Fabric Crossconnect Service

The Fabric Crossconnect service creates an L2 bridge between two given ports on the same device. For example, this service can be used on a SEBA pod to connect OLT devices to a BNG via the aggregation switch.

A fabric crossconnect entry is a tuple (deviceid, vlanid, port1, port2).

For more information, see VLAN Cross Connect

Models

This service is composed of three models:

FabricCrossconnectService global service-related parameters, such as the name of the service. There is currently no additional state here beyond the default XOS Service model.
FabricCrossconnectServiceInstance represents one half of a vlan crossconnect. Fields include the following:
- s-tag the vlan_id that will be connected
- switch_datapath_id switch id where the vlan crossconnect will be enacted
- source_port port number on the switch
BNGPortMapping represents the other half of a vlan crossconnect. Fields include the following:
- s_tag the vlan_id that will be connected. In addition to specifying a single vlan_id, the keyword ANY may be used, or a range (123-456) may be used.
- switch_port port number on the switch
- old_s_tag Field for tracking old s-tag of bngportmapping instance

FabricCrossconnectServiceInstance and BNGPortMapping work together to create the vlan crossconnect tuple, linked by a common s-tag.

Example TOSCA

Below is an example TOSCA recipe that creates a FabricCrossconnectServiceInstance:

tosca_definitions_version: tosca_simple_yaml_1_0
imports:
  - custom_types/fabriccrossconnectservice.yaml
  - custom_types/fabriccrossconnectserviceinstance.yaml
description: Create a FabricCrossconnectServiceInstance
topology_template:
  node_templates:
    service#fabric-crossconnect:
      type: tosca.nodes.FabricCrossconnectService
      properties:
        name: fabric-crossconnect
        must-exist: true

    fcsi:
      type: tosca.nodes.FabricCrossconnectServiceInstance
      properties:
        name: "custom_vm_crossconnect"
        s_tag: 123
        source_port: 3
        switch_datapath_id: "of:0000000000000201"
      requirements:
        - owner:
            node: service#fabric-crossconnect
            relationship: tosca.relationships.BelongsToOne

Below is an example TOSCA recipe that creates a BNGPortMapping for a single s-tag:

tosca_definitions_version: tosca_simple_yaml_1_0
imports:
  - custom_types/bngportmapping.yaml
description: Create a bng port mapping
topology_template:
  node_templates:
    bngmapping:
      type: tosca.nodes.BNGPortMapping
      properties:
        s_tag: "222"
        switch_port: 4

Integration with other Services

The western neighbor of the FabricCrossconnectService is typically an access service such as VOLTService. FabricCrossconnectServiceInstance participates in the dataplane chain for a given subscriber.

FabricCrossConnectService features a method acquire_service_instance(subscriber_service_instance) that may be used as a helper for creating service instances. Given that many subscribers may map to a single s_tag, it's often the case that a single FabricCrossconnectServiceInstance is used by several subscribers. acquire_service_instance does the following:

1) Check to see if an eligible FabricCrossconnnectServiceInstance already exists, and if so links it to the subscriber_service_instance. 2) If no eligible FabricCrossconnectServiceInstance already exists, then a new one will be created and linked.

Synchronization workflow