Lecture 1

Question 1

Define a network protocol

and define PDU

Answer 1

They define communication rules, format and control the data exchange.

Protocol Data Unit

Question 2

Describe LAN

Answer 2

Local area network
Deployment
- Enterprise, Business, Public Hot-Spots

Technologies

• Ethernet (IEEE 802.3)
• WiFi (IEEE 802.11)

Question 3

Advanatges of LAN?

Answer 3

o Low Cost

o Small distances among the nodes, High Data Rates and less complex in terms of management

Question 4

dESCRIBE WAN and MAN

Answer 4

Wide area network

Metropolitan area network

Question 5

Describe Enterprise networks (Ethernet)

Answer 5

typically used in companies, universities, etc.
▪ 1Gbps/10Gbps transmission rates
▪ today, end systems typically connect into Ethernet switch

Question 6

Describe Layer 1: Physical Layer

Answer 6

Defines physical medium and interfaces
• Determines how bits are represented
• Controls transmission rate & bit synchronization
• Controls transmission mode: simplex, half-duplex, & full duplex
• Devices: hubs, cables, connectors, etc…

Question 7

Describe Layer 2: Data Link Layer

Answer 7

• PDU: Frames
• Keeps Link alive & provides connection for upper layer protocols
• Based on physical address space
• Physical addresses are fixed and don’t change when the node is
moved
• Medium/media access control
• Devices: switches, bridges, NIC’s

Question 8

Describe Layer 3: Network Layer

Answer 8

PDU : Packet
• End to end delivery of packets
• Creates logical paths
• Path determination (routing)
• Hides the lower layers making things hardware independent
• Uses logical hierarchical addresses
• Devices: routers, firewalls

Question 9

Describe Layer 4: Transport Layer

Answer 9

PDU: Segment
• Service Point Address used to track multiple sessions between the same systems.
SPA’s are used to allow a node to offer more than one service
• Must reassemble segments into data using sequence numbers
• Can use either connectionless or connection-oriented sessions
• Connectionless sessions rely on upper layer protocols for error control and are often
used for faster less reliable links

Question 10

Describe Layer 5: Session Layer

Answer 10

This layer establishes, maintains, and terminates sessions between
applications
• Sets duplex between applications
• Defines checkpoints for acknowledgements during sessions between
applications
• Multiple connections can be treated as one virtual session.
• Identifies raw data as either application data or session control information
• Uses fields provided by layers 3 & 4 to track dialogs between applications /
services
• Provides translations for naming services

Question 11

Describe Layer 6: Presentation Layer

Answer 11

• Data formatting, translation, encryption, and compression

* Ex: ASCII, HTML, JPEG

Question 12

Describe Layer 7: Application

Answer 12

Provides communication services to applications

• Examples: Video Streaming, VoIP