Question 1

Choose a CORRECT statement about the Internet Service Provider (ISP).
A) Regional ISPs are classified as Tier 1 ISPs.
B) The networks of Tier 1, Tier 2, and Tier 3 ISPs become the Internet backbone.
C) The Internet backbone is mostly owned by governments.
D) The National ISP's network should provide bridging between the Local ISP and Regional ISP networks.
E) The Local and Regional ISP networks are called feeder networks.

Accepted Answer

Local and Regional ISP networks are often referred to as feeder networks because they connect end-users to larger networks, facilitating access to the broader Internet.

Question 2

Choose an INCORRECT statement about the Autonomous System (AS).
A) Routers within an AS use a uniform set of policies for packet routing.
B) The AS becomes a routing domain.
C) Multiple small businesses can belong to the same AS of an ISP.
D) IXPs bridge ISP networks that belong to different Autonomous Systems.
E) Routers within an AS exchange routing information based on the EGP.

Accepted Answer

Routers within an AS exchange routing information based on the IGP (Interior Gateway Protocol), not the EGP (Exterior Gateway Protocol).

Question 3

Choose an INCORRECT statement about the Internet Service Provider (ISP).
A) Point of Presences (POPs) are generally owned by ISPs.
B) The POP of a carrier houses access routers that connect to customer premises.
C) Many carriers run both local/regional ISP and national ISP businesses.
D) Many POPs are interconnected in the ring topology running on optical fibers.
E) With private peering, two ISP networks are connected through an IXP.

Accepted Answer

Private peering refers to the direct connection between two ISP networks without going through an Internet Exchange Point (IXP). Public peering, on the other hand, involves connecting networks via IXPs.

Question 4

The ______ plays a critical role in enabling IP packet forwarding between autonomous systems.
A) DHCP (dynamic host configuration protocol)
B) OSPF (Open shortest path first)
C) ARP (address resolution protocol)
D) BGP (Border Gateway Protocol)
E) IGP (Interior Gateway Protocol)

Accepted Answer

BGP (Border Gateway Protocol) is used to exchange routing information between autonomous systems on the internet, enabling IP packet forwarding between them. DHCP is used for assigning IP addresses to clients, OSPF is used for routing within a single autonomous system, ARP is used for mapping network layer addresses to link layer addresses, and IGP is a generic term for routing protocols used within a single autonomous system.

Question 5

Local or regional ISPs typically access the Internet through ________ .
A) internet exchange points
B) internet gateways
C) public switched data networks
D) virtual private networks
E) peer ISPs

Accepted Answer

Local or regional ISPs typically access the Internet through internet exchange points, which allow them to connect and exchange traffic with other networks and ISPs. Internet gateways, public switched data networks, virtual private networks, and peer ISPs are all possible ways for ISPs to access the Internet, but they are not typically used exclusively by local or regional ISPs.

Question 6

The network access point is equivalent to the ______.
A) private peer
B) internet exchange point
C) internet service provider (ISP)
D) autonomous system (AS)
E) internet gateway

Accepted Answer

The network access point (NAP) is similar to an internet exchange point (IXP). It is a physical location where multiple ISPs and autonomous systems (AS) exchange traffic with one another. This helps to reduce the latency and enhance the performance of the internet. Private peer, ISP, and internet gateway are different components of the internet infrastructure, and they are not equivalent to the network access point.

Question 7

Which protocol is fundamentally different from the others in their missions?
A) RIP
B) OSPF
C) IS-IS
D) BGP
E) IP

Accepted Answer

IP (Internet Protocol) is fundamentally different from RIP (Routing Information Protocol), OSPF (Open Shortest Path First), IS-IS (Intermediate System to Intermediate System), and BGP (Border Gateway Protocol) because it is a network layer protocol used for routing datagrams across network boundaries, while the others are routing protocols used to establish routes within or between autonomous systems.

Question 8

Routers can use ________ to advertise their link-state information to other routers (choose a most specific answer).
A) DHCP
B) OSPF
C) ARP
D) IP
E) TCP

Accepted Answer

OSPF (Open Shortest Path First) is a link-state routing protocol that routers can use to share information about their network topology with other routers. This allows routers to calculate the shortest path to a destination network and make efficient routing decisions. DHCP (Dynamic Host Configuration Protocol) is used for assigning IP addresses to devices on a network. ARP (Address Resolution Protocol) is used for mapping IP addresses to MAC addresses. IP (Internet Protocol) and TCP (Transmission Control Protocol) are both protocols that govern the transfer of data over the internet.

Question 9

Which may NOT be included in the routing table?
A) destination subnetworks
B) subnet masks
C) exit ports
D) next hop IPs
E) host IP addresses

Accepted Answer

Host IP addresses are not included in the routing table. The routing table only holds information about network addresses and the paths to reach them, not individual host addresses.

Question 10

When there is more than one best path for an IP packet in the routing table, their _____ are compared to break the tie?
A) subnet masks
B) exit ports
C) metric values
D) next hop IPs
E) host IP addresses

Accepted Answer

When there are multiple paths with the same destination and subnet mask in the routing table, the metric values are compared to determine the best path. The path with the lowest metric value is chosen as the best path as it indicates the shortest and fastest route.

Question 11

When using the metric value to break a tie between entries in the routing table, the router
A) selects the matching row with the highest metric value.
B) selects the matching row with the lowest metric value.
C) selects the matching row with the latest update value.
D) selects the matching row with the oldest update value.
E) selects the matching row with the highest or lowest value depending on the metric.

Accepted Answer

The router selects the matching row with the lowest metric value as it indicates the shortest path to a destination network. Choosing the highest metric value would mean a longer path to the destination network.

Question 12

A router receives an IP packet with destination of 142.66.39.125. What should be its exit port (interface)?
$$\begin{array} { | l | l | } 
\hline \text { Subnet/mask } & { \text { Exit port } } \
\hline \text { (A) } 142.64 .130 .0 / 16 & \mathrm {~S} 0 / 0 / 0 \
\text { (B) } 142.62 .39 .0 / 24 & \mathrm {~S} 0 / 0 / 1 \
\text { (C) } 142.140 .21 .0 / 7 & \mathrm { Fa } 0 / 0 \
\text { (D) } 142.66 .39 .64 / 25 & \mathrm { Fa } 0 / 1 \
\text { (E) } 0.0 .0 .0 / 0 & \mathrm {~S} 0 / 0 / 1 \
\hline
\end{array}$$
A) A
B) B
C) C
D) D
E) E

Accepted Answer

The IP packet belongs to the subnet 142.66.39.64/25, which is covered by subnet D. Therefore, the exit port should be Fa 0/1.

Question 13

(Refer to the figure below) PC1 is sending a packet to the server. In forwarding the packet, what is R1's next hop IP address? 
A) 172.20.1.241
B) 172.20.2.241
C) 172.20.2.242
D) 172.20.3.241
E) The server's IP address

Accepted Answer

R1's next hop IP address is the IP address of the router connected to the server subnet. In this case, it is 172.20.2.242. Therefore, the correct answer is C.

Question 14

(Refer to the figure below) Which is CORRECT as an entry to the R1's routing table?
 $$\begin{array} { | l | l | } 
\hline \begin{array} { l } 
\text { Destination } \
\text { Network/Subnet Mask }
\end{array} & \begin{array} { l } 
\text { Exit Port/ } \
\text { Interface }
\end{array} \
\hline \text { A) } 172.20 .1 .241 / 24 & \text { FastEthernet0/0 } \
\hline \text { B) } 172.20 .2 .241 / 24 & \text { FastEthernet0/1 } \
\hline \text { C) } 172.20 .3 .241 / 24 & \text { FastEthernet0/1 } \
\hline \text { D) } 172.20 .1 .0 / 24 & \text { FastEthernet0/0 } \
\hline \text { E) } 172.20 .3 .0 / 24 & \text { FastEthernet0/0 } \
\hline
\end{array}$$
A) A
B) B
C) C
D) D
E) E

Accepted Answer

The answer of (Refer to the figure below) Which is...

Question 15

Which may NOT be included in the routing table developed for intra-domain routing?
A) destination network (or subnet) IP addresses
B) subnet masks
C) exit port/interfaces
D) metric values
E) ISP numbers

Accepted Answer

ISPs (Internet Service Providers) are not part of an organization's internal network and are used for inter-domain routing, which is handled by exterior gateway protocols (EGPs) such as BGP (Border Gateway Protocol). Intra-domain routing handles routing within an organization's internal network and includes destination network (or subnet) IP addresses, subnet masks, exit port/interfaces, and metric values in the routing table.

Question 16

When there is no specific matching between an IP packet's destination and the routing table's entries, which subnet address becomes the default route to move the packet?
A) 0.0.0.0/0
B) 1.1.1.1/0
C) 50.50.50.50/0
D) 100.100.100.100/0
E) 255.255.255.255/0

Accepted Answer

The default route is represented by the network address 0.0.0.0 with a subnet mask of 0.0.0.0 or /0, which means match all IP addresses. When there is no specific matching between an IP packet's destination and the router's routing table, the default route is used to move the packet towards its destination network. Therefore, the correct answer is A, 0.0.0.0/0.

Question 17

To determine which entries of the routing table match the destination address of an arriving IP packet, the router rely on their ______ information.
A) subnet mask
B) metric value
C) exit port/interface
D) default gateway
E) next hop

Accepted Answer

The subnet mask information is used by the router to determine which entries in the routing table match the destination address of an arriving IP packet. The subnet mask is used to divide the IP address into a network portion and a host portion, allowing the router to identify which network the destination address belongs to and then use the appropriate routing entry to forward the packet.

Question 18

Choose a FALSE statement about routers and routing.
A) The routing table entry with a larger metric value is a better choice if the metric represents bandwidth.
B) ARP is used to advertise information necessary to develop the routing table.
C) Workstations that connect to the Internet have a static routing table.
D) The default gateway is a router port to which IP packets are sent when the destination is not in the same subnet.
E) The border gateway protocol is an exterior gateway protocol.

Accepted Answer

ARP (Address Resolution Protocol) is used for mapping an IP address to a physical machine address that is recognized in the local network. It does not advertise information to develop the routing table; that is the role of routing protocols.

Question 19

The destination address of a packet arriving at a router is 100.50.30.10, which routing table entry matches the address?
A) 100.50.0.0/24
B) 100.0.0.0/16
C) 100.50.0.0/20
D) 100.48.30.0/21
E) 100.50.0.0/16

Accepted Answer

The destination address 100.50.30.10 falls within the network range of 100.50.0.0/16, which covers all addresses from 100.50.0.0 to 100.50.255.255.

Question 20

Which is the longest match of the IP address 100.50.30.10?
A) 100.50.0.0/24
B) 100.0.0.0/8
C) 100.50.30.0/20
D) 100.50.30.0/22
E) 100.50.0.0/16

Accepted Answer

The longest match for an IP address in routing is the one with the longest subnet mask (or smallest prefix length), which means the most specific match. Among the options, 100.50.30.0/22 has the longest subnet mask (or smallest prefix length), making it the most specific match for the IP address 100.50.30.10.

Quiz 11: Fundamentals of Packet Routing

Choose a CORRECT statement about the Internet Service Provider (ISP) .

Choose an INCORRECT statement about the Autonomous System (AS) .

Choose an INCORRECT statement about the Internet Service Provider (ISP) .

The ______ plays a critical role in enabling IP packet forwarding between autonomous systems.

Local or regional ISPs typically access the Internet through ________ .

The network access point is equivalent to the ______.

Which protocol is fundamentally different from the others in their missions?

Routers can use ________ to advertise their link-state information to other routers (choose a most specific answer) .

Which may NOT be included in the routing table?

When there is more than one best path for an IP packet in the routing table, their _____ are compared to break the tie?

When using the metric value to break a tie between entries in the routing table, the router

(Refer to the figure below) PC1 is sending a packet to the server. In forwarding the packet, what is R1's next hop IP address?

Which may NOT be included in the routing table developed for intra-domain routing?

When there is no specific matching between an IP packet's destination and the routing table's entries, which subnet address becomes the default route to move the packet?

To determine which entries of the routing table match the destination address of an arriving IP packet, the router rely on their ______ information.

Choose a FALSE statement about routers and routing.

The destination address of a packet arriving at a router is 100.50.30.10, which routing table entry matches the address?

Which is the longest match of the IP address 100.50.30.10?