What is GTM (Global Traffic Manager) and what does it do?

Short answer

GTM (Global Traffic Manager) is the module that makes TR7 the authoritative DNS server for domain names and gives the DNS answer according to the health of the targets, the location of the client and the data center metrics. Instead of returning the same fixed address to every query, it gives the address that is healthy and suitable at that moment; in this way, the client is directed to the correct data center before it establishes a connection. GTM is built on DNS Service, domain and record; each domain works in Standalone, Disaster Recovery or Datacenter mode. GTM is licensed separately as the TR7 GTM product (Products & Licensing).

How Does It Work?

1. The NS records of the domain name are updated to point to the address of the DNS Service on TR7 (at the domain name provider, outside TR7). In this way, the queries for the domain name reach GTM.
2. Health Checks and Health Scenarios continuously monitor the status of the targets and of the data centers in the background.
3. The unhealthy addresses of the record are eliminated and the mode of the domain is applied; when a query comes, the remaining addresses are put into the answer according to the Balance Algorithm of the record. If no candidate address remains, the Fail-Safe Records are returned.
4. The client connects directly to the returned address; the application traffic does not pass through GTM.

Details: How does DNS-based traffic management work; when is the decision made?

GTM in TR7

What	Where
Screens	The Configuration Menu → GTM tab
DNS Service, domains and records	Under GTM Services, Service Management and the Domains and Records tabs of each service
Decision definitions (common to all services)	Remote Devices (Data Centers), Health Checks, Health Scenarios, Trigger Actions
Working together with external DNS	Express Profiles (DNS Integration) and DNS Forwarder Profiles
Monitoring	The Dashboard tab of the service and GTM Logs

Details of the parts: What are the basic building blocks of GTM?

Common Misconceptions

• "GTM distributes the traffic through itself." GTM determines only the DNS answer; the client connects directly to the returned address (What is the difference between GTM and the Load Balancer?).
• "A GTM record can point only to a TR7 vService." The address in the record is entered freely; it can also be a server or service outside TR7.
• "A switchover in GTM reaches all clients immediately." Clients and resolvers keep the previous answer in the cache for the TTL period of the record (What are the limits of DNS-based routing; how do TTL and the resolver cache affect the decision?).
• "GTM is only for multi-data-center setups." In Standalone mode, it works as authoritative DNS even in a single data center (I have a single data center; do I need GTM?).

How it is done in the documentation

• GTM (Global Traffic Manager) · What Is GTM (Global Traffic Manager)?
• GTM (Global Traffic Manager) · How Does It Work?
• GTM (Global Traffic Manager) · Operating Modes
• GTM (Global Traffic Manager) · GTM on TR7

Related questions

• What is the difference between GTM and the Load Balancer?
• What are the basic building blocks of GTM?
• What is the difference between the Standalone, Disaster Recovery and Datacenter modes?
• What is the difference between an authoritative DNS server and a recursive resolver?