The router supports traffic steering to an RSVP, MPLS-TP, IPv4 SR-TE, or IPv6 SR-TE LSP. The following shows the OF encoding to be used by an OF controller:
flow_mod:
instruction type: OFPIT_WRITE_ACTIONS or OFPIT_APPLY_ACTION,
action type: OFPAT_OUTPUT,
The port uses SR OS LOGICAL port encoding RSVP-TE, SR-TE, or MPLS-TP LSP as described in the SR OS H-OFS logical port section.
An LSP received in a flow rule is compared against those in the H-OFS logical port table. If the table does not contain the LSP, the rule programming fails. Otherwise, the rule is installed in an ACL filter. As long as any path within the LSP is UP, the redirect rule forwards unicast IPv4 or IPv6 traffic on the current best LSP path by adding an LSP transport label and, in the case of IPv6 traffic, also adding an explicit NULL label.
When an LSP in the H-OFS logical port table goes down, the OF switch removes the LSP from its logical port table and notifies the controller of that fact if the logical port status reporting is enabled. It is up to the OF controller to decide whether to remove rules using this LSP. If the rules are left in the flow table, the traffic that was to be redirected to this LSP instead is subject to a forward action for this flow rule. If the controller does not remove the entries and the system reuses the LSP identified for another LSP, the rules left in the flow table start redirecting traffic onto this new LSP.
In some deployments, an SDN controller may need to learn from the router H-OFS logical ports status. To support this function, the OF switch supports optional status reporting using asynchronous OF protocol messages for ports status change.