Wiring Diagram Quiz

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Quiz
Assign a type of equipment for each of the points in the network, switch, router etc
Assign a media to each link based on distance- copper, fibre, T1 etc
Post your answers in the comments and let's discuss it!

My colleague had mentioned that MPLS was in alot of the questions in the CCNA Security exam as well as Cisco SDM though he was more familiar with the CLI. I just grabbed this image from google because it has alot of components of a network carrying data, voice, media during my search for MPLS, wire speed!.

Cisco ICND1 Flashcard: Are you tech savvy about DSL, the Last Mile, NAT and PAT?

The topic of DSL was covered in the CCNA Bootcamp course as a requirement for the ICND1 Exam.

Internet Resellers
TekSavvy talk has been making the rounds lately on forums at work and online. They're in the news among the other victims of the ongoing CRTC ruling on the "usage based billing" or wholesale billing regulations from large ISPs to small ISPs. I decided to take a look at what folks were talking about - really cheap rates for high speed internet, long distance calling, residential phone and even cable at much lower rates than the standard Bell or Rogers! However the ruling will make unlimited packages impossible or too expensive, as the cost of using Bell or Internet backbone services is transferred to the consumer, say for example Bell will charge TekSavvy or Acanac an extra $22/ Mbit or 22k for 1 Gbps link. The other thing is I didn't quite understand right away, why when the TekSavvy customers had a problem and they called up TekSavvy tech support, a service call would be sent out to Bell or Rogers. Ok I get it, Bell or Rogers still provide the DSL or last mile connection. TekSavvy is an "internet reseller" or ISP.

There is a business arguement for open competition that folks are feeling very strongly about for Open Media debate and a petition. My article is purely about the electrons not the politics.  Back to the basics.

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What is DSL and the Last Mile?
The story begins with the telephone cabling we are already familiar with. It's copper and can carry 300 Hz to 1 MHz of data. However the human voice is only using the 300Hz to 3 kHz portion of the link, DSL can use the remainder 3 kHz to 1 MHz for high speed data, "always on".  DSL stands for Digital Subscriber Line, and this allows the packets to be sent over copper, owned by an ISP. It is not a shared medium, each user has his own direct connection to the DSLAM. It's scalable, adding new users does not impede the network performance. DSL can be used simultaneously as voice.

The cabling part there is also refered to as the local-loop or last-mile or the last step of the local telephone network connection. DSL may be added incrementally in any area with some distance limitations, but is not universally available everywhere in all geographic locations. Equipment required includes the CPE (Customer Premise Equipment) and DSL-Access Multiplexer (Time Division Multiplexer).  There is a physical geographic limitation of 5.5km distance for ASDL, and some folks would consider the "always on" aspect of the DLS as hackable; well whatever.


DSL can be used by a large company to support the "work at home" workers. The worker cannot connect to the enterprise network directly; instead he first connects to the ISP and then an IP connection is made from the Internet to the enterprise network.

There are two categories of DSL
DSL places the data upload and download above the 4kHz window, allowing voice and data transmission to occur simulataneously on the same DSL service.

ADSL Asychronous, higher download bandwidth than upload (less than 5.5 km distance)
VDSL, VDSL 2 is very high data rate
250 Mbps at the source
100 Mbps at 0.5km
500 Mbps at 1km
G Lite, G 992.2
ADSL, ADSL2, ADSL 2+
Consumer DSL aka G.Lite or G992.2

SDSL Synchronous, same capacity both directions
HDSL high data rate DSL
ISDN DSL(IDSL)
G.shdsl, symmetric high bit data rate DSL

In all instances, it's WAN access. It is not cable; cable is best described as a bus network topology, fiber under the street, copper to the home. (Why do I have this in my notes?)

Transceiver - connects the computer of the worker to the DSL, usually a modem with USB or Ethernet cable. Newer DSL transceiver can be installed on routers with 10/100 switch ports for home and office use.

DSLAM - located at Central Office of the carrier. DSLAM combines individual DSL connections into one high capacity link to the ISP and Internet.

Assigning an IP Address
Used to be that when you turned on your computer the ISP would assign an IP address to your computer by DHCP, and then when you were finished with your connection the computer would return the IP address to the pool. The only thing is, people don't usually turn off the computer so this IP address will almost permanently taken. I suppose if it was a work computer, the network administrator could use Private and Public IP addresses translation.

The global internet  is like a large WAN.  Servers need an IP address from  the ISP and interfaces - which are manualy assigned by the ISP or dynamically assigned.  When you have private IP address and need to go on line. The IP addresses will have to be translated by NAT from an Internal  lab to the outside world.

Next Topic:
NAT, PAT and Overloading

Cisco ICND1 Flashcard: Copper Cable Pinouts for RJ-45

There are three types of copper cabling most concerning to Ethernet for the RJ-45 jacks: straight-through, cross-over, and roll-over. You can do a simple visual inspection to determine the pairing and type of cable it is. If you're constructing the cables to a custom length, you could use a special board with the input pins and output pins labelled 1 to 8 and they light up as you decide which order you want them in as you clip on the head. Click!

RJ-45 jacks for Ethernet, also used for ISDN BRI
(Deconflict DB-60 used for connecting synchronous serial interfaces and Cisco routers, configuring WAN links and T1, E1 high speed lines)

RJ-11 jacks for telephone

RJ-48 connectors on CSU/DSU WAN interface EIA-TIA 232 at the customer end.

Cabling

An insulating material covers each individual copper wire in the UTP cable; the wires wrap around each other (twisted pair). They are subject to electromagnetic interference.

Straight Through, UTP (unshielded twisted pair)
Pins 1,2,3 and 6 used
Pin 1 to 1, 2 to 2, 3 to 3, 6 to 6
Best to have the other unused pairs match up too.
Hubs or switches provide the "twist" to match TX to RX
Connects devices at the different layers of the OSI model, ie. Server to Switch

Cross Over
Pins 1,2,3 and 6 used
Pin 1 to 3, 3 to 1
Pin 2 to 6, 6 to 2
Connects devices at the same layer of the OSI model, ie. Router to Router

Roll Over
Used for connecting the console port on router to computer.
Cable is rolled, simply reverse the pins
Pin 1 to 8, 2 to 7, 3 to 6, 4 to 5, 5 to 4, 6 to 3, 7 to 2, 8 to 1
The console port is used for local access to the router, when physical access is required, like for password recovery.


Another way of looking at the pinouts.
Straight Through
sender     receiver
1               1
2               2
receiver   sender
3              3
6              6

Cross Over
sender      receiver
1               3
2               6
receiver   sender
3              1
6              2

Cisco ICND1 Flashcard: Cables and Fiber, Ethernet LAN Connectors

Quiz: Match the type of wiring with the distance
1000BaseCX - copper shielded twisted pair
1000BaseT - that's Cat 5 or 6, four pair UTP
1000BaseSX - that's 780nm laser, 62.5-50micron cores
1000BaseLX - that's 1300nm laser, 9 micron core

(25m, 100m, 250m, 10km)

NIC
An Ethernet NIC (network interface card) is a LAN adapter, which operates both as a Layer 1 (physical layer) and Layer 2 (data-link layer) device, and contains a physical MAC address used in the Layer 2 addressing.

The distance requirements and data rates (available in 10 Mb/s Ethernet, 100 Mb/s Ethernet and 1 Gb/s Ethernet)  will determine the media to use, and the connectors as well.  For example, an RJ-45 connector (has 4 pairs so 8 conductors) is commonly used for unshielded twisted pair (UTP) cable Cat 5. However GigE (Gigabit Ethernet) required Cat 5e (I've heard guyz refer to this as Cat 7 but I believe Cat 5e is the more correct term).

Cables (Copper)
There are two types of Ethernet connection media, copper unshielded twisted pair and fiber optic.
Categories of UTP Cables used for networks at speeds:

• Category 1: telephone, not for data
• Category 2: data transmission up to 4 Mb/s
• Category 3: 10BASE-T, transmit data up to 10 Mb/s
• Category 4: token ring, transmit data up to 16 Mb/s
• Category 5: transmit data up to 100 Mb/s
• Category 5e: transmit data up to 1000 Mb/s (1 Gb/s)
• Category 6: aka thick ethernet, consists of four pairs of 24-gauge copper wires, transmit data up to 1000 Mb/s

When to use a straight through cable or a crossover cable?

Use a Straight-though cable for joining dissimilar equipment together (the switch will do the crossing):

• Switch to router
• Swtich to PC or server
• Hub to PC or server

Use a Crossover cable to connect similar equipment together

• Switch to switch
• Switch to hub
• Hub to hub
• Router to router
• Router Ethernet port to PC NIC
• PC to PC

Fiber Optic  

There are a variety of Fiber Optic Connector tips, but the most common ones I see are
Straight Tip (ST): barrel shaped connector like a BNC, multimode fiber
Subscriber Connector (SC) or SC-Duplex: square face, push pull connection, single mode fiber
Lucent Connector (LC): small connector, popular for use with single mode, can support multimode

Single mode fiber has a single strand of glass, laser light, high bandwidth for longer distances.

Multimode fiber has several strands of glass, LED light, high bandwidth for medium distances.
2km for 100 Mb/s
550m for 1 Gb/s
300m for 10 Gb/s

GBIC
Cisco Fiber-Optic Gigabit Interface Converter (GBIC) is a hot swappable I/O device for the Gigabit Ethernet port in a router; means that other 1000BASE-X can be deployed without having th change the physical interface, or model of router and switch. GBIC can support UTP (copper) and fiber optics.

A fiber optic GBIC is a transciever, by converting serial electric currents to optical signals, and then the optical signals are converted to digital electric currents. Here are three main types:

• Short wavelenth (1000Base-SX)
• Long wavelenth or long haul (1000Base-LX/ LH)
• Extended distance (1000Base-ZX)

I had to order a bunch of Cisco Fiber Optic SFPs and I made a summary list of what formats they came in, to order the correct one. They just slide into the GBIC card. Here are the main types of Cisco SFP, and respectively the application:

• Short haul (1000BASE-T; 1000BASE-SX): Cat 5 100m; multimode fiber to 550m or laser multimode (1km)
• Long haul (1000BASE-LX/LH): both fiber optic (10km) or multimode (550m)
• Long reach (1000BASE-EX, 1000BASE-ZX): single mode 40km; single mode 70 km
• 1000BASE-BX10-D/U: single mode 10km 

Decoding naming conventions.
The "10" refers to the speed, that is 10 Mb/s
"BASE" refers to baseband Ethernet
"T" is twisted Pair
"X" is fiber optic
"L" sounds long, like up to 10km
"S" seems short, like up to 250m
1000BASE-CX is GigE over copper, 25m

FUN FACTS from the Cable Guy
The original purpose of the Multimedia Cable Network Partners Ltd was to develop a product and system standard for providing data and future services on CATV plants.
Cable modems enable two-way high speed data transmission using the same coaxial lines that transmit cable TV.
Cable modems provide access speeds faster than leased lines with lower costs and easier installation.

Exam Quiz
What is the distance of 1000BaseSX?
This is multimode fibre using 62.5 to 50 micron core, 780 nm laser up to 260m

What is needed for Fast Ethernet?
How to run full duplex Ethernet - have two 10 Mbps or 100 Mbps paths, two full duplex compatible NICs, loopback disabled, collision detection disabled, corect software drivers to support two simulataneous data paths, see Ethernet distances

Distance limitation for Cat 5 cabling.
Approximately 100 m or 300 ft.

Distance for T1 cabling, Layer 1 Troubleshooting - about 655 feet.
conf t
controller t1 0

Issue the cablelength long controller configuration command in order to configure transmit and receive levels for a cable length (line build-out) longer than 655 feet for a T1 trunk with a channel service unit (CSU) interface. Issue the cablelength short controller configuration command in order to configure transmit attenuation for a cable length (line build-out) of 655 feet or shorter for a T1 trunk with a DSX-1 interface.