Network Architecture Flashcards
What is Coax?
Coaxial cable, or coax (pronounced /ˈkoʊ.æks/), is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket.
What is a tap?
A tap (a.k.a. directional coupler) has one input, and two output legs, usually labeled "TAP" and "OUT". The TAP leg incurs -6db loss, while the OUT leg incurs very small (~-1db) loss. Taps are used when a cable needs to keep the signal as clean as possible on one leg (to continue to feed TVs/modems on it downstream), while the other leg is to be terminated close to the tap, or loss on it is not crucial.
What is an Amplifier?
The goal and purpose of a distribution amplifier is to increase the strength of received signals to a level that is greater than the signal losses associated with the distribution system. To ensure all your devices receive proper strength signals, it’s important that your distribution amplifier be centrally located (relative to distribution lines), since the longer the lines, the more signal loss there will be within the system.
What is snowshoe?
It also allows some spare wire to be stored, in the event that a line is damaged and needs to be spliced. Called a “service loop”, because you might need it during service. If you didn’t have extra line, you’d have to have two splices, to splice in enough line to cover the distance. This way, you just move the “snowshoes” closer together to get some slack in the extra line.
What is splice case?
A usually weatherproof encasement, commonly made of tough plastic, that envelops the exposed area between spliced cables, i.e., where the jackets have been removed to expose the individual transmission media, optical or metallic, to be joined. Note 1: The closure usually contains some device or means to maintain continuity of the tensile strength members of the cables involved, and also may maintain electrical continuity of metallic armor, and/or provide external connectivity to such armor for electrical grounding. Note 2: In the case of fiber optic cables, it also contains a splice organizer to facilitate the splicing process and protect the exposed fibers from mechanical damage. Note 3: In addition to the seals at its seams and points of cable entry, the splice closure may be filled with an encapsulant to further retard the entry of water. [After FAA] Synonymclosure .
What is a node?
Fiber optic cables go either under or above ground to a different area in the city, to facilities called nodes. In the nodes, information in the hair-sized fiber optic cable is transmitted back onto finger-sized RF cables, which then go to your home. If you don’t have as many high-def channels as you’d like yet, it’s probably because Time Warner is updating the node near you.
What are the differenet access network options?
Access network options are either hybrid fiber coax (HFC) or dedicated fiber access.
What is the key location within the network and how does this work?
Key location within the network is the headend
Some metros this will also be the regional data center (RDC)
Connected to multiple distribution hubs with redundant optical fiber rings
From distribution hub out to the customers is the access network
How did Analog TV work?
How did Digital TV change everything and what is DOCSIS?
What are some differences between Fiber & Cable?
