In-band quality-of-service signaling to endpoints that enforce traffic policies at traffic sources using policy messages piggybacked onto DiffServ bits

• US 7,983,170 B2
• Filed: 12/19/2006
• Issued: 07/19/2011
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Keith, Seth K., Jackowski, Steven J.
• Primary Examiner(s): Ferris; Derrick W
• Assistant Examiner(s): Ghowrwal; Omar
• Application Number:
  US11/613,073
• Publication Number:
  US 20080144502A1
• Time in Patent Office: 1,673 Days
• Field of Search: 370/235, 370/392, 370/229, 370/237, 370/351, 370/389
• US Class Current: 370/237
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/35 by embedding flow control information in regular packets, e.g. piggybacking
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/167 Adaptation for transition between two IP versions, e.g. between IPv4 and IPv6 translation of Internet protocol [IP] addresses H04L61/2503
• CPC Class Codes: H04W 28/0289 Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

IP packets are scheduled at source devices such as cell phones on a private network that connect to the Internet at an edge device. A private traffic controller by the edge device detects pre-Internet congestion on the private network. The private traffic controller uses in-band piggybacked signaling of policy changes by intercepting return packets to the source devices and modifying bits such as DSCP bits in the header. Source traffic controllers in the source devices read the modified DSCP bits and implement specified policy changes, dropping or delaying packets at the source device before transmission. Congestion on RF links from cell phones is reduced by the source traffic controllers dropping packets before transmission. The source device limits or drops future packets in response to the policies signaled by the DSCP bits. Rather than indicate the existing packet'"'"'s priority, private DSCP bits signal policy changes to the source device.

Claims

1. A method for controlling packet traffic on a private network by in-band signaling of policy information to a source device via existing network packets, the method comprising:

(a) sending, by a server via a private network, one or more return packets to a source traffic controller executing on a source device;

(b) detecting, by a private network monitor, a status of congestion of the private network;

(c) determining, by a private traffic controller, to send a network policy to the source traffic controller responsive to the detection, the network policy comprising a new policy for future packets transmitted via the source traffic controller;

(d) intercepting, by the private traffic controller, the one or more return packets;

(e) modifying, by the private traffic controller, one or more Differentiated Services Code Point (DSCP) bits in the one or more return packets to embed a message identifying non-DSCP traffic control instructions for the network policy while maintaining a size of the one or more return packets, the modified one or more DSCP bits not setting priority of the one or more modified return packets;

(f) sending, by the private traffic controller, the one or more modified return packets to the source traffic controller; and

(g) receiving, by the private traffic controller, an acknowledgement of the network policy from the source traffic controller, the source traffic controller modifying the one or more DSCP bits of the one or more return packets to the server to identify the acknowledgement.

2. The method of claim 1, further comprising detecting, by the source traffic controller, that the one or more modified return packets comprise the message.

3. The method of claim 2, further comprising adjusting, by the source traffic controller, a local network policy responsive to the network policy of the message.

4. The method of claim 1, wherein step (c) further comprises generating, by the private traffic controller, the network policy responsive to the status of the network.

5. The method of claim 1, wherein step (b) further comprises detecting, by the private network monitor, an increase in congestion.

6. The method of claim 1, wherein step (b) further comprises detecting, by the private network monitor, a decrease in congestion.

7. The method of claim 1, wherein the one or more DSCP bits do not indicate a priority of a current network packet.

8. The method of claim 1, wherein step (e) further comprises modifying, by the private traffic controller, the one or more DSCP bits to embed the message to identify the network policy to control traffic at the source device.

9. The method of claim 1, wherein step (e) further comprises modifying, by the private traffic controller, the one or more DSCP bits to embed the message to identify the network policy instructing the source traffic controller to one of stop or reduce transmission rates of future packets.

10. A system for controlling packet traffic on a private network by in-band signaling of policy information to a source device via existing network packets, the system comprising:

a server sending via a private network one or more return packets to a source traffic controller executing on a source device;

a private network monitor detecting a status of congestion of the private network;

a private traffic controller determining to send a network policy to the source traffic controller responsive to the detection and intercepting the one or more return packets, the network policy comprising a new policy for future packets transmitted via the source traffic controller;

a packet modifier modifying one or more Differentiated Services Code Point (DSCP) bits in the one or more return packets to embed a message identifying non-DSCP traffic control instructions for the network policy while maintaining a size of the one or more return packets, the modified one or more DSCP bits not setting priority of the one or more modified return packets; and

wherein the private traffic controller sends the one or more modified return packets to the source traffic controller and receives an acknowledgement of the policy from the source traffic controller, the source traffic controller modifying one or more DSCP bits of one or more return packets to the server to identify the acknowledgement.

11. The system of claim 10, wherein the source traffic controller detects that the one or more modified return packets comprise the message.

12. The system of claim 11, wherein the source traffic controller adjusts a local policy for controlling traffic responsive to the network policy of the message.

13. The system of claim 10, wherein the private traffic controller generates the network policy responsive to the status of the network.

14. The system of claim 10, wherein the private network monitor detects an increase in congestion of the private network.

15. The system of claim 10, wherein the private network monitor detects a decrease in congestion.

16. The system of claim 10, wherein the one or more DSCP bits do not indicate a priority of a current network packet.

17. The system of claim 10, wherein the packet modifier modifies the one or more DSCP bits to embed the message to identify the policy to control traffic at the source device.

18. The system of claim 10, wherein the packet modifier modifies the one or more DSCP bits to embed the message to identify the network policy instructing the source traffic controller to one of stop or reduce transmission rates of future packets.

19. A method for controlling packet traffic on a private network by in-band signaling of policy information to a source device via existing network packets, the method comprising:

(a) sending, by a server via a private network, one or more return packets to a source traffic controller executing on a source device;

(b) detecting, by a private network monitor, a status of congestion of the private network;

(c) determining, by a private traffic controller, to send a network policy to the source traffic controller responsive to the detection, the network policy comprising a policy to modify a rate of transmission of future packets transmitted via the source traffic controller;

(d) intercepting, by the private traffic controller, the one or more return packets;

(e) modifying, by the private traffic controller, one or more Differentiated Services Code Point (DSCP) bits in the one or more return packets to embed a message identifying the network policy while maintaining a size of the one or more return packets; and

(f) sending, by the private traffic controller, the one or more modified return packets to the source traffic controller;

(g) extracting, by the source traffic controller, the embedded message in the DSCP bits from the one or more modified return packets, the embedded message comprising a non-DSCP traffic control instruction; and

(h) implementing, by the source traffic controller, the non-DSCP traffic control instruction of the network policy derived from the embedded message; and

(i) receiving, by the private traffic controller, an acknowledgement of the network policy from the source traffic controller, the source traffic controller modifying the one or more DSCP bits of the one or more return packets to the server to identify the acknowledgement.