That is the first lecture so sir only just discuss the Basics and the OSI Model and client server model definations which we discuss in first semester.
The client–server model of computing is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients
Open Systems Interconnection model(OSI Model):
is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers.
Then we discussed Guided and Un-Guided media.
Guided Transmission Media
Waves are guided along solid mediumTwisted Pair
- Pair of twisted conductors
- Twisting reduces interference (two parallel wires constitute a simple antenna; a twisted pair does not.)
- Cheap medium
- Commonly used for communications within buildings and in telephone networks
- Produced in unshielded (UTP) and shielded (STP) forms, and in different performance categories.
- Cables may hold hundreds of pairs. Neighbor pairs typically have different twist lengths to reduce crosstalk.
Coaxial Cable
Pair of conductors separated by insulation
- Offers longer distances and better speeds than twisted pair, due to better shielding.
- Used for cable TV and local-area networks. Had been widely used in telephone systems, but optical fibre is now assuming this task.
Unguided Media
Unguided media relates to data transmission through the air and is commonly referred to as wireless. The transmission and reception of data is carried out using antenna.
There are two main ways that antenna work:
- Directional (in a beam)
- Omnidirectional (all around)
Routing: Routing is the process of selecting best paths in a network. In the past, the term routing was also used to mean forwarding network traffic among networks.
Switches: In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.
Topology: Then we just go through the different topologies like ring ,bus , Mesh ,line , point to point , star etc.For more information click here : Toplogy .
Cross over and Roll over cable: Crossover is something that crosses transmit and receive pairs of a cable. Like in ethernet, or a serial cable (little more complicated!). In ethernet, pairs 1-2 cross with 3-6 on opposite ends of the cable crossing the TX/RX pairs. With a T1, it's 1-2 and 4-5 pairs.
A rollover cable simply has 1,2,3,4,5,6,7,8 on one side and 8,7,6,5,4,3,2,1 on the other side. It needs additional pieces (the DB-9 to RJ45 converters) to make it a null-modem cable (which is technically different than a crossover serial cable, but likely going to get into WAY too much detail to care about right now in your learning!).
