Allied-Telesis AT-iMG624A Router Manual PDF (Setup & Configuration Guide)

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Ethernet command reference

Ethernet

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iMG/RG Software Reference Manual (ADSL Port)

8.6.1.1.5 ETHERNET LIST TRANSPORTS

Syntax

ETHERNET LIST TRANSPORTS

Description

This command lists all Ethernet transports that have been created using the

ETHERNET

ADD TRANSPORT

command. It displays the transport identification number and name,

and the name of the port that it uses to transport Ethernet data.

Example

--> ethernet list transports

Ethernet transports:

ID

|

Name

|

Port

-----|------------|------------

1 | default

| ethernet0

2 | t1

| bunbridge

3 | vlan_2

| ethernet1

-------------------------------

See also

ETHERNET LIST TRANSPORTS

8.7

PPPoE

8.7.1

PPPoE Overview

The PPPoE (Point to Point Protocol over Ethernet) protocol provides user and network management, and

accounting benefits to ISPs and network administrators as ISPs can easily control client connections for xDSL

and cable modems as well as plain Ethernet networks. PPPoE is an extension of the standard Point to Point Pro-

tocol (PPP). The difference between them is expressed in transport method: PPPoE employs Ethernet instead

of serial line connection.

Generally speaking, PPPoE is used to assign IP addresses to clients based on the user authentication as opposed

to open connections where static IP addresses or DHCP are used.

PPPoE has two distinct stages.

There is a Discovery stage and a PPP Session stage.

When a Host wishes to ini-

tiate a PPPoE session, it must first perform Discovery to identify the Ethernet MAC address of the peer and

establish a PPPoE SESSION_ID.

The PPPoE Discovery Stage is made up of four steps: initiation, offer, request, and session confirmation:

The PPPoE Active Discovery Initiation (PADI) packet:

Option

Description

Default Value

name

An existing Ethernet transport. To display transport names,

use the

ETHERNET LIST TRANSPORTS

command.

N/A

number

An existing Ethernet transport. To display transport num-

bers, use the

ETHERNET LIST TRANSPORTS

com-

mand.

N/A

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PPPoE Overview

PPPoE

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iMG/RG Software Reference Manual (ADSL Port)

The PPPoE client sends out a PADI packet to the broadcast address. This packet can also populate the "service-

name" field if a service name has been entered on the dial-up networking properties of the PPPoE broadband

connection. If a service name has not been entered, this field cannot be populated.

The PPPoE Active Discovery Offer (PADO) packet:

The PPPoE server, or Access Concentrator, should respond to the PADI with a PADO if the Access Concentra-

tor is able to service the "service-name" field that had been listed in the PADI packet. If no "service-name" field

had been listed, the Access Concentrator should respond with a PADO packet that has the "service-name" field

populated with the service names that the Access Concentrator can service. The PADO packet is sent to the

unicast address of the PPPoE client.

The PPPoE Active Discovery Request (PADR) packet:

When a PADO packet is received, the PPPoE client responds with a PADR packet. This packet is sent to the uni-

cast address of the Access Concentrator. The client may receive multiple PADO packets, but the client

responds to the first valid PADO that the client received. If the initial PADI packet had a blank "service-name"

field filed, the client populates the "service-name" field of the PADR packet with the first service name that had

been returned in the PADO packet.

The PPPoE Active Discovery Session-confirmation (PADS) packet:

When the PADR is received, the Access Concentrator generates unique session identification (ID) for the

Point-to-Point Protocol (PPP) session and returns this ID to the PPPoE client in the PADS packet. This packet is

sent to the unicast address of the client.

When this process has completed, the client is aware of the address of the Access Concentrator and a session

ID has been established. At this point, a normal PPP session begins. This session can remain established until a

PPPoE Active Discovery Terminate (PADT) packet is sent. The PADT may be sent by either the Access Concen-

trator or the PPPoE client.

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PPPoE

PPPoE Functional Overview

iMG/RG Software Reference Manual (ADSL Port)

8-64

FIGURE 8-4

Example

of PPPoE connection

8.7.2

PPPoE Functional Overview

8.7.2.1 PPPoE Connections

The system is designed to implement more than one embedded PPPoE clients able to connect to external

Access Concentrators. It can support up to 8 PPP simultaneous connections (shared between PPPoE or PPPoA

types).

DSL connection

Internet

shared internet

access server

PPPoE

“Virtual” Connection

ISP’s PPPoE

Server

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PPPoE Functional Overview

PPPoE

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iMG/RG Software Reference Manual (ADSL Port)

8.7.2.2 PPPoE connections over ATM - VLAN Unaware

PPPoE connections can be established over a specific ATM channel without or without

knowledge of VLANs.

If without, all PPPoE frames are untagged and are terminated directly on the IP layer without passing to the

internal CPE bridging process. This limits this PPPoE application to those solutions where the sharing of the

same ATM channel (VPI/VCI) between local PPP interfaces and internal user network traffic is not requiested.

Such a solution implies a strict routed CPE configuration where internal user network traffic can be transported

over an ATM channel already used by a PPP connection only if routed at the IP level.

The configuration of a PPPoE connection over ATM (PPPoEoA) it’s performed in a three stage process:

•

First, an un-numbered IP interface (all zeros ip address) must be created:

ip add interface <ip_name>

•

Second, a PPPoE transport object responsible for the PPPoE session management and PPPoE frames trans-

mission must be created and the ATM channel specified:

pppoe add transport <pppoe_name> dialout pvc <iface> a1 <vpi> <vci>

This command must specify the ATM channel coordinates (VPI/VCI) where PPPoE frames will be exchanged

(always as untagged frames only).

•

Third, the un-numbered IP interface must be attached to the previously created PPPoE transport object.

ip attach transport <ip_name> <pppoe_name>

8.7.2.3 PPPoE connections - VLAN Aware

PPPoE connections can also be established with knowledge of VLANs.

In this case the PPPoE transport is associated with the VLAN - and PPPoE traffic passes through the bridge - and

flows out the ADSL interface - or an Ethernet interface - depending on the VLAN configuration.

The configuration of a PPPoE connection over ATM (PPPoEoA) is performed in a three stage process:

•

First, an un-numbered IP interface (all zeros ip address) must be created:

vlan create <pppoe_vlan> 512

ip add interface <ip_name>

•

Second, a PPPoE transport object responsible for the PPPoE session management and PPPoE frames trans-

mission must be created and the VLAN specified: Note that the name of the pppoe transport must be differ-

ent from the name used for the pppoe vlan.

pppoe add transport <pppoe_name> dialout eth 2 <pppoe_vlan>

•

Third, the un-numbered IP interface must be attached to the previously created PPPoE transport object.

ip attach transport <ip_name> <pppoe_name>

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