WAN Technologies and Switching Methods

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Questions and Answers

What is the primary method of switching used in Wide Area Networks (WAN)?

Cell relay

Circuit switching

Packet switching (correct)

Message switching

Which of the following is NOT a factor to consider when selecting WAN technology?

Flexibility for new technologies

Speed of operation

Personal preferences of the IT team (correct)

Initial and recurring costs

How does switching in WANs improve resource efficiency?

By moving data through intermediate segments instead of directly (correct)

By ensuring all data is transmitted directly to the destination

By limiting the number of nodes in the network

By using more physical connections between nodes

Which type of switching is associated with high-speed packet-switching technology?

Cell relay Signup and view all the answers

Which of the following is optimized for extended travel in WAN protocols?

Levels 1-3 of the OSI reference model Signup and view all the answers

What is one advantage of ATM technology in terms of transmission speeds?

It has defined speeds as high as 622 Mbps. Signup and view all the answers

What is a requirement for deploying ATM networks?

Using ATM-compatible devices. Signup and view all the answers

Which of the following is a downside to ATM networks?

They require ATM-compatible devices that are expensive. Signup and view all the answers

How does ATM achieve reliability and flexibility in data transmission?

Through error checking and correction done by higher-level protocols. Signup and view all the answers

What distinguishes BISDN from traditional ISDN?

BISDN is designed for next-generation networking. Signup and view all the answers

What is the main characteristic of distributed services?

Information is delivered or broadcast to the recipient. Signup and view all the answers

Which technology does BISDN utilize for transmission?

Asynchronous Transfer Mode (ATM) Signup and view all the answers

What is a key difference between using datagram and Virtual Circuits (VCs) in a subnet?

Datagrams require a routing decision for each packet. Signup and view all the answers

What role does the routing algorithm play within routing protocols?

It determines the optimal path for each packet. Signup and view all the answers

Which of the following best describes narrowband ISDN transmissions?

They are based on time division multiplexing (TDM). Signup and view all the answers

What is a key feature of packet switching in comparison to message switching?

Packets are buffered in memory Signup and view all the answers

What is the role of Packet Switching Exchanges (PSEs) in a packet-switched network?

To route packets through various intermediaries Signup and view all the answers

Which of the following services can utilize connection-oriented protocols during packet transmission?

Switched Virtual Circuits (SVCs) Signup and view all the answers

In packet switching, what allows for data rate conversion between stations?

Each station connecting to the local node at its own speed Signup and view all the answers

What is the primary advantage of using a packet-switched network?

Efficient use of resources with line sharing Signup and view all the answers

Which approach in packet switching is characterized by the delivery of packets without establishing a dedicated path?

Datagram Approach Signup and view all the answers

What happens to packet delivery when a network is busy?

Delivery may slow down Signup and view all the answers

Which type of virtual circuit is comparable to making a telephone call?

Switched Virtual Circuit (SVC) Signup and view all the answers

What is the main characteristic of the virtual circuit approach?

A single route is established at the beginning of the session. Signup and view all the answers

Which of the following describes how datagrams are handled in the datagram approach?

Each packet is treated independently and may follow different routes. Signup and view all the answers

What is a primary feature of Frame Relay technology?

It relies on cyclic redundancy checks to detect transmission errors. Signup and view all the answers

Which communication method is characterized as being capable of delivering data, voice, and video simultaneously?

Asynchronous Transfer Mode (ATM) Signup and view all the answers

What is the maximum packet size for Frame Relay technology?

4 KB Signup and view all the answers

In contrast to the virtual circuit approach, which statement is true regarding the datagram approach?

Routing decisions are made on a per-packet basis. Signup and view all the answers

Which statement best describes the method by which ATM transmits data?

It uses fixed-size cells for high-speed data transmission. Signup and view all the answers

What happens when there is congestion in a Frame Relay network?

The sender is requested to reduce transmission speed. Signup and view all the answers

Which technology operates predominantly at the data link layer and involves permanent virtual circuits?

Frame Relay Signup and view all the answers

What is the primary advantage of using a virtual circuit approach for connection-oriented services?

Reduced need for routing decisions per packet. Signup and view all the answers

Which of the following is NOT considered a desirable property of a routing algorithm?

Speed Signup and view all the answers

What does the term 'Next-Hop Routing' refer to?

A routing strategy that saves entries by only specifying the next hop Signup and view all the answers

What is the main difference between routing and forwarding?

Routing is concerned with the correct outgoing line, whereas forwarding gets packets moving Signup and view all the answers

Which of the following characterizes non-adaptive (static) routing algorithms?

Routes are pre-computed and not updated automatically Signup and view all the answers

What could happen if routing algorithms converge slowly?

Routing loops or network outages may occur Signup and view all the answers

What is the primary role of a routing table?

To store entries leading to possible destinations Signup and view all the answers

Which of the following is a factor that can lead to adaptive (dynamic) routing decisions?

Network topology changes Signup and view all the answers

What can be a downside to large routing tables in big internetworks?

They can lead to inefficient table lookups Signup and view all the answers

Study Notes

Wide Area Network (WAN) Technology

WAN technology utilizes protocols at OSI levels 1-3, optimized for extended travel.
WAN technology selection involves several factors: data delivery capacity, operational speed, initial and recurring costs, management needs, and adaptability for new technologies (e.g., voice, video).
Switching is a method of moving data through intermediate steps (segments) instead of a direct connection.
WANs use switching to make resource use more efficient.
Circuit switching creates a dedicated physical connection between sender and receiver.
- The connection remains active until both parties are finished.
- This is optimized for fixed, high-speed data streams.
- A drawback is unused bandwidth is wasted.
- The telephone system is a common example.
Circuit switching advantages: fixed delays, guaranteed continuous delivery.
Circuit switching disadvantages: long connection delays (e.g., between dialing and ringing), inefficient for bursty traffic, optimized for fixed data rates, challenging to handle variable data rates (e.g., 64 Kbps).
Message switching doesn't need a direct physical connection.
Data is broken into blocks, stored by the switching office (e.g., router), and forwarded later.
Intermediate devices can hold the messages.
This method supports variable block sizes but can lead to delays.
It's a store-and-forward network.
Packet switching is similar to message switching, but uses the same block size for efficiency, with a finer limit on block sizes so packets are buffered in memory rather than on disk.
- Suitable for interactive and non-monopoly transmission types.
Packets contain addressing information for both sender and destination.
- Packets are individually routed through intermediate devices (packet switching exchanges or PSES), and these routes can change.
Packet-switched networks handle variable data rates.
- They use dynamic routing and variable routes.
Datagrams and Virtual Circuits are two common approaches for packet switching.
- Virtual circuits provide a dedicated path, established at the session start, for packets.
Datagram packets are independent and may take different routes.
They prioritize speed over dedicated paths.
Connections for both are connection oriented or connectionless.
Frame Relay is a fast packet switching technology for variable-length packets up to 4KB.
ATM (Asynchronous Transfer Mode) is a connection-oriented technology for high-speed transmission of various data types.
Uses cell relay, small fixed size units.
Provides high bandwidth and good reliability.
BISDN (Broadband ISDN) is the next-generation of ISDN, using ATM technology, and can transmit multiple data types simultaneously.
Routing decisions are based on metrics, and a routing protocol determines optimal paths.
Routing protocols handle choosing the best path for the data, and they can be internal or external to an autonomous system (AS).
Routing protocols need to converge rapidly to avoid routing loops.

Routing and Protocols

Routing protocols use metrics (costs) to evaluate the best path for a packet.
Metrics include congestion, bandwidth, delay, geographic distance, number of hops, estimated transit time, and cost.
Routers choose the path with the shortest metric.
Autonomous Systems (AS) are groups of networks working together under a common administrative system.
Internal routing is routing inside an AS; exterior routing is used to route between autonomous systems.
The Optimality Principle ensures the optimal route between any two points.

Routing Algorithms

Non-adaptive (static) routing protocols compute routes in advance without regard for traffic conditions or changes in the network.
Adaptive (dynamic) routing protocols update their routing decisions based on changes in network topology or traffic.
Dijkstra's shortest path algorithm is a static routing algorithm for optimal path selection in a graph.

Additional Concepts

Switching methods (circuit, message, packet) and their characteristics.
WAN technologies (Frame Relay, ATM, BISDN).
Routing concepts and algorithms (static, dynamic, shortest path).
Issues with large networks.

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Description

Test your knowledge on the primary switching methods used in Wide Area Networks (WAN) and their specific technologies. This quiz covers key concepts like ATM, BISDN, and the differences between datagram and Virtual Circuits. Perfect for networking professionals looking to deepen their understanding of WAN protocols.