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Asymmetric
Digital Subscriber Line (ADSL) technology and ATM data encapsulation
offer a cost-effective solution to meet the explosive demand for
high-speed data driven by the World Wide Web (WWW) and other
IP-based applications. ADSL’s unique ability to provide universal
high-speed access and lifeline POTS service over the existing copper
infrastructure makes ADSL a very attractive service solution.
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ATM ADSL
Application |
AFC’s UMC1000
Multi-Service Access Platform (MSAP) provides ATM ADSL service
solutions for all DLC deployment applications, while protecting
current investments in UMC1000 and access network infrastructure.
The ADSL ATM product line from AFC provides plug-in modules that
make it possible to deliver high-speed data/internet access to
subscribers who are served over DLC products. Upcoming UMC1000
system releases will integrate ATM-based full-rate ADSL and ADSL
G.Lite channel units with T1, DS-3c, and OC-3c transceivers for
network uplink and interterminal transport.
Deploying
ADSL in the UMC1000 System
Five system components are
required in order to deploy ADSL service from an existing UMC1000
system.
1. ATM ADSL
Modem and splitter (where required) installed at the customer
premises.
2. One of AFC’s family of ADSL x+y™ channel units
installed in a UMC1000 remote subscriber terminal (RST), or in a
local exchange terminal (LET) for central office-based service
delivery.
3. ATM or TDM transport capacity between the UMC1000
RST and the local exchange terminal (LET).
4. A T1, DS3c, or
OC-3c uplink between the UMC1000 LET and the network service
provider’s ATM network.
5. An ATM switch, router, or other
network element capable of directing the ATM data to its final
destination.
ADSL Modem
CPE
Each AFC ADSL x+y channel unit supports fully compliant
ATM over ADSL service capability between the plug-in card and the
customer premises ADSL modem. Commercially available ATM ADSL modems
support a full range of customer applications—everything from simple
bridging to full router and hub capabilities. PC/LAN interfaces
include 10Base-T Ethernet, Universal Serial Bus (USB), and Network
Interface Card (NIC). The increasing popularity of ATM data services
means that affordable modems and routers are available through many
retail outlets. AFC’s ADSL channel units are compatible with ATM
modems from 3COM Corporation, Efficient Networks, Cayman Systems,
Creative Technology, and other leading ADSL and G.Lite compliant
customer premises equipment.
For full-rate
ADSL, a splitter or micro-filter is required at the customer
premises to separate the POTS and data frequency bands. AFC’s
full-rate ADSL channel units are designed to meet the T1.413, Issue
2 and ITU-T G.992.1 ADSL specifications. All ADSL splitters that
meet the splitter requirements called out in the specifications will
interoperate with AFC’s ADSL channel units and with compliant ADSL
CPE modems. AFC has completed interoperability testing with the
following vendors’ ADSL splitters: Pulse, Siecor, and Wilcom. AFC’s
G.Lite line cards meet ITU-T 6.992.2 specifications. Although many
homes will not require splitters or micro-filters for use with
G.Lite ADSL, many access providers deploy micro-filters with all
G.Lite systems to simplify operations and reduce deployment
variability.
ADSL Line
Cards
Each ATM-enabled ADSL line card provides a combination
of “x” ADSL circuits and CO band splitters, plus “y” lifeline Plain
Old Telephone Service (POTS) circuits—all integrated on a single
plug-in card. AFC’s product line of ADSL service cards supports
splitterless G.Lite at downstream data rates up to 1.536 Mbps, and
full-rate ADSL at downstream data rates up to 8 Mbps. Upstream data
rates up to 640 kbps are supported. AFC’s full-rate ADSL channel
units are software provisionable to support G.Lite line code;
however, a micro-filter or splitter will still be
required.
| ADSL x+y |
Integrated
Circuits |
ADSL Technology |
Deployment Applications |
|
ADSL |
POTS |
|
|
 |
| ADSL 2+6 |
2 |
6 |
Full Rate |
High-speed business and multimedia
services |
| ADSL 6+6 |
6 |
6 |
G.Lite |
High-speed internet access |
ADSL x+y Comparison Chart
The UMC1000
integrated ADSL x+y plug-in cards allow service providers to
maintain density of POTS services from all DLC nodes, while also
eliminating the need to deploy overlay networks, remote DSLAMs, and
splitter shelves.
Transport
To maximize deployment flexibility and
use of existing network resources while also enabling new high-speed
services, AFC has implemented broadband ADSL ATM services over both
existing TDM transport and upgraded end-to-end broadband ATM
transport. With AFC’s Edge Access ATM implementation, service
providers can take advantage of ATM CPE and switching resources,
while continuing to use existing TDM transport facilities (copper,
fiber, wireless) for delivery of ATM cells between the network and
the home. Using Edge Access ATM over existing TDM transport, ATM
cells are transported over a virtual ATM pipe of provisioned Nx64
connections on traditional TDM transceivers. The UMC1000 system
supports up to 672 DS0s of voice and data traffic.
As growth in ATM
ADSL services demands increased transport capacity, the UMC1000 is
ready to enable full broadband ATM access. Native ATM broadband
transport is supported across the UMC1000 System using DS3c and
OC-3c transceivers. With broadband ATM transport, the UMC1000
initially supports data rates up to 155 Mbps. Traditional voice
services and high-speed data are transported together as cells over
the ATM transport, with Quality of Service (QoS) provided by the CPU
and ATM switching capabilities embedded on each ADSL and ATM
transceiver card.
Uplink
A T1, DS3c, or OC-3c channel unit is used to
interconnect the UMC1000 LET and the service provider’s ATM network.
Each channel unit provides the uplink for ATM cells arriving from
all ADSL service cards, regardless of whether the ATM data was
transported across the UMC1000 as Edge Access ATM or as part of the
ATM transport. In addition to providing the uplink facility, the
DS3c and OC-3c also provide a single point for statistical
multiplexing of all ATM cell traffic within a UMC1000 system. By
statistically multiplexing ATM cells prior to uplink to the ATM
network, the UMC1000 can provide ATM ADSL service to many more
customers via oversubscription than with traditional circuit-based
TDM data services. By aggregating ATM data from several UMC1000
remote and local terminals, service providers can maximize the use
of ATM switch and network resources.
Two methods are
available to statistically multiplex ATM data at the remote
subscriber terminal, depending on the level of multiplexing desired.
First, each ADSL x+y channel unit can statistically multiplex the
ATM cells across all ADSL circuits on that card. For instance, an
ADSL 6+6™ channel unit aggregates the ATM cells from all six G.Lite
circuits prior to inserting the ATM cells into the ATM or TDM
transport. Additionally, if Edge Access ATM is used, all ADSL
channel units in an entire remote terminal can be aggregated and
statistically multiplexed onto a single ATM virtual
circuit.
ATM
Network
The network service provider must supply an ATM
switch capable of accepting T1, DS3c, or OC-3c interfaces.
Alternatively, a Broadband Remote Access Server may be used to
terminate the ATM PPP sessions and route the IP data to an Internet
Service Provider.
UMC1000
Solution
AFC’s UMC1000 multiservice access platform enables
service providers to deploy cost-effective access solutions capable
of bridging the gap in demand for today’s narrowband services to the
growing needs for broadband, multi-media services of the
future.
ADSL ATM Application Note, February,
2000 | 
Application Note 
