Network Monitoring Sessions
- What is a network monitoring session
- How a network monitoring session works
- What to do when some sessions are marked as disabled
What you are going to learn:
A network monitoring session is configured between two monitoring agents to measure the network performance between these two agents. Every 500 ms, packets are sent between the agents and the network metrics (such as latency, jitter, packet loss, packet duplication, packet reordering and DSCP propagation) are calculated based on those packets.
Communication between agents 
To measure the network performance between two monitoring agents, the agents must communicate together. When a monitoring session is created by a Network Monitoring Template, the system automatically selects one agent as the Client Agent and the other one as the Server Agent. Learn more on Network Monitoring Role Selection.
The client agent sends a packet to the server every 500 ms and the server replies back when it receives the packet. The measurement information is added inside the packet by both agents. By default, the port 23999/UDP is used for the network performance monitoring packets. Firewall settings might need some changes to permit the measurement packets. Learn more on Firewall Configurations.
Every minute, the client agent reports the performance measurements to the Obkio Cloud for analysis. In case of a session down (i.e. session timeout), both agents will report that information to the Obkio Cloud as soon as it detects a session timeout.
Monitoring Session Status
The Monitoring Session Status is there to guide the user's attention towards the monitoring sessions with issues to help pinpoint the root cause as soon as possible. In the Obkio App, there are four monitoring session statuses:
- Red - The session is either down or severely degraded
- Yellow - The session is degraded
- Green - Everything is good
- Grey - No data, Unknown Status or Agent in maintenance
The status changes based on the presence (or not) of a Network Issue on the monitoring session. The status is based on the severity levels:
- Critical: Dark Red
- Error: Light Red
- Warning: Dark Yellow
- Information: Light Yellow
- OK: Green
Disabled Monitoring Sessions
In a Subscription Plan, there are a limited number of monitoring sessions that can be created. This number is global to the entire organization and is often referred to as a pool of sessions. The number of monitoring sessions depends on the number of created monitoring agents and the number of monitoring sessions per agent that are added to the pool. For example, the Premium plan offers 10 monitoring sessions per agent. This means that an account with 50 agents will have a maximum of 500 monitoring sessions.
If the number of created monitoring sessions by the network monitoring templates is higher than the number of monitoring session available in the pool, tha last created session will be disabled. If this happens, one can either modify the Network Monitoring Templates or change the Subscription Plan.
Session is waiting for data
Once a session is correctly created and configured, the monitoring agents will receive the session configuration and start the network measurements. It can take up to 10 minutes to see data after a configuration change.
Now, if you don't have data after 10 minutes, maybe the two agents are not able to communicate together. Take a look at the following articles:
Session Data Upload Buffer
If the monitoring agent is not able to send the session data to the Obkio Cloud, it will store the data in its memory for up to 8 hours. During that time, it will keep trying to upload the data until it is successful. This delay will be reduced if the monitoring agent detects that the host doesn't have enough memory available.
