Section 33.1.2 – Westermo RedFox Series User Manual
Page 752
Westermo OS Management Guide
Version 4.17.0-0
a PSTN by use of modems.
❼ PPP over Ethernet: PPP can be used on Ethernet (or DSL) by use of the PPP
over Ethernet (PPPoE) protocol[
]. WeOS provides a PPPoE client service,
which is commonly used when connecting to an ISP via an xDSL connection.
As of WeOS v4.17.0, WeOS units can establish a single PPP connection using
PPPoE, and a single PPP connection over serial port
33.1.2
Phases in the PPP connection establishment
The two units establishing a PPP connection are referred to as peers in PPP
terminology[
]. Here we will either denote them as PPP peers, or as PPP client
and PPP server when referring the unit initiating the connection (i.e., dial-out) or
the unit waiting for an incoming call (i.e., dial-in) respectively.
Establishment of a PPP connection is divided into several phases, as shown in
❼ ”Low-level” link establishment (Pre-PPP): Before a PPP connection can be
established, a point-to-point ”link” must exist, either as a physical link (serial
line), or as a logical link (PPP over Ethernet or PPTP/L2TP
– PPPoE: To create a point-to-point connection over an Ethernet, the PP-
PoE protocol is used. Once the PPPoE handshake has finished, the PPP
Link Establishment phase can start. See
for more infor-
mation on PPPoE specific settings.
– PPP over Serial Port: For PPP over serial link, it is enough to configure the
serial ports and the external modem (if used) to establish the physical
link. No pre-PPP phase exists – the PPP Link Establishment phase starts
immediately. See
for additional information on how to
configure the serial port and modem.
❼ PPP Link Establishment Phase: Once the point-to-point link is up, the PPP
peers start to exchange PPP Link Control Protocol (LCP) messages. LCP is
used to negotiate general settings, which are independent of the network
layer protocol(s) used on top, e.g., the maximum receive unit (MRU), or what
authentication protocol to use (if any). LCP is also used by the PPP peers to
2
PPP can be run over the serial port of the WeOS serial port, but not via its console port. See
for information on WeOS units equipped with serial ports.
3
As of WeOS v4.17.0, PPTP or L2TP are not yet supported.
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