SNR S2940-8G-v2, Руководство по настройке

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SNR S2940-8G-v2 Switch Configuration Guide
PPPoE Intermediate Agent Configuration
PADO (PPPoE Active Discovery Offer) packet to client according to the received source MAC
address of PADI packet, the packet will take sever name and service name.
3. Client sends PADR packet: The third step, client selects a server to process the session
according to the received PADO packet. It may receives many PADO packets for PADI
message of the first step may be sent to many servers (select the server according to whether
the service information of PADO packet match with the servce information needed by client).
MAC address of the other end used for session will be known after server is selected, and
send PADR (PPPoE Active Discovery Request) packet to it to announce server the session
requirement.
4. Server responds PADS packet: The fourth step, server establishes a session ID according
to the received PADR packet, this session ID will be sent to client through PADS (PPPoE
Active Discovery Session-confirmation) packet, hereto PPPoE discovery stage is completed,
enter session stage.
PADT (PPPoE Active Discovery Terminate) packet is an especial packet of PPPoE, it's Ethernet
protocol number (0x8863) is the same as four packets above, so it can be considered a packet
of discovery stage. To stop a PPPoE session, PADT may be sent at the discretional time of the
session. (It can be sent by client or server)
PPPoE Intermediate Agent supplies a function that identify and locate the user. When passing
network access device, PADI and PADR messages sent by client with the access link tag of this
device at PPPoE discovery stage, so as to exactly identify and locate the user on server.
If the direct-link access device is LAN switch, the added information include: MAC, Slot ID, Port
Index, Vlan ID, and so on. This function is implemented according to Migration to Ethernet-based
DSL aggregation.
PPPoE Intermediate Agent Exchange Process
PPPoE Intermediate Agent exchange process is similar to PPPoE exchange process, for the first
exchange process, the access link tag is added to PADI and PADR packets. The exchange pro-
cess is as follows:
Host
PPPoE Intermediate
Agent / Relay
Access Concentrator
PADI
PADI + LineID
PADO
PADO
PADR
PADR + LineID
PADS
PADS
LCP Message Exchange
NCP Message Exchange
Date Exchange
P
PP
oE
D
is
co
ve
ry
St
ag
e
P
PP
oE
Se
ss
io
n
St
ag
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Figure 54.1: PPPoE IA protocol exchange process
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