Loading patent…
AssigneeGeneral Instrument Corporation
InventorsKing-Shan Lui, Whay Chiou Lee
Estimating the term…
Bridges (10, 12, 14) are used to interconnect local area networks transparently. In the IEEE 802.1D standard for bridges, a spanning tree is built among the bridges for loop-free frame forwarding (FIG. 10). Although this approach is simple, it does not support all-pair shortest paths. A novel bridge protocol is employed that attempts to find and forward frames over alternate paths that are shorter than their corresponding tree paths on the standard spanning tree, and makes use of the standard spanning tree for default forwarding. The protocol, referred to as the Spanning Tree Alternate Routing (STAR) Bridge Protocol, is backward compatible with the IEEE 802.1D standard and has a complexity that is comparable to that of the standard and other existing protocols and further includes an ability to prioritize the forwarding of frames over at least two different paths responsive to a priority value carried by a frame to be forwarded.
Apparatus for determining paths for forwarding frames among end stations in a system of interconnected local area networks, comprised of:
Apparatus for determining a path for forwarding a frame received at a bridge in a system comprised of a plurality of interconnected local area networks (LANs) each having a plurality of end stations, and a spanning tree incorporating a plurality of bridges of first and second groups for loop-free forwarding a frame from a source end station to a destination end station wherein said source and destination end stations may reside in different LANs, said bridges of said first and second groups having means for determining a tree path for loop-free forwarding of said frame;
A method for determining a path for forwarding a frame in a system having a plurality of end stations interconnected by first and second types of bridges which create a loop-free spanning tree for transferring frames between end stations, comprising:
A method for prioritizing the forwarding of frames among end stations in a system of local area networks interconnected by a first and second types of bridges, comprising:
A method for establishing a protocol for prioritizing forwarding of frames among end stations in a system of local area networks interconnected by first and second types of bridges, comprising:
A method for determining paths for forwarding frames among end stations in a system of interconnected local area networks, comprising first and second groups of frame forwarding devices comprising bridges, for interconnecting local area networks, comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
Routing or path finding of packets in data switching networks: shortest path evaluation
LAN interconnection over a backbone network, e.g. Internet, Frame Relay: lAN interconnection over a bridge based backbone
Digital communication
Term end not estimated
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to employing a bridge protocol for interconnecting two or more local area networks (LANs). More particularly the invention relates to apparatus and method, which is backward compatible with existing 802.1D Spanning Tree Bridge Protocol, for improving routing capability of spanning tree forwarding without a significant increase in complexity and which enables traffic prioritized path differentiation and provides load balancing by supporting alternate paths selected according to one of two or more priority values carried by a frame to be forwarded.
The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals denote like elements, and:
FIG. 1 is a diagram showing bridge protocol architecture for connecting two LANs via remote or local bridging;
FIG. 2 is a bridge state transition diagram for the STAR Bridge Protocol;
I. Spanning Tree Alternate Routing (Star) Bridge Protocol
I.A. Bridge States
The ensuing detailed description provides preferred exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the preferred exemplary embodiments will provide those skilled in the art an enabling description for implementing a preferred exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims.