# Agent-server communication in OpManager - Push/Pull mode

## How can I reduce the bandwidth usage by the agent-server communication?

Switching the agents to **Push Mode** of communication with the server can help **reduce bandwidth usage,** while also saving a lot of processing power and allowing OpManager to function more efficiently.

Agent-server communication in OpManager's [agent-based monitoring](https://www.manageengine.com/network-monitoring/help/agent-monitoring.html) can happen in two modes:

1. **Pull mode:** This is where the agent(s) **contact the OpManager server in specific intervals** to fetch all changes with respect to that device's monitors. This is the default mode of communication and is best suited when there are minimal number of agent-monitored devices.

2. **Push mode:** From OpManager version 12.5.4xx onwards, a new "Push mode" is also being supported.

   - In this method, a small program called the **Notification Server** is initiated as soon as OpManager starts. All agents will register with this server, and so this Notification Server maintains an **active connection with all the agents** that are available in the OpManager server.
   - When changes are being made to any monitors (including addition of new monitors) that are being monitored using agents, the Notification server sends an **"update call" in real-time** to the corresponding agent asking it to contact OpManager immediately.
   - The agent then responds to the call, fetches the changes from the server and updates the monitor details accordingly.

Since the frequency of agent-server communication is much less than with the Pull Mode, the bandwidth consumed by the agent-server communication is also reduced.

## How can I switch between the Push and Pull communication modes in the agent?

The communication mode can be changed manually from the Registry Editor of the agent-monitored device. The steps to do it are as follows:

1. Open **Registry Editor** (Start > Run > regedit or search for "regedit" in the Start Menu) in the agent-monitored device.

   ![Registry Editor window to enable push mode in agent communication](https://cdn.manageengine.com/network-monitoring/kb/images/push-mode-registry-editor.jpeg)

2. Go to the following path: **HKEY_LOCAL_MACHINE → SOFTWARE → Wow6432Node → ManageEngine → OpManagerAgent.**

3. If your device has a 32-bit Operating System, the path would be **HKEY_LOCAL_MACHINE → SOFTWARE → ManageEngine → OpManagerAgent.**

4. Right-click on "RequestFlowType" value, click "Modify" and provide any one of these values:

   1. For Push mode: **PUSH_MODEL**
   2. For Pull mode: **PULL_MODEL**

5. Save your changes and restart the OpManagerAgent service to apply the new settings.