Alcatel-Lucent 7750 SR-OS, Configuration Manual

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Hybrid OpenFlow Switching
Page 580 7750 SR OS Router Configuration Guide
Hybrid OpenFlow Switch Steering using Filter Policies
A router H-OFS instance is embedded into line card IPv4 and IPv6 filter policies to achieve OF-
controlled Policy Based Routing (PBR). When H-OFS instance is created, embedded filters (IP
and IPv6) required for that instance are automatically created. The filters are created with names,
as follows:
“_tmnx_ofs_<ofs_name>”
, with the same name for IPv4 and IPv6 filters used.
If embedded filters cannot be allocated due to the lack of filter policy instances, the creation of an
H-OFS instance will fail. When the H-OFS instance is deleted, the corresponding embedded filters
are freed.
The H-OFS can be embedded only in ingress filter policies on line cards/platforms supporting
embedded filters (FP2-based or newer) and for services supporting H-OFS. Embedding of an H-
OFS in filter policies on unsupported services is blocked, embedding of an H-OFS in filter policies
in unsupported direction or on unsupported hardware follows the general filter policy
misconfiguration behavior and is not recommended. Unsupported match fields are ignored. Other
match criteria may cause a packet to match an entry.
As soon as an H-OFS instance is created, the controller can program OF rules for that instance. For
instance, the rules can be created prior to the H-OFS instance embedding into a filter policy or
prior to a filter policy with H-OFS instance embedded being assign to an interface. This allows
operator to either pre-program H-OFS steering rules, or to disable the rules without removing them
from a flow table by removing the embedding. An error is returned to controller if it attempts to
program rules not supported by the system. The following lists examples of the errors returned:
• unsupported instr: [OFPET_BAD_INSTRUCTION, OFPBIC_UNSUP_INST]
• unsupported action: [OFPET_BAD_ACTION, OFPBAC_BAD_TYPE]?
• unsupported output port : [OFPET_BAD_ACTION,
OFPBAC_BAD_OUT_PORT]?
• unsupported match field: [OFPET_BAD_MATCH, OFPBMC_BAD_FIELD]?
• unsupported match value: [OFPET_BAD_MATCH, OFPBMC_BAD_VALUE]?
• output port invalid/deleted after flow_mod is sent to filter:
OFPET_BAD_ACTION, OFPBAC_BAD_OUT_PORT]?
As the OF controller updates traffic steering rules, the Hybrid OpenFlow Switch updates the flow
table rules. This automatically triggers programming of the embedded filter, which consequently
causes instantiation of the rules for all services/interfaces that have a filter policy embedding this
H-OFS instance. Embedding filter policy configuration/operational rules apply also to embedded
filters auto-created for an H-OFS instance (see Embedded Filter Support for ACL Filter Policies
section of this guide). Note that MPLS cannot be deleted if OFS rules are created that redirect to an
LSP.