Chapter 8 - Wide Area Networks Flashcards Preview

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Flashcards in Chapter 8 - Wide Area Networks Deck (29)
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What is a Wide Area Network (WAN)?

- Networks and hosts are spread out over large distances (country or continent wide).
- Interconnect several MANs
- Typically owned by network providers
- Inter-processer distance 1000+ km


Describe the link type that the WAN usually uses

- Typically fiber
- Possibly microwave
- Link speed of 1 to 40 Gb/s (Ethernet); 622 Mb/s to 39.8 Gb/s (SONET); 54 – 170 Mb/s (Microwave)


Draw the WAN topology

See Slide 2 of IT Infrastructure Diagrams Keynote


Draw the WAN services view diagram

See Slide 3 of IT Infrastructure Diagrams Keynote


Name two common carrier services regulatory bodies.

Canadian Radio-Television and Telecommunications Commission (CRTC)
Federal Communications Commission (FCC)


What are the four main WAN circuit types?

- Circuit switched
- Dedicated circuit
- Packet switched
- Virtual Private Network


Describe the circuit switched network

- Uses the Public Switched Telephone Network
- (according to the textbook it uses a cloud architecture)
- Oldest WAN service
- Dial up


What are the two types of circuit switched networks?

- Plain Old Telephone Service (POTS)
- Integrated Services Digital Network (ISDN)


What are the two main problems with circuit switched networks?

- Each time you want to transfer data you have to create a new connection
- The data rates are low


Describe dedicated circuit networks (also called leased line or private line service)

- Creates a point-to-point link between two customer locations.
- Ends of link are terminated by a Customer Premises Equipment (CPE)
- Typically billed a flat fee per month for unlimited use.


Draw the textbook diagram of a dedicated circuit network topology

See Slide 4 of the IT Infrastructure Diagrams Keynote


What are the three basic dedicated circuit network architectures? Draw them.

- Ring (slide 7 of diagrams keynote): Linked in a ring topology. Can be rerouted around a failed link.
- Star (slide 8 of diagrams keynote): customer cites are linked through a central router (can become a bottleneck). Link failure only affects one location.
- Partial/Full Mesh (slide 9 of diagrams keynote): each customer site has multiple links to other customer sites. More expensive.


What are the two main services of dedicated circuit networks?

- T-Carrier
*both use time division multiplexing


What type of network is likely going to replace SONET?

Optical Transport Network (OTN)


Draw the basic architecture of a Packet Switched Network

See slide 12 of the IT Infrastructure Diagrams slide deck


What are the main differences between Circuit Switched Networks and Packet Switch Networks?

Circuit Switched: physical circuit connects two endpoints of customer premises equipment and is not shared by any other devices.
Packet Switched: Multiple data streams from different connections share the same physical connection.


What are the four types of packet switched services

- Asynchronous Transfer Mode (ATM) (legacy)
- Frame Relay (legacy)
- Multiprotocol Label Switching (IP/MPLS)
- Ethernet Services


Name some advantages of ethernet services

- Ethernet technology is ubiquitous - it works with existing infrastructure.
- It represents a simplified network design and management


Name three types of ethernet services

- Metro internet
- Wide Area Ethernet (WAE)
- Virtual private LAN Service


Packet switched network: Describe Multi-Protocol Label Switches

Allows carriers to define a specific path through the core network for a particular customer's data. It requires special routers and headers.


What are the three special headers needed for Multi-Protocol Label Switches (MPLS)?

- Insert label
- Switch label
- Remove label


Multi-Protocol Label Switch (MPLS) are sometimes called ____________

Layer 2.5


What are the three Multi-Protocol Label Switch (MPLS) services?

- MPLS Virtual Private LAN Service
- Virtual Leased Line (VLL)
- Virtual Private Routed Network (VPRN)


What is a Virtual Private Network? Draw a diagram

- Creates a private tunnel through the common carrier network.
- Can be either provider or customer provisioned
- see slides 18-19 for diagram


How does a customer provisioned VPN differ from a provider provisioned VPN?

Customer provisioned VPN:
- uses customer provided and managed equipment.
- user computer must run VPN software that is compatible with the VPN gateway


What is IPsec VPN? draw a supporting diagram

IPsecurity VPN:
- uses customer provided and managed VPN gateway to terminate VPN connections
- user computer runs IPsec software provided by gateway vendor
- IPsec encapsulates and encrypts data sent between PC and gateway


What are the three main types of IPsec VPNs?

- Intranet VPN
- Extranet VPN
- Access VPN


What are three main factors to consider when purchasing WAN services?

- effective data rates and cost
- reliability
- network integration


Name some ways to improve performance for WANs.

1. Upgrade routers that connect to the WAN
2. Analyse traffic to find circuits approaching capacity
3. Examine why circuits are at capacity
4. Shift Network Usage
5. Redesign the network