Method for building virtual private networks using routers

• US 7,583,617 B2
• Filed: 05/24/2005
• Issued: 09/01/2009
• Est. Priority Date: 05/24/2005
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Rosenberg, Eric, Uttaro, James
• Primary Examiner(s): Ryman, Daniel J
• Assistant Examiner(s): DECKER, CASSANDRA L
• Application Number:
  US11/135,820
• Publication Number:
  US 20060268740A1
• Time in Patent Office: 1,561 Days
• Field of Search: 370/254
• US Class Current: 370/254
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 41/145 involving simulating, designing, planning or modelling of a network
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00

Abstract

A method for forming a communications network using routers. The first step is analyzing a router location to determine if the router location is VPN resource constrained or interface-constrained. The VPN resource constrained router network comprises at least at least two groups of routers and the same number of customer groups. The next step is connecting the first group of customers and routers, and the second group of customers and routers, using a round robin connectivity methodology and saving information in each router'"'"'s database. The interface-constrained router network, comprises no more routers than the value [Q*], wherein [Q*] represents the number of routers that can be used by a group of customers so that VPN resources will not be exhausted faster than interface resources for the group of routers, then connecting customers to the group of routers using a round robin connectivity methodology and saving information in each router'"'"'s database.

Claims

1. A method for forming a communications network using routers, the method comprising:

a. analyzing a router location to determine if the router location is Virtual Private Network (VPN) resource constrained or interface constrained;

b. if the router location is interface constrained, forming an interface constrained router network, comprising;

i. a group of routers numbering at most [Q*] wherein [Q*] represents a number of routers that is used by a defined group of customers so that VPN resources will not be exhausted faster than interface resources for the group of routers, wherein [Q*] is determined by dividing a quantity of VPN resources available from a router [R] by an average amount of VPN resources averaged over a defined group of customers [F] forming a value [VR], and then dividing a quantity of interfaces available from a router in a group of routers [B] by an average number of interfaces[P] averaged over the defined group of customers forming [IR], and then dividing [VR] by [IR], where [Q*] equals [VR] divided by [IR];

ii. distributing customer connections for the defined group of customers over the group of routers numbering at most [Q*] using a round robin connectivity methodology; and

iii. saving in a database information on each connected customer; and

c. if the router location is not interface constrained, forming a VPN resource constrained router network.

2. A method for forming a communications network using routers, the method comprising:

a. analyzing a router location to determine if the router location is Virtual Private Network (VPN) resource constrained or interface constrained;

b. if the router location is interface constrained, forming an interface constrained router network, comprising;

i. a group of routers numbering at most [Q*] wherein [Q*] represents a number of routers that is used by a defined group of customers so that VPN resources will not be exhausted faster than interface resources for the group of routers;

ii. distributing customer connections for the defined group of customers over the group of routers numbering at most [Q*] using a round robin connectivity methodology; and

iii. saving in a database information on each connected customer; and

c. if the router location is not interface constrained, forming a VPN resource constrained router network,

wherein the analyzing of the router location comprises;

i. determining an average number of interfaces [P], averaged over a plurality of customers, needed to operate the communications network for a customer at the router location;

ii. determining a quantity of interfaces [B] available on a router at the router location;

iii. determining an average amount of VPN resources [F], averaged over the defined group of customers, needed to operate the communications network for the customer at the router location;

iv. determining an amount of VPN resources [R] available on the router;

v. dividing [B] by [P], forming an interface ratio [IR]; and

vi. dividing [R] by [F] forming a VPN resource ratio [VR]; and

if [IR] is greater than [VR], then forming the VPN resource constrained router network and if [VR] is greater than [IR] then forming the interface constrained router network.

3. The method of claim 2, wherein the determining the average number of interfaces needed to operate the communications network for the customer is determined by using existing customer data at the router location.

4. The method of claim 2, wherein the determining the average amount of VPN resources needed to operate the communications network for the customer is determined by using existing customer data at the router location.

5. The method of claim 2, wherein the average number of interfaces [P] needed in a router location is from 1 to 50 BGP sessions.

6. The method of claim 2, wherein the average amount of VPN resources needed to operate the communications network is from 10 to 10,000 routes.

7. The method of claim 2, wherein the quantity of interfaces [B] is from 500 to 3000 BGP sessions.

8. The method of claim 2, wherein the VPN resource is from 100,000 to 1,000,000 routes.