About cross-domain discovery

Cross-domain discovery can be configured to join two or more discovered domains together.

For performance or operational reasons, networks are often discovered in sections, known as discovery domains. For example, if your network is so large that discovering it in one discovery takes too long, you might choose to split network discovery into different domains.

Discovering the network in domains can be more convenient and faster. You can also choose to have different configuration options for different domains. For example, each domain has its own poll policies. However, there are disadvantages to discovering the network in pieces. If a device in domain A is connected to a device in domain B, this connection is not represented in the topology database or in the GUI. Domains must be viewed separately.

If you want to visualize multiple domains linked together in one network view, you must enable, configure, and run cross-domain discoveries. Connections between devices in different domains are found and added to the topology.

When all discovered domains have been aggregated, Network Views can be composed of devices from all domains. In the Network Hop View, searches for devices can span domains.

Note: Cross-domain network views can not be polled; only network views from individual domains can be polled.

Considerations for splitting the network into domains

Links between devices in different domains are not as easy to discover as links between devices within one domain.

It is important to scope your discovery domains to ensure the minimum of links between domains. For example, you would not normally split the network such that highly connected switches were in different domains. Natural splits for domains are often along geographical lines.

Restriction:

However you split your network, you must ensure that any given device appears in only one domain. That is, the discovery domains must not overlap if you want to join them together using cross-domain discovery.