Introduction to the Hotwire DSLAM
1-12
8000-A2-GB21-30
April 1998
Data Rates
The Hotwire DSL card employs Rate Adaptive Digital Subscriber Line (RADSL)
devices based on Carrierless Amplitude & Phase (CAP) technology. The RADSL
speed is asymmetric. This means that the downstream rate (from the DSLAM to
the RTU) is faster than the upstream rate (from the RTU to the DSLAM).
You can manually set the speed (providing the line you are using can support the
specified speed) or set the mode to rate adaptive. When the mode is set to rate
adaptive, the Hotwire DSLAM determines the line speed during the initial
handshaking session between the DSLAM and the RTU based on the local loop
length, the amount of noise on the loop, and the user-configurable upper and
lower speed limits.
The following are the maximum upstream and downstream data rates:
H Maximum upstream data rate: 1088 kbps (1.088 Mbps)
H Maximum downstream data rate: 7168 kbps (7.168 Mbps)
Data rates and data transmission distances vary depending on existing telephone
line conditions (i.e., the DSL cards measure performance during operation and
can adjust the upstream or downstream rate to match changing local loop
characteristics because of temperature, humidity, or electrical interference). Also,
the maximum data rate will be dependent on the RTU in use.
For a complete listing of the DSL card data rates and information on how to set
the line speed, see Chapter 5,
DSL Card Configuration
, of the
Hotwire DSLAM for
8540 and 8546 DSL Cards User’s Guide
.
Overview of the Hotwire DSLAM
Network Model
The Hotwire DSLAM and the Hotwire RTUs provide high-speed connectivity to
the Internet, corporation, or other network service from the end-user system.
The Hotwire DSLAM network model can be implemented in a number of ways.
For example:
H A Small Office/Home Office (SOHO) implementation with one or more users
connected to a LAN needing high-speed connectivity to an Internet Service
Provider (ISP).
H A SOHO implementation with one or more users connected to a LAN needing
high-speed connectivity to the corporate LAN or Intranet.
H A campus implementation needing internetworking between several sites,
each with a LAN.
