Cisco 100-101 Set 4

Front 1

1. Which of the following are functions of OSI Layer 3 protocols? (Choose two answers.)
a. Logical addressing
b. Physical addressing
c. Path selection
d. Arbitration
e. Error recovery

Back 1

a. Logical addressing
c. Path selection

Front 2

2. Imagine that PC1 needs to send some data to PC2, and PC1 and PC2 are separated by several routers. Both PC1 and PC2 sit on different Ethernet LANs. What are the largest entities (in size) that make it from PC1 to PC2? (Choose two answers.)
a. Frame
b. Segment
c. Packet
d. L5 PDU
e. L3 PDU
f. L1 PDU

Back 2

c. Packet
e. L3 PDU

Front 3

3. Which of the following is a valid Class C IP address that can be assigned to a host?
a. 1.1.1.1
b. 200.1.1.1
c. 128.128.128.128
d. 224.1.1.1
e. 223.223.223.255

Back 3

b. 200.1.1.1

Front 4

4. What is the assignable range of values for the first octet for Class A IP networks?
a. 0 to 127
b. 0 to 126
c. 1 to 127
d. 1 to 126
e. 128 to 191
f. 128 to 192

Back 4

d. 1 to 126

Front 5

5. PC1 and PC2 are on two different Ethernet LANs that are separated by an IP router. PC1’s IP address is 10.1.1.1, and no subnetting is used. Which of the following addresses could be used for PC2? (Choose two answers.)
a. 10.1.1.2
b. 10.2.2.2
c. 10.200.200.1
d. 9.1.1.1
e. 225.1.1.1
f. 1.1.1.1

Back 5

d. 9.1.1.1
f. 1.1.1.1

Front 6

6. Imagine a network with two routers that are connected with a point-to-point HDLC serial link.
Each router has an Ethernet, with PC1 sharing the Ethernet with Router1 and PC2 sharing the Ethernet with Router2. When PC1 sends data to PC2, which of the following is true?
a. Router1 strips the Ethernet header and trailer off the frame received from PC1, never to be used again.
b. Router1 encapsulates the Ethernet frame inside an HDLC header and sends the frame to Router2, which extracts the Ethernet frame for forwarding to PC2.
c. Router1 strips the Ethernet header and trailer off the frame received from PC1, which is exactly re-created by Router2 before forwarding data to PC2.
d. Router1 removes the Ethernet, IP, and TCP headers and rebuilds the appropriate headers before forwarding the packet to Router2.

Back 6

a. Router1 strips the Ethernet header and trailer off the frame received from PC1, never to be used again.

Front 7

7. Which of the following does a router normally use when making a decision about routing TCP/IP packets?
a. Destination MAC address
b. Source MAC address
c. Destination IP address
d. Source IP address
e. Destination MAC and IP address

Back 7

c. Destination IP address

Front 8

8. Which of the following are true about a LAN-connected TCP/IP host and its IP routing (forwarding) choices? (Choose two answers.)
a. The host always sends packets to its default gateway.
b. The host sends packets to its default gateway if the destination IP address is in a different
class of IP network than the host.
c. The host sends packets to its default gateway if the destination IP address is in a different
subnet than the host.
d. The host sends packets to its default gateway if the destination IP address is in the same
subnet as the host.

Back 8

b. The host sends packets to its default gateway if the destination IP address is in a different
class of IP network than the host.
c. The host sends packets to its default gateway if the destination IP address is in a different
subnet than the host.

Front 9

9. Which of the following are functions of a routing protocol? (Choose two answers.)
a. Advertising known routes to neighboring routers
b. Learning routes for subnets directly connected to the router
c. Learning routes, and putting those routes into the routing table, for routes advertised to the
router by its neighboring routers
d. Forwarding IP packets based on a packet’s destination IP address

Back 9

a. Advertising known routes to neighboring routers
c. Learning routes, and putting those routes into the routing table, for routes advertised to the
router by its neighboring routers

Front 10

10. A company implements a TCP/IP network, with PC1 sitting on an Ethernet LAN. Which of the following protocols and features requires PC1 to learn information from some other server device?
a. ARP
b. ping
c. DNS
d. None of the other answers are correct

Back 10

c. DNS

Front 11

List the two main concepts of routing

Back 11

Layer 3 packets are forwarded based upon the Destination Layer e address in the packet
The data link layer reencapsulates the layer 3 packets for transmission across each link

Front 12

How large is an IPv4 header?

Back 12

20 bytes

Front 13

List 2 statements about how IP expects IP addresses to be grouped into networks or subnets

Back 13

• All IP addresses in the same group must not be separated from each other by a router.
• IP addresses separated from each other by a router must be in different groups.

Front 14

Breakdown of IPv4 address space

Back 14

By first octet: 0 – Reserved
1 – 126 – Class A
127 – Reserved
128 – 191 – Class B
192 – 223 – Class C
224 – 239 – Class D
240 – 255 – Class E

Front 15

How many hosts can a Class A network have?

Back 15

16,777,214

Front 16

How many hosts can a Class B network have?

Back 16

65,534

Front 17

How many hosts can a Class C network have?

Back 17

254

Front 18

How many Class A networks are possible?

Back 18

126

Front 19

How many Class B networks are possible?

Back 19

16,384

Front 20

How many Class C networks are possible?

Back 20

2,097,152

Front 21

List of the three types of unicast IP Networks

Back 21

Class A, Class B, and Class C IP addresses

Front 22

How do you identify a network?

Back 22

By network ID, AKA network number or network address

Front 23

Two-step process of how hosts route (forward) packets

Back 23

1.Determine if the packet is in the same subnet, and forward it to the host if it is.
2. Forward the packet to the default gateway/default router if the packet is not on the same subnet

Front 24

four-step process of how routers route (forward) packets

Back 24

1. Process the frame against the FCS. If it fails, discard it.
2. If not discarded, discard the data link header and trailer. This leaves the IP packet.
3. Use routing table to determine what route to take. Identifies outgoing interface, and possibly next-hop router IP address.
4. Encapsulate IP packet inside new data link header & trailer

Front 25

Goals of IP routing protocols regarding filling the routing table

Back 25

To dynamically learn and fill the routing table with a route to each subnet in the internetwork

Front 26

Goals of IP routing protocols regarding handling multiple routes to a subnet

Back 26

If more than one route to a subnt is available to plac the best route in the routing table

Front 27

Goals of IP routing protocols regarding bad routes

Back 27

To notice when routes in the table are no longer valid, and to remove them from the routing table.

Front 28

Goals of IP routing protocols regarding recovering from bad routes

Back 28

If a route is removed from the routing table and another route through another neighboring router is availabke to add the route to the routing table. (often viewed as the same goal regarding removing routes)

Front 29

Goals of IP routing protocols regarding adding new routes or replacing lost routes

Back 29

To work quickly when adding new routes or replacing lost routes. (convergence)

Front 30

Goals of IP routing protocols regarding loops

Back 30

loops are bad.
Routing protocols aim to avoid this process.

Front 31

3 steps routing protocols use to lear routes

Back 31

1. Each router (regardless of protocol) adds one route to its routing table for each directly-connected subnet
2. Each router's routing protocol tells its neighbors about the routes in its routing table
3. After learning a new route, the router's protocol adds a route to itse IP routing table, with the next-hop router of that route typically beign the neighbor from which the route was learned.

Front 32

Purpose of DNS name and resolution

Back 32

Allows user-friendly names to be used instead of network addresses

Front 33

Process of DNS name and resolution

Back 33

1. When resolving a name to address, the host first queries the DNS server for the network address
2. The DNS server may escalate the request until it gets a reply
3. The DNS server replies to the host with the network address
4. The host can now contact the server by network address

Front 34

2-step Process of ARP

Back 34

1. Host sends an ARP request to the network broadcast address (all devices on LAN) containing sender's IP and MAC, and the target's IP.
2. Target responds to initial request (unicast) including their IP and MAC addresses.

Front 35

Define ARP

Back 35

Address Resolution Protocol. An Internet protocol used to map an IP address to a MAC address.

Front 36

What defines ARP?

Back 36

Defined in RFC 826.

Front 37

Define default router (default gateway)

Back 37

On an IP host, the IP address of some router to which the host sends packets when the packet’s destination address is on a subnet other than the local subnet.

Front 38

Define DNS

Back 38

Domain Name System. An application layer protocol used throughout the Internet for translating host names into their associated IP addresses.

Front 39

Define dotted decimal notation (DDN)

Back 39

The format used for IP version 4 addresses, in which four decimal values are used, separated by periods (dots).

Front 40

Define host name

Back 40

The alphameric name of an IP host.

Front 41

Define IP network

Back 41

An IPv4 network would be any network that can be routed to using IPv4

Front 42

Define IP packet

Back 42

An IP header, followed by the data encapsulated after the IP header, but specifically not including any headers and trailers for layers below the network layer.

Front 43

Define IP subnet

Back 43

Subdivisions of a Class A, B, or C network, as configured by a network administrator.

Front 44

What is the purpose of IP Subnets?

Back 44

They allow a single Class A, B, or C network to be used instead of multiple networks, and still allow for a large number of groups of IP addresses, as is required for efficient IP routing.

Front 45

Define IPv4 addresss

Back 45

A 32-bit address assigned to hosts using TCP/IP. Each address consists of a network number, an optional subnetwork number, and a host number. The network and subnetwork numbers together are used for routing, and the host number is used to address an individual host within the network or subnetwork.

Front 46

Define ping

Back 46

An Internet Control Message Protocol (ICMP) echo message and its reply. Ping often is used in IP networks to test the reachability of a network device.

Front 47

Define routing protocol

Back 47

A set of messages and processes with which routers can exchange information about routes to reach subnets in a particular network. Examples of routing protocols include the Enhanced Interior Gateway Routing Protocol (EIGRP), the Open Shortest Path First (OSPF) protocol, and the Routing Information Protocol (RIP).

Front 48

Define routing table

Back 48

A list of routes in a router, with each route listing the destination subnet and mask, the router interface out which to forward packets destined to that subnet, and as needed, the next-hop router’s IP address.

Front 49

Define subnetting

Back 49

The process of subdividing a Class A, B, or C network into smaller groups called subnets.

Front 50

Define unicast IP address

Back 50

Generally, any address in networking that represents a single device or interface, instead of a group of addresses (as would be represented by a multicast or broadcast address).

Front 51

Define path selection

Back 51

It can either refer to the routing process or how routing protocols select the best route among the competing routes to the same destination.

Front 52

What is the default router?

Back 52

It is also known as the default gateway

Front 53

Define Next Hop router

Back 53

In an IP route in a routing table, part of a routing table entry that refers to the next IP router (by IP address) that should receive packets that match the route.