Load balancing switch protocols

• US 6,580,715 B1
• Filed: 01/11/1999
• Issued: 06/17/2003
• Est. Priority Date: 05/04/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Bare, Ballard C.
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US09/228,110
• Time in Patent Office: 1,618 Days
• Field of Search: 370/238, 370/238.1, 370/252, 370/254-258, 370/389, 370/392, 370/395.1, 370/396, 370/367, 370/400-409, 709/105, 709/238, 709/220, 709/222
• US Class Current: 370/396
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/243 using M+N parallel active paths
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226

Abstract

A switch to switch protocol for network load balancing which permits parallel redundant paths in a network to be utilized while reducing broadcast or problems inherent in prior switch configuration protocols. In particular, the present invention includes in the protocol a hello packet protocol which serves to exchange load balancing information among switches within a common load balance domain. Further, the hello packet protocol of the present invention enables detection and correction of improperly configured loops outside a load balance domain.

Claims

1. A method operable within a network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches in order to identify switches within the load balance domain and switches outside the load balance domain, said hello packets include identification information identifying a particular port in a switch that generates a hello packet;

b) identifying if said corresponding ports are within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches.

2. The method of claim 1 wherein said hello packets include hello request packets and hello response packets and wherein the step of exchanging includes the steps of:

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet.

3. The method of claim 2 wherein the step of identifying includes the step of:

identifying the corresponding port on said first switch as within said load balance domain in response to receipt of said hello response packet.

4. The method of claim 2 further comprising the step of:

identifying the corresponding port of said first switch as outside said load balance domain in response to failure to receive said hello response packet in response to transmission of said hello request packet from said first switch to said second switch.

5. The method of claim 4

wherein the step of transmitting hello request packets comprises the step of:

periodically transmitting said hello request packet from said first switch to said second switch, and

wherein the method further comprises the step of;

identifying a dead port within said load balance domain in accordance with said hello request packets.

6. The method of claim 5 wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the step of identifying a dead port includes the steps of:

first detecting, in said second switch, the expiration of a dead period of time equal to said hello time parameter value during which no hello request packet is received from said first switch;

detecting, in response to the step of first detecting, a consecutive number of dead periods during where said consecutive number is equal to said dead count parameter value; and

identifying said corresponding port of said second switch as a dead port in response to the detection of said consecutive dead periods.

7. The method of claim 2 wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the step of exchanging further comprises the steps of:

negotiating said hello time value and said dead count parameter between said first switch and said second switch.

8. The method of claim 7 wherein the step of negotiating includes the step of:

transmitting additional hello request packets with a modified hello time parameter value until a hello response packet is received with an equal hello time parameter value.

transmitting additional hello request packets with a modified dead count parameter value until a hello response packet is received with an equal dead count parameter value.

9. The method of claim 7 wherein the step of negotiating includes the step of:

transmitting additional hello request packets with a modified dead count parameter value until a hello response packet is received with an equal dead count parameter value.

10. The method of claim 2 wherein said hello request packets include a source MAC address value identifying the transmitting switch and identifying the port of the transmitting switch from which the hello request packet is transmitted and wherein the method further comprises the step of:

identifying an illegal configuration of network devices associated with a switch which received an illegal hello request packet.

11. The method of claim 10 wherein the step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on a port of a switch where each of said multiple hello requests identifies a different source MAC address.

12. The method of claim 10 wherein the step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on multiple ports of a switch where each of said multiple hello requests identifies an identical source MAC address.

13. A network switch including a computer readable storage medium tangibly embodying a method operable within said network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches in order to identify switches within the load balance domain and switches outside the load balance domain, said hello packets include identification information identifying a particular port in a switch that generates a hello packet;

b) identifying if said corresponding ports are within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches.

14. The switch of claim 13 wherein said hello packets include hello request packets and hello response packets and wherein the method step of exchanging includes the steps of:

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet.

15. The switch of claim 14 wherein the method step of identifying includes the step of:

identifying the corresponding port on said first switch as within said load balance domain in response to receipt of said hello response packet.

16. The switch of claim 14 wherein the method further comprises the step of:

identifying the corresponding port of said first switch as outside said load balance domain in response to failure to receive said hello response packet in response to transmission of said hello request packet from said first switch to said second switch.

17. The switch of claim 16

wherein the method step of transmitting hello request packets comprises the step of:

periodically transmitting said hello request packet from said first switch to said second switch, and

wherein the method further comprises the step of;

identifying a dead port within said load balance domain in accordance with said hello request packets.

18. The switch of claim 17 wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the method step of identifying a dead port includes the steps of:

first detecting, in said second switch, the expiration of a dead period of time equal to said hello time parameter value during which no hello request packet is received from said first switch;

detecting, in response to the step of first detecting, a consecutive number of dead periods during where said consecutive number is equal to said dead count parameter value; and

identifying said corresponding port of said second switch as a dead port in response to the detection of said consecutive dead periods.

19. The switch of claim 14 wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the method step of exchanging further comprises the steps of:

negotiating said hello time value and said dead count parameter between said first switch and said second switch.

20. The switch of claim 19 wherein the method step of negotiating includes the step of:

transmitting additional hello request packets with a modified hello time parameter value until a hello response packet is received with an equal hello time parameter value.

transmitting additional hello request packets with a modified dead count parameter value until a hello response packet is received with an equal dead count parameter value.

21. The switch of claim 19 wherein the method step of negotiating includes the step of:

transmitting additional hello request packets with a modified dead count parameter value until a hello response packet is received with an equal dead count parameter value.

22. The switch of claim 14 wherein said hello request packets include a source MAC address value identifying the transmitting switch and identifying the port of the transmitting switch from which the hello request packet is transmitted and wherein the method further comprises the step of:

identifying an illegal configuration of network devices associated with a switch which received an illegal hello request packet.

23. The switch of claim 22 wherein the method step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on a port of a switch where each of said multiple hello requests identifies a different source MAC address.

24. The switch of claim 22 wherein the method step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on multiple ports of a switch where each of said multiple hello requests identifies an identical source MAC address.

25. A method operable within a network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches;

b) identifying said corresponding ports as within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches;

wherein said hello packets include hello request packets and hello response packets and wherein the step of exchanging includes the steps of;

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet;

identifying the corresponding port of said first switch as outside said load balance domain in response to failure to receive said hello response packet in response to transmission of said hello request packet from said first switch to said second switch;

wherein the step of transmitting hello request packets comprises the step of;

periodically transmitting said hello request packet from said first switch to said second switch; and

wherein the method further comprises the step of;

identifying a dead port within said load balance domain in accordance with said hello request packets;

wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the step of identifying a dead port includes the steps of;

first detecting, in said second switch, the expiration of a dead period of time equal to said hello time parameter value during which no hello request packet is received from said first switch;

detecting, in response to the step of first detecting, a consecutive number of dead periods during where said consecutive number is equal to said dead count parameter value; and

identifying said corresponding port of said second switch as a dead port in response to the detection of said consecutive dead periods.

26. A method operable within a network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches;

b) identifying said corresponding ports as within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches;

wherein said hello packets include hello request packets and hello response packets and wherein the step of exchanging includes the steps of;

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet;

wherein said hello request packets include a source MAC address value identifying the transmitting switch and identifying the port of the transmitting switch from which the hello request packet is transmitted and wherein the method further comprises the step of;

identifying an illegal configuration of network devices associated with a switch which received an illegal hello request packet.

27. The method of claim 26 wherein the step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on a port of a switch where each of said multiple hello requests identifies a different source MAC address.

28. The method of claim 26 wherein the step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on multiple ports of a switch where each of said multiple hello requests identifies an identical source MAC address.

29. A network switch including a computer readable storage medium tangibly embodying a method operable within said network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches;

b) identifying said corresponding ports as within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches;

wherein said hello packets include hello request packets and hello response packets and wherein the method step of exchanging includes the steps of;

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet;

wherein the method step further comprises the step of identifying the corresponding port of said first switch as outside said load balance domain in response to failure to receive said hello response packet in response to transmission of said hello request packet from said first switch to said second switch;

wherein the method step of transmitting hello request packets comprises the step of;

periodically transmitting said hello request packet from said first switch to said second switch; and

wherein the method further comprises the step of;

identifying a dead port within said load balance domain in accordance with said hello request packets;

wherein said hello request packets include a hello time parameter value and include a dead count parameter value and wherein the method step of identifying a dead port includes the steps of;

first detecting, in said second switch, the expiration of a dead period of time equal to said hello time parameter value during which no hello request packet is received from said first switch;

detecting, in response to the step of first detecting, a consecutive number of dead periods during where said consecutive number is equal to said dead count parameter value; and

identifying said corresponding port of said second switch as a dead port in response to the detection of said consecutive dead periods.

30. A network switch including a computer readable storage medium tangibly embodying a method operable within said network switch for exchanging information among a plurality of network switches within a load balance domain, said method comprising the steps of:

a) exchanging hello packets between corresponding ports on a first switch of said plurality of network switches and a second switch of said plurality of network switches;

b) identifying said corresponding ports as within said load balance domain in accordance with the exchanged hello packets; and

repeating steps a) and b) for each port on switches of said plurality of switches;

wherein said hello packets include hello request packets and hello response packets and wherein the step of exchanging includes the steps of;

transmitting a hello request packet from said first switch to said second switch; and

receiving, in said first switch, a hello response packet transmitted from said second switch to said first switch in response to transmission of said hello request packet;

wherein said hello request packets include a source MAC address value identifying the transmitting switch and identifying the port of the transmitting switch from which the hello request packet is transmitted and wherein the method further comprises the step of;

identifying an illegal configuration of network devices associated with a switch which received an illegal hello request packet.

31. The switch of claim 30 wherein the method step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on a port of a switch where each of said multiple hello requests identifies a different source MAC address.

32. The switch of claim 30 wherein the method step of identifying an illegal configuration includes the step of:

detecting reception of multiple hello request packets on multiple ports of a switch where each of said multiple hello requests identifies an identical source MAC address.