MIS140 - Exam 1

Transport

• Deals with end-to end issues such as segmenting the message for network transport, and maintaining the logical connections between sender and receiver. • Links application layer to the network with end to end connections. • Network address translation • Breaks long messages into packets • Ensures packet delivery and flow control

Physical

• Defines how individual bits are formatted to be transmitted through the network • Actually move bits

Media Access Control

AKA MAC, controls the flow of information by using ACKS for good packet or NAKs for bad packet, which require retransmission. Such as stop and wait ARQ or contineous ARQ

You decide to create your own protocol for Data Link Layer. Define the fields necessary for your protcol

Data Start Length Destination Address Control EDV Vlan Source Address

Give a specific example of 'header' information that would be optional in a HTTP request/response cycle

Date: Sept. 27, 2012 Server Information: Apache 2.2 URL: http://www.yahoo.com Content Type: Text/HTML

Data Link

Deals with message delineation, error control, and network medium access control.

Presentation

Formats data for presentation to the user. Provides data interfaces, data compression and translation between different data formats. Encryption/decryption

Give a specific example of 'header' information that would be required in a HTTP request/response cycle

HTTP version: version 1.1 Status Code: 202 Response: Ok

Message delineation

Indicates when the message starts and stops. Also contains EDV for errors, source address, and other functions in the frame.

Presentation

Name the layer where SSL encryption occurs

Transport

Name the layer where ensuring end to end reliable packet delivery occurs

Data Link

Name the layer where media access control occurs

Application

Name the layer where message creation occurs

Data Link

Name the layer where message delineation occurs

Physical

Name the layer where moving bits occurs

Physical

Name the layer where multiplexing occurs

Network

Name the layer where routing occurs

Transport

Name the layer where segmentation occurs

Session

Name the layer where the accounting occurs

Application

Provides a set of utilities used by application programs. Create, send, and respond to messages. Network monitoring and management.

Session

Responsible for initiating, maintaining and terminating each logical session between sender and receiver. Session accounting and logging.

Network

Responsible for making routing decisions. Choose the best route through the network Identification of hardware layer address.

Assume that we are trying to multiplex three logical circuits onto a DS-0, or 64kbps, circuit. If our single criterion is to minimize data transmission time, which method, FDM, or TDM, would you recommend? Why?

TDM because FDM uses guardbands that take away from thecircuit and it is at 3 logical circuit, it allows more frequent time to switch back.

What six factors are used to select the most appropriate media for communication

Type of network Cost Transmission distance Security error rates Transmission speed.

Error control

contains EDV for checking for errors in the message by using mathematical calculations such as checksum. If a error is detected, the packet will retransmission.

In clean, error free, and interference free analog transmission, what three basic factors could be changed to obtain a higher data rate

increases wave/second decreases wave/symbol increases bit/symbol