SGS-6341-Series User Manual

Add TL
V tag as 0x0105 for PPPoE IA, TA
G_LENGTH is length field of vendor tag;
0x00000DE9 is “ADSL Forum” IANA entry of the fixed 4 bytes; 0x01 is type field of Agent
Circuit ID, length is length field and Agent Circuit ID value field; 0x02 is type field of Agent
Remote ID, length is length field and Agent Remote ID value field.
PPPoE IA supplies a default circuit ID value, the default circuit ID (The figure in the following)
includes 5 fields, ANI (Access Node Identifier) can be configured by user, its length is less than
47 bytes. If there is no ANI configured, MAC is accessed by default, occupy 6 bytes and use
space symbol to compart, “eth” occupies 3 bytes and uses space symbol to compart, “Slot ID”
occupies 2 bytes, use “/” to compart and occupy 1 byte, “Port Index” occupies 3 bytes, use “:”
to compart and occupy 1 byte, “Vlan ID” occupies 4 bytes, all fields use ASCII, user can
configure circuit ID for each port according to requirement.
ANI
(n byte)
Space
( 1byte)
eth
(3 byte)
Space
(1 byte)
Slot ID
(2 byte)
/
(1byte)
Port Index
(3 byte)
:
(1 byte)
Vlan ID
(4 byte)
Figure 51-3: Agent Circuit ID value
MAC of the access switch is the default remote ID value of PPPoE IA. remote ID value can be
configured by user flexibly, the length is less than 63 bytes.
51.1.2.4 Trusted Port of PPPoE Intermediate Agent
Discovery stage sends five kinds of packets, PADI and PADR packets sent by client to server,
PADO and PADS packets sent by server to client, and PADT packet can be sent by server or
client.
In PPPoE IA, for security and reduced traffic, set a port connected server as trusted port, set
ports connected client as untrusted port, trusted port can receive all packets, untrusted port
can receive only PADI, PADR and PADT packets which are sent to server. To ensure client
operation is correct, it must set the port connecting to server as trusted port. Each access to
device has a trusted port at least.
PPPoE IA vendor tag can not exist in PPPoE packets sent by server to client, so we can strip
and forward these vendor tags if they exist in PPPoE packets. Strip function must be
configured on trusted port, enabling strip function not to take effect on untrusted port.
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User’s Manual of SGS-6341 series