Administrator's Guide

2.5 Topology manager
The topology manager computes the broadcast tree to avoid loops and broadcast storms. On a
given switch it also does the following:
• Provides a list of discovered ports on a given switch.
• Indicates whether a switch port is an edge port (connection point) or part of a link.
• Indicates whether a port is in a blocked or open state by determining whether ingress broadcast
traffic is allowed through the port.
• Verifies whether a path exists between two nodes.
• Enumerates the clusters of OpenFlow-capable switches.
• For a given switch, provides details of the cluster to which it belongs.
• The Topology Manager provides notification to subscribed applications regarding changes
in the broadcast tree and cluster. This enables development of intelligent and proactive
applications that can subscribe to topology change notifications.
2.6 Topology viewer
The topology viewer creates and updates a network graph for visualizing the network the controller
discovers. The Reload button will force a reload of all the nodes and links from the server. For
enhanced performance, the topology view caches nodes and links. In some situations this cache
may get out of sync with the controller. Performing a “Reload” will clear out the topology viewer
cache and regenerate the topology view.
The topology viewer uses the services of the topology manager and link manager.
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