Provider Bridges (Qinq) - FibroLAN Falcon Gen-3 M-Class User Manual

Falcon M-Class | User Guide
4.7.4

Provider Bridges (QinQ)

The use of an extra VLAN header (service provider tag) as part of the Ethernet frame header to
provide differentiation between traffic flows (whether a separate service, or a separate customer)
is common in service provider networks. It extends the notion of bridging from that of bridging
between LAN segments or virtual LANs (defined by traditional VLAN tags), to bridging between
customers or services.
Providers can use the service provider VLAN tag to identify Ethernet traffic that belongs to a
specific Service, and give it the correct treatment (e.g. if the service is more important or time
sensitive than others it can get the right QoS handling).
The µFalcon S is designed to serve as an NTU for Metro-Ethernet access applications. Such
applications use the Provider Bridges (802.1ad) standard to enable Ethernet services
implementation.
The Provider Edge Bridge inserts a Service Tag (S-Tag) on all frames received from the
Customer network.
This enables implementation of transparent L2 service for high numbers of customers.
Determination of which service to assign a frame to can be based on:
1. Ingress port – All frames received on a specific ingress port will be assigned to a single
service (encapsulated with the same S-Tag).
Such functionality when used for point-to-point service is defined as EPL (Ethernet Private
Line) in MEF specs.
2. Ingress port + C-Tag – A frame received on a specific ingress port will be assigned to a
service based on the port and a table that maps the VLAN tag, on the incoming frame (C-
Tag) to the service tag (S-Tag).
Such functionality, when used for point-to-point service, is defined as EVPL (Ethernet
Virtual Private Line) in MEF specs.
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