RuggedCom RuggedRouter RX1100 - Manual (Page 94)

11. Configuring PPPoE/Bridged Mode On ADSL
Revision 1.14.3 94 RX1000/RX1100™
11. Configuring PPPoE/Bridged Mode On ADSL
11.1. Introduction
This chapter familiarizes the user with:
• Configuring PPPoE and Bridged Mode Links
• Viewing status
11.1.1. ADSL Fundamentals
An ADSL (Asymmetric Digital Subscriber Line) line is a communications link running over regular
POTS telephone service. The link is asymmetric, supporting data transfer at up to 8 Mbps from the
network and up to 1 Mbps to the network. The actual bandwidth depends upon the distance between
the router and telco central office, the maximum distance of which may be up to 5480 m. An ADSL
card must connect to a central ADSL DSLAM for its connection.
ADSL shares ordinary telephone lines by using frequencies above the voice band. ADSL and voice
frequencies will interfere with each other. If the line will be used for both data and voice, a “splitter”
should be installed to divide the line for DSL and telephone.
ADSL is almost always used to make a connection to the Internet via an ISP. There are two methods
for establishing the connection, PPPoe and Bridged mode.
ADSL uses the ATM protocol to communicate with the central office DSLAM. ATM uses virtual
channels to route traffic and the DSL connection needs to know which virtual channels to use. Most
providers use VPI=0 and VCI=35. There are exceptions to this. Some providers that use different
settings are listed in the following table.
Provider VPI VCI
Typical Provider 0 35
Bell South 8 35
New Edge 0 38
Sprint 8 35
US West/Qwest 0 32
11.1.2. PPPoE/Bridged Mode Fundamentals
In PPPoE (Point-to-Point Protocol Over Ethernet) the PPP dial-up protocol is used with Ethernet over
ADSL as the transport. PPPoE supports the protocol layers and authentication widely used in PPP
and enables a point-to-point connection to be established in the normally multipoint architecture of
Ethernet.
As your PPPoE connection is established a PPP interface will be created. The name will be “pppX”
where X is the same as the interface number. Use this interface name in firewall rules.
11.1.2.1. Authentication, Addresses and DNS Servers
PPP authentication utilizes PAP or CHAP. Your ISP will provide you with a user-ID and password
which you will enter in the GUI. The authentication process will assign a local IP address and