An overview of the major components Networking An overview of the major components

Names Your computer (in front of you) is the local host You access “stuff” on remote computers, called servers; your computer becomes a client Servers have different roles: web server, video server, file server, etc

Issues How will each computer be identified? How will you control who talks and when? What kind of wire? How many wires in cable? What type of connectors? When two PCs access one file, what happens? How can access to data and peripherals be controlled?

The parts We need a client; a PC that is requesting information or services We need a Network Interface Card (NIC)to identify client; a way to break files into packets for transmission and reassemble packets We need wire/cables or some method to get data from point A to point B PC Operating System has to understand and communicate over the network We need a server

Topologies

Frames and NICs Data is moved in frames, much as you would move your belongings in boxes between apartments Every NIC has a Media Access Control address (MAC) that is unique; 48-bits long as 12 hex characters Frame MAC to MAC from Data CRC

Hardware Protocol Network Technology Defines the packet type Defines cabling and connectors used Defines everything necessary to get data from one computer to another We have two: Ethernet and Token Ring

Ethernet Mid-70’s by Digital Equipment, Intel and Xerox Dominant standard, thanks to Internet Three versions: coaxial, unshielded twisted pair and fiber optic Because frame type is constant, versions can be mixed on the network

Token Ring Developed by IBM Centered on communication with mainframe systems Completely incompatible with Ethernet Used to connect to IBM’s “Big Iron” systems and thus is far from dead More on this later

UTP Ethernet 10BaseT, or 100BaseT, or 1000BaseT 10-, 100-, 1000Mbps (1 Gbps) Uses a star bus topology, typically Use Unshielded Twisted Pair (UTP) cable (4 pairs = 8 wires) Connect to Hub (or Switch) which contains the bus One PC per segment; 100 meters per segment

CAT levels What Mike does not tell you is that the number of twists per inch/foot Of cable increase as the CAT level increases

EZ-RJ-45 has holes here so wires stick out during assembly 1 Wiring Standards 8 EZ-RJ-45 has holes here so wires stick out during assembly

More on cabling The space up in the false ceiling, in walls and under a raised floor is called a plenum space You should run plenum (non-toxic) cable in a plenum space It is 3x to 5x more expensive than PVC cable

Crossover Cable Connect two PCs without hub 1-3, 2-6, 3-1 and 6-2 or “A” on one end and “B” on the other Be sure to mark these cables! Note that only 4 wires are required

Hubs and Switches In a star bus network, all devices connect to a central hub or switch (now that prices have come down). Max 1024 devices to a switch. When a wire breaks, only that device looses the network connection – the rest of the network remains functional Hubs act as repeaters, amplifying the signals – can use them to extend cable runs past 100 meters (~360 feet) They need electrical power…or PoE Hubs rebroadcast signal to all ports; switch tries to be selective

Duplex Full-duplex: can both send and receive at the same time Half-duplex: either send or receive – like “push to talk” phones

Fiber Optic Ethernet Uses light to transmit data therefore immune to noise and grounding issues Up to 2000 meters cable length Used for “backbone” runs Half-duplex, so need two cables Tends to be delicate, expensive and difficult to use – shows up in data centers and seldom on desktops What is Verizon doing with Fios?

Fiber Terminations Round ST Square SC LC

Fiber Modes LED-based light source uses Multimode cable – multiple light signals at the same time each using a different reflection angle Good for short distances Laser light-based use single-mode; high transfer rates over long distances but rare Most fiber cable is multimode; delicate and expensive

Coax/BNC Old form of networking – did not require hub/switch; still used in cable modems, TV and satellite connections Type F connectors used in cable modems, etc. screw together BNC connectors are quarter-turn Can be RG-6 or RG-59 (thinner); 75-ohm impedance

Typical connection

Structured Cabling The idea is to create a safe, reliable cabling infrastructure for all of the devices that need interconnection Start with switches, cabling and PCs Components of a network, such as how the cable runs through the walls and where it ends up Connections leading outside your network Standards from TIA/EIA

Structured Components Telcom room – place where all wires lead to Horizontal cabling – from telcom room to work area (run) Work areas – where the PCs are

Horizontal Cabling Use solid core wire – better conductor but stiff Away from the dreaded vacuum cleaners! Idea is that it does not get moved around very much, if at all

Telco Room Equipment racks – from railroad days – 19” wide Tall: 1.75” – called a U Devices are 1U, 2U or 4U – mostly Patch Panels allow wiring punchdown on back side and patch cables on the front side Patch panels have CAT rating, so check it

RJ-45 Jack Crimping Take Network+ , Cisco or follow the book’s figures EZ-RJ-45 jacks may be more expensive, but they are worth every penny

Work Area Wall plate to terminate horizontal run Plates have CAT ratings too Mike suggests looking here first if the user has lost connection to the network