Method for DNS response reordering based on path quality and connection priority for better QOS
Described embodiments provide systems and method for reordering the IP addresses within a DNS response. The servers associated with a domain can often be located across multiple locations. The paths from a client to each of those different servers can have different link qualities. Additionally, the connection between the client and the domain can have different quality requirements. The present solution can consider the link qualities and the connection quality requirements to reorder the IP addresses within a DNS response. By reordering the IP addresses, the system can control to which of the servers the client connects and can ensure that the connection is made over a path that can fulfill the connection's quality requirements.
1. A method for domain name system (DNS) response reordering comprising:
receiving, by a device, a domain name system (DNS) response to a DNS request of a client, the DNS response comprising a list of IP addresses corresponding to a plurality of sites associated with a domain to which the client is attempting to establish the connection;
assigning, by the device via a priority policy, based on the domain or a classification of the connection to be established, a priority to the connection to be established between the client and the domain;
determining, by the device, for each link of a plurality of links between the device and the plurality of sites, a link quality of the link between the device and a respective site, the link corresponding to a respective IP address of the list of IP addresses;
modifying, by a DNS response reorderer, based on the link quality of at least one link of the plurality of links and the priority assigned to the connection to be established between the client and the domain, an order of the list of IP addresses; and
transmitting, by the device, the modified order of the list of IP addresses to the client.
2. The method of claim 1 , further comprising:
identifying, by the device, the domain of the DNS request; and
wherein identifying, by the device, the priority of the connection includes identifying the priority of the connection based on the identified domain of the DNS request.
3. The method of claim 1 , wherein determining for each link of a plurality of links between the device and the plurality of sites, the link quality of the link between the device and a respective site includes determining at least one of a metric corresponding to utilization of the link, a metric corresponding to latency of the link, a metric corresponding to a jitter of the link or a metric corresponding to packets dropped by the link.
4. The method of claim 1 , wherein the link quality of the link is based on at least one of a metric corresponding to utilization of the link, a metric corresponding to latency of the link, a metric corresponding to a jitter of the link or a metric corresponding to packets dropped by the link.
5. The method of claim 1 , further comprising identifying, from the list of IP addresses corresponding to the plurality of sites, the plurality of links between the device and the plurality of sites.
6. The method of claim 1 , further comprising identifying the plurality of sites corresponding to the IP addresses included in the list of IP addresses responsive to performing a lookup using the IP addresses.
7. The method of claim 1 , wherein modifying the order of the list of IP addresses includes replacing, at a first position of the list of IP addresses, a first IP address with a second IP address having a higher link quality responsive to determining that the priority of the connection is above a threshold.
8. The method of claim 1 , wherein modifying the order of the list of IP addresses includes replacing, at a first position of the list of IP addresses, a first IP address with a second IP address having a lower link quality responsive to determining that the priority of the connection is below a threshold.
9. The method of claim 1 , wherein receiving the DNS response to the DNS request includes intercepting, by the device, the DNS response from a DNS server to the client.
10. A system for domain name system (DNS) response reordering comprising:
a device intermediary to a plurality of clients and one or more domain name system (DNS) servers, the device including:
a DNS response parser configured to:
receive a DNS response to a DNS request of a client, the DNS response comprising a list of IP addresses corresponding to a plurality of sites associated with a domain to which the client is attempting to establish the connection, and
assign via a priority policy, based on the domain or a classification of the connection to be established, a priority to the connection to be established between the client and the domain;
a link quality estimator configured to:
determine, for each link of a plurality of links between the device and the plurality of sites, a link quality of the link between the device and a respective site, the link corresponding to a respective IP address of the list of IP addresses;
a DNS response reorderer configured to:
modify, based on the link quality of at least one link of the plurality of links and the priority assigned to the connection to be established between the client and the domain, an order of the list of IP addresses; and
transmit the modified order of the list of IP addresses to the client.
11. The system of claim 10 , wherein the DNS response parser is configured to:
identify the domain of the DNS request; and
wherein to identify the priority of the connection, the DNS response parser is further configured to identify the priority of the connection based on the identified domain of the DNS request.
12. The system of claim 10 , wherein to determine for each link of a plurality of links between the device and the plurality of sites, the link quality of the link between the device and a respective site, the link quality estimator is configured to determine at least one of a metric corresponding to utilization of the link, a metric corresponding to latency of the link, a metric corresponding to a jitter of the link or a metric corresponding to packets dropped by the link.
13. The system of claim 10 , wherein the link quality of the link is based on at least one of a metric corresponding to utilization of the link, a metric corresponding to latency of the link, a metric corresponding to a jitter of the link or a metric corresponding to packets dropped by the link.
14. The system of claim 10 , wherein the DNS request parser is further configured to identify, from the list of IP addresses corresponding to the plurality of sites, the plurality of links between the device and the plurality of sites.
15. The system of claim 10 , wherein the DNS request parser is further configured to identify the plurality of sites corresponding to the IP addresses included in the list of IP addresses responsive to performing a lookup using the IP addresses.
16. The system of claim 10 , wherein to modify the order of the list of IP addresses, the DNS response reorderer is configured to replace, at a first position of the list of IP addresses, a first IP address with a second IP address having a higher link quality responsive to determining that the priority of the connection is above a threshold.
17. The system of claim 10 , wherein to modify the order of the list of IP addresses, the DNS response reorderer is configured to replace, at a first position of the list of IP addresses, a first IP address with a second IP address having a lower link quality responsive to determining that the priority of the connection is below a threshold.
18. The system of claim 10 , wherein to receive the DNS response to the DNS request, the device is configured to intercept the DNS response from a DNS server to the client.