Method and apparatus to establish a tap-point in a switched network using self-configuring switches having distributed configuration capabilities

• US 5,940,376 A
• Filed: 01/29/1997
• Issued: 08/17/1999
• Est. Priority Date: 01/29/1997
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Cabletron Systems Incorporated (Extreme Networks, Inc.)
• Inventors: Len, Theodore C., Clements, Bruce G., Yanacek, Judith A.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US08/790,473
• Time in Patent Office: 930 Days
• Field of Search: 370/250, 370/254, 370/245, 370/244, 370/255, 370/251, 370/248, 370/242, 379/34, 379/35, 379/133
• US Class Current: 370/250
• CPC Class Codes: H04L 2012/5617 Virtual LANs; Emulation of LANs
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A method and apparatus for monitoring data sent between a source node and destination node in a switched network, wherein the switches configure themselves to establish a connection path to a probe switch to receive the monitored data. The source and destination are identified along with the probe switch. An originating switch on a path between the source and destination is identified and connections between the originating switch and the probe switch are established. The originating switch sends out a first message and when the probe switch receives the first message, it returns a second message to the originating switch. Each switch between the originating switch and the probe switch that receives the first and second messages configures itself to establish the connection path.

Claims

1. A method of monitoring data transmitted between a source node and a destination node in a switched network, the network comprising a plurality of network switches with at least one network switch connected between the source and destination nodes through which the data between the source and destination nodes passes, each network switch including a connection table, the method comprising steps of:

(a) identifying one network switch connected between the source and destination nodes to be an originating switch;

(b) identifying one network switch to be a probe switch, the probe switch having a probe attached to a probe port;

(c) identifying all intermediate network switches connected in a path between the originating switch and the probe switch; and

(d) configuring the originating switch, the probe switch and all intermediate network switches to pass data transmitted from at least one of the source node and the destination node to the probe port of the probe switch.

2. The method as recited in claim 1, wherein the originating switch is a same switch as the probe switch.

3. The method as recited in claim 1, wherein step (c) comprises steps of:

retrieving a connection table of the one network switch; and

determining the one network switch to be the originating switch when there is an entry in the retrieved connection table for the source node and destination node pair.

4. The method as recited in claim 1, wherein step (c) comprises steps of:

sending a tap request message out from the originating switch on a flood path, the flood path leading to all network switches in the network, the tap request message including an address of the probe switch and a port number identifying the probe port; and

in each respective network switch in the flood path;

receiving the tap request message;

identifying a tap request port on which the tap request message was received;

comparing the probe switch address to an address of the respective switch;

when the respective switch address is not equal to the probe switch address,

sending out the tap request message on the flood path from the respective switch; and

when the respective switch address is equal to the probe switch address, sending a tap response message on the tap request port and establishing a connection between the probe port and the tap request port in the connection table of the respective switch.

5. The method as recited in claim 4, wherein the address of a switch is the Media Access Control (MAC), address of the switch.

6. The method as recited in claim 4, wherein step (d) comprises steps of:

in each respective network switch in the path between the originating switch and the probe switch, other than the originating switch and the probe switch, when the tap response message is received, identifying a tap response port on which the tap response message was received, establishing a connection between the tap request port and the tap response port and sending the tap response out the tap request port; and

in the originating switch, when the tap response is received, identifying the tap response port on which the tap response was received and establishing a connection between at least one of the source node and the destination node and the tap response port.

7. The method as recited in claim 6, wherein each step of establishing the connection between the tap request port and the tap response port in the respective network switch comprises steps of:

creating an entry in the connection table of the respective network switch; and

the created entry identifying the source node and destination node, the tap request port and the tap response port.

8. The method as recited in claim 4, wherein:

when the respective network switch in the flood path receives the tap request message and the respective network switch address is not equal to the address of the probe switch and a tap request port on which the tap request message was received is the only port on which the flood path is accessed by the respective network switch, identifying the respective network switch as being at a terminal end of the flood path.

9. In a switched network including a plurality of switches and having a source node and a destination node sending data to one another through a first switch on a first path therebetween, a method of monitoring the data at a probe switch having a probe port and a data probe connected to the probe port, the method comprising steps of:

(a) identifying all switches in a second path from the first switch to the probe switch; and

(b) each switch on the second path configuring itself in response to a message received from an adjacent switch on the second path so as to pass data from at least one of the source node and the destination node to the data probe.

10. The method as recited in claim 9, further comprising a step of:

(c) the first switch configuring itself so as to pass data from the destination node to the source node and to the data probe.

11. The method as recited in claim 9, further comprising a step of:

the first switch sending a tap request message to switches identified on a flood path to which the first switch is connected, the tap request message including a first address of the source node, a second address of the destination node, a third address of the probe switch and a port number of the probe port.

12. The method as recited in claim 11, further comprising steps of:

in each respective switch that receives the tap request message;

identifying a tap request port on which the tap request message was received;

comparing the third address to a respective switch address;

when the third address is not equal to the respective switch address, sending the tap request message to all other switches identified on the flood path to which the respective switch is connected except that switch connected to the tap request port; and

when the third address is equal to the respective switch address, creating an entry in a connection table of the respective switch so that the data received from at least one of the source node and the destination node on the tap request port is directed to the data probe, and sending a probe switch found message out on the tap request port.

13. The method as recited in claim 12, further comprising steps of:

in each respective switch that receives the probe switch found message;

identifying a probe-found port on which the probe switch found message was received;

creating an entry in a connection table of the respective switch so that data received from at least one of the source node and the destination node is directed to the probe-found port; and

when the respective switch is not the first switch, sending the probe switch found message out on the tap request port.

14. A method of establishing a tap connection between at least one of a source node and a destination node in a switched network, the method comprising steps of:

sending a first message to an originating switch in a path between the source and destination nodes;

the originating switch forwarding the first message so as to be received by all other switches in a flood-path within the switched network;

in each respective switch which receives the first message, determining if the respective switch is a probe switch and when the respective switch is the probe switch, sending a second message out a first port on which the first message was received and establishing a connection between the first port and a probe port to which a probe is connected and when the respective switch is not the probe switch, sending the first message so as to be received by other switches in the flood-path; and

in each respective switch which receives the first and second messages, establishing a connection between the first port and a second port on which the second message was received and sending the second message out the first port.

15. A self-configuring switch for establishing, in a switched network, a tap connection between at least one of:

a source node and a destination node, and a probe switch, the self-configuring network switch comprising;

means for receiving a tap request message identifying a particular tap request;

means for identifying a tap request port on which the tap request message is received;

means for comparing an address of the self-configuring network switch to a probe switch address in the tap request message;

means for sending the tap request message out a flood path port, other than the tap request port, when the comparing means determines that the self-configuring network switch address is not equal to the probe switch address;

means for sending a tap response message out on the tap request port when the comparing means determines that the self-configuring network switch address is equal to the probe switch address;

means for establishing a connection between the tap request port and a probe port, to which a probe is attached, when the comparing means determines that the self-configuring network switch address is equal to the probe switch address;

means for receiving a tap response message identifying the particular tap request;

means for identifying a tap response port on which the tap response message is received;

means for establishing a connection between the tap request port and the tap response port when both a tap request message and a tap response message have been received; and

means for sending the tap response message out the tap request port when both a tap request message and tap response message have been received.

16. In a switched network including a plurality of switches, one switch of the plurality of switches being a probe switch having a probe port to which a probe is attached, the switched network having a source node and a destination node, a method of monitoring, at the probe switch, data sent between the source and destination nodes, the method comprising steps of:

(a) identifying an originating switch in a first path between the source and destination nodes;

(b) identifying all switches in a second path from the originating switch to the probe switch; and

(c) each switch on the second path configuring itself, in response to a message received from an adjacent switch on the second path, so as to pass data from at least one of the source node and the destination node to the probe switch.

17. The method as recited in claim 16, wherein step (a) comprises steps of:

in each respective switch in the plurality of switches;

retrieving a local directory table of the respective switch;

examining each entry in the local directory table; and

when a local directory table entry is found for the source node, determining the respective switch to be the originating switch.

18. The method as recited in claim 16, wherein step (a) comprises steps of:

in each respective switch in the plurality of switches;

retrieving a local directory table of the respective switch;

examining each entry in the local directory table; and

when a local directory table entry is found for the destination node, determining the respective switch to be the originating switch.

19. The method as recited in claim 17, further comprising a step of:

the originating switch sending a tap request message to switches identified on a flood path to which the originating switch is connected, the tap request message including a first address of the source, a second address of the destination, a third address of the probe switch and a port number of the probe port.

20. The method as recited in claim 19, further comprising steps of:

in each respective switch that receives the tap request message;

identifying a tap request port on which the tap request message was received;

comparing the third address to a respective switch address;

when the third address is not equal to the respective switch address, sending the tap request message to all other switches identified on the flood path to which the respective switch is connected except that switch connected to the tap request port; and

when the third address is equal to the respective switch address, creating an entry in a connection table of the respective switch so that the data received from at least one of the source node and the destination node on the tap request port is directed to the data probe and sending a probe switch found message out on the tap request port.

21. The method as recited in claim 20, further comprising steps of:

in each switch that receives the probe switch found message;

identifying a probe-found port on which the probe switch found message was received;

creating an entry in a connection table of the respective switch so that data received from at least one of the source node and the destination node is directed to the probe-found port; and

when the respective switch is not the first switch, sending the probe switch found message out on the tap request port.

22. The method as recited in claim 18, further comprising a step of:

the originating switch sending a tap request message to switches identified on a flood path to which the originating switch is connected, the tap request message including a first address of the source, a second address of the destination, a third address of the probe switch and a port number of the probe port.

23. The method as recited in claim 22, further comprising steps of:

in each respective switch that receives the tap request message;

identifying a tap request port on which the tap request message was received;

comparing the third address to a respective switch address;

when the third address is not equal to the respective switch address, sending the tap request message to all other switches identified on the flood path to which the respective switch is connected except that switch connected to the tap request port; and

when the third address is equal to the respective switch address, creating an entry in a connection table of the respective switch so that the data received from at least one of the source node and the destination node on the tap request port is directed to the data probe and sending a probe switch found message out on the tap request port.

24. The method as recited in claim 23 further comprising steps of:

in each switch that receives the probe switch found message;

identifying a probe-found port on which the probe switch found message was received;

creating an entry in a connection table of the respective switch so that data received from at least one of the source node and the destination node is directed to the probe-found port; and

when the respective switch is not the first switch, sending the probe switch found message out on the tap request port.

25. A self-configuring switch for monitoring data sent between a first node and a second node in a switched network including said switch, the data being sent through a first switch on a first path between the first and second nodes within the switched network, the data being monitored at a third node, the switch comprising:

means for searching for all switches in a second path from the first switch to the third node; and

configuring means for configuring the switch in response to a message received from an adjacent switch in the second path so as to pass data from at least one of the first and second nodes to the third node.