To enable a VLAN on the switch to be bridged throughout the service provider network, you define service instances. A service instance definition includes the service name, the type of forwarding to use, and QoS information. A service instance is also associated with a unique service VLAN (or SVLAN), which is identified by the service VLAN ID (or S-VID).
The administrator can subscribe individual ports to a service. When a port subscribes to a service, a VLAN is created on the switch (if it does not already exist) and the subscribing port is configured as a participant in the SVLAN. The service provider port (called the Network-to-Network, or NNI, port) is also configured as a participant in the SVLAN in order to transmit and receive upstream/downstream traffic.
A subscription includes match criteria such as the customer VLAN ID, such as C-VID, priority, S-VID. When an incoming packet on UNI-P matches the subscription criteria on the port, the switch adds the service VLAN tag to the packet and, optionally, re-marks the C-VID/removes the C-tag before forwarding/redirecting to the service provider network. When an incoming packet on UNI-S matches the subscription criteria on the port, the switch may remark S-VID and/or remarks C-VID/removes C-tag to the packet before forwarding/redirecting to the service provider network. LCOS SX supports up to 4K service subscriptions per switch/port.
When a TLS service is subscribed on a port, then the port's P-VID is set to be the S-VID of the TLS service. The P-VID of the NNI port is set to the Management VLAN. The default management VLAN is 1. Creation and participation behavior of VLANs on the switch is the same for all types of services (TLS, E-LAN, E-Tree, E-Line) of services.
In LCOS SX software, VLANs and participation of ports (customer and service provider ports) is configured automatically based on service and subscription configuration. It is recommended that administrators do not create or change VLANs and port VLAN participations on any ports. Manual configuration of VLANs and port participations may result in undefined behavior in the system.
