Quiz On CCENT/CCNA Icnd2 Chapt. 4 & 5

Note that sometimes VLSM stands for variable-length subnet masking, which refers to the process of using different masks in the same classful network, whereas variablelength subnet mask refers to the subnet masks themselves.

The correct syntax lists a subnet number, then a subnet mask in dotted decimal form, and then either an outgoing interface or a next-hop IP address.

The ping 2.1.1.2 command does not use a host name, so no DNS server is required. A DHCP client does not need to know the DHCP server’s IP address to use DHCP. There’s no such thing as an ARP server. However, to send the packet to another subnet,the PC needs to know the IP address of its default gateway.

The host might need to use Dynamic Host Configuration Protocol (DHCP) to acquire an IP address, and it would likely use Domain Name System (DNS) to resolve www.ciscopress.com into an IP address. It would also use Address Resolution Protocol (ARP) to find the default gateway’s MAC address, because the ARP cache would have
been cleared as part of the boot process.

With classless routing enabled, the router uses the default route if no other routes are matched. The line beginning “Gateway of last resort . . .” lists the IP address of the next-hop router, 168.13.1.101, which will be used as the default route.

RIP-2, EIGRP, and OSPF are the routing protocols that support VLSM. VLSM (Variable Length Subnet Masking) allows the use of different subnet mask lengths within the same network, which helps in efficient utilization of IP addresses. RIP-1 does not support VLSM as it only uses classful routing, where the subnet mask is fixed for all subnets. However, RIP-2, EIGRP, and OSPF support VLSM by allowing the use of different subnet masks for different subnets within the network.

All the listed answers include the range of all three subnets, except for 10.3.64.0 255.255.224.0, which implies an address range of 10.3.64.0–10.3.95.255. Of the other three answers, 10.3.64.0 255.255.192.0 is the smallest range (10.3.64.0–10.3.127.255). It also happens to be the smallest single summary route that includes all three subnets listed in the question.

The “S” code means that the route is a static route, which is defined with the ip route global configuration command.

Subnet 10.5.0.0 255.255.240.0 implies range 10.5.0.0–10.5.15.255, which does not overlap. 10.4.0.0 255.254.0.0 implies range 10.4.0.0–10.5.255.255, which does overlap. 10.5.32.0 255.255.224.0 implies range 10.5.32.0–10.5.63.255, which does overlap. 10.5.0.0 255.255.128.0 implies range 10.5.0.0– 10.5.127.255, which does overlap.

The correct answer is "When to use a default route." This is because the decision to use a default route or not is influenced by whether a router is performing classful or classless routing. In classful routing, a default route is used when there is no specific route for a destination network. In classless routing, a default route is used as a backup or last resort when there are no more specific routes available for a destination network. Therefore, the choice of using a default route is affected by the routing protocol and its classification as classful or classless.

Discontiguous networks are allowed as long as autosummarization is disabled. OSPF does not even support autosummarization, so using OSPF would solve the problem. RIP-1 cannot disable autosummarization. EIGRP can disable autosummarization, but it is on by default.

RIP-2, EIGRP, and OSPF support manual route summarization. Manual route summarization is a technique used to reduce the size of routing tables by aggregating multiple network prefixes into a single summary route. RIP-2, EIGRP, and OSPF allow network administrators to manually configure summary routes, which improves network efficiency and reduces the amount of routing information exchanged between routers.

RIP-1, RIP-2, and EIGRP perform autosummarization by default. Autosummarization is a feature in routing protocols that allows the summarization of multiple subnets into a single summarized route. This helps in reducing the size of the routing table and conserving network resources. OSPF, on the other hand, does not perform autosummarization by default.

10.0.0.0 255.0.0.0 implies a range of all addresses that begin with 10, and 10.1.0.0 255.255.0.0 implies a range of all addresses that begin with 10.1, so both these answers include all the address ranges listed in the question. 10.1.32.0 255.255.224.0 implies a range of 10.1.32.0–10.1.63.255, which includes all addresses listed in the question. 10.1.55.0 255.255.255.0 implies a range of only 10.1.55.0–10.1.55.255, which does not include all addresses. 10.1.48.0 255.255.248.0 implies a range of 10.1.48.0–10.1.55.255, which omits two of the subnets listed in the question.