TRANSPARENT WIRELESS BRIDGE ROUTE AGGREGATION

• US 20080232383A1
• Filed: 03/19/2007
• Published: 09/25/2008
• Est. Priority Date: 03/19/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: RAHMAN, Shahriar, MEIER, Robert
• Granted Patent: US 7,684,355 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update

Abstract

In an example embodiment, there is described herein a “Wireless Route Aggregation Protocol” (WRAP) that is used to aggregate multiple wireless links into a WRAP “route bundle” that functions as a single logical LAN bridge link. WRAP link aggregation can be used for example to increase the bandwidth and robustness of the wireless path between two wired Ethernet LANs.

Claims

1. An apparatus, comprising:

a primary port;

a secondary port; and

control logic coupled to the primary port and the secondary port;

wherein the control logic is responsive to determining the secondary port is coupled to a secondary network to operate as a secondary bridge; and

wherein the control logic is responsive to operating as a secondary bridge to communicate with at least one other wireless bridge to select a master secondary bridge that is a designated bridge for the secondary network.

2. An apparatus according to claim 1, wherein the master secondary bridge is a secondary bridge having a lowest path cost to a primary network.

3. An apparatus according to claim 1, wherein the control logic is responsive to being selected the master secondary bridge to acquire a neighbor list from the at least one other wireless bridge.

4. An apparatus according to claim 3, wherein the control logic is responsive to receiving the neighbor list to execute a route aggregation algorithm that determines the highest aggregate bandwidth to bridge the secondary network to a primary network.

5. An apparatus according to claim 3, wherein the control logic is operable to direct the at least one other wireless bridge to connect a secondary link endpoint to a primary link endpoint associated with a primary bridge coupled to a primary network.

6. An apparatus according to claim 1, further comprising the control logic is responsive to being selected the master secondary bridge to create a cross route between a descendant station and a primary network through the at least one other wireless bridge.

7. An apparatus according to claim 6, wherein an inbound frame from the descendant station is received through the secondary port and is routed through the secondary port to the at least one other wireless bridge for routing to the primary network.

8. An apparatus according to claim 6, wherein an outbound frame for the descendant station is received from at least one other wireless bridge and is routed on the secondary network.

9. An apparatus according to claim 6, wherein the control logic is responsive to a connection to the at least one other wireless bridge being lost to establish a new cross route for the descendant station through a second of the at least one other wireless bridge.

10. An apparatus according to claim 1, further comprising the control logic is responsive to being selected master secondary bridge to send a message via the primary port to a primary bridge associated with a primary network to inform the primary bridge that the primary bridge is the master primary bridge for the secondary network.

11. An apparatus according to claim 1, further comprising the control logic is responsive to determining master secondary bridge is one of the at least one other secondary bridges to switch the Ethernet port to a blocked state;

wherein while the Ethernet port is in the blocked state only control frames and data frames associated with a previously established cross route are routed through the Ethernet port.

12. An apparatus according to claim 1, further comprising the control logic is further responsive to determining that the primary port is coupled to a primary network to operate as a primary bridge.

13. An apparatus according to claim 12, further comprising the control logic is responsive to operating as a primary bridge to communicate with at least one other wireless bridge coupled to the primary network to select a super root based on highest root priority.

14. An apparatus according to claim 12, further comprising the control logic is responsive to operating as a primary bridge to establish a cross route for a descendant node coupled to a secondary bridge associated with the secondary port responsive to receiving a message from the secondary bridge to establish the cross route.

15. An apparatus according to claim 12, further comprising the control logic is responsive to operating as a primary bridge to only bridge outbound frames to the secondary network responsive to having a previously established cross route for a destination of the frame.

16. An apparatus according to claim 12, further comprising the control logic is responsive to operating as a primary bridge to operate as a master primary bridge responsive to receiving a message from a master secondary bridge associated with the secondary port, wherein the master primary bridge maintains a cross route table for cross routes established between at least one other wireless bridge associated with the primary network and the secondary network.

17. An apparatus according to claim 16, further comprising the control logic is operable to bridge frames from the primary network to the secondary network responsive to no cross route being established for a destination of the frame.

18. A method, comprising:

designating a single wireless route selected from a route bundle comprising a plurality of wireless routes coupling two Ethernet local area networks (LANs) as a spanning tree path between the two Ethernet LANs;

establishing cross routes between the two Ethernet LANs using unselected plurality of wireless routes coupling the two Ethernet LANs employing a route aggregation protocol; and

grouping the cross routes into an aggregate route bundle;

wherein a first of the two Ethernet LANs is established as a primary local area network (LAN) and a second of the two Ethernet LANs is established as a secondary LAN.

19. A method according to claim 21 further comprising:

selecting a single wireless bridge, which has a wireless route to the primary LAN and an Ethernet connection to the secondary LAN, as the Master Secondary Bridge for the secondary LAN;

designating at least one other wireless bridge which has a wireless route to the primary LAN and an Ethernet connection to the secondary LAN as a Slave Secondary Bridge on the secondary LAN

reporting wireless neighbor information to the Master Secondary Bridge by the Slave Secondary Bridge,

compiling the neighbor information from the Slave Secondary Bridge by the Master Secondary Bridge;

determining a best set of wireless links to interconnect the secondary LAN to the primary LAN;

establishing cross links to between the Slave Secondary Bridge and parent wireless bridges coupled to the primary LAN by the Master Secondary Bridge; and

assigning a descendant station in a sub tree rooted at the secondary LAN to a cross route by the Master Secondary Bridge.

20. A method according to claim 19, further comprising:

forwarding all inbound and outbound frames for a cross-routed station a single bidirectional cross route;

establishing the forwarding path to the cross route endpoint on the primary LAN for outbound frames sent to the station using standard source address learning, wherein standard source address learning establishes the forwarding path to the Master Secondary Bridge for inbound frames sent by the station;

forwarding an outbound frame for the cross routed station to the Mater Secondary Bridge encapsulated with an outbound Ethernet tunnel header by the Slave Secondary Bridge; and

forwarding an inbound frame for the cross-routed station to a Slave Secondary Bridge encapsulated with an inbound Ethernet tunnel header by the Master Secondary Bridge;

wherein the inbound Ethernet tunnel header comprises an Ethernet Media Access Control (MAC) addresses of the Master Secondary Bridge, an Ethernet MAC address of the Slave Secondary Bridge and an Ethernet tunnel protocol identifier.