LAYER-2 PACKET RETURN IN PROXY-ROUTER COMMUNICATION PROTOCOL ENVIRONMENTS

• US 20100027544A1
• Filed: 07/30/2008
• Published: 02/04/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: Blue Coat Systems Incorporated (Gen Digital Inc.)
• Inventors: Li, Qing
• Granted Patent: US 8,509,235 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/66 Layer 2 routing, e.g. in Ethernet based MAN's
• CPC Class Codes: H04L 45/741 Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6

Abstract

A Layer 2 packet return mechanism in a proxy, such as a web cache, operatively associated with a redirecting router. In a particular embodiment, the present invention provides a Layer 2 packet return mechanism in a Web Cache Communication Protocol (WCCP) network environment. In one embodiment, the present invention provides an efficient mechanism allowing a proxy or web cache to recognize WCCP redirected packets, forwarded using Layer 2 forwarding mechanisms, and subsequently to return unprocessed packets to the original forwarding WCCP router using a Layer 2 packet return mechanism.

Claims

1. A method comprising:

maintaining a data structure comprising one or more entries, each entry comprising a link layer address of a redirecting router corresponding to an established proxy-router association of one or more established proxy-router associations for redirection of packets;

associating, at a link layer process, redirected packets received with corresponding redirecting routers identified in the data structure; and

using link layer address information in the data structure to construct link layer headers for returning the redirected packets to the redirecting router.

2. The method of claim 1 further comprising

establishing a proxy-router association with a redirecting router for redirection of packets;

and

adding, responsive to establishing the router-proxy association, link layer address information of the re-redirecting router to the data structure.

3. The method of claim 1 further comprising

deleting, response to termination of a router-proxy association with a redirecting router, a corresponding entry in the data structure.

4. The method of claim 1 wherein the redirected packets each comprise a link layer header including a source link layer address, and wherein the associating redirected packets, for one or more redirected packets, comprises

accessing, at the link layer process, the data structure against the source link layer address of a packet to identify a matching entry in the data structure;

and

if the data structure includes a matching entry, marking the packet as a router-redirected packet and associating the packet with the matching entry.

5. The method of claim 1 further comprising

receiving, at the link layer process, a redirected packet returned from a higher layer process;

accessing the data structure to identify an entry associated with the packet; and

constructing a destination link layer address for the packet based on address information of the entry of the data structure associated with the packet.

6. The method of claim 1 wherein the link layer address information comprises a Media Access Control (MAC) address.

7. The method of claim 1 wherein the router-proxy association is a Service Group defined by a Web Caching Communication Protocol.

8. A method, comprising:

receiving, at a link layer process, a redirected packet from a redirecting router, wherein the redirected packet comprises a link layer header including a source link layer address;

accessing, at the link layer process, a router table against the source link layer address to identify a matching entry in the router table; and

if the router table includes a matching entry, marking the packet as a router-redirected packet and associating the packet with the matching entry.

9. The method of claim 8 further comprising:

receiving, at the link layer process, the redirected packet returned from a higher layer process;

accessing the router table to identify an entry associated with the packet; and

constructing a destination link layer address for the packet based on address information of the entry of the router table associated with the packet.

10. The method of claim 8 further comprising

establishing a proxy-router association with a redirecting router for redirection of packets;

and

adding, responsive to establishing the router-proxy association, link layer address information of the re-redirecting router in an entry of the router table.

11. The method of claim 8 further comprising

deleting, response to termination of a router-proxy association with a redirecting router, a corresponding entry in the router table.

12. The method of claim 10 wherein the link layer address information comprises a Media Access Control (MAC) address.

13. The method of claim 10 wherein the router-proxy association is a Service Group defined by a Web Caching Communication Protocol.

14. An apparatus, comprising:

one or more network interfaces,

a memory;

one or more processors;

a proxy-router intercommunication module comprising computer-executable instructions stored on a computer readable medium, the instructions readable by the or more processors to;

establish proxy-router associations with one or more redirecting routers for redirection of packets;

cause, responsive to a successful association with a redirecting router, an entry for the redirecting router to be added to a redirecting router table;

a network communications protocol stack comprising a link layer module comprising computer-executable instructions stored on a computer readable medium, the instructions readable by the one or more processors, the instructions, when read and executed, for causing the one or more processors to;

access a source link layer address of a received packet stored in the memory;

associate, responsive to finding an entry in the redirecting router table that matches the source link layer address, the received packet with the found entry;

receive the redirected packet returned from a higher layer process;

access the redirecting router table to identify an entry associated with the redirected packet; and

construct a destination link layer address for the packet based on address information of the entry of the forwarding router table associated with the packet.

15. The apparatus of claim 14 further comprising computer-executable instructions for causing the one or more processors to

tag, responsive to finding an entry in the redirecting router table that matches the source link layer address, the received packet as a redirected packet.

16. The apparatus of claim 14 further comprising computer-executable instructions for causing the one or more processor to

cause, responsive to a termination of the association with the redirecting router, the entry for the redirecting router to be deleted from the redirecting router table.

17. The apparatus of claim 14 wherein the source link layer address of the received packet comprises a Media Access Control (MAC) address.

18. The apparatus of claim 14 wherein the router-proxy associations are Service Groups defined by a Web Caching Communication Protocol.

19. The apparatus of claim 14 wherein the proxy-router intercommunication module further comprises computer-executable instructions, when read and executed, for causing the one or more processors to:

cause, responsive to termination of an association with a redirecting router, an entry for the redirecting router to be deleted from the redirecting router table.