Broadband

Broadband, actually not very strict definition, generally based on current dial-up speed limit at 56Kbps (Bits conference, the speed of data transmission used units) for dividing line, will 56Kbps and the following access called "narrowband", on the access method is classified as "broadband". Broadband, from the general point of view, it is able to meet the understanding of what people can feel the sensations of media on the network transmission required bandwidth, so it is also a dynamic, the concept of development. The current broadband to family users refers to the transmission rate more than 1-m, can satisfy a speech and image information transmission requirements. Including: fiber, xDSL (ADSl, HDSL), Cable, ISDN (strictly speaking not a broadband).

Introduction the FCC (full name, the federal communications commission) 2010 on 24, 2007 the word for "broadband" under a definition, the FCC think broadband means for 4Mbps, download speed on video, can realize 1Mbps behavior such as multimedia applications, and at the same time maintain basic Web browsing and E-mail characteristics.

Broadband network can be divided into three parts: switching, access network transmission,. Broadband network of related techniques also divided into three classes: transmission technology, exchange technology, access technology.

Broadband transmission network mainly SDH (synchronous digital series) based high-capacity fiber-optic network;

Broadband by switching is ATM (asynchronous transfer mode) technology integrated services digital network;

Broadband access network mainly fiber access, copper access, HFC/copper access, wireless access, etc.

DSL

(Digital Subscriber Line Digital Subscriber loop) technique is based on ordinary telephone Line of broadband access technology, it is respectively in the same copper wire transfer data and voice signal, data signal is not through the telephone exchange equipment, reduced the telephone exchanges load; And don't need to dial, have been online, belongs to the special line Internet connection. DSL including ADSL, speeds, HDSL and VDSL etc.

VDSL

VDSL (was - to - Digital Subscriber loop - bit rate high-speed Digital Subscriber loop) is, simply, rapid VDSL is ADSL version. Use the biggest VDSL, short distances next transfer rate can amount to 55Mbps, upload rate can amount to 19.2 Mbps, or even higher.

Cable Modem

Cable modem cable modems and name cable modems, commonly known as the cable cat, it is in recent years with the expansion of network application and developed, mainly using cable network for data transmission.

Cable companies generally 42MHZ ~ 860MHZ from isolated between TV channels 6MHZ channel for several downward transmit data. Usually by 64QAM downward data (quadrature am) modulation mode, the highest rate can reach 256QAM 27Mbps, if adopted, the highest rate can amount to 36Mbps. Uplink data between general through 5 ~ 42MHZ for a period of spectrum, in order to effectively restrain it accumulate, general selection uplink noise than 64QAM QPSK QPSK modulation, more suitable for noise environment, but rate is low. Uplink rate tiptop 10Mbps.

At present, the Cable Modem access technology in the development of global especially North America a momentum by more than 100% each year, the number pace,

CableModem thoroughly solved the sound image transmission and cause jams, its rate has reached 10Mbps above, descending rate is higher. While the traditional Modem although has developed a rate 56Kbps products, but its theory for transmitting limit 64Kbps, think again already are unlikely to improve.

The key is formed CableModem construction.this equipment, HFC (hybrid nets (HFC) with optical fiber, light node main twigs inside the village type bus coaxial cable connected to the network users, the transmission frequency can be as high as 550/860MHz. In HFC network transmission of data, users terminal (computer) needed to use the CableModem.

We can see the development of future network CableModem is essential thing, but now is not yet available CableModem of international standards, each manufacturer product transmission rate are not the same. Therefore, high-speed broadband access construction.this CableModem remains to establish the international standard issued.

Fiber-optic access

Optical fiber access network (OAN) is using optical fiber transmission technology, namely the access between local switches and users all or part of the communication system using optical fiber transmission. Optical fiber has brought it, long-distance transmission ability, good secrecy, strong anti-jamming capability etc, and is the main technology future access. Use more FTTX access, including FTTH way home, direct users means fiber generally need only a subscriber line. In the short term, but it is a long-term economic prevents the development direction and the final access network solutions.