Controller Packet Forwarding When Hybrid Mode Is Enabled - HP HPE VAN SDN Controller 2.7 Administrator's Manual

Controller packet forwarding when hybrid mode is enabled

Figure 49 Controller operation with hybrid mode enabled
When hybrid mode is enabled (the default), the specific packet types for which the controller
monitors and overrides switch forwarding rules depends on the applications installed and running
in the controller. That is, the controller overrides normal packet forwarding rules in the OpenFlow
switch with application-specific forwarding rules, such as:
copying ARP request/reply and DHCP offer/ACK packets to the controller so that it can
discover end-hosts
stealing BDDP packets to the controller so that it can discover inter-switch links
changing the priority on Microsoft Lync packets to improve instant messaging speed
monitoring DNS requests to detect dangerous end-host behavior
Packets in flows that the controller does not examine or direct are forwarded through normal
switching operations without controller intervention.
NOTE: Hewlett Packard Enterprise recommends that hybrid mode be enabled when controlling
traditional, established networks where applications-related traffic is responsible for only a subset
of the overall traffic load on the network. Hybrid mode is commonly enabled in established
networks where new applications are installed and running on the controller, creating a need to
override normal switching behavior for specific flows.
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