Chapter_6_Network Layer

What are two types of router interfaces? (Choose two.) > SVI > LAN > DHCP > Telnet > WAN

> LAN* > WAN*

Which two pieces of information are in the RAM of a Cisco router during normal operation? (Choose two.) > Cisco IOS* > backup IOS file > IP routing table* > basic diagnostic software > startup configuration file

> Cisco IOS* > IP routing table* (The Cisco IOS file is stored in flash memory and copied into RAM during the boot up. The IP routing table is also stored in RAM. The basic diagnostic software is stored in ROM and the startup configuration file is stored in NVRAM.)

Refer to the exhibit. Which route from the PC1 routing table will be used to reach PC2?

A

Which three commands are used to set up secure access to a router through a connection to the console interface? (Choose three.) > interface fastethernet 0/0 > line vty 0 4 > line console 0 > enable secret cisco > login > password cisco

> line console 0* > login * > password cisco *

Which statement describes a hardware feature of a Cisco 1941 router that has the default hardware configuration? > It does not have an AUX port. > It has three FastEthernet interfaces for LAN access. > It has two types of ports that can be used to access the console. > It does not require a CPU because it relies on Compact Flash to run the IOS.

> It has two types of ports that can be used to access the console.* (The connections in a Cisco 1941 router include two types of ports that are used for initial configuration and command-line interface management access. The two ports are the regular RJ-45 port and a new USB Type-B (mini-B USB) connector)

Following default settings, what is the next step in the router boot sequence after the IOS loads from flash? > Perform the POST routine. > Locate and load the startup-config file from NVRAM. > Load the bootstrap program from ROM. > Load the running-config file from RAM.

> Locate and load the startup-config file from NVRAM.* (There are three major steps to the router boot sequence: Perform Power-On-Self-Test (POST) Load the IOS from Flash or TFTP server Load the startup configuration file from NVRAM)

What IPv4 header field identifies the upper layer protocol carried in the packet? > Protocol > Identification > Version > Differentiated Services

> Protocol*

Open the PT Activity. The enable password on all devices is cisco. Perform the tasks in the activity instructions and then answer the question. For what reason is the failure occurring? > PC1 has an incorrect default gateway configured. > SW1 does not have a default gateway configured. > The IP address of SW1 is configured in a wrong subnet. > PC2 has an incorrect default gateway configured.

> SW1 does not have a default gateway configured.* (The ip default-gateway command is missing on the SW1 configuration. Packets from PC2 are able to successfully reach SW1, but SW1 is unable to forward reply packets beyond the local network without the ip default-gateway command issued.)

Refer to the exhibit. R1 receives a packet destined for the IP address 192.168.2.10. Out which interface will R1 forward the packet? > FastEthernet0/0 > FastEthernet0/1 > Serial0/0/0 > Serial0/0/1

> Serial0/0/1*

Which characteristic describes an IPv6 enhancement over IPv4? > IPv6 addresses are based on 128-bit flat addressing as opposed to IPv4 which is based on 32-bit hierarchical addressing. > The IPv6 header is simpler than the IPv4 header is, which improves packet handling. > Both IPv4 and IPv6 support authentication, but only IPv6 supports privacy capabilities. > The IPv6 address space is four times bigger than the IPv4 address space.

> The IPv6 header is simpler than the IPv4 header is, which improves packet handling.*

OQ

OQ

A router boots and enters setup mode. What is the reason for this? > The IOS image is corrupt. > Cisco IOS is missing from flash memory. > The configuration file is missing from NVRAM. > The POST process has detected hardware failure.

> The configuration file is missing from NVRAM.*

Which field in the IPv4 header is used to prevent a packet from traversing a network endlessly? > Time-to-Live > Sequence Number > Acknowledgment Number > Differentiated Services

> Time-to-Live* (The value of the Time-to-Live (TTL) field in the IPv4 header is used to limit the lifetime of a packet. The sending host sets the initial TTL value; which is decreased by one each time the packet is processed by a router. If the TTL field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address. )

When a connectionless protocol is in use at a lower layer of the OSI model, how is missing data detected and retransmitted if necessary? > Connectionless acknowledgements are used to request retransmission. > Upper-layer connection-oriented protocols keep track of the data received and can request retransmission from the upper-level protocols on the sending host. > Network layer IP protocols manage the communication sessions if connection-oriented transport services are not available. > The best-effort delivery process guarantees that all packets that are sent are received.

> Upper-layer connection-oriented protocols keep track of the data received and can request retransmission from the upper-level protocols on the sending host.*

What type of route is indicated by the code C in an IPv4 routing table on a Cisco router? > static route > default route > directly connected route > dynamic route that is learned through EIGRP

> directly connected route* (C - directly connected S - static D - EIGRP * - candidate default)

What are two characteristics of IP? (Choose two.) > does not require a dedicated end-to-end connection > operates independently of the network media > retransmits packets if errors occur > re-assembles out of order packets into the correct order at the receiver end > guarantees delivery of packets

> does not require a dedicated end-to-end connection * > operates independently of the network media* (The Internet Protocol (IP) is a connectionless, best effort protocol. This means that IP requires no end-to-end connection nor does it guarantee delivery of packets. IP is also media independent, which means it operates independently of the network media carrying the packets)

What is one advantage that the IPv6 simplified header offers over IPv4? > smaller-sized header > little requirement for processing checksums > smaller-sized source and destination IP addresses > efficient packet handling

> efficient packet handling* (The IPv6 simplified header offers several advantages over IPv4: · Better routing efficiency and efficient packet handling for performance and forwarding-rate scalability · No requirement for processing checksums · Simplified and more efficient extension header mechanisms (as opposed to the IPv4 Options field) · A Flow Label field for per-flow processing with no need to open the transport inner packet to identify the various traffic flows)

What routing table entry has a next hop address associated with a destination network? > directly-connected routes > local routes > remote routes > C and L source routes

> remote routes* (Routing table entries for remote routes will have a next hop IP address. The next hop IP address is the address of the router interface of the next device to be used to reach the destination network)

Which characteristic of the network layer in the OSI model allows carrying packets for multiple types of communications among many hosts? > the de-encapsulation of headers from lower layers > the selection of paths for and direct packets toward the destination > the ability to operate without regard to the data that is carried in each packet > the ability to manage the data transport between processes running on hosts

> the ability to operate without regard to the data that is carried in each packet* (The feature of its operation without regard to the data carried in each packet allows the network layer to carry packets for multiple types of communications.)

What is the purpose of the startup configuration file on a Cisco router? > to facilitate the basic operation of the hardware components of a device > to contain the commands that are used to initially configure a router on startup > to contain the configuration commands that the router IOS is currently using > to provide a limited backup version of the IOS, in case the router cannot load the full featured IOS

> to contain the commands that are used to initially configure a router on startup*