination MAC address > source MAC address > subnet mask > network number

> destination IP address* > subnet mask* (The result of ANDing any IP address with a subnet mask is a network number. If the source network number is the same as the destination network number, the data stays on the local network. If the destination network number is different, the packet is sent to the default gateway (the router that will send the packet onward toward the destination network).)

The exhibit consists of a network diagram that shows R1 with three network connections: two Ethernet segments and a WAN link. The WAN link connects R1 to a second router R2. R2 is the DCE on the WAN link. The configuration shown is as follows: R1(config)# interface serial 0/0/0 R1(config-if)# description Link to R2 R1(config-if)# ip address 209.165.200.225 255.255.255.252 R1(config-if)# exit R1(config)# Refer to the exhibit. A network administrator has configured R1 as shown. When the administrator checks the status of the serial interface, the interface is shown as being administratively down. What additional command must be entered on the serial interface of R1 to bring the interface up? > IPv6 enable > clockrate 128000 > end > no shutdown

> no shutdown* (By default all router interfaces are shut down. To bring the interfaces up, an administrator must issue the no shutdown command in interface mode.)

Refer to the exhibit. If PC1 is sending a packet to PC2 and routing has been configured between the two routers, what will R1 do with the Ethernet frame header attached by PC1? > nothing, because the router has a route to the destination network > remove the Ethernet header and configure a new Layer 2 header before sending it out S0/0/0 > open the header and replace the destination MAC address with a new one > open the header and use it to determine whether the data is to be sent out S0/0/0

> remove the Ethernet header and configure a new Layer 2 header before sending it out S0/0/0*

Which software is used for a network administrator to make the initial router configuration securely? > SSH client software > Telnet client software > HTTPS client software > terminal emulation client software

> terminal emulation client software*

What is the effect of configuring the ipv6 unicast-routing command on a router? > to assign the router to the all-nodes multicast group > to enable the router as an IPv6 router > to permit only unicast packets on the router > to prevent the router from joining the all-routers multicast group

> to enable the router as an IPv6 router*

A network administrator configures a router by the command ip route 0.0.0.0 0.0.0.0 209.165.200.226. What is the purpose of this command? > to forward all packets to the device with IP address 209.165.200.226 > to add a dynamic route for the destination network 0.0.0.0 to the routing table > to forward packets destined for the network 0.0.0.0 to the device with IP address 209.165.200.226 > to provide a route to forward packets for which there is no route in the routing table

> to provide a route to forward packets for which there is no route in the routing table* (The command ip route 0.0.0.0 0.0.0.0 adds a default route to the routing table of a router. When the router receives a packet and does not have a specific route toward the destination, it forwards the packet to the next hop indicated in the default route. )

Fill in the blank. When a router receives a packet, it examines the destination address of the packet and looks in the ———- table to determine the best path to use to forward the packet.

>: Routing*

OLDV

Study

Refer to the exhibit. Match the description with the routing table entries. (Not all options are used.) Graphic contains output of show ip route as follows: R3# show ip route 172.16.0.0/24 is subnetted, 3 subnets C 172.16.0.0 is directly connected, Serial0/1/0 D 172.16.1.0 [90/21024000] via 172.16.0.1, 00:22:15, Serial0/1/0 C 172.16.2.0 is directly connected, Serial0/1/0 10.0.0.0/24 is subnetted, 1 subnets S 10.2.0.0/24 [1/0] via 172.16.2.2 C 10.3.0.0 is directly connected, FastEthernet0/0 > route source protocol = > destination network = > metric = > administrative distance = > next hop = > route timestamp = _____________________________________________ > 172.16.2.2 > 10.3.0.0 > 21024000 > 3 > 1 > 00:22:15 > D > C

route source protocol = D (which is EIGRP) destination network = 10.3.0.0 metric = 21024000 administrative distance = 1 next hop = 172.16.2.2 route timestamp = 00:22:15