TCP/IP & other protocols [A Level]

The ​ (a)   layer is used to provide ​ (b)   for applications that want to ​ (c)   across a ​ (d)   , often the Internet.

• application
• services
• communicate
• network

SMTP (for e-mail), FTP (for file transfer) and HTTP (for web browsing) all operate on which layer?

• Internet

• Transport

• Application

• Link

The transport layer uses the ​ (a)   to establish an ​ (b)   with the recipient computer. It ​ (c)   into packets and ​ (d)   them sequentially. Adds the ​ (e)   to be used based on the HTTP protocol.

• Transmission Control Protocol (TCP)
• end‐to‐end connection
• splits data
• numbers
• port number

Reorder the following (1 being the first layer, 4 being the last)

• Link

• Application

• Transport

• Internet

The ​ (a)   layer uses the ​ (b)   to address packets with the source and ​ (c)   IP addresses. A router forwards each packet to an endpoint called a ​ (d)   defined by the combination of IP address and ​ (e)   .

• network
• Internet Protocol (IP)
• destination
• socket
• port number

This layer operates across a physical connection.

• Application layer

• Link layer

• Network layer

• Transport layer

When receiving data at the destination:

The Link Layer removes the ​ (a)   from each packet and passes it to the Network Layer. The Network Layer removes the ​ (b)   from each packet and passes it to the ​ (c)   Layer. The Transport Layer removes the ​ (d)   from each packet, reassembles the packets in the correct order and passes them to the Application Layer. The ​ ​ (e)   Layer presents the data for the user in a browser.

• MAC address
• IP address
• Transport
• port number
• Application

A ​ (a)   uniquely identifies a ​ (b)   device with a Network Interface Card (NIC). This may be the ​ (c)   computer, or a ​ (d)   in transit. Packets move up and down the lower layers of the stack as they hop across routers, changing their source and ​ (e)   MAC addresses as they go

• MAC address
• physical
• destination
• router

Match the following port number with the protocol...

• IMAP

• 80

• HTTP

• 20

• FTP

• 143

• SSH

• 443

• HTTPS

• 22

File Transfer Protocol is an ​ (a)   level protocol used to ​ (b)   across a network. FTP uses the ​ (c)   model with separate data and control ​ (d)   operating on ports 20 and 21. Usernames and passwords are frequently used to protect access to files and to identify users. Access can also be provided ​ (e)   where any user can access the FTP site.

• application
• move files
• client server
• channels
• anonymously