Course ILT Network cabling and devices Unit objectives Discuss network communication methods Identify the characteristics and appropriate implementation techniques of various types of cables and connectors Discuss coaxial and fiber optic cables (and, of course, UTP – unshielded twisted pair, AKA CAT3, 5, 5e, 6, 6e, 7, etc.) Discuss Ethernet and Token Ring devices

Course ILT More on Full Duplex Benefits The bandwidth of a full-duplex communication is more than double that of half-duplex: –first, for example, if you have a 10Mbps network, the bandwidth is 10 Mbps is each direction, or effectively, 20 Mbps. –second, full-duplex only works with point- to-point links; i.e., you cannot, for example, implement CSMA/CD using full- duplex. The very nature of CSMA/CD suggests that every host listens and then only one host transmits.

Course ILT Full Duplex Benefits (continued) On a LAN, full-duplex is normally implemented on a switch port; with a WAN, full-duplex, point-to-point connections normally end at router interfaces. Because there are only two parties to a full- duplex communication, there are no collisions! Without collisions, there is no retransmission of data, further speeding the transfer rate. Finally, a host never has to wait for another host to finish transmitting before it can send! The further increases the “throughput”. (Distinguish throughput – the actual rate of transmission, from bandwidth and also from goodput.

Course ILT Topic A Topic A: Network communication methods Topic B: Cables and connectors Topic C: Coaxial and fiber optic cables Topic D: Ethernet and Token Ring devices

Course ILT Baseband vs. broadband The baseband transmission method uses the media in such a way that the entire capacity of the cable is taken up by a single transmission In broadband communications the communicators use different frequencies to separate their messages from others by using the same media at the same time

Course ILT Data signals can be sent over a network cable in one of two ways: broadband or baseband. Baseband signaling only sends a single signal over the cable. This type of signaling is typically used in Ethernet networks, (with the exception of 10Broad3 standard - rarely used). Baseband uses very simple transceiver devices that send and receive signals on a cable. The simplicity behind baseband signaling is that only three states need to be distinguished: one, zero and idle. Broadband transceivers are much more complex because they must be able to distinguish those same states, but on multiple channels within the same cable. Because of its simplicity, baseband signaling is used on most Ethernet networks. Baseband vs. broadband (cont)

Course ILT One way to look at the difference is based on the technology used. You can give someone 56k on a broadband service and give someone 11Mb on a Linksys WiFi router that is baseband networking! The distinctions are not always clear. –56k - dialup - narrowband, this includes the so-called compressed services that give you 300k downloads –128k - ISDN - narrowband, also a glorified dialup –DSL, Cable, Fixed Wireless(PTMP) - Broadband, these are carrier grade services offering anywhere from 56k - 5Mb. –WiFi – networking/baseband - While it is providing a fast connection it is just resending the broadband it is given to be shared by all. –T1, Fiber, P2P wireless – “Backhaul” - Not really broadband. Used to deliver connections from the internet to the broadband device or network. But it is broadband for test purposes; just remember all the frequency-hopping and switching in the various transmission methods. Baseband vs. broadband (cont)

Course ILT Broadband in telecommunications refers to a signaling method that includes or handles a relatively wide range of frequencies, which may be divided into channels or frequency bins. Broadband is always a relative term, understood according to its context. The wider the bandwidth, the greater the information-carrying capacity. For example, the FCC says 200 Kbps = broadband (even if in one direction!) Anything under that, however is not necessarily baseband; baseband is defined by the use of only one frequency. In terms of speed, though, <200K just isn’t fast enough to be labeled “broadband” – probably for consumer protection purposes Baseband vs. broadband (cont)

Course ILT So what we are left with is: –1. The use of multiple signals with a bandwidth greater than 200 Kbps is broadband. –2. The use of multiple signals with a bandwidth less than 200 Kbps is “narrowband”. –3. The use of a single frequency in a system than provides any level of bandwidth is baseband. –4. “Backhaul / broadband” – where your connection is essentially a delivery mechanism for a broadband implementation. Baseband vs. broadband (cont)

Course ILT Half-duplex vs. full-duplex Half-duplex communications need that each participant only transmits when the other is listening By using full-duplex communications, both parties can transmit simultaneously The benefit of full-duplex mode is less delay in transmitting a message, because a computer could receive and transmit information simultaneously

Course ILT Throughput, Bandwidth, & Goodput Bandwidth is the capacity for a given system to transfer data over a connection. Throughput is the average rate of successful message delivery over a communication channel. Goodput is the application level throughput, i.e. the number of useful bits per unit of time forwarded by the network from a certain source address to a certain destination, excluding protocol overhead, and excluding retransmitted data packets.

Course ILT Activity A-1 – (pg 5-3) Discussing communication methods

Course ILT Topic B Topic A: Network communication methods Topic B: Cables and connectors Topic C: Coaxial and fiber optic cables Topic D: Ethernet and Token Ring devices

Course ILT Twisted pair properties Twisted pair is made of insulated copper wires that have been twisted around each other to form wire pairs Twisted-pair cabling is divided into two categories –Unshielded Twisted Pair (UTP) –Shielded Twisted Pair (STP)

Course ILT Unshielded Twisted Pair (UTP) UTP is a set of twisted pairs within a plastic sheath The common use for this type of cable is telephone wiring and LAN communications Two popular UTP cabling types are Category 3 (all but obsolete) and Category 5 UTP (AKA “CAT5” and “CAT3”). Newer types include Category 5e and Category 6 (5e is no longer “new”; it is the defacto standard for new network installations, per the TIA/EIA. The TIA is the Telecommunications Industry Association and the EIA is the Electronic Industries Association.

Course ILT Unshielded Twisted Pair (UTP)

Course ILT UTP installation During UTP installation hardware connectivity is accomplished by using an RJ-45 connector. The wires in a CAT5, 6 or 7 cable, for example are arranged into pairs: each cable carries 8 wires, or 4 pairs. The classification as CAT 5, 6, etc. is made base on the number or the frequency of the twists in each wire! The twists in wire pairs in a UTP cable are put in to protect against electrical interference – from on wire affecting another. A cancellation effect. The interference is called “crosstalk”. More twists also allows longer cable runs.

Course ILT UTP installation: Note that the maximum length of an ethernet cable run using CAT 5e UTP is 100 meters. This length includes all three of the segments between the networking device – e.g., the router, and the workstation: next pg

Course ILT Max Distances for Horizontal Cabling (Using CAT5 UTP in an Ethernet network) 3 Meters – 90 Meters – 6 Meters 3 Meters: Work area patch cable. From computer to wall 90 Meters: What is considered the Horizontal Cabling. From wall outlet to the patch panel in the MDF or IDF – Main or Intermediate Distribution Facility (Server Room). 6 Meters: The patch cable that cross connects a patch panel (in the MDF)

Course ILT Shielded Twisted Pair (STP) STP includes a protective sheathing around the copper wire The twisted pair is wrapped in foil to cut down on outside interference (RFI – radio frequency interference) and electromagnetic radiation

Course ILT Twisted Pair IEEE (Token Ring) Originally, it used STP and the IBM hermaphroditic connectors (below), but has since been adapted to use UTP and RJ-45 connectors Token Ring networks run at either 4 Mbps or 16 Mbps

Course ILT Type 1 ( 2 twisted pairs, #22 AWG – American Wire Gauge)

Course ILT Type 2 ( 4 twisted pairs, #22 AWG – American Wire Gauge)

Course ILT Type 6 ( 2 twisted pairs, #26 AWG – American Wire Gauge)

Course ILT Activity B-1 – (pg 5-8) Discussing twisted pair cabling

Course ILT RJ-45 RJ-45 connector and Ethernet –For 10BaseT and 100BaseTX, pins 1, 2, 3, and 6 are needed to transport data. Of the 4 active pins, two are positive – one transmit (#1) and one receive (#3), and two are negative – again one transmit (#2) and one receive (#6). –With full-duplex, all 8 pins are used. RJ-45 connector and Token Ring –Many Token Ring cards have a modular connector. The active pin assignments are pins 3, 4, 5, and 6

Course ILT RJ45 Connectors

Course ILT Full-Duplex pinout Ethernet 1000BaseT (Twisted Pair Pinout) Pin #Signal NameFunction 1BI_DA+ i.e., Transmit/Receive, positiveBi-directional pair +A 2BI_DA- i.e., Transmit/Receive, negativeBi-directional pair -A 3BI_DB+ i.e., Transmit/Receive, positiveBi-directional pair +B 4BI_DC+ i.e., Transmit/Receive, positiveBi-directional pair +C 5BI_DC- i.e., Transmit/Receive, negativeBi-directional pair -C 6BI_DB- i.e., Transmit/Receive, negativeBi-directional pair -B 7BI_DD+ i.e., Transmit/Receive, positiveBi-directional pair +D 8BI_DD- i.e., Transmit/Receive, negativeBi-directional pair -D The wires are not necessarily bi-directional, i.e., you can have 2 positive transmit and 2 positive receive; the same is true for the negative wires: 2 to send and 2 to receive.

Course ILT RJ-45 (cont) The RJ-45 connector is also widely used for digital telephone sets, serial data transmissions, and many other applications. The standards for how ethernet cables are configured and wired are determined by the TIA/EIA – “Telecommunications Industry Association/ Electronic Industry Association.” The T568A and T568B standards, for example, determine the order in which the individual wires are arranged inside an ethernet cable: Orange, Orange/White, Green/White, Blue, etc.

Course ILT RJ45 pin positions

Course ILT RJ45 pin positions: Straight-through cable

Course ILT RJ45 pin positions: Crossover cable

Course ILT Other Twisted-Pair Cable connectors The classic Token Ring cable has a DB-9 connector at one end and an IBM-style hermaphroditic data connector at the other Some manufacturers use the RJ-11 and RJ-14 modular connectors RJ-11 is a 4-pin connector while RJ- 14 connectors have six pins (used for telephone jacks)

Course ILT RJ-11

Course ILT RJ-14

Course ILT Activity B-2 (page 5-12) Terminating with an RJ-45 connector

Course ILT IEEE 1394 (FireWire) External serial bus standard with speeds of up to 400 Mbps Apple Computer, Inc. trademarked the term FireWire for its 1394 products Most commonly used to connect peripherals to computers It is possible to connect two computers together for basic file sharing

Course ILT IEEE 1394 specifications Each FireWire port (bus) can support up to 63 devices The total number of buses that can be linked together is 1,024 Transfer speeds include 100 Mbps, 200 Mbps and 400 Mbps The supported distance for devices is 15 feet Can be extended by adding repeaters every 15 feet for a maximum distance of 225 feet

Course ILT IEEE 1394 cabling (& connectors) 6 wire STP –Two pairs of separately shielded twisted pairs –Two power wires –All encased in an overall shielded cable –Uses a 6-pin connector on both ends 4 wire STP –Same as 6 wire STP but without power wires –Uses a 4-pin connector on both ends

Course ILT IEEE 1394 cabling (& connectors) Another configuration uses either type of cable, with a 4-pin connector on one end and a 6-pin connector on the other Standard cabling is 28 AWG Supports both asynchronous and isochronous data transfer

Course ILT Activity B-3 (page 5-15) Discussing FireWire

Course ILT Topic C Topic A: Network communication methods Topic B: Cables and connectors Topic C: Coaxial and fiber optic cables Topic D: Ethernet and Token Ring devices

Course ILT Properties of coaxial cable Coaxial cable is composed of two conductors that share the same axis For proper functioning, coaxial cable must always be terminated at both ends and the outer conductor grounded at only one end Transmissions over coaxial cable might be either baseband or broadband

Course ILT Five Factors (page 5-17) –Cost: Moderate –Installation: Clumsy, compared to UTP –Capacity: Up to Fast Ethernet – 100 Mbps –Attenuation: Better than UTP. 2 types of coax: Thinnet or 10Base2: This is the common type of coax that we are used to see being used for cable TV. It can go 185 meters between repeaters, which is better than UTP’s 100 meters.185 is close to 200, hence the “2” in 10Base2 Thicknet or 10Base5: This is horrible stuff; heavy, a pain to work with and connected using “vampire taps”. It can span 500 meters! between repeaters, hence the “5” in 10Base5. –EMI Immunity: Less sensitive than UTP. Properties of coaxial cable

Course ILT BNC cable connector The standard BNC, or “bayonet nut connector”, is considered a 2-pin connector This is a rather interesting construction. The inner core of a cable is usually the part that carries the data; but it is highly unusual for an outer, protective covering to do double duty as a second conductor!

Course ILT BNC cable connector

Course ILT Activity C-1 Terminating with a BNC connector

Course ILT Fiber optic cable

Course ILT Fiber optic properties Fiber optic cable can support data rates up to 4 Gbps (not true; fiber can easily handle 10 Gbps. See IEEE standards for 10 Gigabit ethernet!) over distances ranging from 2 to 25 km (again, too conservative! Fiber can span dozens and even hundreds of miles – especially single-mode). Common fiber optic cables are classified based on the diameter of their core

Course ILT Fiber optic cable types Multimode Fiber (MMF) –Typically has a 62.5 micron core –Light travels down the core in many rays –Works with LED light sources of different wavelengths Single Mode Fiber (SMF) –Very small core of about 9 microns –Light travels down the cable in one ray –Optimal for very fast transmissions –(and the light source is a laser, not an LED).

Course ILT Fiber optic connectors Fiber Optic Association ST: This and SC are the most common and the most often tested. “Keyed BNC”. On the left, below. SC: A “push-pull” connector. Both the transmit and receive fibers are contained in a single clip. On the right, below.

Course ILT FSD: (Fixed Shroud Device) – e.g., the MIC (Media Independent Connector). Left. LC: Smaller connector; to save space. On the right, below. Fiber optic connectors - cont

Course ILT MTRJ: Another space-saver. Used with single or multi-mode. On the left. SMA: A threaded connector. Obsolete. Twisting the end to remove it was a bad idea! On the right, below: Fiber optic connectors - cont

Course ILT 5 Factors (page 5-19) –Cost: Expensive (but usually worth it). –Installation: Slow and technical. Be careful; mistakes can cost a lot of money and you can injure your eyes. –Capacity: Up to 10 Gigabit Ethernet – 10Gbps –Attenuation: Very little. Book says 25 Km, but single mode fiber optic runs can span dozens of miles given the right conditions! In the cert exam, give the more conservative distance in the book. –EMI Immunity: Immune! Also, very secure (you can cut into a copper-based cable and get information; you cannot “read” the light that passes through a fiber cable. Properties of Fiber Optic cable

Course ILT Activity C-2 (page 5-21) Discussing fiber optic cables

Course ILT Topic D Topic A: Network communication methods Topic B: Cables and connectors Topic C: Coaxial and fiber optic cables Topic D: Ethernet and Token Ring devices

Course ILT Ethernet devices Ethernet hub –Take the signal transmitted from one computer and propagates it to all the other computers on the network Hubs operate at the Physical Layer. The prototypical hub just receives a signal, boosts it a bit and sends it on its way. It never looks at any addresses – it doesn’t know how!) Types of hubs –Passive –Active –Switching –Intelligent

Course ILT Passive hubs Take incoming electrical signals on one port and pass them down the cable on its other ports – a simple rebroadcast. All nodes see the signal just as if they were all connected on a physical bus topology Many passive hubs have indicator lights for power, network traffic, link state per port, and collisions But a passive hub doesn’t really even need a power source to perform its job. It is not a repeater; so it does not expand the limit of the topology – e.g., 100M for ethernet.

Course ILT Active hubs Repair weak signals by actually retransmitting the data with proper transmission voltage and current This essentially resets the cable length limitations for each port on the hub Other active hubs have the ability to resynchronize data that has been received from a NIC. So they can check the timing of the data that enters the hub. This is almost a Transport layer function! An active hub extends the max distance of a network topology. With the “5-4-3” rule, you can have up to 4 “repeaters” (active hubs) to create 5 “segments”, extending the max distance for ethernet from 100M to 500M!

Course ILT Switching hubs Each port on a switching hub is isolated from the other ports On power up, it listens to each port and records the NIC hardware address attached (this is a task normally done by a switch!) Takes incoming packets and looks inside at the destination hardware address Instead of rebroadcasting this packet on all the ports, it only sends the packet out the port connected to the destination machine. –This is definitely a “layer 2” job, normally done by a switch or a bridge. A hub normally does not look at the MAC address of any device – it doesn’t know how to read them! This isn’t the only job of a switch, just one of the very important ones. They also can be “auto-sensing”, so can adjust the speed of outgoing packets, and handle both 10 and 100 Mbps machines in the same network segment. With this feature, some machines can run at 100 Mbps and others can be running at 10 Mbps, and the hub can handle both!

Course ILT Intelligent hubs The term intelligent hub is more nebulous than the terms discussed to this point An intelligent hub might –have management features –support SNMP (Simple Network Management Protocol) –be able to log into the hub (?) itself and perform tasks –have advanced features Make sure you understand features

Course ILT Activity D-1 Discussing Ethernet devices

Course ILT Token Ring devices Are devices that are analogous to Ethernet hubs (but the functions are not at all the same!) Called MSAUs - see another Power Point for Token Ring

Course ILT MSAUs

Course ILT Miscellaneous devices Devices used for network cabling other than Ethernet and Token ring include: –Network patch panels – a bank of connectors between a network device on one side (a switch, normally) and all the wall jacks in an area on the other. –Transceivers – a device that allows one type of media to be connected to another. On one side is an AUI port; on the other is some kind of connector for the particular “channel access method”, like an RJ45, or a coax BNC, a fiber optic SC or ST, etc.

Course ILT Activity D-2 – (page 5-27) Discussing Token Ring and other devices

Course ILT Unit summary Discussed network communication methods Learned about UTP, STP and FireWire Learned about coaxial and fiber optic cables Discussed network devices