Zusammenfassung der Ressource
1.5 Network Topologies, Protocols and Layers
- reasons why you may have chosen to use a Star network topology
- • They are very reliable
- • If one connection fails it does not affect the rest of the network
- • It is relatively easy to add additional devices onto the network
- • It is relatively fast as each device has its own connection to the
switch / server.
- • There are few data collisions
- disadvantages of using a Star network topology instead of a Mesh network
topology
- • There is a high level of dependence on one single, central device.
- • If the central device fails the whole network will fail.
- • The use of a switch or router could increase the cost of the whole network.
- • The performance of the network will be dependent upon the specification of the central device /
switch.
- • The number of additional devices that can be added to the network could be restricted by the central
device / switch.
- protocol
- A set of rules that govern how devices communicate
- protocol that is used to transmit data between different networks
- Transmission Control Protocol / Internet Protocol. TCP/IP
- POP
- Post office protocol.
- HTTP and HTTPS
- HTTP transmits data over the internet in a unsecure format whereas HTTPS
uses encryption so that any data that is intercepted is meaningless
- Data is transmitted across a network in packets. Three
items that each data packet will contain
- Network address source
- Network address destination
- Packet number / sequence
- Payload
- HTTP
- Used by web browsers to communicate with web servers.
- IMAP
- Used to retrieve emails
- SMTP
- Used to send emails
- Protocols are divided into layers. Why are
layers used
- Network communication components are standardised which helps to
ensure that different types of hardware and software are able to
communicate.
- Through separating the overall network
communication processes it makes
troubleshooting easier should an error occur
- • To ensure that if changes are made in one layer they
do not affect any other layers
- Through dividing overall network communication into smaller,
individual components it makes the software development process
more straightforward.
- Packet switching is used to send data on the internet
- The difference between an IP address and a MAC address
- A MAC address is permanently assigned to a device on the
network whereas an IP address may change when the device
joins a different network.
- Devices may have either a
static or dynamic IP address
- A static IP address never changes, whereas a dynamic IP address may change
when you log on to a network or change networks.
- FTP
- File Transfer Protocol.
- POP3
- Post Office Protocol version 3
- To retrieve emails, only award the
mark for retrieve (or similar). The
protocol cannot be used to send
emails
- steps of sending a packet