System and method for providing path protection of computer network traffic

• US 7,409,706 B1
• Filed: 10/02/2001
• Issued: 08/05/2008
• Est. Priority Date: 10/02/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: O'Rourke, Chris, Batz, Robert M.
• Primary Examiner(s): Zand; Kambiz
• Assistant Examiner(s): Poltorak; Peter
• Application Number:
  US09/970,364
• Time in Patent Office: 2,499 Days
• Field of Search: 714/4, 714/10, 726/11, 726/13, 718/105
• US Class Current: 726/11
• CPC Class Codes: H04L 63/0218 Distributed architectures, e.g. distributed firewalls
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/1036 Load balancing of requests to servers for services different from user content provisioning, e.g. load balancing across domain name servers
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A computer network includes an inside network and an external network. The inside network may communicate with the external network over a first path through a first inner load balancer, a first set of firewalls, and a second outer load balancer. The inside network may also communicate with the external network over a second path through a second inner load balancer, a second set of firewalls, and a second outer load balancer. In normal operating conditions, traffic is flowing on both the first and second paths. Probes are passed over each path to monitor the operating status of the path. If a failure occurs in the first inner load balancer, its operating status is changed to standby and the second inner load balancer becomes active for the traffic previously handled by the first inner load balancer. The associated first outer load balancer, recognizing that a probe has not been received to indicate an operating state of the first path, changes its state to standby so that the second outer load balancer becomes active for the traffic previously handled by the first outer load balancer.

Claims

1. A system for providing path protection for computer network traffic, comprising:

a first outer load balancer operable to handle a first portion of network traffic from an external network;

a second outer load balancer operable to handle a second portion of the network traffic from the external network;

a first inner load balancer operable to provide the first portion of the network traffic to an inside network, wherein the first portion of the network traffic from the external network has only odd numbered source addresses and the second portion of the network traffic from the external network has only even numbered source addresses;

a second inner load balancer operable to provide the second portion of the network traffic from the external network to the inside network;

a first group of firewalls operable to provide secured routing of network traffic only from the first outer load balancer to the first inner load balancer;

a second group of firewalls operable to provide secured routing of network traffic only from the second outer load balancer to the second inner load balancer;

each of the inner and outer load balancers operable to individually detect a firewall failure in the respective first and second groups of firewalls;

wherein the first and second outer load balancers are operable to send probes to the respective first and second inner load balancers, the first and second outer load balancers operable to determine an operating state of the first and second inner load balancers in response to the probes.

2. The system of claim 1, wherein the first and second outer load balancers receive the respective first and second portions of the network traffic from the external network in accordance with a hot standby routing protocol.

3. The system of claim 1, wherein the first outer load balancer determines that a failure has occurred in the first inner load balancer, the first outer load balancer operable to adjust its traffic flow routing such that the first portion of the network traffic from the external network is handled by the second outer load balancer and the second inner load balancer.

4. The system of claim 3, wherein the first outer load balancer determines that there is no longer a failure condition in the first inner load balancer, the first outer load balancer operable to adjust its traffic flow routing so that the first portion of the network traffic from the external network is once again handled by the first outer load balancer and the first inner load balancer.

5. The system of claim 1, wherein the first inner load balancer is operable to receive traffic from the inside network having only an odd numbered destination address, the second inner load balancer operable to receive traffic from the inside network having only an even numbered destination address, the first outer load balancer operable to provide traffic with the odd numbered destination address to an external network, the second outer load balancer operable to provide traffic with the even numbered destination address to the external network.

6. The system of claim 5, wherein the first inner load balancer is operable to adjust its operational state to standby in response to an error condition therein, the second inner load balancer operable to adjust its operational state to active for traffic with the odd numbered destination address.

7. The system of claim 6, wherein the first outer load balancer identifies an error condition in the first inner load balancer according to one of the probes.

8. A method for providing path protection for computer network traffic, comprising:

determining an operational status of all devices on a first path and a second path;

providing separation of devices on the first path from devices on the second path;

processing a first portion of traffic from an inside network only on the first path in response to devices on the first path being in an operational state;

processing a second portion of traffic from the inside network only on the second path in response to devices on the second path being in an operational state, wherein the first portion of the network traffic from the inside network is associated with only odd numbered destination addresses and the second portion of the network traffic from the inside network is associated with only even numbered destination addresses;

securely routing the first portion of traffic from the inside network on the first path;

securely routing the second portion of traffic from the inside network on the second path;

providing the first portion of traffic from the inside network transported only on the first path to an external network;

providing the second portion of the traffic from the inside network transported only on the second path to the external network.

9. The method of claim 8, further comprising:

receiving the first portion of traffic from the inside network only on the second path in response to any device on the first path being in a non-operational state.

10. The method of claim 9, further comprising:

securely routing the first portion of the traffic from the inside network with the second portion of the traffic from the inside network only on the second path.

11. The method of claim 10, further comprising:

providing the first portion of traffic from the inside network with the second portion of the traffic from the inside network only on the second path to an external network.

12. The method of claim 8, further comprising:

processing a first portion of traffic from the external network only on the first path in response to devices on the first path being in an operational state;

processing a second portion of traffic from the external network only on the second path in response to devices on the second path being in an operational state.

13. The method of claim 12, further comprising:

processing the first portion of traffic from the inside network on the second path with the second portion of the traffic from the inside network in response to any device on the first path being in a non-operational state;

processing the first portion of traffic from the external network on the second path with the second portion of the traffic from the external network in response to the first portion of traffic from the inside network being processed on the second path.

14. The method of claim 12, further comprising:

receiving the first portion of traffic from the external network only on the second path with the second portion of the traffic from the external network in response to any device on the first path being in a non-operational state.

15. A system for providing path protection for computer network traffic, comprising:

means for determining an operational status of all devices on a first path and a second path;

means for providing separation of devices on the first path from devices on the second path;

means for receiving a first portion of traffic from an inside network only on the first path in response to devices on the first path being in an operational state;

means for receiving a second portion of traffic from the inside network only on the second path in response to devices on the second path being in an operational state, wherein the first portion of traffic from the inside network is associated with only odd numbered destination addresses and the second portion of traffic from the inside network is associated with only even numbered destination addresses;

means for securely routing the first portion of traffic from the inside network on the first path;

means for securely routing the second portion of traffic from the inside network on the second path;

means for providing the first portion of traffic from the inside network transported only on the first path to an external network;

means for providing the second portion of the traffic from the inside network transported only on the second path to the external network.

16. The system of claim 15, further comprising:

means for receiving the first portion of traffic from the inside network on the second path in response to any device on the first path being in a non-operational state.

17. The method system of claim 15, further comprising:

means for receiving a first portion of traffic from the external network on the first path in response to devices on the first path being in an operational state;

means for receiving a second portion of traffic from the external network on the second path in response to devices on the second path being in an operational state;

means for receiving the first portion of traffic from the external network on the second path in response to any device on the first path being in a non-operational state.

18. A system for providing path protection for computer network traffic, comprising:

a first outer load balancer associated with a first set of firewalls and a first inner load balancer on a first path between an external network and an inside network, the first outer load balancer operable to provide traffic from the inside network received only through the first inner load balancer and the first set of firewalls on the first path to the external network;

a second outer load balancer associated with a second set of firewalls and a second inner load balancer on a second path between the external network and the inside network, the second outer load balancer operable to provide traffic from the inside network received only through the second inner load balancer and the second set of firewalls on the second path to the external network;

wherein traffic from the inside network on the first path is associated with only odd numbered destination addresses and traffic from the inside network on the second path is associated with only even numbered destination addresses;

wherein the first outer load balancer is operable to adjust its traffic flow routing in response to a failure condition associated with the inner load balancer on the first path so that all traffic from the inside network is received by the second outer load balancer.

19. The system of claim 18, wherein the first outer load balancer is operable to adjust its traffic flow routing in response to probes checking the operational state of devices on the first path.