Virtual Private LAN Services
7750 SR OS Services Guide Page 507
Ingress VLAN Swapping
This feature is supported on VPLS and VLL service where the end to end solution is built using
two node solutions (requiring SDP connections between the nodes).
In VLAN swapping, only the VLAN-id value will be copied to the inner VLAN position.
Ethertype of the inner tag will be preserved and all consecutive nodes will work with that value.
Similarly, the dot1p bits value of outer-tag will not be preserved.
Figure 83: Ingress VLAN Swapping
The network diagram describes the network where at user access side (DSLAM facing SAPs)
every subscriber is represented by several QinQ SAPs with inner-tag encoding service and outer-
tag encoding subscriber (DSL line). The aggregation side (BRAS or PE facing SAPs) the is
represented by DSL line number (inner VLAN tag) and DSLAM (outer VLAN tag). The effective
operation on VLAN tag is to drop inner tag at access side and push another tag at the aggregation
side.
Fig_36
SAP per DSL &
per application
DSLAM
MPLS network
SAP per
DSLAM
BRAS
Lb= VC label
D-VLAN= DSLAM
CPE
SAP per
DSLAM
L-VLAN= DSL lineC-VLAN= application
Service per application
per DSLAM
Service per application
per DSLAM
Video
Payload LbL
Payload LC Payload DL
Payload C
Ingress PE Egress PE
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