Signaling for reserving a communications path

• US 20020196808A1
• Filed: 02/21/2002
• Published: 12/26/2002
• Est. Priority Date: 02/21/2001
• Status: Active Grant

• Current Assignee: Polytechnic University (New York University)
• Original Assignee: Polytechnic University (New York University)
• Inventors: Douglas, Brian Charles, Karri, Ramesh, Veeraraghavan, Malathi, Wang, Haobo
• Granted Patent: US 7,212,495 B2
• Time in Patent Office: Days
• US Class Current: 370/468
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0278 WDM optical network architectures
• CPC Class Codes: H04J 3/1682 Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5631 Resource management and allocation
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A call signaling protocol that uses simplified messaging to set up, confirm set up, tear down, and confirm tear down of a connection. The available capacity of communications links is tracked so that it can be quickly determined whether or not a link can handle a call. Segments (e.g., time slots, wavelengths, etc.) of a link having enough available capacity are allocated by a separate operation. Connection state information is also tracked. The simple messages and information used by the signaling protocol permits it to be easily implemented in hardware. Such an implementation enables high-speed, high-capacity, call signaling.

Claims

1. For use with a node of a communications network, a method for setting up a connection in response to a request, the method comprising:

a) determining a next link of the connection based on routing information;

b) determining whether the determined next link of the connection has sufficient capacity to meet that requested by the request;

c) if the determined next link of the connection is determined to not have sufficient capacity to meet that requested by the request, repeating (b) and (c) at least once to try an alternative next link;

d) if the determined next link of the connection is determined to have sufficient capacity to meet that requested by the request, then updating connection admission control information to decrease the capacity of the link to reflect the capacity requested by the request.

2. The method of claim 1 wherein if the determined next link of the connection is determined to have sufficient capacity to meet that requested by the request, then further requesting a connection identifier.

3. The method of claim 2 further comprising:

e) accepting a requested connection identifier received; and

f) providing an interface number and allocation control information to an interface associated with the interface number.

4. The method of claim 3 further comprising:

g) if an interface receives an interface number and allocation control information associated with the interface number, then

i) determining a bit-vector corresponding to the interface number,

ii) determining a first available part of the link, and

iii) marking the bit vector such that bits corresponding to the determined first available part of the link are marked as unavailable.

5. The method of claim 4 wherein the link is a time division multiplexed link.

6. The method of claim 4 wherein the link is a wavelength division multiplexed link.

7. The method of claim 1 further comprising:

e) accepting allocated capacity information;

f) updating switch mapping information in response to the received allocated capacity information; and

g) updating state information based on the allocated capacity information.

8. The method of claim 3 further comprising:

g) accepting allocated capacity information;

h) updating switch mapping information in response to the received allocated capacity information;

i) updating state information based on the allocated capacity information; and

h) generating a set up message including the connection identifier and the interface.

9. For use with a node of a communications network, the node having interfaces terminating communications links, an apparatus for setting up a connection in response to a request, the apparatus comprising:

a) at least one storage device storing

i) routing information;

ii) connection admission control information; and

b) a programmable device adapted to

i) determine a next link of the connection based on the routing information;

ii) determine whether the determined next link of the connection has sufficient capacity to meet that requested by the request of the call;

iii) repeat (ii) and (ii) at least once to try an alternative next link if the next link of the connection is determined to not have sufficient capacity to meet that requested by the request; and

iv) update the connection admission control information to decrease the capacity of the link to reflect the capacity requested by the request if the determined next link of the connection is determined to have sufficient capacity to meet that requested by the request.

10. The apparatus of claim 9 wherein the programmable device is a field programmable gate array.

11. The device of claim 9 wherein the programmable device is further adapted to request a connection identifier if the determined next link of the connection is determined to have sufficient capacity to meet that requested by the request.

12. The device of claim 11 wherein the programmable device is further adapted to

accept a requested connection identifier;

and

provide an interface number and allocation control information to an interface associated with the interface number.

13. The device of claim 12 wherein the programmable device is further adapted to

if an interface receives an interface number and allocation control information associated with the interface number, then

i) determining a bit-vector corresponding to the interface number,

ii) determining a first available part of the link, and

iii) marking the bit vector such that bits corresponding to the determined first available part of the link are marked as unavailable.

14. The device of claim 13 wherein the link is a time division multiplexed link.

15. The device of claim 13 wherein the link is a wavelength division multiplexed link.

16. The device of claim 9 wherein the programmable device is further adapted to

accepting allocated capacity information;

updating switch mapping information in response to the received allocated capacity information; and

updating state information based on the allocated capacity information.

18. The machine readable medium of claim 17 wherein the state of the connection is selected from a groups of states consisting of (A) closed, (B) setup sent, (C) established, and (D) release sent.

19. The machine readable medium of claim 17 wherein the characteristic of the connection stored in the fifth field is a bandwidth value required by the connection.

17. For use with a node of a communications network, the node having interfaces terminating communications links, and being adapted to effect a signaling protocol for establishing a connection, a machine readable medium having a machine readable data structure comprising a plurality of entries, each of the entries including:

a) a first field for storing an index for indexing the entry based on an identifier of a connection used locally by the node;

b) a second field for storing a second identifier of the connection used by a node upstream of the node in the connection;

c) a third field for storing a third identifier of the connection used by a node downstream of the node in the connection;

d) a fourth field for storing a state of the connection; and

e) a fifth field for storing a characteristic of the connection.

20. For use in call signaling protocol, a method for use by a node of a communications network to determine a link of a connection, the method comprising:

a) determining a next hop of the connection based on routing information;

b) determining a link associated with the determined next hop;

c) determining whether or not the determined link has sufficient communications resources to satisfy the call; and

d) only if it is determined that the determined link has sufficient communication resources to satisfy the call, then allocating communication resources of the link to the call.

21. The method of claim 20 wherein the communications resources is bandwidth.

22. The method of claim 20 wherein the link is a multiplexed link having channels, and

wherein the act of allocating communication resources of the link to the call includes determining available channels of the link until the sum of capacity of the determined available channels is enough to satisfy the call.

23. The method of claim 22 wherein the link is a time division multiplexed link and wherein the channels are time-slots.

24. The method of claim 22 wherein the link is a wavelength division multiplexed link and wherein the channels are wavelengths.

26. The apparatus of claim 25 wherein the communications resources is bandwidth.

27. The apparatus of claim 25 wherein the link is a multiplexed link having channels, and

wherein the means for allocating communication resources of the link to the call includes means for determining available channels of the link until the sum of capacity of the determined available channels is enough to satisfy the call.

28. The apparatus of claim 27 wherein the link is a time division multiplexed link and wherein the channels are time-slots.

29. The apparatus of claim 27 wherein the link is a wavelength division multiplexed link and wherein the channels are wavelengths.

25. For use in call signaling protocol, an apparatus for use by a node of a communications network adapted to determine a link of a connection, the apparatus comprising:

a) means for determining a next hop of the connection based on routing information;

b) means for determining a link associated with the determined next hop;

c) means for determining whether or not the determined link has sufficient communications resources to satisfy the call; and

d) means for allocating communication resources of the link to the call only if it is determined that the determined link has sufficient communication resources to satisfy the call.