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Questions and Answers
Which network technology is primarily associated with connection-oriented networking?
Which network technology is primarily associated with connection-oriented networking?
What was a key design goal of the original ARPANET?
What was a key design goal of the original ARPANET?
Which of the following is a standard for wireless LANs?
Which of the following is a standard for wireless LANs?
What type of network design allows for packets to be routed independently?
What type of network design allows for packets to be routed independently?
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Which protocol is NOT associated with connection-oriented networks?
Which protocol is NOT associated with connection-oriented networks?
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What was the maximum connection speed for IMPs in the ARPANET?
What was the maximum connection speed for IMPs in the ARPANET?
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Which of these networks operates on the connectionless packet-switching principle?
Which of these networks operates on the connectionless packet-switching principle?
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What is a main difference between connection-oriented and connectionless networks?
What is a main difference between connection-oriented and connectionless networks?
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What is the primary advantage of using fixed-size ATM cells in routing?
What is the primary advantage of using fixed-size ATM cells in routing?
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How does ATM ensure that cells arrive in the correct order?
How does ATM ensure that cells arrive in the correct order?
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What is a significant drawback of ATM cells compared to variable-length IP packets?
What is a significant drawback of ATM cells compared to variable-length IP packets?
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What is the typical speed of ATM networks that was specifically chosen for HDTV transmission?
What is the typical speed of ATM networks that was specifically chosen for HDTV transmission?
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In ATM networking, what happens to the cells once they reach their destination?
In ATM networking, what happens to the cells once they reach their destination?
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Which architectural feature is characteristic of ATM networks?
Which architectural feature is characteristic of ATM networks?
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What is one of the benefits of small size cells in ATM networks?
What is one of the benefits of small size cells in ATM networks?
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What type of service does ATM provide compared to the Internet in terms of packet delivery?
What type of service does ATM provide compared to the Internet in terms of packet delivery?
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What was the primary reason that X.25 networks were deployed in the 1970s?
What was the primary reason that X.25 networks were deployed in the 1970s?
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Which characteristic is NOT associated with Frame Relay?
Which characteristic is NOT associated with Frame Relay?
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What is the main application of Frame Relay technology?
What is the main application of Frame Relay technology?
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Which of the following describes ATM technology?
Which of the following describes ATM technology?
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What distinguishes X.25's data packets from those in Frame Relay?
What distinguishes X.25's data packets from those in Frame Relay?
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What major disadvantage did X.25 face during its operation?
What major disadvantage did X.25 face during its operation?
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In which decade did Frame Relay primarily emerge as a replacement for X.25?
In which decade did Frame Relay primarily emerge as a replacement for X.25?
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Which of the following statements best explains why a flat monthly rate with unlimited calling could benefit a telephone company?
Which of the following statements best explains why a flat monthly rate with unlimited calling could benefit a telephone company?
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Study Notes
Communication Systems and Computer Networks (1404703) - Part 5
- Course Title: Communication Systems and Computer Networks
- Course Code: 1404703
- Instructor: Prof. Shawkat K. Guirguis
- Part: 5
- Date: 2024-11-04
Example Networks
- Internet
- X.25, Frame Relay, and ATM
- Ethernet
- IEEE 802.11 (wireless LAN standard)
The Internet
- History: Evolved from ARPANET. Its subnet included minicomputers (IMPs - Interface Message Processors). IMPs connected with 56 kbps. For reliability, each IMP was connected to at least two other IMPs. It was a datagram network, eventually evolving to the World Wide Web.
The ARPANET (2)
- Design: Show diagram of the original ARPANET design. Includes host-IMP protocol, Host-host protocol, IMP-IMP protocol, Subnet, and IMP elements.
The ARPANET (Diagram)
- Shows a visual representation of the ARPANET's structure and components. Specific nodes (e.g., UCLA, SRI, etc.) are visible.
Connection-Oriented Networks
- Conflict: A historical tension exists between proponents of connectionless (datagram) and connection-oriented subnets.
View 1: Connectionless Subnets
- Motivation: The ARPANET/Internet community prioritized fault tolerance as a result of the intention for network survival in case of nuclear attack which eliminated the need to consider customer billing.
- Approach: Each packet routed individually, independently of others. If routers fail, further packets find alternate routes.
View 2: Connection-Oriented Subnets
- Model: Telephone model, where connections must be established prior to sending data and maintained throughout the transmission.
- Characteristics: All data/packets travel along the same path; disrupted if any link fails.
Why do Telephone Companies Like Connection-Oriented Networks?
- Quality of Service: Guaranteed service during a call (no dropped calls).
- Billing: Simple charging based on connection time/duration.
Quality of Service
- Resource Reservation: Setting up connections in advance allows reservation of resources (buffers, CPU cycles) to guarantee better performance.
- Busy Signals: Insufficient resources result in rejection, indicated by a busy signal.
- Connectionless Problems: In a connectionless network, if overloaded, routers drop packets, resulting in choppy and poor quality service.
Billing
- Charging Model: Traditional phone systems charge per connection duration (per minute) for long-distance calls.
- Complexity: Maintaining records for different users in a connectionless model is more complex (requires logging each data packet), making a per minute model simpler.
X.25 and Frame Relay
- X.25: First connection-oriented public data network. Deployed during the 1970s. Telephone companies expected one data network per country. Required a connection for every data transfer, like a telephone call. Each connection was given a unique number.
- Frame Relay: Replaced X.25. Connection-oriented with no error or flow control. Packets sent in order. A Wide Area LAN analogue.
X.25 & Frame Relay (cont.)
- Packet Format: Data packets were relatively simple, with a header (12-bit connection number, packet sequence number, acknowledgement number, and bits) and up to 128 bytes of data.
- Success: X.25 networks enjoyed moderate success for a time before giving way
Asynchronous Transfer Mode (ATM)
- Importance: More important connection-oriented network than X.25 and Frame Relay. However, unlike telephone systems (synchronous), ATM is connection-oriented.
- Goal: Integrate all types of communication (voice, data, cable TV, etc.) through a single advanced networking system.
ATM (cont.)
- Problems: Bad timing, technology, implementation, and political/regulatory issues contributed to the difficulties in implementing ATM.
- Outcome: ATM has been successful in handling certain types of networking within larger networks, but it hasn't succeeded in everything from a commercial perspective as a major worldwide networking solution.
ATM Virtual Circuits
- Connection Establishment: Prior to sending data, a connection packet sets up routing.
- Resource Reservation: As the setup packet travels, the routers reserve resources (e.g., buffer space).
ATM Virtual Circuits (cont.)
- Virtual Circuits: Equivalent to physical circuits in telephone systems. Each connection has a unique ID. Either side can send data after establishing a connection.
- Cell Format: Fixed-size cells (53 bytes) comprised of a header (5 bytes) for connection identifier, and payload (48 bytes) of data. Routers can easily manage these fixed-size cells.
ATM Virtual Circuits (cont.)
- Cell Routing: Cell routing is done in hardware, very rapidly, to speed up data transfer.
ATM Virtual Circuits (cont.)
- Cell Delivery: In ATM, cells follow the same route and arrive in order. However, cells' delivery is not guaranteed.
ATM Virtual Circuits (cont.)
- Common Speeds: Most typical speeds were 155 Mbps and 622 Mbps. 155 Mbps was chosen to match HD TV speeds. 622 was developed to support several 155 Mbps channels. Chosen to accommodate AT&T SONET systems.
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Description
This quiz covers the fifth part of the Communication Systems and Computer Networks course, focusing on various network types such as the Internet, X.25, and Ethernet. It also explores the historical development of the Internet from ARPANET, including detailed diagrams and protocols. Test your knowledge on these essential components in network communication.
