Apparatus and method for managing network congestion

1. A method for managing congestion on a network, the method comprising:

establishing a buffer threshold bounding a first and a second buffer region;

maintaining a rejection indicator for each of a plurality of network connections; and

preventing the buffering of a transmission bound for a first of said plurality of network connections if:

said buffer threshold is exceeded;

said rejection indicator of said first of said plurality of network connections indicates that no transmission bound for said first of said plurality of network connections was previously rejected since said threshold last became exceeded; and

said rejection indicator of any other of said plurality of network connections indicates that a transmission bound for said other of said plurality of network connections was previously rejected since said threshold last became exceeded.

2. A method according to claim 1 and further comprising rejecting said transmission bound for said first of said plurality of network connections.

3. A method according to claim 2 and further comprising setting said rejection indicator of said first of said plurality of network connections to indicate that said transmission bound for said first of said plurality of network connections has been rejected.

4. A method according to claim 1 and further comprising setting any of said rejection indicators to indicate that no transmission has been rejected once said threshold is no longer exceeded.

5. A method for managing congestion on a network, the method comprising:

maintaining a maximum buffer allocation for each of a plurality of network connections,

maintaining a rejection indicator for each of said plurality of network connections,

increasing said maximum buffer allocation for a first of said plurality of network connections, and

decreasing said maximum buffer allocation for at least a second of said plurality of network connections, wherein said increasing and decreasing occur when:

said rejection indicator of said first of said plurality of network connections indicates that a transmission bound for said first of said plurality of network connections was previously rejected, and

said rejection indicator of said second of said plurality of network connections indicates that no transmission bound for said second of said plurality of network connections was previously rejected.

6. A method according to claim 5 wherein an aggregate of said increasing is substantially proportionate to an aggregate of said decreasing.

7. A method according to claim 5 and further comprising:

establishing a buffer threshold bounding a first and a second buffer region for each of said plurality of network connections;

maintaining a current buffer allocation for each of said plurality of network connections; and

performing said increasing and decreasing steps when said current buffer allocation of said first of said plurality of network connections exceeds said buffer threshold of said first of said plurality of network connections.

8. A method according to claim 7 and further comprising rejecting a transmission bound for said first of said plurality of network connections.

9. A method according to claim 8 and further comprising setting said first rejection indicator to indicate that said transmission bound for said first of said plurality of network connections has been rejected.

10. A method according to claim 7 and further comprising setting any of said rejection indicators to indicate that no transmission has been rejected, wherein said resetting occurs when all of said rejection indicators indicate that a transmission has been rejected.

11. Network congestion management apparatus comprising

a network switch connectable with a plurality of network connections and comprising:

buffer having a first and a second buffer region;

a threshold indicator for monitoring a threshold intermediate said first and second buffer regions; and

a rejection indicator for each of said plurality of network connections;

wherein said network switch is operative to prevent the buffering of a transmission bound for a first of said plurality of network connections if:

said threshold indicator indicates that said threshold is exceeded;

said rejection indicator of said first of said plurality of network connections indicates that no transmission bound for said first of said plurality of network connections was previously rejected since said threshold last became exceeded; and

said rejection indicator of any other of said plurality of network connections indicates that a transmission bound for said other of said plurality of network connections was previously rejected since said threshold last became exceeded.

12. Network congestion management apparatus according to claim 11 wherein said network switch is further operative to reject said transmission bound for said first of said to plurality of network connections.

13. Network congestion management apparatus according to claim 12 wherein said network switch is further operative to set said rejection indicator of said first of said plurality of network connections to indicate that said transmission bound for said first of said plurality of network connections has been rejected.

14. Network congestion management apparatus according to claim 11 wherein said network switch is further operative to set any of said rejection indicators to indicate that no transmission has been rejected once said threshold is no longer exceeded.

15. Network congestion management apparatus comprising:

a network switch connectable with a plurality of network connections and comprising:

a buffer for each of said plurality of network connections, each of said plurality of network connections having a maximum buffer allocation; and

a rejection indicator for each of said plurality of network connections;

wherein said network switch is operative to:

increase said maximum buffer allocation for a first of said plurality of network connections; and

decrease said maximum buffer allocation for at least a second of said plurality of network connections, wherein said increasing and decreasing occur when:

said rejection indicator of said first of said plurality of network connections indicates that a transmission bound for said first of said plurality of network connections was previously rejected; and

said rejection indicator of said second of said plurality of network connections indicates that no transmission bound for said second of said plurality of network connections was previously rejected.

16. Network congestion management apparatus according to claim 15 wherein said network switch is further operative to increase said maximum buffer allocation for said first of said plurality of network connections in a manner that is substantially proportionate to an aggregate decrease of said maximum buffer allocation of said at least second of said plurality of network connections.

17. Network congestion management apparatus according to claim 15 and wherein said network switch further comprises:

a threshold indicator for monitoring a threshold intermediate a first and a second buffer region for each of said buffers, each of said plurality of network connections having a current buffer allocation; and

a rejection indicator for each of said plurality of network connections;

wherein said network switch is additionally operative to adjust any of said maximum buffer allocations when said threshold indicator indicates that said current buffer allocation of said first of said plurality of network connections exceeds said threshold of said first of said plurality of network connections.

18. Network congestion management apparatus according to claim 17 wherein said network switch is additionally operative to reject a transmission bound for said first of said plurality of network connections.

19. Network congestion management apparatus according to claim 18 wherein said network switch is additionally operative to set said first rejection indicator to indicate that said transmission bound for said first of said plurality of network connections has been rejected.

20. Network congestion management apparatus according to claim 17 wherein said network switch is additionally operative to set any of said rejection indicators to indicate that no transmission has been rejected, wherein said resetting occurs when all of said rejection indicators indicate that a transmission has been rejected.

21. A method according to claim 1 wherein said network is a packet-switched network and wherein transmissions therethrough comprise packets.

22. Network congestion management apparatus according to claim 1 wherein said network is a packet-switched network and wherein transmissions therethrough comprise packets.

23. A method according to claim 3 and 15 further comprising:

counting the number of times that transmission buffering is performed for said first of said plurality of network connections subsequent to said setting of said rejection indicator of said first of said plurality of network connections; and

setting said rejection indicator of said first of said plurality of network connections to indicate that no transmission has been rejected once said counting equals a predetermined value.

24. Network congestion management apparatus according to claim 12 wherein said network switch is further operative to count the number of times that transmission buffering is performed for said first of said plurality of network connections subsequent to said setting of said rejection indicator of said first of said plurality of network connections and set said rejection indicator of said first of said plurality of network connections to indicate that no transmission has been rejected once said counting equals a predetermined value.

25. A method according to claim 5 wherein said network is a packet-switched network and wherein transmissions therethrough comprise packets.

26. Network congestion management apparatus according to claim 15 wherein said network is a packet-switched network and wherein transmissions therethrough comprise packets.