SNR S2989G-48TX-RPS — настройка функций безопасности в PPPoE: Руководство пользователя [350/553]

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S2989G-24TX Operation Manual

Chapter 6 Security Function Configuration

6-77

its’ 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.

6.10.1.2.1 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 process is as follows:

Figure 6-26 PPPoE IA protocol exchange process

6.10.1.2.2 PPPoE Packet Format

PPPoE packet format is as follows:

Ethernet II frame

PPPoE data

Version

Type

Code

Session ID

Length Field

TLV1

……

TLV N

Destination MAC

Source MAC

Type Field

PPPoE Data

CRC Check Sum