CCNA Introduction to Networks Chapter 6
What are two functions that are provided by the network layer? (Choose two.)
directing data packets to destination hosts on other networks providing end devices with a unique network identifier Refer to curriculum topic: 6.1.1 The network layer is primarily concerned with passing data from a source to a destination on another network. IP addresses supply unique identifiers for the source and destination. The network layer provides connectionless, best-effort delivery. Devices rely on higher layers to supply services to processes.
Which feature on a Cisco router permits the forwarding of traffic for which there is no specific route?
gateway of last resort Refer to curriculum topic: 6.2.2 A default static route is used as a gateway of last resort to forward unknown destination traffic to a next hop/exit interface. The next-hop or exit interface is the destination to send traffic to on a network after the traffic is matched in a router. The route source is the location a route was learned from.
Which three commands are used to set up a password for a person who attaches a cable to a new router so that an initial configuration can be performed? (Choose three.)
login line console 0 password cisco
Which two commands can be used on a Windows host to display the routing table? (Choose two.)
route print netstat -r
Which command displays a summary chart of all router interfaces, their IP addresses, and their current operational status?
show ip interface brief
During the process of forwarding traffic, what will the router do immediately after matching the destination IP address to a network on a directly connected routing table entry?
switch the packet to the directly connected interface
What is the command netstat -r used for?
to display the host routing table Refer to curriculum topic: 6.2.1 The command netstat -r displays the host routing table to verify the routes and costs that a computer uses to communicate to certain networks.
When connectionless protocols are implemented at the lower layers of the OSI model, what are usually used to acknowledge the data receipt and request the retransmission of missing data?
upper-layer connection-oriented protocols
Which two files, if found, are copied into RAM as a router with the default configuration register setting boots up? (Choose two.)
IOS image file Startup configuration
What is a service provided by the Flow Label field of the IPv6 header?
It informs network devices to maintain the same path for real-time application packets.
Fill in the blank. In a router,________ is the nonvolatile memory where the diagnostic software, the bootup instructions, and a limited IOS are stored.
ROM
Which value, that is contained in an IPv4 header field, is decremented by each router that receives a packet?
Time-to-Live Refer to curriculum topic: 6.1.3 When a router receives a packet, the router will decrement the Time-to-Live (TTL) field by one. When the field reaches zero, the receiving router will discard the packet and will send an ICMP Time Exceeded message to the sender.
Which two interfaces will allow access via the VTY lines to configure the router? (Choose two.)
WAN interfaces LAN interfaces
Refer to the exhibit. Fill in the blank. A packet leaving PC-1 has to traverse _____ hops to reach PC-4.
3
A technician is configuring a router that is actively running on the network. Suddenly, power to the router is lost. If the technician has not saved the configuration, which two types of information will be lost? (Choose two.)
ARP cache routing table
Why is NAT not needed in IPv6?
Any host or user can get a public IPv6 network address because the number of available IPv6 addresses is extremely large.
A packet arrives at a router interface. The router goes through a series of steps to determine where the packet should be forwarded. Place the steps of the router forwarding process in the correct order.
(Not all options are used.) 1 Examine Packet Header 2 Determine Destination Network 3 Examine Routing Table 4 Identify Exit Interface to Destination from route entry 5 Move packet to forwarding interface
Which statement about router interfaces is true?
A configured and activated router interface must be connected to another device in order to operate.
During troubleshooting procedures, from which location will most Cisco routers load a limited IOS?
ROM Refer to curriculum topic: 6.3.1 ROM is used to store bootup instructions, basic diagnostic software, and a copy of a limited IOS. NVRAM stores the startup configuration file. RAM provides temporary storage of the running configuration file. Flash is used to store the full Cisco IOS on a device.
Match the commands to the correct actions. (Not all options are used.)
provides security on the console = router(config-line)# Password class displays a message when the router is accessed = router(config)# banner motd configures a name on the router = router(config)# hostname CL1
Which router bootup sequence is correct?
1 - perform the POST and load the bootstrap program 2 - locate and load the Cisco IOS software 3 - locate and load the startup configuration file or enter setup mode Refer to curriculum topic: 6.3.2 When a router is powered on, it undergoes a POST to verify that the hardware is functional, after which it proceeds by locating and loading the Cisco IOS software and then loading the startup configuration file if one is present.
When transporting data from real-time applications, such as streaming audio and video, which field in the IPv6 header can be used to inform the routers and switches to maintain the same path for the packets in the same conversation?
Flow Label Refer to curriculum topic: 6.1.4 The Flow Label in IPv6 header is a 20-bit field that provides a special service for real-time applications. This field can be used to inform routers and switches to maintain the same path for the packet flow so that packets will not be reordered.
After troubleshooting a router, the network administrator wants to save the router configuration so that it will be used automatically the next time that the router reboots. What command should be issued?
copy running-config startup-config
Here is a link to the PT ActivityView in a new window. Open the PT activity. Perform the tasks in the activity instructions and then answer the question. Which interfaces in each router are active and operational?
R1: G0/0 and S0/0/0 R2: G0/1 and S0/0/0 R1>enable R1# show ip int brief Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 192.168.20.1 YES manual up up GigabitEthernet0/1 192.168.30.1 YES manual administratively down down Serial0/0/0 209.165.200.225 YES manual up up Serial0/0/1 unassigned YES unset administratively down down Vlan1 unassigned YES unset administratively down down R2>enable R2#show ip int brief Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 10.1.2.1 YES manual administratively down down GigabitEthernet0/1 10.1.3.1 YES manual up up Serial0/0/0 209.165.200.226 YES manual up up Serial0/0/1 unassigned YES unset administratively down down Vlan1 unassigned YES unset administratively down down Refer to curriculum topic: 6.4.2 The command to use for this activity is show ip interface brief in each router. The active and operational interfaces are represented by the value "up" in the "Status" and "Protocol" columns. The interfaces in R1 with these characteristics are G0/0 and S0/0/0. In R2 they are G0/1 and S0/0/0.
How does the network layer use the MTU value?
The MTU is passed to the network layer by the data link layer Refer to curriculum topic: 6.1.2 The data link layer indicates to the network layer the MTU for the medium that is being used. The network layer uses that information to determine how large the packet can be when it is forwarded. When packets are received on one medium and forwarded on a medium with a smaller MTU, the network layer device can fragment the packet to accommodate the smaller size.
Within a production network, what is the purpose of configuring a switch with a default gateway address?
The default gateway address is used to forward packets originating from the switch to remote networks. Refer to curriculum topic: 6.4.3 A default gateway address allows a switch to forward packets that originate on the switch to remote networks. A default gateway address on a switch does not provide Layer 3 routing for PCs that are connected on that switch. A switch can still be accessible from Telnet as long as the source of the Telnet connection is on the local network.
A computer has to send a packet to a destination host in the same LAN. How will the packet be sent?
The packet will be sent directly to the destination host.
How do hosts ensure that their packets are directed to the correct network destination?
They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route.
Which IPv4 header field is responsible for defining the priority of the packet?
differentiated services
During the boot process, in what memory location will the router bootstrap program look for the IOS image if a TFTP server is not used?
flash Refer to curriculum topic: 6.3.2 The IOS image is typically stored in flash memory. If the image is not in flash memory when the router boots, the router bootstrap program can look for it on a TFTP server.
Which two files are loaded into RAM by the router when it boots? (Choose two.)
startup configuration IOS image Refer to curriculum topic: 6.3.2 A router loads the IOS image file and startup configuration file into RAM when it boots. Then the startup configuration file is copied into RAM as the running configuration file. The power-on self-test (POST) is a process that occurs on almost every computer during bootup. A bootstrap program is a program that is executed just after the POST.
A technician is manually configuring a computer with the necessary IP parameters to communicate over the corporate network. The computer already has an IP address, a subnet mask, and a DNS server. What else has to be configured for Internet access?
the default gateway address
When would the Cisco IOS image held in ROM be used to boot the router?
when the full IOS cannot be found