Conti vit y 251 ABOT D eployment
Version 1. 0
April 26, 2004
equivalent to 251's Single User Account feature (SUA). Therefore, traffic sent from the Contivity
Gateway private network to the C200 private network does not make it further than the C200
assigned address.
In Client Emulation configuration, the CO site is able to manage C200 but is not able to manage
C200’s private LAN since M:1 NAT inbound traffic cannot establish connections without port
forwarding enabled. For full VPN capabilities, users should setup Branch Office Tunnels, either
ABOT or static BOT.
1.6 ADSL
brief
ADSL (Asymmetric Digital Subscriber Line) is a proven technology that takes the advantage of
standard copper loops telephone lines to provide high-speed Internet “always on” access. ADSL
has its downstream capacity higher than its upstream capacity. E.g. Contivity 251 ADSL supports
downstream rates up to 8Mbps and upstream rates up to 832Kbps.
ADSL uses signal frequencies above those used by voice or fax, so the data signal does not
interfere with telephone signal.
In SOHO site, data traffic and voice traffic are separated by splitters. On CO site, they are
separated by a Digital Subscriber Line Access Multiplexer (DSLAM) switch. Voice traffic is then
sent to PSTN, while data traffic is sent to ATM backbone connecting to ISP and Internet.
The diagram below illustrates the key elements of ADSL.
Figure 4 ADSL Major Components
DSLAM
splite
Internet
ATM or FR
splite
ISP
PSTN
SOHO
Phone
wi re
fax
phone
PC
Contiv ity 251
Or ADSL Modem
CO
8M
0.8M
