SYSTEMS AND METHODS FOR NTIER CACHE REDIRECTION

• US 20120203825A1
• Filed: 02/08/2012
• Published: 08/09/2012
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Choudhary, Akshat, Gavini, Anil Kumar, Shetty, Anil
• Granted Patent: US 8,996,614 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06

Abstract

The present disclosure describes systems and methods for load balancing multiple application delivery controllers (ADCs) in multiple tiers. An upper layer of the tier comprises ADCs that load balance the plurality of ADCs of a lower layer of the tier. In order to appropriately share and maintain client IPs for transparent cache redirection scenarios, the transport layer (Transport Control Protocol (TCP)) port range is split among the ADCs of the lower tier. The lower tier ADCs would then create a connection only using a source port assigned to them. The response from the origin will then be sent to the upper level ADC which looks at the destination port and forward the packet to the correct lower tier ADC. Hence, the ADCs at two levels will work in conjunction to provide transparent cache direction.

Claims

1. A method for managing layers of intermediary devices providing cache redirection of client requests, the method comprising:

(a) receiving, by a first intermediary device of a first layer of one or more intermediary devices that load balance a plurality of intermediary devices of a second layer, a first request of a client to an origin server, each of the plurality of intermediary devices of the second layer configured to receive requests on a predetermined range of ports different than another intermediary device of the second layer;

(b) forwarding, by the first intermediary device of the first layer to a second intermediary device of the plurality of intermediary devices of the second layer, the first request of the client responsive to load balancing the first request;

(c) transmitting, by the second intermediary device of the second layer responsive to determining the first request is cacheable, the first request to a cache server;

(d) transmitting, by the second intermediary device to the origin server, a second request sent from the cache server to the origin server responsive to a cache miss; and

(e) transmitting, by the first intermediary device of the first layer, the response to the second request from the origin server to the second intermediary device of the second layer responsive to applying a policy-based route rule on a destination port identified via the response as corresponding to a port of the predetermined range of ports of the second intermediary device.

2. The method of claim 1, wherein step (a) further comprises allocating an available transport control protocol port range among each of the plurality of intermediary devices of the second layer.

3. The method of claim 1, wherein step (a) further comprises identifying, by the first intermediary device, a source internet protocol (IP) address of the first request responsive to being configured in a mode to forward the source IP address without changing the source IP address.

4. The method of claim 1, wherein step (b) further comprises forwarding, by the first intermediary device, the first request to the second intermediary device without changing the source IP address of the first request.

5. The method of claim 1, wherein step (c) further comprises determining, by the second intermediary device, that the first request is cacheable responsive to applying an expression of a policy to content of the first request.

6. The method of claim 1, wherein step (c) further comprises inserting, by the second intermediary device, the client'"'"'s internet protocol address into the first request sent to the cache server.

7. The method of claim 1, wherein step (d) further comprises receiving, by the second intermediary device from the cache server, the second request transmitted by the cache server using the destination IP address and destination port of the origin server and the source IP address and source port of the cache server.

8. The method of claim 1, wherein step (d) further comprises modifying, by the second intermediary device, the second request to use the client'"'"'s IP address as the source IP address and to use a source port selected from the predetermined range of ports allocated to the second intermediary device.

9. The method of claim 1, wherein step (e) further comprises applying, by the first intermediary device, the policy-based routing rule based on matching the destination port of the response to the predetermined range of ports for the second intermediary device and identifying an IP address of the second intermediary device as a next hop.

10. The method of claim 1, wherein step (e) further comprises transmitting, by the second intermediary device, the response to the first request of the first client based on the response of the origin server forwarded by the first intermediary device.

11. A system for managing tiers of intermediary devices providing cache redirection of client requests, the system comprising:

a first layer comprising one or more intermediary devices;

a second layer comprising a plurality of intermediary devices in communication with and load balanced by the one or more intermediary devices of the first layer, each of the plurality of intermediary devices of the second layer configured to receive requests on a predetermined range of ports different than another intermediary device of the second layer;

a first intermediary device of the one or more intermediary devices of the first layer receiving a first request of a client to an origin server and forwarding, responsive to load balancing, the first request to a second intermediary device of the plurality of intermediary devices of the second layer;

wherein the second intermediary device of the second layer transmits the first request to a cache server responsive to determining the first request is cacheable and responsive to a cache miss forwards to the origin server a second request sent from the cache server to the origin server; and

wherein the first intermediary device of the first layer transmits the response to the second request from the origin server to the second intermediary device of the second layer responsive to applying a policy-based route rule on a destination port identified via the response as corresponding to a port of the predetermined range of ports of the second intermediary device.

12. The system of claim 11, wherein each of the plurality of intermediary devices of the second layer is allocated a portion of an available transport control protocol port range.

13. The system of claim 11, wherein the first intermediary device identifies a source internet protocol (IP) address of the first request responsive to being configured in a mode to forward the source IP address without changing the source IP address.

14. The system of claim 11, wherein the first intermediary device transmits the first request to the second intermediary device without changing the source IP address of the first request.

15. The system of claim 11, wherein the second intermediary device determines that the first request is cacheable responsive to applying an expression of a policy to content of the first request.

16. The system of claim 11, wherein the second intermediary device inserts the client'"'"'s internet protocol address into the first request sent to the cache server.

17. The system of claim 11, wherein the second intermediary device from the cache server receives the second request transmitted by the cache server, the second request comprising the destination IP address and destination port of the origin server and the source IP address and source port of the cache server.

18. The system of claim 11, wherein the second intermediary device modifies the second request to use the client'"'"'s IP address as the source IP address and to use a source port selected from the predetermined range of ports allocated to the second intermediary device.

19. The system of claim 11, wherein the first intermediary device applies the policy-based routing rule based on matching the destination port of the response to the predetermined range of ports for the second intermediary device and identifies an IP address of the second intermediary device as a next hop.

20. The system of claim 11, wherein the second intermediary device transmits the response to the first request of the first client based on the response of the origin server forwarded by the first intermediary device.