CECS 474 Computer Network Interoperability. CHAPTE R 12 Access & Interconnection Technologies. Tracy Bradley Maples, Ph.D. Computer Engineering & Computer Science Cal ifornia State University, Long Beach. Notes for Douglas E. Comer, Computer Networks and Internets (5 th Edition) .
Access & Interconnection
Tracy Bradley Maples, Ph.D.
Computer Engineering & Computer Science
Cal ifornia State University, Long Beach
Notes for Douglas E. Comer, Computer Networks and Internets (5th Edition)
Internet access technology refers to a data communications system that connects an Internet subscriber to an ISP (such as a telephone company or cable company).
Defn: Downstream refers to data traveling from an ISP in the Internet to a subscriber.
Defn: Upstream refers to data traveling from a subscriber to an ISP.
Note: Most Internet users follow an asymmetric pattern where a subscriber receives more data from the Internet than sending.
Defn:Narrowband refers to technologies that deliver data at up to 128 Kbps.
For example:The maximum data rate for dial-up phone lines is 56 Kbps and is classified as a narrowband technology.
Defn:Broadbandgenerally refers to technologies that offer high data rates, but the exact boundary between broadband and narrowband is blurry.
• Many people suggest that broadband technologies must deliver more than 1 Mbps.
• Unfortunately, this is not always the case. Thus, broadband may sometimes mean any speed higher than a dial-up line.
+ Fiber to the House (FTTH)
DSL (Digital Subscriber Line) is also a technology for providing digital services across the local loop.
There are several variants of of DSL which differ by the first word in their title, so they are collectively, xDSL.
Defn: Telephone companies use the term trunk to denote a high-capacity circuit, and have created a series of standards for digital trunk circuits
Synchronous Transport Signal (STS) standards specify the details of high-speed connections: