Spanning tree bypassing method and apparatus

• US 20040255050A1
• Filed: 07/18/2002
• Published: 12/16/2004
• Est. Priority Date: 01/22/2002
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kinoshita, Hiroshi, Higashitaniguchi, Atsuko, Takehiro, Tsuyoshi
• Granted Patent: US 7,072,952 B2
• Time in Patent Office: Days
• US Class Current: 709/252
• 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
• CPC Class Codes: H04L 45/18 Loop-free operations
• CPC Class Codes: H04L 45/48 Routing tree calculation

Abstract

A route bypassing a root node is constructed in a network in which a spanning tree is formed. A received frame is sent out on a designated port as well as on a root port by using a designated-port data send-out function, provided that a transmitting port for the received frame is learned on the root port. When a frame is received on a blocking port, a transmitting port for a frame whose destination matches the source address of the received frame is temporarily learned on the blocking port by using a blocking-port learning function, on the condition that the destination of the received frame is already learned on some other port. When a frame whose destination matches the temporarily learned address is received, the temporary learning is changed to normal learning by using a temporarily learned address-based data transfer function.

Claims

1. A spanning tree bypassing method comprising the steps of:

(a) in a first node, sending a first frame, whose destination address is a first address and whose source address is a second address, out on a designated port as well as on a root port when the first frame is received, provided that learning is done so as to send any frame destined for the first address out on the root port; and

(b) in a second node having received the first frame on a blocking port, sending a second frame, whose destination address is the second address, out on the blocking port when the second frame is received.

2. A method according to claim 1, wherein the step (b) includes the substeps of:

(i) performing temporary learning so as to send any frame destined for the second address out on the blocking port, when the first frame is received on the blocking port; and

(ii) sending the second frame, whose destination address is the second address, out on the blocking port by switching the temporary learning to normal learning when the second frame is received.

3. A method according to claim 2, wherein, in the substep (b) (i), the temporary learning is performed on the condition that learning is already done as to on which port a frame destined for the first address is to be sent out.

4. A method according to claim 1, wherein, in the step (a), the first frame is sent out on all designated ports.

5. A spanning tree bypassing apparatus comprising:

means for sending a first frame, whose destination address is a first address, out on a designated port as well as on a root port when the first frame is received, provided that learning is done so as to send any frame destined for the first address out on the root port; and

means for sending a second frame, whose destination address is a second address, out on a blocking port when the second frame is received after a third frame whose source address is the second address was received on the blocking port.

6. An apparatus according to claim 5, wherein the blocking-port send out means includes:

means for performing temporary learning so as to send any frame destined for the second address out on the blocking port, when the third frame is received on the blocking port; and

means for sending the second frame, whose destination address is the second address, out on the blocking port by switching the temporary learning to normal learning when the second frame is received.

7. An apparatus according to claim 6, wherein the temporary learning means performs the temporary learning on the condition that learning is already done as to on which port a frame destined for a destination address of the second frame is to be sent out.

8. An apparatus according to claim 5, wherein the designated-port send-out means sends the first frame out on all designated ports.