Briefly describe the OSI model and its importance when discussing network security.

OSI model is a hypothetical networking framework that uses specific protocols and mechanisms in every layer of it.

Explanation:

This model is used to divide the network architecture into seven different layers conceptually, these layers are: physical, data link, network, transport, session, presentation and application. In every layer, there also involves some security postures and mechanisms that a security professional must know to detect and put the secutiry method effectively.

The implementation of security methods within the OSI model starts with the first three layers of the OSI model called the media layers, which are: physical, data link and network layer. The physical layer is used for defining the technical qualifications of the data connectivity. Since the security in this layer is critical, it is recommended to unplug the cable of the primary sistem.

The data link layer is a comprises of data packets transported from the physical layer. Any colapse in this layer or data breach can impede the working of the network layer. Vulnerabilities that can be used and attacks that can be made in this layer are MAC address spoofing as well as Virtual LAN circumvention.

The network layer is the last one, and has an association with the real world. It deals with addressing and routing of packets. Strengthening this layer needs techniques of firm anti-spoofing, proper implementation of firewalls and routing filters as well as secure routing protocols.

Every layer needs proper security postures. Different ports and protocols are used for different situations.