WorksheetsFundamentals of WANs and IP Routing Quiz
Total questions: 116
Worksheet time: 58mins
What is the primary difference between a leased line and a circuit-switched WAN?
Leased lines are packet-switched
Circuit-switched WANs provide permanent physical circuits
Leased lines provide constant availability
Circuit-switched WANs are always-on
In a Frame Relay network, what identifies a virtual circuit?
IP address
DLCI
MAC address
Subnet ID
What layer of the OSI model does Frame Relay operate at?
Physical
Data Link
Network
Transport
Which protocol is commonly used to provide dynamic addressing for WAN interfaces?
RIP
DHCP
PPP
OSPF
What is the purpose of split-horizon in distance-vector routing protocols?
Prevent routing loops
Increase convergence speed
Reduce packet size
Balance the load
How does OSPF calculate the best path?
Hop count
Bandwidth
Delay
Cost
Which routing protocol uses administrative distance to select routes?
RIP
OSPF
EIGRP
All of the above
What is the default administrative distance of OSPF?
90
110
120
100
What does the term 'autonomous system' refer to in routing?
Group of VLANs
Logical router domain
Group of networks under common administration
Routing domain without NAT
What type of route is manually configured by a network administrator?
Static route
Default route
Dynamic route
Summary route
What is the main benefit of link-state routing protocols over distance-vector?
Faster hop calculation
Lower CPU usage
Faster convergence
Easier configuration
Which WAN technology uses permanent virtual circuits?
ISDN
ATM
MPLS
Frame Relay
In OSPF, what is the purpose of the DR (Designated Router)?
To filter routes
To summarize routes
To reduce LSA flooding
To manage neighbor tables
What command would show the OSPF process ID on a Cisco router?
show ip ospf
show ospf id
show protocols
show ip route ospf
What is a key feature of PPP over HDLC?
Compression
Error detection
Authentication options
Packet ordering
Which IP address class allows for the most hosts on a single network?
Class A
Class B
Class C
Class D
What is a key benefit of CIDR over classful addressing?
Simpler subnetting
More efficient use of IP space
Faster routing
Easier DNS resolution
Which of the following is NOT a valid reason for route summarization?
Reduce routing table size
Simplify routing logic
Improve convergence time
Increase route specificity
What does MTU define?
Time-to-live
Minimum frame size
Maximum frame size
Data priority
Which protocol uses hello packets to discover neighbors?
EIGRP
RIP
OSPF
BGP
What happens when a router receives a packet with a TTL of 1?
It decrements and forwards
It sends it back to sender
It drops the packet and sends ICMP time exceeded
It ignores the TTL
Which WAN protocol supports multilink connections?
PPP
HDLC
Frame Relay
MPLS
What is the main role of ARP in IP networking?
IP-to-IP resolution
MAC-to-IP resolution
IP-to-MAC resolution
DNS mapping
A default route is also known as:
Last-hop route
Static override
Gateway of last resort
Fallback route
Which protocol uses DUAL algorithm for path calculation?
OSPF
EIGRP
RIP
BGP
How many bits are in an IPv4 address?
64
32
48
128
Which of the following WAN technologies is considered legacy and no longer commonly used?
MPLS
ATM
Metro Ethernet
DSL
What does MPLS use for forwarding decisions?
IP address
MAC address
Labels
Ports
Which OSPF packet type is used for neighbor discovery?
LSA
DBD
Hello
LSU
What is the default OSPF cost formula?
10⁶ / Bandwidth in Kbps
Bandwidth in Mbps / 100
100 / Bandwidth in Mbps
10 / Delay
Which of the following is used to identify a router in OSPF?
Router name
Loopback address
MAC address
Hostname
What does the term “convergence” mean in routing?
Route caching
Complete route summarization
All routers have updated and consistent routing info
Dynamic address translation
Which of the following is NOT a routing protocol?
RIP
NAT
OSPF
BGP
Which IP protocol number is used by OSPF?
89
88
6
17
What is the main purpose of BGP in enterprise networks?
Intra-domain routing
IP assignment
WAN encryption
Inter-domain routing
What is a hold-down timer in routing?
Prevents route flapping
Increases hop count
Delays convergence
Sends constant updates
What is the main drawback of distance-vector protocols?
High bandwidth use
Slow convergence and routing loops
Poor scalability
Complex configuration
What does RIP use to determine the best route?
Cost
Delay
Hop count
Bandwidth
Which of the following protocols supports VLSM?
RIP v1
OSPF
IGRP
Static Routing only
Which technology is typically used in broadband WANs?
Frame Relay
ISDN
DSL
ATM
What is the default hello interval for OSPF on broadcast links?
10 seconds
30 seconds
40 seconds
60 seconds
What metric does EIGRP use?
Cost
Hop count
Composite metric (bandwidth + delay + reliability + load)
Time-to-live
Which routing protocol is classful?
OSPF
EIGRP
RIP v1
RIP v2
What does a router do if no matching route is found for a destination?
Drops the packet
Sends it to loopback
Uses default gateway if defined
Floods it out all interfaces
What encapsulation type is Cisco proprietary on serial links?
PPP
Frame Relay
HDLC
Ethernet
Which protocol enables mutual authentication over WAN links?
DHCP
CHAP
RIP
DNS
Which of the following does not support route authentication by default?
OSPF
RIP
EIGRP
BGP
What field in the IP header decreases with every router hop?
Source IP
Destination IP
TTL
Protocol
Which OSPF network type elects a DR and BDR?
Point-to-point
Broadcast
Non-broadcast
Loopback
What is the purpose of LSA Type 1 in OSPF?
Advertise AS external routes
Summarize area border routers
Advertise router’s own links
Define backbone topology
What do WAN technologies primarily standardize in long-distance communication?
Transmission rates and packet TTL
Cabling types and IP headers
Electrical signaling and framing rules
Application protocols and MTU sizes
What describes the trend regarding leased-line WANs in modern networks?
Their use is expanding due to simplicity
They are widely adopted in LANs
Their relevance is declining with newer options
They now rely on wireless technologies
How are Ethernet WANs functionally adapted for long-distance communication?
By using entirely different MAC protocols
By operating only over copper links
By integrating carrier-grade enhancements
By replacing IP headers with serial encapsulation
Which best differentiates Ethernet WANs from legacy leased lines?
Leased lines require NAT, Ethernet does not
Ethernet uses packet switching, leased lines are circuit-based
Leased lines allow higher bandwidth than Ethernet
Ethernet requires synchronous communication
What fundamental network layers are defined by WAN technologies?
Session and Transport
Network and Presentation
Physical and Data-Link
Application and Network
What role do routers play in a leased-line WAN between LANs?
They provide DHCP services to all LAN hosts
They allow Ethernet switches to connect to each other
They connect LANs to the WAN and route traffic between them
They convert WAN signals into wireless broadcast
What is the primary purpose of a WAN link between two routers?
To provide local broadcast capabilities
To encapsulate HTTP traffic
To connect two LANs across distance
To assign MAC addresses to both ends
Which cabling method enables full-duplex operation on a leased line?
Coaxial with a shared bus
Single-pair telephone cable
Fiber-optic simplex
Two separate wire pairs for send and receive
How does a leased line simulate a direct Ethernet crossover cable?
By using a switch at each end
By routing frames through multiple routers
By enabling simultaneous bidirectional communication
By disabling collision detection
What does the telco actually provide to a customer who leases a line?
Exclusive cable ownership
Scheduled wireless access
A virtual IP tunnel
Usage rights to a telco-managed physical path
Why does a leased line not physically exist as a single long cable?
Because it is built using optical repeaters only
Because telcos use a network of cables and switches internally
Because all data is routed through satellite
Because leased lines must terminate at Layer 3 devices
How is full-duplex achieved over a leased line?
Through token-based access
With time-division multiplexing
By using two distinct transmission paths
By alternating signal direction every second
What layer of the OSI model is primarily involved in the delivery of bits over a leased line?
Layer 2 – Data Link
Layer 7 – Application
Layer 3 – Network
Layer 4 – Transport
What makes a leased line different from a dial-up connection?
Leased lines use Layer 7 packet switching
Leased lines offer permanent, always-on connectivity
Leased lines rely on dynamic IP addresses
Leased lines only function during peak hours
In what way is a leased line similar to a direct Ethernet cable?
It operates over coaxial only
It allows for broadcast domains across WAN
It functions as a point-to-point connection
It supports wireless fallback
What does the customer typically not control in a leased-line WAN setup?
The LAN devices at either end
The IP addressing scheme
The routing protocol
The underlying telco infrastructure
What is the primary billing model for leased lines?
Pay-per-packet
Prepaid bandwidth tokens
Monthly flat-rate leasing
Usage-based data throttling
Why do routers need to be placed at each end of a leased-line WAN link?
To control Layer 1 error correction
To assign subnet masks
To route IP packets between networks
To enable VPN encryption by default
Which of the following accurately describes the ownership of a leased line?
Owned by the customer for dedicated use
Co-owned by the ISP and customer
Temporarily rented by the customer for burst usage
Owned and maintained by the telco, leased to the customer
What aspect of leased lines contributes to their reliability in WAN connections?
Use of dynamic routing
Static IP assignment by DNS
Direct physical circuits dedicated to one customer
The presence of loopback plugs at endpoints
What is the term 'circuit' referencing when used in the context of a leased circuit?
A virtual route between multiple routers
An electrical connection between two endpoints
A fiber loop used in token-ring networks
A logical tunnel across shared infrastructure
Why is the term “serial” used in “serial line”?
Because it uses parallel bit transmission
Because it supports multiple endpoints
Because it transmits bits sequentially over time
Because it utilizes frequency-hopping channels
Which of the following accurately describes a point-to-point link?
A broadcast-enabled connection between multiple LANs
A topology where multiple devices share a physical medium
A direct connection between exactly two network devices
A link that uses IP tunnels for multiple subnet routing
What does the term “T1” specifically refer to?
A general name for all types of leased lines
A leased line offering up to 100 Mbps
A dedicated line with variable transmission rates
A leased line that transmits at 1.544 Mbps
Why are the terms “WAN link” and “link” considered vague in this context?
Because they refer only to wireless WANs
Because they don’t specify a technology or topology
Because they imply broadcast rather than point-to-point
Because they only describe OSI Layer 7 functionality
What does the term 'Private line' imply about data transmission?
Data is encrypted before transmission
Other telco customers can access the line on demand
The path is shared, but uses logical VLAN segmentation
Only the leasing customer has access, ensuring privacy
Which of the following pairs are often used interchangeably to describe a leased line?
Router and Switch
VPN and VLAN
Circuit and Line
Frame and Segment
In the term “Serial link,” what characteristic of data transmission is being highlighted?
The ability to transmit data on multiple channels simultaneously
The fact that bits flow one at a time in order
The use of optical wavelengths for transmission
The encapsulation of data using Ethernet headers
What distinguishes a point-to-point line from a shared network medium?
It uses asynchronous signal timing
It operates over satellite exclusively
It connects only two endpoints without sharing
It requires dynamic IP assignment
Which term listed in the table is associated with both privacy and exclusivity of transmission?
Serial line
Point-to-point link
Private line
WAN link
What must physically exist to enable a leased line between two routers?
A satellite uplink for both routers
A VPN overlay across LAN switches
A physical path connecting the two routers
A wireless mesh linking endpoints
How do telcos simulate a direct cable between two customer routers?
By using optical tunneling with MPLS
By assigning the same subnet to both ends
By configuring a complex internal switch network
By encrypting packets at Layer 7
What role do central offices (COs) play in telco infrastructure?
They act as firewalls for leased-line endpoints
They store cloud backups for all leased-line traffic
They house telco equipment and connect to city buildings
They perform DNS translation for routing
What does the telco configure its switches to do along the leased line path?
Drop broadcast traffic
Assign IP addresses
Use parts of cable capacity to send data in both directions
Control frame sequencing at Layer 4
What OSI layer does a leased line service typically operate at?
Layer 3 – Network
Layer 7 – Application
Layer 2 – Data Link
Layer 1 – Physical
Which of the following is NOT defined by a leased line service itself?
The physical path between endpoints
The availability of the link
The data-link protocol used
The bandwidth capacity
Which protocols are most commonly used at Layer 2 on leased lines between routers?
DHCP and DNS
HDLC and PPP
MPLS and BGP
Ethernet and Wi-Fi
Why is HDLC considered simpler than Ethernet?
HDLC supports dynamic addressing
HDLC does not need to handle multiple destinations
HDLC uses IP directly without framing
HDLC works only on wireless links
Why is the address field in an HDLC frame typically unimportant?
Because all data is broadcast to all nodes
Because each frame is compressed
Because the destination is implied in a point-to-point link
Because HDLC uses DNS for destination resolution
What type of control does a data-link protocol like HDLC provide?
Application access to files
Secure encryption of packet contents
Correct delivery of frames over the physical link
Automatic routing to unknown networks
Why do telcos install cables from their central offices to most buildings?
To enable VPN tunneling for remote work
To supply power to routers directly
To create physical paths needed for leased lines
To limit the use of wireless WAN connections
How does a leased line ensure data can travel in both directions?
By configuring routers to alternate transmission every millisecond
By leasing two separate routers from the telco
By using switching that splits cable capacity for bidirectional use
By converting digital signals into analog for return paths
What does HDLC stand for?
High-Dynamic Link Control
High-Density Local Channel
High-Level Data Link Control
Host-Dedicated Link Communication
In what situation would the address field of an HDLC frame be used?
In point-to-point links with implied destinations
In shared media networks where multiple endpoints exist
In Wi-Fi mesh networks
In cloud-based overlays
What function does HDLC share with Ethernet despite its simpler setup?
Support for broadcast and multicast
Header fields for frame error checking and control
Dynamic hostname resolution
Automatic subnet segmentation
What is the purpose of the HDLC flag field?
To indicate the destination of the frame
To identify errors in the transmitted data
To mark the beginning and end of a frame
To determine the Layer 3 protocol being used
Which HDLC field aligns with the Ethernet 'Destination Address'?
Flag
Address
Control
Type
What is the role of the Control field in HDLC for modern router-to-router links?
It is used for NAT translation
It is essential for identifying the frame type
It is mostly unused today
It replaces the flag field
Why do routers require a 'Type' field in HDLC frames?
To compress the data payload
To track error correction metrics
To identify the encapsulated Layer 3 protocol
To determine the path through the telco core
Which HDLC variant includes a Type field?
ISO HDLC
PPP over Ethernet
Cisco proprietary HDLC
Ethernet HDLC Lite
What is a limitation of standard ISO HDLC when used with routers?
It cannot be used on leased lines
It does not support error detection
It lacks a Type field for protocol identification
It only works over Wi-Fi connections
What does the FCS field in HDLC represent?
Frame Control Switch
Frame Check Sequence
Frame Control Signal
Final Channel Section
How many bytes long is the Type field in Cisco’s proprietary HDLC format?
1 byte
2 bytes
4 bytes
Variable length
Which field is used by the HDLC receiver to recognize the start of a new frame?
Address
Control
FCS
Flag
What makes Cisco HDLC incompatible with other vendors' routers?
It uses Ethernet frame headers
It is encrypted with a Cisco key
It adds a proprietary Type field not defined by ISO
It replaces FCS with a checksum hash
What is the role of a router in the context of WAN communication?
It encrypts data before transmission
It establishes physical links to client devices
It forwards IP packets toward the final destination
It monitors IP addressing changes on local hosts
In the routing process, what decision does PC1 make before sending a packet to PC2?
Whether to encapsulate the data in an HDLC frame
Whether to assign a public or private IP address
Whether to send the packet directly to PC2 or to its default gateway
Whether to create a VPN tunnel for packet delivery
What is the role of R1 in the figure when PC1 sends a packet to PC2?
R1 delivers the packet directly to PC2 using ARP
R1 drops the packet if PC2 is not on its LAN
R1 forwards the packet over the leased line to R2
R1 translates the IP address of PC2 into a MAC address
When sending data over the WAN, what kind of frame does Router R1 typically use?
Ethernet frame with VLAN tag
PPP frame encapsulated in MPLS
HDLC frame encapsulating the IP packet
Frame Relay frame with BECN
Which layer is responsible for determining the next-hop IP address in routing decisions?
Layer 1 - Physical
Layer 2 - Data Link
Layer 3 - Network
Layer 4 - Transport
Which of the following statements is true regarding the encapsulation of packets over a WAN?
The WAN link uses a single persistent frame for all transmissions
Each device along the path re-encapsulates the packet in a new data-link frame
HDLC frames are only generated by the destination router
IP packets are never altered or re-encapsulated once they leave the source
In Figure 3-5, what is the function of Router R2 in packet forwarding?
Terminate the HDLC session and route the packet onto the LAN toward PC2
Broadcast the IP packet to all LAN clients
Replace the IP address of PC1 with its own
Translate the IP packet into a frame for MPLS delivery
Which part of the OSI model is responsible for encapsulating IP packets in HDLC frames?
Layer 2 - Data Link
Layer 1 - Physical
Layer 4 - Transport
Layer 5 - Session
What does the WAN data-link layer contribute to the end-to-end packet delivery?
Global address resolution
Determining hop-by-hop routing logic
Physical transmission and framing over each link
Prioritizing packets based on application type
Which statement best explains how the routers treat the IP packet during transmission?
Routers fragment and reassemble the IP packet at each hop
Routers modify the application payload but preserve the header
Routers keep the IP packet intact and change only the data-link frame
Routers encrypt the packet before forwarding it to the next hop
Which statement best describes a leased line’s physical appearance?
A single continuous cable stretching directly between routers
Two Ethernet cables, one from each router, that meet at a shared midpoint
A logical connection created by the telco through multiple cables and switching devices
Fiber optics connecting both routers directly without any intermediate
