TCP & UDP

What is the primary function of the Application Layer?

The Application Layer contains protocols that perform high-level functions, such as configuring and managing network hosts and operating services like the web and email.

What is used by each application protocol to allow a client to connect to a server?

A TCP or UDP port.

• What is the purpose of application protocols in the TCP/IP suite?

They are used to configure and manage network hosts and to operate services.

What are some examples of services operated by application protocols in the TCP/IP suite?

Services include the web and email.

How does a client connect to a server using an application protocol?

Each application protocol uses a TCP or UDP port to allow a client to connect to a server.

What is the primary function of the Internet Protocol (IP)?

IP provides packet addressing and routing within a network of networks.

What is an "end system host"?

A device, such as a PC, laptop, mobile device, or server, that can communicate on an IP network.

What is the role of a router in an IP network?

A router is an intermediate system that forwards data from one IP network to another.

What is the purpose of the Address Resolution Protocol (ARP)?

ARP is a function that allows a host to query which MAC address is associated with an IP address, enabling message delivery from the Internet layer to the Link layer.

What are the key characteristics of IP's delivery method?

IP provides best-effort delivery, which is unreliable and connectionless. Packets may be lost, delivered out of sequence, duplicated, or delayed.

• What is the primary responsibility of the Link layer?

• Putting frames onto the physical network.

• What types of protocols are not contained within the Link layer?

• TCP/IP protocols.

Name some local networking products and media that operate at the Link layer.

Ethernet, Wi-Fi, and WAN interfaces such as DSL and cable modems.

Where do communications on the Link layer take place?

Only on a local network segment, not between different networks.

What is data at the Link layer packaged in, and what identifies node interfaces?

Data is packaged in a unit called a frame, and node interfaces are identified by a MAC address.

What is the primary function of the Transport layer?

The Transport layer determines how each host manages multiple connections for different application layer protocols at the same time.

What are the two main protocols used by the Transport layer?

The two main protocols are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

What are the key characteristics of Transmission Control Protocol (TCP)?

• Guarantees connection-oriented forwarding of packets.

• Identifies and recovers from lost or out-of-order packets.

• Mitigates the unreliability of IP.

• Used by most TCP/IP application protocols.

What are the key characteristics of User Datagram Protocol (UDP)?

• Provides unreliable, connectionless forwarding.

• Faster and has less transmission overhead than TCP.

• Used in time-sensitive applications like speech or video where some packet loss can be tolerated.