OSI Model

What is transmitted information referred to at layers 5, 6, and 7 of the OSI model?

Data

What is transmitted information referred to at layer 4 of the OSI model?

Segments

What is transmitted information referred to at layer 3 of the OSI model?

Packets

What is transmitted information referred to at layer 2 of the OSI model?

Frames

What is transmitted information referred to at layer 1 of the OSI model?

Bits

Physical Layer (Layer 1)

Where transmission of bits across the network occurs and includes physical and electrical network characteristics.

Asynchronous communication

Uses start and stop bits to indicate when transmissions occur from the sender to the receiver.

Synchronous communication

Uses a reference clock to coordinate the transmission by both sender and receiver.

Broadband

Divides bandwidth into separate channels

Baseband

Uses all available frequencies on a medium to transmit data.

What layer do hubs, access points, and media converters operate on?

Layer 1

Data Link Layer (Layer 2)

Packages data into frames and transmits those frames on the network.

Logical Link Control (LLC)

Provides connection services and allows acknowledgement of receipt of messages.

Isochronous communication

Network devices use a common reference clock source and create time slots for transmission.

What layer do Network Interface Cards, bridges, and switches operate on?

Layer 2

Internet Control Message Protocol (ICMP)

Sens error messages and operation information to an IP destination.

At what layer do routers and multi-layer switches operate?

Layer 3

What is information called when being transported using a TCP connection?

Segment

What is information called when being transported using a UDP connection?

Datagram

Windowing

Allows the clients to adjust the amount of data in each segment to maximize throughput.

At what layer do TCP and UDP operate?

Layer 4

At what layer to WAN accelerators, load balancers, and firewalls operate?

Layer 4

Session Layer (Layer 5)

Keeps conversations separate to prevent intermingling of data.

H.323

Used in layer 5 to setup, maintain, and tear down voice and video connections.

Real-Time Transport Protocol (RTP)

Layer 5 protocol used to stream audio/video.

NetBIOS

Used in layer 5 to share files over a network.

Presentation Layer (Layer 6)

Formats the data to be exchanged and secures that data with proper encryption.

Application Layer (Layer 7)

Provides application-level services where users communicate with the computer.

Application Services

Unites communicating components from more than one network application. S

Service advertisement

Sending out of announcements to other devices on the network to state the services they offer.

Protocol Data Unit (PDU)

A single unit of information transmitted in a computer network.

What is added to a PDU as it goes through the transport layer?

Source and destination ports.

What is added to a PDU as it goes through the network layer?

Source and destination IP addresses.

What is added to a PDU as it goes through the data link layer?

Source and destination MAC addresses.

At what level of the OSI model do Ethernet and USB operate?

The physical layer (Layer 1)

At what level of the OSI model does PPP, ATM, and Ethernet operate?

The data link layer (Layer 2)

At what level of the OSI model do IP, ARP, ICMP, and IPsec operate?

The network layer (Layer 3)

At what level of the OSI model does TCP and UDP operate?

The transport layer (Layer 4)

At what level of the OSI model do Netbios, PPTP, and PAP operate?

The session layer (Layer 5)

At what level of the OSI model do SSL and TLS operate?

The presentation layer (Layer 6)

At what level of the OSI model do HTTP, FTP, DNS, SNMP, and Telnet operate?

The application layer (Layer 7)