System for selecting a proxy pair based on configurations of autodiscovered proxies on a network

• US 8,762,569 B1
• Filed: 01/17/2013
• Issued: 06/24/2014
• Est. Priority Date: 05/30/2006
• Status: Active Grant

• Current Assignee: Riverbed Technology, LLC (Riverbed Technology Incorporated)
• Original Assignee: Riverbed Technology Incorporated
• Inventors: Ly, Kand, Ioffe, Maksim, Landrum, Alfred, Day, Mark Stuart
• Primary Examiner(s): Luu, Le H
• Application Number:
  US13/744,364
• Time in Patent Office: 523 Days
• Field of Search: 709/220, 709/221, 709/226, 709/223, 709/224, 709/225, 709/238, 709/239, 709/240, 709/242, 709/243, 709/219, 709/206, 709/230, 709/246, 370/352
• US Class Current: 709/239
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/288 Distributed intermediate devices, i.e. intermediate devices for interaction with other intermediate devices on the same level
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

Network devices include proxies and where multiple proxies are present on a network, they can probe to determine the existence of other proxies. Where more than two proxies are present and thus different proxy pairings are possible, the proxies are programmed to determine which proxies should form a proxy pair. Marked probe packets are used by proxies to discover each other and probing is done such a connection can be eventually formed even if some probe packets fail due to the marking. Asymmetric routing can be detected and proxies configured for connection forwarding as necessary.

Claims

1. In a network wherein a plurality of proxies are operating in paths between at least one client and at least one server wherein multiple network paths are possible between a client and a server, a method of detecting asymmetric routing wherein packets from the client to the server take one network path and packets from the server to the client take a different network path, the method comprising:

receiving, at a first proxy, a request to initiate a connection;

modifying the request to initiate a connection to include a probe message;

sending the modified request into the network;

receiving, at a second proxy, the modified request;

determining, at the second proxy, an asymmetric path, wherein said determining comprises at least one of;

detecting whether a client-side proxy receives a reset message from the client with an invalid header relative to packet headers that are expected from a symmetrical path, or

detecting whether a server-side proxy receives an acknowledgement message from the server with an invalid header relative to packet headers that are expected from a symmetrical path; and

modifying a second proxy state to a state wherein the second proxy defers from establishing a proxy pair for the connection being requested.

2. The method of claim 1, further comprising caching, at each of the first and second proxies, a pair of addresses, comprising an address of the client for the connection and an address of the server for the connection.

3. In a network wherein a plurality of proxies are operating in paths between at least one client and at least one server wherein multiple network paths are possible between a client and a server, a set of non-transitory computer-readable storage mediums storing instructions that, when executed by a first proxy and a second proxy, cause the first proxy and second proxy to perform a method of detecting asymmetric routing wherein packets from the client to the server take one network path and packets from the server to the client take a different network path, the method comprising:

receiving, at the first proxy, a request to initiate a connection;

modifying the request to initiate a connection to include a probe message;

sending the modified request into the network;

receiving, at the second proxy, the modified request;

determining, at the second proxy, an asymmetric path, wherein said determining comprises at least one of;

detecting whether a client-side proxy receives a reset message from the client with an invalid header relative to packet headers that are expected from a symmetrical path, or

detecting whether a server-side proxy receives an acknowledgement message from the server with an invalid header relative to packet headers that are expected from a symmetrical path; and

modifying a second proxy state to a state wherein the second proxy defers from establishing a proxy pair for the connection being requested.

4. The set of non-transitory computer-readable storage mediums of claim 3, wherein the method further comprises caching, at each of the first and second proxies, a pair of addresses, comprising an address of the client for the connection and an address of the server for the connection.

5. In a network wherein a plurality of proxies are operating in paths between at least one client and at least one server wherein multiple network paths are possible between a client and a server, a system for detecting asymmetric routing wherein packets from the client to the server take one network path and packets from the server to the client take a different network path, the system comprising:

a first proxy comprising;

a first processor;

a first non-transitory computer-readable storage medium storing instructions that, when executed by the first processor, cause the first proxy to perform a first method, the first method comprising;

receiving, at the first proxy, a request to initiate a connection,

modifying the request to initiate a connection to include a probe message, and

sending the modified request into the network; and

a second proxy comprising;

a second processor;

a second non-transitory computer-readable storage medium storing instructions that, when executed by the second processor, cause the second proxy to perform a second method, the second method comprising;

receiving, at the second proxy, the modified request,

determining, at the second proxy, an asymmetric path, wherein said determining comprises at least one of;

detecting whether a client-side proxy receives a reset message from the client with an invalid header relative to packet headers that are expected from a symmetrical path, or

detecting whether a server-side proxy receives an acknowledgement message from the server with an invalid header relative to packet headers that are expected from a symmetrical path; and

modifying a second proxy state to a state wherein the second proxy defers from establishing a proxy pair for the connection being requested.

6. The system of claim 5, wherein the first method further comprises caching, at the first proxy, a pair of addresses, comprising an address of the client for the connection and an address of the server for the connection, and wherein the second method further comprises caching, at the second proxy, a pair of addresses, comprising an address of the client for the connection and an address of the server for the connection.