Table of Contents
What a WAN is.
WAN technologies, components, and services.
A network connecting two or more networks over long distances.
usually companies can't afford to set up a WAN between their offices, so they rely on service providers who have the nessisary equipment.
The "Cloud" is a representation of a global network of servers that make up the internet. To get data from point a to point b, the data will travel through the cloud by going from server to server until it gets to where it needs to be.
A dedicated path that goes from point A to point B in the cloud is created.
This creates a circuit between ever device along the path on the cloud and keeps this link up throughout the entire conversation.
Can be a permanent link or a temporary link.
Ideal for transmitting data that must arrive quickly in the order it's sent , such as real time Audio / Video.
Data is broken down into packets and each packet gets individually routed through the cloud.
The packets do not all have to take the exact same path to the destination, they just take the most optimal path.
Packets are then reassembled at destination.
Singular packets that did not make it can be individually requested and required.
Ideal for transmitting data that must arrive quickly in the order it's sent , such as real time Audio / Video.
A PTSN is set up with a server with two modems installed at two locations, with data being transferred into analog signals by the modems and transferred along a telephone network.
ISDN is an extension of PSTN, using PSTN or T-Carrier (explained below) lines to transmit multiple digital data channels.
It uses a packet switching technology called frame relay.
Frame relay establishes a permanent virtual circuit through the WAN cloud to transmit data.
Evolution of frame relay.
An Edge Router sending out info inserts a label between the IP header and the MAC Address.
This label describes characteristics about where the data should be forwarded.
MPLS routers use these labels to transmit data rather than IP destination addresses.
Uses routers and switches (typically fiber optics) to create a metropolitan area network within a city.
Uses star or mesh topology to connect businesses to each other and the internet.
Set up and maintained by an ISP for businesses.
Usually built on top of existing MPLS infrastructure , leading them to be cheaper and faster than other WAN services.
Distributed switching is an architecture in which multiple switches act as one switch
often used in telephone networks, sometimes called host-remote switching
used in rural areas where a full dedicated telephone exchange is too much
Existing wires use only one Twisted Pair
Analog signals used through local loop
Speed:
56 Kbps
Uses two pairs of copper cables to transmit data. One pair is for transmission and one is for reception.
T1 runs over two pairs of STP Cable
can also run over coaxial, fiber optic, or satellite
T3 runs over fiber optic cable
T1 has 24 channels that run at 64 Kbps
T3 has 672 channels that run at 64 Kbps
Has a Channel Service Unit which manages the digital channel
Has a Digital Service Unit which reads/writes synchronous digital signals
You can connect CSU and DSU interfaces with a T1 Crossover Cable
T3 is also known as Digital Signal 3 (DS3)
Mainly used in North America
Speed:
T1:
1.544 Mbps
T3:
44.736
Mbps
2.048 Mbps / 34.368 Mbps
Similar to T Carrier
E1 has 32 channels that run at 64 Kbps
E3 runs 16 E1 channels at one time
Also has CSU and DSU
Mainly used in Europe
Speed:
E1:
2.048 Mbps
E3:
34.368
Mbps
1.544 Mbps / 32.064 Mbps
Identical to T1
J1 has 24 channels that run at 64 Kbps
J3 runs 480 channels at 64 kbps
Also has CSU and DSU
Mainly used in Japan
Speed:
J1:
1.544
Mbps
J3:
32.064
Mbps
Use wavelength division multiplexing (WDM) to increase capacity of communication over fiber optic cabling.
Starts at OC-1 (51.84 Mbps)
Every other OC-# is just # times 51.84
Ex. OC-3 is 155.52 Mbps.
Goes up to OC-768 a 39.2 Gbps.
WDM: uses different wavelengths (colors) of laser light on a fiber optic to allow for bidirectional communication and multiplication of capacity.
Dense wavelength-division multiplexing (DWDM) can carry 40 or 80 different signals.
Coarse wavelength-division multiplexing (CWDM) can carry 16 different signals.
Speed:
OC-1:
51.84 Mbps
OC-3: 155.52 Mbps
OC-192:
10 Gbps
Is the collection of equipment that makes up a WAN network
Owned and maintained by telecommunications companies
Reason it is called a cloud is because the physical structure might vary but common connection points may overlap
As a network administrator, you won't know where the data goes as it is in the cloud. It's only important that it goes from point A to point B safely and in one piece.
Switching facility connected to the WAN.
Provides WAN cloud entry and exit points
Cable that extends from the central office to the customer location
Owned by the WAN service provider
Typically uses UTP, but can also use fiber optic or other media
Nicknamed "Last Mile", its the last portion of the WAN up until the customer.
A physical cable and termination jack at an originations premises (The company purchasing internet from a provider)
Carrier is responsible for everything before the Demarc, Customer is responsible for everything after.
Also known as minimum point of entry or end user point of termination (MPOE, EU-POT)
Usually on the bottom floor of a building.
For a house, its usually a small box on the side of the house.
Devices located on the customer premises.
Wiring, devices customer owns.
Devices leased from provider.
Smart Jack, Demarc, Local Loop, Copper line drivers, Repeaters
Mega Switch Computer Capable of handling a large number of packets.
It decides which circuits on a wan that packets will take
Typically located in the central offices, inside the cloud.