Introduction to Connecting to the Internet Flashcards
modem
modulator demodulator- converts analog to dialog
bard rate
a measurement of how many bits can be passed across a phone line in a second
broadband
any connectivity technology that isn’t dial-up
T1 (historically)
transmission system 1- carry 24 simultaneous phone calls across a single piece of twisted pair copper
What does T1 mean nowadays?
any twisted pair copper connection capable of speeds of 1.544 mbs
T3
28 T1s multiplexed together resulting in a throughput speed of 44.736 mbs
DSL
digital subscriber line- uses modern phone lines (made of twisted pair copper) but operates at a frequency that doesn’t interfere with phone calls so they can occur at the same time as data transfers
What type of connections does DSL form and what is its implication?
Point-to-point connections (from home/office directly to the CO)= DSL ISPs can guarantee a certain amount of bandwidth
DSLAM
digital subscriber line access multiplexer- establishes long-running data connections across phone lines for DSL
long-running connection
the connection is established when DSLAM is powered on and isn’t torn down until it’s powered off
ADSL
asymmetric digital subscriber line- has faster download (inbound) speeds and slower upload (outbound) speeds
SDSL
symmetric digital subscriber line- upload and download speeds the same,
most have an upper cap of 1.544 mbs
HDSL
high bit-rate digital subscriber line- speeds >1.544 mbs
What’d the Cable Communications Policy Act of 1984 do?
deregulated cable TV business in US and resulted in massive boom in growth and adoption that spread across the world- holy shucks
cable broadband
provides high-speed internet access over the same coaxial cable as TV but at a frequency that doesn’t interfere with TV braodcast
cable modem
a device that sits at the edge of a consumer’s network and connects it to the CMTS
CMTS
cable modem termination system- what connects lots of different cable connections to an ISP’s core network
shared bandwidth technology
many users share a certain amount of bandwidth until the transmission reach the ISP’s core network
How large are CMTSs?
anywhere from a single city block to an entire subdivision in the suburbs
How far can fiber cables carry a signal before it degrades?
many, many miles
How far can twisted copper cables carry a signal before it degrades?
1000s of feet max
FTTX
fiber to the x
FTTN
fiber to the neighborhood
Describe FTTN
data is delivered to a single physical cabinet that serves a certain amount of the population. From there, twisted pair copper of coax is used for the last length of the distance.
FTTB
fiber to the building/business/basement- twisted pair copper used to connect those inside the building.
FTTH
fiber to the home- run to each individual in a neighborhood or apartment building
ONT
optical network terminator- converts data from protocols the fiber network can understand to those that more traditional twisted pair copper can understand
WAN demarcation point
where each network part of the WAN ends and the ISP’s network takes over
WAN local loop
the area between the demarcation point and the ISP’s actual core network, so from the demarcation point to the provider’s local, regional office (from which it would connect to the core network and Internet)
what type of cabling is used in local loops?
something like T-carrier or a high-speed optical connection
which layer of the networking layer do WAN protocols work at?
the data link layer in order to transport data from site to site
point-to-point VPN
establishes a VPN tunnel between 2 sites so that users can access network resources without establishing their own connections
