1. Networking, Part Two Two

2. 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?

3. Fiber Terminations Round ST Square SC

4. 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

5. 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

6. Typical connection

7. Hubs Input on one port (does not matter which port) Signal is amplified and sent out on all ports Easy way for long cable runs run-hub-run Initially very expensive, have gotten cheaper over time and are now seldom used

8. Switches Successor to hub Automatically creates point-to-point connection between any two ports Again, price has come way down

9. Bridges Started out as hubs that could connect different media (coax and UTP) Developed into switches Now have intelligence that can do simple routing

10. NAS Network Attached Storage Just shares files (hard disk storage) Can be headless – no keyboard, video or mouse Use some form of Web interface to configure Also called Network Appliance

11. Routers Must have at least two connections – one into a network and one out to another network Hello, CISCO; when you go beyond the home

12. 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

13. Structured Components Telcom room – place where all wires lead to Horizontal cabling – from telcom room to PCs Work areas – where the PCs are

14. Horizontal Cabling Use solid core wire – better conductor but stiff Away from the dreaded vacuum cleaners!

15. 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 out

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

17. 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

18. TCP/IP review Dotted decimal notation Subnet mask to identify network number and node number Class A: 1-126 Class B: 128-191 Class C: 192-223 TCP is connection-oriented; UDP is connectionless (User Datagram Protocol)

19. TCP/IP Services HTTP – HyperText Transfer Protocol Telnet – Allows remote access to a device Ping – Can one host reach another? Tracert – How to get from one point to another Most services are command-line based

20. DHCP Dynamic Host Configuration Protocol Will assign IP address, DNS server(s) and other configuration data Your home router does this function

21. Automatic Private Addressing Automatic Private IP Addressing (APIPA) When you can’t see (reach) a DHCP server 169.254.X.X - X and X are random numbers less than 255 Will broadcast the address to see if anyone else is using it Can only talk to other 169.254’s

22. IPv6 Not just a superset of IPv4; uses 128 bits Always has eight groups of four hexadecimal characters Leading zeros can be dropped from any group Can drop group(s) of zeros and replace with :: - but only once in an address V6 loopback address ::1 Subnet mask uses Classless Inter-Domain Routing (CIDR) where /x is the number of bits in mask

23. More IPv6 Computer boots and assigns itself a link-local address (FE80:: ) – first 64 bits

24. IPv6 Last part of address is, for Windows, a random value for the last 64 bits. Another way to do it is to use MAC address called Extended Unique Identifier, 64 bit or EUI-64 The last 64 bits are node so subnet is never longer than /64 IANA passes out /32 subnets to big ISPs and end users; ISPs had out /48 and /64 subnets Subnet Masks are mostly between /48 and /64

25. Global Addresses Need a GA to get to Internet Easiest way is to request it from default gateway router with Router Solicitation message (FF02::2) Router responds with Router Advertisement which is its network ID and subnet (and DNS) Computer generates the rest of address as before (random or MAC)

26. Wired Network NIC – The physical hardware that connects the computer system to the network media Protocol – The language that the computer systems use to communicate Network Client – The interface that allows the computer system to speak to the protocol

27. NIC Expansion card or built-into the motherboard Windows will recognize, configure and provide driver(s) for most current NICs If not, Add Hardware Wizard will automatically run and ask for driver media If you have to run the Add Hardware Wizard, you did something really, really wrong Duplex – both talk and listen Half-duplex – talk or listen

28. Link Lights Can have one to four, any color(s) Give status – something will light up when cable is connected at both ends If no lights, you have network problems to fix (first place to look) Switches also have link lights so you can check both ends of connection Solid green means connectivity; flashing green means intermittent connectivity

29. Wake on LAN Send either a special pattern or “magic packet” Have to configure both Windows (network) and CMOS to have this work

30. Sharing Drives and Folders Set both the Network and NTFS permissions; set Network to everyone full control then tune with NTFS permissions Can map a network location to a drive letter Make sure File and Printer Sharing is turned on

31. UNC Universal Naming Convention : universal to Microsoft anyway \\server\resource

32. NET command Type NET at command prompt

33. NBTSTAT NetBIOS over TCP/IP Statistics NetBIOS long gone but command remains Useful to see what is connected to network

34. Troubleshooting For exams: it is getting a computer back on the network Need to take a giant leap up in quality of skills Is it the computer, the network, or both?

35. Losing Physical Connectivity Pretty obvious in Windows with red Xs and dialog boxes Can also find link lights out on network connection Is cable unplugged at either end? Is NIC disabled in Device Manager? If you only see yourself in Network Discovery Check if any other stations are down Failed NIC can lose connectivity

36. Cable Testing Many disconnect problems are in the patch cable to the wall Midrange Time-Domain Reflectometer (TDR) can be handy to pinpoint break in cable Replace the whole cable, don’t try to patch it (pun intended!) Use a tone-tester to find other end of a cable

37. Fail to connect to New Resource Often a configuration issue – make sure it is shared correctly Make sure you have valid user and password Do you have permission(s)? Correct homegroup/domain/workgroup?

38. Fail to connect to used resource Try nbtstat –s Try net view Check that serving system is on and connected to network