Lecture 10: Transport Layer, Security and Internet Applications Flashcards
Is the Transport Layer dealing with getting entire message from:
a) Network to Network
b) Device to Device
c) Process to Process
c) Process
Name two resposiblities of Transport Layer.
1) Segmentation and reassembly (packetisation).
2) Service point addressing (making sure message gets to correct port number of correct process).
Which layer is resposible for:
a) Errors inside single network?
b) Errors inbetween networks?
a) Datalink.
b) Transport.
What are three factors of error control that sequence numbers look after?
Sequence control, packet loss control and duplication control.
What does UDP stand for and is it connectionless or connection-oriented?
User Datagram Protcol and connectionless. Used for streaming.
What does TCP stand for and is it connectionless or connection-oriented?
Transmission vControl Protocol and connection-oriented.
What are the two resposibilities of the Session layer?
1) Dialog control: determining whether half-duplex or full-duplex (one way or two way comms, respectively).
2) Synchronisation: defines sync checkpoints in case of error or disaster recovery.
What are the three resposibilities of the Presentation layer?
1) Translation: translating between character sets.
2) Encryption: for security purposes.
3) Compression: reducing data size for efficiency purposes.
Name some different genres of security.
Computer security, computer system security, network security, physical security, operational security, procedural security and comms security.
What is a symmetric algorithm with regards to security?
The encryption key is the same as the decryption key.
Name three characteristics for ensuring protected information.
Confidentiality (cryptography and steganography), integrity (hash functions), authenticity (digital signatures).
Does public key system use asymmetric or symmetric algorithm?
Asymmetric.
What is the application layer resposible for?
It is the interface between users and the network.
Name some application layer protocols on the internet.
Email, WWW, remote access, file transfer, address translation, host configuration.
Describe the client-server model.
There is a client application that can request information or resources from a server application. There can be many clients to a single server and client is usually only running when required whereas server is usually all the time.
What are the two types of clients? Describe t hem.
Fat clients: perform most of processing for themselves.
Thin clients: perform little or no processing for themselves.
What is the DNS format?
From right to left, 2 letter country code, then domain name, organistion’s name and computer’s name.
What does a VPN do?
It treats the internet as if it were your own LAN. It protects it and sometimes requires encryption.
Name some types of email applications.
Simple Mail Transfer Protcol (SMTP), Multipurpose Internet Mail Extension (MIME), Post Office Protocol (POP)
What is remote access? Name two types.
Remote access allows a user to remotely log into and operate a computer from another one. SSH and TELNET.
What are the two connections that File Transfer Protocol establishes?
Control connection and data transfer connection.
What is the most common format for toring information pages on the WWW?”
Hypertext Markup Language (HTML)
What protocol must a web browser use to make requests to a web server?
Hypertext Transfer Protocol (HTTP)
