【轉貼】ADSL Standards and Protocols

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Supports multi-mode for auto detection of ADSL protocol
This mode allows the modem to negotiate the correct modulation against the ISP(s) and Telco(s) equipment. There are four industry-supported modulations: T1.413, G.DMT, G.Lite, and CAP. This modem supports all but the CAP modulation. The CAP has been replaced by the defacto standard, G.DMT, which is supported.


Supports T1.413 issue 2

This is an ANSI standard which defines the requirements for the single asymmetric digital subscriber line (ADSL) for the interface between the telecommunications network and the customer installation in terms of their interaction and electrical characteristics.

Supports DMT Full-Rate ADSL: up to 8 Mbps downstream, up to 1 Mbps upstream (G.992.1 and T1.413, Issue 2)

This is the International Telecommunications Union’s (ITU’s) recommendation for the single asymmetric digital subscriber line (ADSL) for the interface between the telecommunications network and the customer installation in terms of their interaction and electrical characteristics.

Supports G.Lite ADSL: up to 1.5 Mbps downstream, up to 512 Kbps upstream (G.992.2)

This is the International Telecommunications Union’s (ITU’s) recommendation which allows for high-speed "always on" digital communications over a standard copper phone line at lower speeds than the G.DMT recommendation. The decrease in speed allows the technology to share the local loop without the need for a splitter at the entry point.

Supports DSL handshaking (G.994.1)

A method for DSL systems to negotiate mutually supported operating modes.

WAN Service Protocols
RFC 2516 PPP over Ethernet (PPPoE)

PPPoE stands for point-to-point protocol over Ethernet. It is a method of encapsulating your data for transmission over a bridged Ethernet topology.

RFC 2364 PPP over ATM (PPPoA)

PPPoA stands for point-to-point protocol over ATM, also known as point-to-point protocol over AAL5. It is a method of encapsulating your data for transmission over an Asynchronous Transfer Mode (ATM) interface.

RFC 1483 Multi-protocol over ATM (proceeded by RFC 2684)

RFC 1483 is an Internet standard for carrying connectionless routed and bridged Protocol Data Units (PDUs) over an ATM network.

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G.992.1
Asymmetrical digital subscriber line (ADSL) transceivers

G.992.2
Splitterless asymmetric digital subscriber line (ADSL) transceivers

G.992.3
Asymmetric digital subscriber line transceivers 2 (ADSL2)

G.992.4
Splitterless asymmetric digital subscriber line transceivers 2 (splitterless ADSL2)

G.992.5
Asymmetrical Digital Subscriber Line (ADSL) transceivers - Extended bandwidth ADSL2 (ADSL2+)