HP VAN SDN Controller Administrator Guide v3

NOTE: LinkManager operation requires LLDP to be enabled on OpenFlow
switches in the network.
Operation includes:
• Learning and maintaining all inter-switch links in the control domain.
• Providing data used by the controller topology module to construct
end-to-end paths.
• Deciphering port state changes.
• Generates link events to notify interested listeners.
• Identifies "multi-hop" links between disconnected segments of the control
domain.
• Providing information used by applications to reconfigure flows when
a link goes down.
To avoid sending LLDP discover packet on certain ports such as an edge
port, LinkManager maintains a special list of ports identified as "Suppressed
LLDP Ports". Adding ports to the suppressed LLDP list can be done using
the REST API.
Link Service marks the LLDP TLV it sends by associating a unique ID in one
of the optional LLDP TLVs. This enables Link Service to differentiate the LLDP
messages it generates from the ones generated by the switches.
As it is possible for non-OpenFlow devices to be present between
OpenFlow switches, Link Service also sends out BDDP messages to discover
"multi-hop links", which refer to a link between two OpenFlow switches
on a path through one or more non-OpenFlow devices.
2.3 Application Manager 21