What is the difference between Global Traffic Manager (GTM) and Server Load Balancer (SLB)?
A: First, GTM distributes application service traffic by resolving domain names to multiple IP addresses through DNS, allowing different users to access different IP addresses. It also dynamically updates the DNS resolution IP list through health checks to achieve fault isolation and failover. End users connect directly to the service IP address without going through GTM. SLB, on the other hand, distributes user access requests in real-time to different servers by proxying these requests. End user traffic must pass through SLB.
Generally, SLB is used for load balancing within the same region, while GTM can be used for load balancing across multiple SLB addresses in different regions.
The comparison between the two is shown in the following table:
Comparison item | Network Layer | Backend address | Weighted round-robin | Cross-region difficulty | Fault isolation time | Session persistence |
Global Traffic Manager | 3 layers | Domain name, IP | Support | Easy | Minute-level | Not supported |
Server Load Balancer (SLB) | 4, 7 | IP | Support | Challenge | Second-level | Support |
What is the difference between Global Traffic Manager (GTM) and Cloud DNS?
A: Global Traffic Manager is built on "Cloud DNS" and "CloudMonitor" as underlying services. GTM integrates the intelligent resolution capabilities of DNS and the application service monitoring capabilities of CloudMonitor to provide customers with features such as nearby access for users from different networks or regions, health checks for application service status, and automatic failover.
Can the CNAME access domain name of Global Traffic Manager (GTM) be directly accessed through a URL?
A: No, you cannot use the CNAME access domain name of GTM directly as the final URL for user access. The CNAME access domain name provided by GTM, like those provided by CDN and other products, can only be used for service registration mapping and cannot be used as the final user access URL.
How does Global Traffic Manager (GTM) determine if an application service has failed?
A: GTM integrates application service monitoring and provides 14 monitoring nodes globally. It can use a combination of multiple monitoring points to determine if a service is abnormal. Customers can choose to monitor application services using ping, tcp, or http methods to detect service failures.
Ping health check: Can determine if an application service has failed based on packet loss rate and response time.
TCP health check: Can determine if an application service has failed based on the response time of the tcp port.
HTTP(S) health check: Can determine if an application service has failed based on HTTP(S) response time and return code information.
How long does it take for Global Traffic Manager (GTM) failover to take effect?
A: After multiple tests and verifications by the testing team, when an application service fails, GTM can detect the failure and switch over in as little as 1 minute. The total network recovery time = fault detection time + network-wide effect time.
Due to changes in the monitoring platform probes and TTL caching by ISPs across the country, the network-wide effect test results may vary when using different monitoring platforms and at different testing times.
The Standard Edition can detect failures and switch over in as little as 4 minutes
Fault detection time: GTM can guarantee fault detection time. The current default health check configuration can accurately detect failures and switch over in about 4 minutes.
Network-wide effect time: GTM cannot guarantee the final effect time across the entire network because it is limited by the TTL cache settings of ISPs across the country and different network environments. Therefore, the network-wide effect time depends on the cache setting time of ISPs across the country.
The Ultimate Edition can detect failures and switch over in as little as 1 minute
Fault detection time: When the health check interval is set to 15 seconds, TTL is 1 second, and the consecutive failure count is 3, failures can be accurately detected in about 1 minute after they occur.
Network-wide effect time: GTM cannot guarantee the final effect time across the entire network because it is limited by the TTL cache settings of ISPs across the country and different network environments. Therefore, the network-wide effect time depends on the cache setting time of ISPs across the country.
Can domain names be used in the address pool of Global Traffic Manager (GTM)?
A: Yes, you can. The GTM address pool can contain IP addresses or domain names, but IP addresses and domain names cannot exist in the same address pool. When multiple domain names are filled in the address pool, the address pool performs round-robin load balancing on these domain names by default.
Can Global Traffic Manager (GTM) implement intelligent DNS access?
A: Yes, you can. GTM integrates intelligent DNS resolution. Currently, you can use GTM for intelligent DNS resolution for China's 4 major ISPs, 7 major regions, and 6 continents outside China, enabling users from different networks or regions to access nearby services and improve access speed.
Does Global Traffic Manager (GTM) support "session persistence"?
A: No, it does not. GTM is a DNS-level management system. It uses DNS responses to route clients to the appropriate application service address. Clients connect directly to the application service IP address, not through GTM. Therefore, GTM cannot see the HTTP traffic between the client and server, so it cannot implement "session persistence" functionality.
Can a domain name use both Global Traffic Manager (GTM) and CDN at the same time?
A: Yes, you can. CDN can be used in front of GTM. For more information, see GTM implementation for CDN origin site IP disaster recovery switching solution.
Can I add CNAME access domain names provided by CDN service providers to the address pool of Global Traffic Manager (GTM)?
A: You can add them, but you cannot achieve the best effect for health checks and failover. Generally, CDN has many nodes, while GTM has limited health check monitoring nodes, so it cannot obtain accurate health check status and perform switching. Please try to avoid this usage method.