Chapter 1: WAN Concepts

Question 1

What is purpose of WAN?

Answer 1

WANs are used to connect LANs, remote sites, home users to internet, LAN-WAN using security and privacy solutions.

Question 2

Identify common WAN topologies.

Answer 2

• Point-to-Point (dedicated leased-line, like T1/E1)
• Hub-n-Spoke (single homed, multi-spoke using VIs)
• Full Mesh (each router has connection to each other, large number of VIs)
• Dual-homed ( typically dual-homed hub-n-spoke)
• Ring (nodes connected in circular pattern)

Question 3

List WAN scopes.

Answer 3

• Small Office (single LAN, single broadband WAN)
• Campus Network (small-medium business, special equipment and tech to connect to Internet)
• Branch Networks (Each branch with campus network, negotiated WAN links to connect branches)
• Distributed Network (multinational business, complex WAN strategies to connect regional & branch offices, partners, clients, and telecommuters)

Question 4

Which layers does WAN primarily operates in?

Answer 4

• Layer 1 (how to provide a stateful connection)

* Layer 2 (how data is encapsulated)

Question 5

List WAN terminology.

Answer 5

• Customer Premises Equipment (owned by the business or leased by provider [both DCE & DTE])
• Data Communications Equipment (provides communication link between customers and WAN cloud)
• Data Terminal Equipment (connects subscribers to DCE)
• Demarcation Point (separates customer from provider equipment)
• Local Loop (cable that connects to service provider)
• Central Office (service provider local facility)
• Toll Network (all cabling and equipment inside WAN provider network)

Question 6

Describe/draw the WAN topology

Answer 6

https://frankfu.click/wp-content/uploads/2016/01/WAN-access-Options.jpg

Question 7

Describe Leased Line.

Answer 7

• Layer 1
• T-carrier circuit, dedicated customer use
• Provides data framing & multiplexing hierarchy
• Scalable (fractional multi DS0[1/24] or full DS1[24/24 1.544 Mbps])
• Sync Optical Networking (uses frame partitioning for low bandwidth services - each called Virtual Tribituary)

Question 8

What are the 2 types of Switching Methods?

Answer 8

• Circuit-Switched Networks (uses dedicated bandwidth, e.g Dialup, Telephone call, ISDN)
• Packet-Switched Networks (may use shared bandwidth, e.g Frame Relay, ATM[cell based, fixed length], Ethernet WAN[separates user with QinQ for vlan & mac-in-mac mac tunnel], MPLS, VSAT)

Question 9

Briefly describe Public WAN technology.

Answer 9

• Digital Subscriber Loop (always-on connection using telephone lines)
• Cable (network access thru cable television networks, also always-on)
• wireless (minicipal WIFI, WiMAX, Satelite Internet)
• 3G/4G/5G wireless and LTE
• VPN (site-site or remote access)

Question 10

What types of devices does WAN include?

Answer 10

• Dialup Modem (converst digital to voice frequency to transmit over dialup network)
• Access Server (coordinates dial-in and dial-out user communications)
• Broadband Modem (used with high-speed DSL or cable Internet service)
• CSU/DSU (used to convert digital leased line singal into frames that LAN can interpret and backwards)
• WAN Switch (multiport internetworking device, used in service provider network)
• Router (provides WAN access ports to connect to service provider network)
• Core Router/Multilayer Switch (within backbone of WAN, used for forwarding IP packets at full line speed over multiple interfaces)