Physical Layer In Network (CCNA)

Open Systems Interconnection Model (OSI)

Physical Layer In Network CCNA
Physical Layer In Network CCNA


Open systems interconnection model (OSI)

Set of rules applied globally over the world, how network should be build.

Open systems interconnection model have 7 layer :-

  1. Physical Layer
  2. Data Link Layer
  3. Network Layer
  4. Transport Layer
  5. Session Layer
  6. Presentation Layer
  7. Application Layer

Data link layer, network layer and transport layer stands for CCNA.

First Starting With :-

Physical Layer :-

devices you can touch.

  1. Cables :-

  • A. X base T cable :- Known as Ethernet Cable.

X :- stands for the speed of cable (how much mb can transmit per second).

Base band singling :- (only can be one signal on wire at a time), broad band signalling can be more than one signal at a time

T Twisted pair :- wire twisted together, more twisted wire means more copper, mean more clean signal

Types of X base T cabling :-

  • Straight through cable
  • Cross over cable

Similar devices type will use cross over cable between them, different devices type will use straight through cable between them.

  • There is also unshielded cable and shielded cable of X base T cabling :-

Shielded cable :- used in places that have electric magnetic field interference Like air condition unit.

  • B. Serial cable (v.35) :- used in connecting serial port on router (between router and another router).
  • C. Rollover cable (console cable) :-

connect console port of a sisco device to the computer (communication port), this cable enables you to connect directly to router and you can open up a terminal emulation program.(between computer and router)

CCNA physical layer, repeater device and hub device.

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