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Cisco SCE 8000 10GBE Software Configuration Guide
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Chapter 14 Value-Added Services (VAS) Traffic Forwarding
How VAS Traffic Forwarding Works
illustrates the data flow from the subscriber to the network. Data flow from the network to
the subscriber works in the same way, but is received on the network port (N) and transmitted on the
subscriber port (S).
Figure 14-2
Data Flow in a VAS System
Non-VAS Data Flow
The data flow steps for a non-VAS flow are:
1.
A subscriber packet is received at the Cisco SCE platform Port 1 (S).
2.
The Cisco SCE platform classifies the flow as non-VAS flow.
3.
The packet is sent to the network on Port 2 (N).
VAS Data Flow
A VAS data flow is slightly more complex than the basic data flow. It is received and transmitted in the
same manner as the basic non-VAS Cisco SCE platform flow, but before it is transmitted to its original
destination, it flows through the VAS server.
The data flow steps for a VAS flow are:
1.
A subscriber packet is received at the Cisco SCE platform Port 1 (S).
2.
The Cisco SCE platform classifies the flow as a VAS flow.
3.
The Cisco SCE platform adds a VLAN tag to the packet.
4.
The VLAN tag is used by the Ethernet switch to route the packet to the proper VAS server.
The packet now has a VLAN tag, which is indicated by the red line.
1-S
2-N
3-S
4-N
1-S
2-N
3-S
No VAS
4-N
SCE
VAS
157201
S
N
S
N
VAS (without VLAN)
VAS (with VLAN)