Virtual path management in hierarchical ATM networks

• US 6,304,549 B1
• Filed: 05/08/1997
• Issued: 10/16/2001
• Est. Priority Date: 09/12/1996
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Veeraraghavan, Malathi, Srinivasan, Santhanam
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): KWOH, JASPER C
• Application Number:
  US08/852,892
• Time in Patent Office: 1,622 Days
• Field of Search: 370/252, 370/254, 370/398, 370/395, 370/397, 370/409, 370/410, 370/468, 370/450, 370/230
• US Class Current: 370/230
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 2012/5621 Virtual private network [VPN]; Private-network - network-interface (P-NNI)
• CPC Class Codes: H04L 2012/5635 Backpressure, e.g. for ABR

Abstract

This is a method for dynamic and distributed management of Virtual Path Connections (VPCs) in a hierarchical ATM network. VPC parameters, including VPC type (heterogeneous or homogeneous), source node characteristics, end-to-end VPC constraints (GoS and QoS), and the number of on-demand connections to be supported, are determined or specified. Network resources, such as bandwidth and buffer size availability, are also determined. The parameters and information relating to the network resources are sent to a connection server that computes an optimal physical route for the VPC, allocates resources along the computed route, and notifies switches along the route of the new allocation of resources. The switches then change their respective configurations to accommodate the new allocation.

Claims

1. Dynamic virtual path connection management system in a hierarchical ATM network comprising:

a) means for obtaining parameters characterizing a virtual path desired to be provisioned between said two switching nodes in said network and communicating said parameters to a first control device associated with a said switching node in said network;

b) means for communicating information relating to switching element resources currently available at each switching node contained in said network to said first control device;

c) means for computing from said parameters and switching element resource information an optimal route between said two switching nodes that is capable of realizing a virtual path connection there between; and

,

d) means for allocating switching element resources for switching elements contained in said computed route.

2. Dynamic virtual path connection management system according to claim 1, wherein said route of said virtual path connection includes one or more switches and interconnecting links, said means for computing including means for allocating bandwidth and buffer size resources among each said one or more switches along said route.

3. Dynamic virtual path connection management system according to claim 1, further comprising a first message routing scheme for communicating messages sequentially between each said switch of said route.

4. Dynamic virtual path connection management system according to claim 3, further comprising a second message routing scheme for simultaneously communicating resource allocation messages in parallel from said computing means to each of its associated switches along the route.

5. Dynamic virtual path connection management system according to claim 2, further including a switch server associated with a switch along said route, said switch server for receiving resource allocation messages from said computing means and for configuring its associated switch in accordance with bandwidth and buffer resource constraints.

6. Dynamic virtual path connection management system according to claim 1, further including means for monitoring service usage along said route of said realized virtual path connection, whereby said computing means re-allocates said resources of said virtual path connection for accommodating on demand service changes along said route.

7. Dynamic virtual path connection management system according to claim 6, wherein said means for monitoring service usage of said virtual path connection includes monitoring on demand service requests at each said switch for a predetermined window of time, each said switch server associated with a respective switch communicating status of said switch to said computing means.

8. Dynamic virtual path connection management system according to claim 2, wherein said computing means compares said bandwidth resources of a particular switch with first and second predetermined threshold values, and communicates a message to said particular switch to decrease bandwidth allocation of said switch when said virtual path connection usage at said switch falls below said first predetermined threshold or, increase bandwidth allocation of said switch along said route when said virtual path connection usage at said switch increases above said second predetermined threshold.

9. Dynamic virtual path connection management system according to claim 2, wherein said computing means computes a new virtual path connection between said two nodes when a prior computed route for said virtual path connection is unable to achieve computed bandwidth resource allocations.

10. Dynamic virtual path connection management system according to claim 1, further including means for determining whether there are physical failures or additions of one of interconnecting links, nodes, or primary servers elements in said ATM network, and communicating information of failed or added elements via said first message routing system to other nodes in the system.

11. Method for automatically provisioning a communication channel between two switching nodes of an ATM network including a plurality of interconnected switching nodes, each said switching node including at least a switching element and an associated switch control device;

said method comprising;

a) providing at least two connection servers for path management in said ATM network;

b) associating each said switching node with one of said at least two connection servers;

c) obtaining parameters characterizing said communication channel, said parameters includes end-to-end Cell Loss Ratio and Cell Transfer Delay between said two switching nodes of said ATM network;

d) communicating said parameters to a first connection server associated with a said switching node in said network;

e) periodically communicating information relating to switching element resources currently available at each switching node contained in said network to said first connection server;

f) from said parameters and periodically communicated current switching element resource information, computing an optimal route between said two switching nodes that is capable of realizing said communication channel and apportioning end-to-end Cell Loss Ratio and Cell Transfer Delay among said switching elements along said optimal route, and allocating new switching element resources for switching elements contained in said computed route; and

g) communicating allocated switching element resources Lo each switch control device associated with a switching node along said route, each said switch control device configuring a respective switching element to maintain said new switching resources allocated thereto.

12. Method for automatically provisioning a communication channel according to claim 11, wherein said end-to-end Cell Loss Ratio is apportioned equally among said switching elements along said route.

13. Method for automatically provisioning a communication channel according to claim 11, wherein said end-to-end Cell Transfer Delay is apportioned equally among said switching elements along said route.

17. Method for automatically provisioning a communication channel according to claim 11, wherein said step g) of communication allocated switching element resources to each respective switch control device includes communicating allocated switching element resources sequentially between each said switching element of said route.

18. Method for automatically provisioning a communication channel according to claim 11, wherein said ATM network implements a message routing scheme for sequentially communicating allocated switching element resources between each respective switch control device along said route.

19. Method for automatically provisioning a communication channel according to claim 17, wherein said first connection server is associated with one or more of a group of switching nodes, said step g) of communicating allocated switching element resources to each respective control device includes communicating allocated switching element resources substantially simultaneously from said first connection server to each said switch control device of an associated node computed as part of said route.

20. Method for automatically provisioning a communication channel according to claim 17, wherein said first connection server maintains topological information regarding status of switching element resources for nodes in said computed route.

21. Method for automatically provisioning a communication channel according to claim 17, wherein said ATM network is organized as groups of interconnected nodes, said first connection server maintaining topological information regarding status of switching element resources for its associated group of nodes in said computed route.

22. Method for automatically provisioning a communication channel according to claim 21, wherein said ATM network contains one or more groups of nodes organized in a first hierarchical level, each said group of nodes having an associated connection server for communicating in a second hierarchical level, said method further including the step of communicating topological information of available switching element resources contained in nodes between connection servers of each associated one or more groups of nodes at said second hierarchical level.

23. Method for automatically provisioning a communication channel according to claim 22, whereby a computer route contains switching nodes located in different groups, said step g) of communicating allocated switching element resources to each receptive switch control device along said route includes communicating allocated switching element resources sequentially between nodes of one group to nodes located in subsequent groups.

24. Method for automatically provisioning a communication channel according to claim 11, wherein said switching element resources include bandwidth and buffer size of said switching elements, each said switch control device configuring a respective switching element to maintain new bandwidth resources allocated thereto.

25. Method for automatically provisioning a communication channel according to claim 24, further including the steps of:

h) monitoring switching element resource usage along said route of said communication channel; and

i) re-allocating said switching element resources of nodes contained along said route for accommodating on demand service changes along said route.

26. Method for automatically provisioning a communication channel according to claim 25, wherein said monitoring step h) includes continually repeating steps c), d) and e).

27. Method for automatically provisioning a communication channel according to claim 26, wherein said re-allocating step i) includes comparing said bandwidth resource information with a predetermined threshold and increasing said bandwidth resources of one or more switching elements along said route when on demand service along said route increases above a predetermined threshold, and decreasing said bandwidth resources of a switching element along said route when on demand service along said route decreases below a predetermined threshold.

28. Method for automatically provisioning a communication channel according to claim 27, wherein said re-allocating step i) includes increasing said buffer quantity of a switch along said route when on demand service along said route increases above a predetermined threshold.

29. Method for automatically provisioning a communication channel according to claim 25, wherein said re-allocating resources step i) includes computing a second route between said two nodes by repeating steps c) through 0 when on demand service along said route increases above a predetermined threshold.

30. Method for automatically provisioning a communication channel according to claim 11, wherein said parameters characterizing said communication channel between said two nodes include a number of calls to be accommodated in the communication channel.

31. Method for automatically provisioning a communication channel according to claim 11, wherein the computing step further includes obtaining parameter data comprising specified call blocking probabilities and offered traffic and calculating thereform the number of calls accommodated by the communication channel.

32. Method for automatically provisioning a communication channel according to claim 25, wherein said monitoring step further includes the step of determining whether there are physical failures or additions of one of links, nodes, or connection servers in said ATM network.

33. Method for automatically provisioning a communication channel according to claim 32, wherein said message routing scheme includes exchanging information to establish an identity for a said switch and a corresponding connection server for said switch in said ATM network.

14. Method for automatically provisioning a communication channel between two switching nodes of an ATM network including a plurality of interconnected switching nodes, each said switching node including at least a switching element and an associated switch control device;

said method comprising;

a) providing at least two connection servers for path management in said ATM network;

b) associating each said switching node with one of said at least two connection servers;

c) obtaining parameters characterizing said communication channel;

d) communicating said parameters to a first connection server associated with a said switching node in said network;

e) periodically communicating information relating to switching element resources currently available at each switching node contained in said network to said first connection server;

f) from said parameters and periodically communicated current switching element resource information, computing an optimal route between said two switching nodes that is capable of realizing said communication channel and allocating new switching element resources for switching elements contained in said computed route; and

,

g) communicating allocated switching element resources to each switch control device associated with a switching node along said route, said communicating performed sequentially between each switching node along said route by means of a PNNI message routing scheme, each said switch control device configuring a respective switching element to maintain said new switching resources allocated thereto.

15. Method for automatically provisioning a communication channel between two switching nodes of an ATM network including a plurality of interconnected switching nodes, each said switching node including at least a switching element and an associated switch control device;

said method comprising;

a) determining where to set up said communication channel by monitoring online traffic between end nodes and determining a number of connection setup requests over a certain window of time;

b) determining whether said number of connection setup requests exceeds a predetermined threshold;

c) computing a route between said end nodes by providing at least two connection servers for path management in said ATM network, associating each of said switching node with one of said at least two connection servers and obtaining parameters characterizing said communication channel;

d) communicating said parameters to a first connection server associated with a said switching node in said network;

e) periodically communicating information relating to switching element resources currently available at each switching node contained in said network to said first connection server;

f) from said parameters and periodically communicated current switching element resource information, computing an optimal route between said two switching nodes that is capable of realizing said communication channel and allocating new switching element resources for switching elements contained in said computed route; and

,

g) communicating allocated switching element resources to each switch control device associated with a switching node along said route, each said switch control device configuring a respective switching element to maintain said new switching resources allocated thereto.

16. Method for automatically provisioning a communication channel between two switching nodes of an ATM network including a plurality of interconnected switching nodes, each said switching node including at least a switching element and an associated switch control device;

said method comprising;

a) providing at least two connection servers for path management in said ATM network;

b) associating each said switching node with one of said at least two connection servers;

c) obtaining parameters characterizing said communication channel;

d) communicating said parameters to a first connection server associated with a said switching node in said network;

e) periodically communicating information relating to switching element resources currently available at each switching node contained in said network to said first connection server;

f) from said parameters and periodically communicated current switching element resource information, computing an optimal route between said two switching nodes that is capable of realizing said communication channel and allocating new switching element resources for switching elements contained in said computed route,

g) allocating bandwidth resources for each switching element by;

determining an upper threshold on the bandwidth to be allocated, said upper threshold being the minimum of the maximum bandwidth available on an outgoing link from a switch and the peak rate of the traffic along said computer route, determining upper thresholds on the Cell Transfer Delay and Cell Loss Ratio that the connection can experience at a particular switch, and determining the maximum buffer space available at said particular switch;

h) communicating allocated switching element resources to each switch control device associated with a switching node along said route, each said switch control device configuring a respective switching element to maintain said new switching resources allocated thereto.