Internet Box- All about

Architecture of IP transmission
Architecture of IP transmission

Internet box : cable

It is essential to have a cable modem to be able to benefit from the Internet
Internet box
ADSL is a technology developed to be able to pass computer data through telephone lines. The high frequency bands of ADSL are those not used by the telephone (300 - 3400 Hz), multiplexing and modulation techniques are implemented.
However, using the high frequencies of the telephone line implies the use of a filter on both sides of the line so that there is no disturbance. The streams are asymmetric, which means that
and telephony via cable. Indeed, digital data signals are transmitted through radio frequency spectrum signals on the cable. Cable modems are used to convert digital data into a modulated radio frequency signal and vice versa.


Cable modems are bidirectional and allow sending and receiving IP data at the same time. These modems can reach speeds of 43 Mbps uphill and 10 Mbps downhill.
They use QAM (Quadrature Amplitude Modulation) or PSK (Phase Shift Keying) techniques for this. The cable modem therefore serves as a modulation converter between wired networks and Ethernet networks.
The data is transmitted on frequencies of the cable network different from those used by the TV
Digital terrestrial TV
Two major types of broadcasting exist for television; the so-called analogue and digital television. The analogue television appeared the first. This is widely spread around the world. However, this type of diffusion is ageing and not very innovative.
For this reason analogue television is currently tending to disappear to give way to digital television. Digital television is largely based on analogue television. The
.

To transmit the voice, the operators chose to rely on existing technologies. It is therefore via voice over IP that telephony has been established among cable operators.
IP phones, faxes, computers and televisions are connected to the cable modem via an Ethernet bus.
A DOCSIS application layer is used to connect the HFC network to an IP network via the Headend or CMTS (Cable Modem Termnation System).
This is the head-of-network equipment. It is located in the local station and connects all subscribers in the area. It will therefore convert the data from the IP network into a radio frequency signal to transmit them over the HFC network. It will also do the opposite. It thus makes it possible to communicate the HFC network with other networks such as the Internet
Internet box
ADSL is a technology developed to be able to pass computer data through telephone lines. The high frequency bands of ADSL are those not used by the telephone (300 - 3400 Hz), multiplexing and modulation techniques are implemented.
However, using the high frequencies of the telephone line implies the use of a filter on both sides of the line so that there is no disturbance. The streams are asymmetric, which means that
or the analog CATV
Digital terrestrial TV
Two major types of broadcasting exist for television; the so-called analogue and digital television. The analogue television appeared the first. This is widely spread around the world. However, this type of diffusion is ageing and not very innovative.
For this reason analogue television is currently tending to disappear to give way to digital television. Digital television is largely based on analogue television. The
network.

The CMTS is the equivalent of the DSLAM for xDSL technologies. Typically for domestic consumers the speed of the downstream data stream is limited between 512 kbit/s to 10 Mbit/s, and the upstream stream between 256 kbit/s and 1 Mbit/s.
Three types of communication must be distinguished that propagate over a wired network :
- Downstream Broadcast Channel : for television broadcasting.
- Downstream Interactive Channel : for communication from the operator to the subscriber.
- Upstream Return Channel : for communication from the subscriber to the operator.

The Upstream Return and Downstream Interactive bandwidths are distributed by the CMTS for the different subscribers.

DVB/DAVIC

The technology of \Digital Video Broadcast\ (DVB) and \Digital Audio Video Council\ (DAVIC) is the European standard for digital television. They have to be in line with the guidelines and European standards.
Specification DVD
The CD player
It's a drive optical drive that reads through a laser diode optical discs called CDs or CD, be it CD or computer CD-ROM. When it is used to listen to music CDs, the CD player can be integrated into various types of portable devices or servants, to a radio handset, etc. It can also be a separate, portable device or domestic, to connect to a channel Hi-Fi, an audio amplifier or headphones.
Computer, the CD player is e
2.0 also called DVD
The CD player
It's a drive optical drive that reads through a laser diode optical discs called CDs or CD, be it CD or computer CD-ROM. When it is used to listen to music CDs, the CD player can be integrated into various types of portable devices or servants, to a radio handset, etc. It can also be a separate, portable device or domestic, to connect to a channel Hi-Fi, an audio amplifier or headphones.
Computer, the CD player is e
- RCC (Return Channel for Cable) is standardized under the name ETSS 200800.
The standard is based on a layer ATM using LLC/SNAP (RFC 1483) and an AAL5 adaptation layer to encapsulate the IP packet (IP switching to an IP routing on an ATM switch).
For the communication between the subscriber terminal (STM) and the facilities of the local station (TDR), he uses the ATM signaling protocol or a proxy with DSM - CC.

DOCSIS and PacketCable

The consortium CableLabs has been created in May 1988 and brings together operators, actors or the cable TV
Digital terrestrial TV
Two major types of broadcasting exist for television; the so-called analogue and digital television. The analogue television appeared the first. This is widely spread around the world. However, this type of diffusion is ageing and not very innovative.
For this reason analogue television is currently tending to disappear to give way to digital television. Digital television is largely based on analogue television. The
industry.
He has established several specifications for the transport of IP packet : DOCSIS and PacketCable.

The American standard DOCSIS (Data Over Cable Service Interface Specification) defines the requirements for the interfaces of the cable modems used for the dissemination of data at great speed by cable TV
Digital terrestrial TV
Two major types of broadcasting exist for television; the so-called analogue and digital television. The analogue television appeared the first. This is widely spread around the world. However, this type of diffusion is ageing and not very innovative.
For this reason analogue television is currently tending to disappear to give way to digital television. Digital television is largely based on analogue television. The
.
In March 98 ITU (International Telecommunications Union) accepts DOCSIS as standard for modems cables under the name ITU or DOCSIS 1.0.
To deliver data services DOCSIS Wired on a network, a channel of radio frequency of 6 MHz in the 50-750 MHz frequency band is allocated to the descending traffic and another channel of 6 Mhz in the band 5-42 MHz for the traffic amount.

Headend equipment CMTS communicating through these channels with modems cables located at the Subscriber.
These are external equipment that connect to the computer through an Ethernet card or a USB
USB
The USB bus is also said to \Hot pluggable\, that is to say that you can connect and disconnect a USB with the PC on. The system installed on the PC (Windows, linux...) recognizes it immediately. The USB has a very interesting feature : it's the mode standby when not using the device. Also known as \Power conservation\ : Indeed the USB bus gets suspended after 3 ms if it is no longer used. During this mode, the co
interface. The method used by DOCSIS TDMA(Time Division Multiple Access)/SCD
The CD player
It's a drive optical drive that reads through a laser diode optical discs called CDs or CD, be it CD or computer CD-ROM. When it is used to listen to music CDs, the CD player can be integrated into various types of portable devices or servants, to a radio handset, etc. It can also be a separate, portable device or domestic, to connect to a channel Hi-Fi, an audio amplifier or headphones.
Computer, the CD player is e
MA(Synchronous Code Division Multiple Access).
This access method differs from the Ethernet system, as the DOCSIS system experiences no collision.
The software in initialization stage DOCSIS is usually (highly simplified) :

- 1 the modem sends a request DHCP way to know the network configuration to use.
- 2 the CMTS returns its local IP address (not to be confused with the IP address of the computer on the Internet
Internet box
ADSL is a technology developed to be able to pass computer data through telephone lines. The high frequency bands of ADSL are those not used by the telephone (300 - 3400 Hz), multiplexing and modulation techniques are implemented.
However, using the high frequencies of the telephone line implies the use of a filter on both sides of the line so that there is no disturbance. The streams are asymmetric, which means that
), its gateway, and more specifically the IP address of the server TFTP and the name of the configuration file has to go look for.
- 3 the modem connects to the server TFTP and request the configuration file named above, this file contains, among other relative information the connection speed of the modem, its priority on the network, and the number of authorized computers access the modem at the same time.
4. the modem - informs him CMTS that it has received the file, and that it is ready to operate (synchronization phase).

After this, the computers connected to the modem may themselves request their login information via the DHCP, and act like on a quite conventional LAN.
Finally in February 2002 arrives DOCSIS 2.0. This new standard brings a symmetry of the bandwidth between the rising and falling tracks.
This is due to the evolution of Internet
Internet box
ADSL is a technology developed to be able to pass computer data through telephone lines. The high frequency bands of ADSL are those not used by the telephone (300 - 3400 Hz), multiplexing and modulation techniques are implemented.
However, using the high frequencies of the telephone line implies the use of a filter on both sides of the line so that there is no disturbance. The streams are asymmetric, which means that
usage by users with the advent of the peer-to-peer, voice over IP, video conferencing...

IPsec must ensure the security of data outside the cable network. H.263 for video compression and G.711, G.726 and G.729 for audio compression.
Finally for managing centralized telephone internet
Internet box
ADSL is a technology developed to be able to pass computer data through telephone lines. The high frequency bands of ADSL are those not used by the telephone (300 - 3400 Hz), multiplexing and modulation techniques are implemented.
However, using the high frequencies of the telephone line implies the use of a filter on both sides of the line so that there is no disturbance. The streams are asymmetric, which means that
work signalling CableLabs uses MGCP. MGCP (Medio Gateway Control Protocol) to ensure signaling cable telephony services.

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