In the United States, the standard for ATM on optical media is SONET (Synchronous Optical Network). SONET standards allow for a base data rate of 51.84 Mbps. Multiples of this rate are called “Optical Carrier” (OC) levels. Common OC levels include:
| OC Level | Data Rate |
| OC-1 | 51.84MBps |
| OC-3 | 155.52MBps |
| OC-12 | 622.08MBps |
| OC-48 | 2.488GBps |
The international equivalent of SONET is SDH (Synchronous Digital Hierarchy).
The T-series connections are digital carrier systems introduced in the United States by the Bell System in the 1960s. This system was the first successfully to support DS-1 formatted digitized voice transmission that connected directly to a network. You’ll often see T1 and T3 lines in Internet Service Provider (ISP) connections.
To get a T-series line, all you have to do is lease it from the telephone company.
T-series connections can use the standard copper pair cables found in most telephone services, or a backbone (aka, “trunk”) line. T-series connections currently use Time Division Multiplexing (TDM), which divides the bandwidth into 24 channels and a control line.
When you see T1 or T2 or etc, the T stands for “T series.” Common T-series lines and their speeds include:
When you see an E1, E3, etc., it indicates the European counterpart of a T series line. E-series lines do not generally run at the same speeds at their T-series counter parts. For instance, an E1 line runs at 2.048MBps and an E3 operates at 34.368 MBps.
| Protocol or Service | Function |
| RAS (Remote Access Server) |
A computer with one or more modems installed to facilitate remote connections to a network. |
| PPP (Point-to-Point Protocol) |
Establishes a session between serial point-to-point links and encapsulates IP datagrams for transmission; also establishes standards for other transmission functions such as error detection. |
| PPTP (Point-to-Point Tunneling Protocol) |
Allows the creation of a Virtual Private Network, which gives users a secure, direct connection to a server or corporate network via the Internet. |
| ICA | Client software used in Citrix connections. |
Microsoft
RAS Error Code List
PPTP
FAQ
Pigeon Packet Transfer Protocol,
Just for fun ;-)
SLIP/PPP
Homepage
How to set
up an ICA/Citrix connection to hyperion