GLOBAL SERVER LOAD BALANCER APPARATUS AND METHOD FOR DYNAMICALLY CONTROLLING TIME-TO-LIVE

• US 20160112500A1
• Filed: 12/31/2014
• Published: 04/21/2016
• Est. Priority Date: 10/21/2014
• Status: Active Grant

• Current Assignee: Samsung SDS (China) Co., Ltd. (Samsung Group)
• Original Assignee: Samsung SDS (China) Co., Ltd. (Samsung Group)
• Inventors: KIM, Sung-Il, KIM, Sung-Duck, KIM, Jin-Yeob
• Granted Patent: US 9,954,941 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 41/0896 Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests

Abstract

Disclosed are a global server load balancer (GSLB) apparatus and a method for dynamically controlling cache time-to-live (TTL) in the GSLB apparatus. The GSLB apparatus which performs load balancing among a plurality of local servers includes a domain name system (DNS) query processor that receives a query message from a DNS server, a server selector that selects a local server among the plurality of local servers based on the received query message, a load calculator that collects state information of the GSLB apparatus, and calculates a load of the GSLB apparatus from the collected state information, and a TTL controller that updates a TTL of the GSLB apparatus based on the calculated load.

Claims

1. A global server load balancer (GSLB) apparatus which performs load balancing among a plurality of local servers, comprising:

a domain name system (DNS) query processor configured to receive a query message from a DNS server;

a server selector configured to select a local server among the plurality of local servers based on the received query message;

a load calculator configured to collect state information of the GSLB apparatus, and to calculate a load of the GSLB apparatus from the collected state information; and

a time-to-live (TTL) controller configured to update a TTL value of the GSLB apparatus based on the calculated load,

wherein the DNS query processor, the server selector, the load calculator, and the TTL controller, are implemented via at least one central processing unit (CPU) or at least one hardware processor, and

wherein the DNS query processor is further configured to transmit a response message including information about the local server selected in the server selector and the updated TTL, to the DNS server.

2. The apparatus of claim 1, wherein the state information of the GSLB apparatus comprises at least one from among CPU use rate, a memory use rate, auxiliary storage device input/output (I/O) quantity, network I/O quantity, and an amount of received query messages per unit time.

3. The apparatus of claim 1, wherein, the TTL controller is further configured to update the TTL value so that the updated TTL value is in a range between a predetermined maximum value and a predetermined minimum value, the TTL value being increased when the load exceeds a threshold value, and the TTL value being decreased when the load is less than or equal to the threshold value.

4. The apparatus of claim 3, wherein an initial TTL value is set as the predetermined maximum value.

5. The apparatus of claim 3, wherein, when the load exceeds the threshold value, the TTL controller updates the TTL value to a value between the predetermined maximum value of the TTL value and an intermediate value, the intermediate value being between the predetermined maximum value and a previous TTL value.

6. The apparatus of claim 3, wherein, when the load is equal to or less than the threshold value, the TTL controller updates the TTL value to a value between the predetermined minimum value of the TTL value and a value obtained by subtracting a predetermined reduction value from a previous TTL value.

7. A method for controlling a time-to-live (TTL) value which is performed in a global server load balancer (GSLB) apparatus for performing load balancing among a plurality of local servers, the method comprising:

receiving a query message from a domain name system (DNS) server;

selecting a local server from the plurality of local servers;

collecting state information of the GSLB apparatus and calculating a load of the GSLB apparatus from the collected state information;

updating a TTL value of the GSLB apparatus based on the calculated load; and

transmitting a response message comprising information about the selected local server and the updated TTL value, to the DNS server.

8. The method of claim 7, wherein the state information of the GSLB apparatus comprises at least one from among a central processing unit (CPU) use rate, a memory use rate, auxiliary storage device input/output (I/O) quantity, network I/O quantity, and an amount of received query messages per unit time.

9. The method of claim 7, wherein the updating of the TTL value comprises:

updating the TTL value so that the updated TTL value is in a range between a predetermined maximum value and a predetermined minimum value, the TTL value being increased when the load exceeds a threshold value and the TTL value being decreased when the load is less than or equal to the threshold.

10. The method of claim 9, wherein an initial TTL value is set as the predetermined maximum value.

11. The method of claim 9, wherein, when the load exceeds the threshold value, the updating of the TTL value comprises updating the TTL value to a value between the predetermined maximum value of the TTL value and an intermediate value, the intermediate value being between the predetermined maximum value and a previous TTL value.

12. The method of claim 9, wherein, when the load is equal to or less than the threshold value, the updating of the TTL value comprises updating the TTL value to a value between the predetermined minimum value of the TTL and a value obtained by subtracting a predetermined reduction value from a previous TTL value.

13. A computer program which is combined with hardware and stored in a non-transitory computer readable recording medium, the program configured to execute:

receiving a query message from a domain name system (DNS) server;

selecting a local server from a plurality of local servers;

collecting state information of a global server load balancer (GSLB) apparatus and calculating a load of the GSLB apparatus from the collected state information;

updating a time-to-live (TTL) value of the GSLB apparatus based on the calculated load; and

transmitting a response message comprising information about the selected local server and the updated TTL value to the DNS server.