How relays work

A relay is an agent that is configured to redistribute software and security updates to other agents. Relays help your deployment perform well as it grows and scales.

Default relays are available inside Workload Security. Agents should be able to use them if they can connect to Workload Security. You might need more relays for performance or cost reasons.

Alternatively, software updates (but not security updates) can be distributed by a local mirror web server.

How relays distribute updates

The following information is only applicable to relay update functionality for versions earlier than 20.0.0-3445. See also Improvements to the relay.

Relays are organized into relay groups. The relays provided by Workload Security are in a relay group named Primary Tenant Relay Group. If you decide to deploy your own relays, you will need to create at least one more relay group.

Agents get a randomly ordered list of relays for their assigned relay group. When an agent needs to download an update, it tries the first relay. If there is no response, the agent tries the next in the list until it can successfully download the update. Because the list is random for each agent, this distributes load evenly across relays in a group.

When to deploy your own relays

If you need to reduce bandwidth and costs on your Internet or WAN connection, deploy a relay inside your own network. This reduces how much external traffic occurs when protected computers need to download updates. Deploying your own relays is also useful if you have network segments with limited bandwidth.

For instructions on how to deploy your own relays, see Deploy more relays.

Improvements to the relay

Major improvements to self-deployed relays were introduced with agent version 20.0.0-3445. Earlier versions of the relay download every supported agent software package (all versions, all platforms) from Workload Security, and every security update from their primary security update source. This takes approximately 400 GB of disk space and downloads can take several hours to complete. The new relay is a reverse proxy which only downloads and caches agent software packages and security updates that are requested by agents, rather than downloading all released updates. Also, the new relay downloads both the agent software packages and security updates directly from Workload Security relays.

These relay improvements are currently in preview and only available to specific customers. For more information about accessing the latest relay improvements, contact Trend Micro Support.

When you deploy a new relay or upgrade an existing relay to version 20.0.0-3445 or later and you have opted into the relay improvements preview, as per the preceding note, you will get the new and improved relay functionality and, if upgrading, will notice an immediate decrease in the amount of disk space required. There are some key differences to be aware of with the new relay functionality:

• New relays cannot be arranged in a hierarchy. If you have older relays arranged in a hierarchy and upgrade them to agent version 20.0.0-3445 or later, those relays will each get their updates directly from the relays provided by the Workload Security service.
• New relays for agent version 20.0.0-3771 and earlier cannot connect to Workload Security relays via proxy. This support is added in version 20.0.0-3964.
• The Secondary Source setting (Administration > System Settings > Updates > Security Updates > Secondary Source) includes a new option: Allow Agents/Appliances to download security and software updates from Primary Tenant Relay Group if user-deployed Relays are not accessible. This option is disabled by default, so does not affect any previous settings. When enabled, you can download security and software updates from the Primary Tenant Relay Group to help resolve any issues arising from relays you have deployed.

Information about older relays

The following information is only applicable to older relays whose agent version is earlier than 20.0.0-3964.

Relay groups for older agents can be organized in a hierarchy: one or more first-level (parent) relay groups download updates directly from Workload Security and the Primary Security Update Source (usually via their Internet or WAN connection), and then second-level (child) relay groups download updates indirectly via the first-level group, and so on. If you put a child relay on each local network, then agent updates usually use the local network connection, as opposed to remote connections to the Internet. This saves external connection bandwidth (a typical performance bottleneck) and makes updates faster, especially for large deployments with many networks or data centers.

Performance and bandwidth usage can be affected by relay group hierarchy that can specify the following:

• Update order—Child relay sub-groups download from their parent group, which must finish its own download first. Therefore a chain of sub-groups can be useful if you want a delay, so that all updates are not occurring at the exact same time.
• Cost—If large distances or regions are between your parent and child relay groups, it might be cheaper for them to download directly instead of via parent relay groups.
• Speed—If many or low-bandwidth subnets are between your parent and child relay groups, it might be faster for them to download directly or via a grandparent instead of via parent relay groups. However, if too many relays do this, it will consume external connection bandwidth and eventually decrease speed.

Your relay group hierarchy could minimize Internet and internal network bandwidth usage. Only one parent relay group might use the Internet connection, while sub-groups would download from the parent, over their local network connection. Agents would download from their local relay group.

Large scale deployments might have many agents connect to each relay. This requires relays on more powerful, dedicated servers (instead of more relays on shared servers). For more information, see Deep Security Agent and Relay sizing.

Hierarchies are set up during relay group creation.