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Configuring PPP in AOS Quick Configuration Guide

Configuring PPP in AOS Quick Configuration Guide

Configuring PPP in AOS Quick Configuration Guide

Point-to-Point Protocol (PPP) is a Layer 2 protocol that facilitates communications between two devices over Layer 1 links such as T1 and Ethernet, and can be used over ATM for ADSL links. PPP negotiations exchange transmit sizes, layer 3 protocol types, and layer 3 information. For a more detailed explanation of PPP, please consult the guide titled “Configuring and Troubleshooting PPP”.


To establish a PPP connection you will need a Layer 1 connection; such as a T1, ADSL or Ethernet. Be sure that your Layer 1 connection is free of errors before continuing with this setup.

  • AOS Device
  • Established T1, ADSL (ATM) or Ethernet Link
  • PPP Capable Peer


All versions of AOS are capable of negotiating PPP.


All AOS hardware is capable of negotiating PPP.

Basic Web Interface Configuration

This guide explains how to access the various types of PPP, and then how to configure PPP. Find the appropriate “accessing” section below, and then follow the “configuring ppp” section.

Accessing PPP over a T1,  E1, Serial or DDS  interface Configuration:

This guide assumes the T1 or E1 interface has already been configured and is ‘UP’.

1)      Click “Physical Interfaces”

2)      Click on the interface that will transport the PPP connection. (Example: T1 1/1)

3)      Set the “Encapsulation Mode” to “PPP”.

4)      Click Apply.

Accessing PPP over ATM for ADSL Configuration:

This guide assumes the ATM interface has already been created.

1)      Click “Physical Interfaces” or “Public Interface” depending on your product.

a.       After “Physical Interfaces” click “ATM 1” next to the ADSL interface. Then click “ATM 1.1” under “Configured Permanent Virtual Circuits”

2)      Set “PPP” as the “Interface Mode”

3)      Click Apply.

Accessing PPP over Ethernet Configuration:

This guide assumes the Ethernet Interface is configured and enabled.

1)      Click “Physical Interfaces”, “Public Interface” or “VLANs” as your product requires.

a.       If you are connecting a Switched interface to the PPPoE connection, click “VLANs”. (Example Product: 1224R), then click on the target VLAN.

b.      After “Physical Interfaces” click the Ethernet interface over which PPP will be transported. (Example: eth 0/1)

2)      Set “Interface Mode” to “PPPoE”.

3)      Click Apply.

Configuring PPP in the Web Interface:

Depending on your Layer 1 interface type, your options may vary slightly.

1)      If your provider requires authentication, select the appropriate type from “Sent Authentication Type”

a.       Enter the appropriate username and password

b.      You do not need to set the “Peer Authentication Type” if available.

2)      Set the “Address Type” according to your providers requirements.

a.       Negotiated – provider will dynamically assign an address

b.      Static – You will manually enter an address

c.       Unumbered – PPP interface will assume the address of the target interface

d.      None – no address will be used; not likely

3)      Click “Apply”.

Use the “Status for PPP..” box at the bottom of the PPP configuration page to view the status of the PPP connection.

Basic Command Line Interface Configuration

Access the Command Line via the Console Port or Telnet. The following commands will configure a PPP interface over a T1 interface or a Serial interface.

1)      Enter enabled mode and enter the enable password if prompted.

a.       Syntax: enable

b.      Hostname> enable

2)      Enter Global Configuration mode.

a.       Syntax: configure terminal

b.      Hostname#: configure terminal

3)      Create the PPP interface with a unique identifying number.

a.       Syntax: interface ppp <number>

b.      Hostname(config)#: interface ppp 1

4)      Assign the PPP Interface an IP Address.

a.       Syntax: ip address <A.B.C.D>  <subnetmask | /prefix-length>

b.      Hostname(config-ppp 1)#: ip address

5)      Cross-connect the interface with a Layer 1 interface (T1 and Serial shown)

a.       Syntax: cross-connect <number> <interface> <slot/port> [<tdm-group numberppp <ppp number>

b.      Hostname(config-ppp 1)#: cross-connect  1  t1 1/1   9   ppp 1

c.       Hostname(config-ppp 1)#: cross-connect  1  ser 1/1      ppp 1

Note: There is no tdm-group number specified for the serial cross-connect because serial interfaces do not make use of tdm-groups.

6)      If your provider requires CHAP Authentication, set chap username and password.

a.       Syntax: ppp chap hostname <username>

b.      Hostname(config-ppp 1)#: ppp chap hostname someusername

c.       Syntax: ppp chap password <password>

d.      Hostname(config-ppp 1)#: ppp chap password somepassword

7)      If your provider requires PAP Authentication, set pap username and password

a.       Syntax: ppp pap sent-username <username> password <password>

b.      Hostname(config-ppp 1)#: ppp pap sent-username someusername password somepassword

😎      Enable the PPP interface.

a.       Syntax: no shutdown

b.      Hostname(config-ppp 1)#: no shutdown

9)      View the status of the PPP interface.

a.       Syntax: do show interface ppp <ppp number>

b.      Hostname(config-ppp 1)#: do show interface ppp 1

Example Command Line Configurations

The following shows example configurations for all possible layer 1 interface types and PPP connections.

T1 Interface:

interface t1 1/1

tdm-group 9 timeslots 1-24 speed 64

no shutdown


interface ppp 1

                ip address

                cross-connect 1  t1 1/1  9  ppp 1

                no shutdown

E1 Interface:

interface e1 1/1

tdm-group 9 timeslots 1-31 speed 64

no shutdown


interface ppp 1

                ip address

                cross-connect 1  e1 1/1  9  ppp 1

                no shutdown

Serial Interface:

interface serial 1/1

no shutdown


interface ppp 1

                ip address

                cross-connect 1  serial 1/1  ppp 1

                no shutdown

Ethernet Interface (PPP over Ethernet):

interface eth 0/1

                no shutdown


interface ppp 1

                ip address

                cross-connect  1  eth 0/1  ppp  1

ADSL Interface (PPP over ATM):

interface adsl 1/1

no shutdown



interface atm 1 point-to-point

no shutdown

cross-connect 1 adsl 1/1 atm 1


interface atm 1.1 point-to-point

no shutdown

pvc 8/35

no ip address


interface ppp 1

ip address

cross-connect 2 atm 1.1 ppp 1

no shutdown

DDS Interface:

interface dds 1/1

                no shutdown


interface ppp 1

                ip address

                cross-connect  1  dds 1/1  ppp 1

                no shutdown

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