Global server load balancing (GSLB) is a network technique that distributes the network traffic into multiple servers within an organization located at different geographical areas. Many websites receive multiple customer visits and high network traffic, and one DNS server can't handle all the queries and responses alone; network traffic must be distributed equally to different servers in order to prevent delay and downtime on the client's side.
GSLB-enabled DNS servers provide faster, more reliable responses for clients by routing network traffic based on two key aspects: the DNS server closest to the client's location and the availability of server.
DNS queries from clients at different locations across the globe are received by the DNS server. The GSLB-enabled DNS server will look for the authoritative DNS server location closest to the client's location to provide that server's IP address. This reduces the network latency and speeds up response times, providing clients with immediate answers from nearby DNS servers.
GSLB uses load balancing algorithms to determine how network traffic gets distributed. ManageEngine CloudDNS provides three types of algorithms:
Standard mode is the basic algorithm in which the GSLB will direct a client's DNS query to an IP or host if its available; if there is no available nameserver, there will be no load distribution, and the client will receive an error message.
Round robin is a simplified algorithm where the network traffic is distributed to all the nameservers equally. For example, the first request goes to the first server, the second request goes to the second server, and so on.
Failover mode is where the network traffic will be distributed to backup IPs or hosts when the primary IP or host faces a failure. There are two types of failover mode:
Weight-based failover distributes the traffic to multiple IPs or hosts based on their weights. The IP or host with the highest weight will be considered the primary option for traffic distribution. But the distribution will be rotated between the main host and the backup ones.
Priority-based failover allows the application to set priority for an IP or host, and the prioritized host will be considered first for directing queries; only when the prioritized host fails, the queries will be directed to backups.
GSLB fastens the DNS response for clients by distributing traffic to the authoritative nameserver nearest to clients location, thus improving the network efficiency and performance.
Distributing the network traffic across multiple servers will make them active and available for quick responding to clients. This means that clients can now access the organization's website without any delay.
With the help of GSLB, the organization can now expand the network by adding new servers in new locations near clients for seamless network services.
GLBS ensures that all the network traffic isn't transferred to one server to avoid overloading that server with queries. This increases the reliability of services.
Faster responses from the nameserver near the clients' locations streamlines DNS services.
When a server faces downtime, GSLB will immediately redirect the traffic to the next server to ensure DNS services are delivered without delay.
ManageEngine CloudDNS filters and DNS monitoring features help you enable GSLB and empower streamlined network traffic distribution across global audience.
CloudDNS filters out DNS queries and directs them to specific hosts for DNS responses. These filters play an important role in directing queries to the appropriate servers based on factors like geolocation, Autonomous System Number (ASN), and IP, providing clients quicker responses and enabling administrators to enforce operational policies. CloudDNS provides three filters for these factors.
Geo Filters narrow down the DNS queries based on client's geographical location. This filter helps you reach clients from different locations by directing queries across multiple servers. It also helps you manage local servers, geo restrictions, and response speed. This can prevent network latency and improve efficiency.
ASN Filters use a 16-digit or 32-digit numerical value referred to as distinct identifiers that are assigned to each network of the internet. These filters help exclude networks of certain ISPs or CDNs, allowing you to direct clients of an ASN value to enter a specific network. ASN Filters help with complying with security policies, business agreements, and regulations.
IP Filters distribute traffic to different hosts based on the individual client's IP address or its prefixes. These filters can be used to direct selective client IPs to the organization's hosts, which helps with security.
With the DNS monitoring features in CloudDNS, monitor the status, capacity, performance, and availability of your DNS servers and records, which are crucial for traffic distribution. DNS monitoring also plays an important role not only in improving network efficiency and security but also in reducing downtime.
GSLB monitors the status and availability of the nameservers, and when any of the servers in a group fail, GSLB will redirect the network traffic to the next available server, maintaining the DNS service without delay.
GSLB improves disaster recovery by automatically redirecting traffic to the nearest available hosts in case of a failure. This ensures that applications of the organization remain available even during outages or disasters, thus minimizing downtime and increasing consistency.
By distributing the traffic across multiple nameservers and providing the option of adding additional servers when demand increases, GSLB improves the scalability of the organization's DNS service, allowing more clients to visit their application without errors.
Yes, GSLB can be used for email servers, VoIP services, and any other internet-facing applications that can benefit from traffic distribution and failover mechanisms. This benefits many organizations regarding network traffic distribution.
