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Network Visibility can collect metrics for the following object types:
- Network links between tiers, or between tiers and load balancers/TCP endpoints
- Connections between nodes, or between nodes and load balancers/TCP endpoints
Troubleshooting a performance issue in Network Visibility is often a matter of "drilling down" from an application issue (flow) to a network issue (link) to the root cause (connection). See Workflows and Example Use Cases.
App Agents collect metrics for application flows between tiers, as shown in the Application Flow Map. This diagram shows the calls, transactions, and messages for Application X between Tiers 1 and 2.
Network Agents collect metrics for network links, which you can view in the Network Dashboard. A network link is the set of all traffic between two tiers, or between a tier and an intermediate load balancer or TCP endpoint. If an application flow transports traffic via a load balancer, Network Visibility creates a link on each side and calculates metrics for each link. This diagram shows the network traffic for Application X sent and received by the two tiers via a load balancer.
Individual nodes send and receive traffic over connections. In Network Visibility, a Connection is a set of all traffic with the same Source IP, Destination IP, Destination Port, and Protocol. This diagram shows the individual Connections that the four nodes use to send and receive traffic for Application X via the load balancer.