System and method for automatically identifying and analyzing currently active channels in an ATM network

• US 6,195,352 B1
• Filed: 03/15/1996
• Issued: 02/27/2001
• Est. Priority Date: 03/15/1996
• Status: Expired due to Term

• Current Assignee: NetScout Systems Incorporated
• Original Assignee: Network Associates, Inc.
• Inventors: Cushman, Paul W., Mehta, Bakulesh A., Won, King L.
• Primary Examiner(s): TON, DANG T
• Application Number:
  US08/616,603
• Time in Patent Office: 1,810 Days
• Field of Search: 395/200.11, 395/200.19, 370/230, 370/232, 370/234, 370/235, 370/391, 370/392, 370/395, 370/399, 370/412, 370/466, 370/468, 370/474, 370/471, 370/465, 370/401, 370/351, 370/352
• US Class Current: 370/395.6
• CPC Class Codes: H04L 2012/5626 Network management, e.g. Intelligent nets
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A system and method for identifying and analyzing active channels in an asynchronous transfer mode (ATM) network. The system and method open a plurality of ATM network channels during a time period; automatically monitor each of the plurality of open channels to identify any active channels from among the open channels; and automatically identify the type of traffic transmitted on the open channels. By systematically identifying the active channels in the ATM network, the ATM network analysis device can further analyze the traffic on the active channels. The present invention includes at least three functions: network data detection and capture, active channel determination, and ATM Application Layer (AAL) service type categorization. A network data detector and identifier (DDI) performs the functions of network data detection and capture. The DDI connects to an ATM network and captures, copies, and repeats cells transmitted on the network and copies cells of interest to the DDI for further analysis. Active channel determination is performed by an active channel determinator (ACD) which is connected to the DDI. The ACD uses a user-defined total potential connection list which contains a range of channels to be tested for active channel identification.

Claims

1. A method for identifying active channels in an asynchronous transfer mode (ATM) network, the ATM network having a plurality of channels, the method comprising:

(A) identifying a first set of channels on the ATM network including the step of determining a first range of channels wherein said first set of channels is either a subset of said first range of channels or equal to said first range of channels;

(B) opening said first set of channels at a first time including the steps of;

(1) selecting a second channel from said first set of channels;

(2) opening said second channel if said second channel is not identified as active; and

(3) removing said second channel from said first set of channels if said second channel is identified as active;

(C) automatically monitoring said first set of open channels to identify a channel that is active; and

repeating steps (A), (B), and (C) until all channels in said first range have been selected to be in said first set.

2. A method for identifying active channels in an asynchronous transfer mode (ATM) network, the ATM network having a plurality of channels, the method comprising:

(A) identifying a first set of channels on the ATM network;

(B) opening said first set of channels at a first time; and

(C) automatically monitoring said first set of open channels to identify a channel that is active wherein step (C) includes steps of;

selecting a second channel, said second channel being one of said open channels;

monitoring said second channel for data cells;

determining if a data cell corresponding to said second channel was received since said first time; and

identifying said second channel as active if a data cell was received on said second channel since said first time.

3. The method of claim 2, further comprising the step of:

repeating said steps of selecting a second channel, monitoring said second channel, determining if a data cell corresponding to said second channel was received, and identifying said second channel as active, for each channel in said first set of channels.

4. The method of claim 2, further comprising the step of:

removing said second channel from said first set of channels if said second channel is identified as active.

5. The method of claim 4, further comprising the step of:

repeating steps (A), (B), and (C).

6. The method of claim 4, further comprising the step of:

removing said second channel from said first set of channels if said second channel is a special use channel.

7. The method of claim 6, further comprising the step of:

repeating steps (A), (B), and (C).

8. The method of claim 2, further comprising the step of:

removing said second channel from said first range of channels if said second channel is identified as active.

9. A method for identifying active channels in an asynchronous transfer mode (ATM) network, the ATM network having a plurality of channels, the method comprising:

(A) identifying a first set of channels on the ATM network;

(B) opening said first set of channels at a first time;

(C) automatically monitoring said first set of open channels to identify a channel that is active; and

(D) automatically identifying an ATM application layer (AAL) service type used by data cells on an active channel.

10. The method of claim 9, wherein step (D) includes the steps of:

(1) receiving a first data cell associated with a first active channel; and

(2) identifying said AAL service type using contents of said first data cell if said first active channel was identified as active in step (F).

11. The method of claim 10. wherein step (D)(2) includes the steps of:

(a) determining if a first three-bit portion of said first data cell is equal to one of a binary value of one and a binary value of three; and

(b) identifying said AAL service type as an AAL service type five if said first three-bit portion of said first data cell is equal to one of a binary value of one and a binary value of three.

12. The method of claim 11, wherein step (D)(2) further comprises the step of:

(c) determining if said AAL service type is an AAL service type three-four, including the steps of;

identifying said AAL service type as an AAL service type three-four if a first two-bit portion of said first data cell corresponds to a value representing one of a beginning of message segment type and a continuation of message segment type and if a first six-bit portion of said first data cell is equal to a binary forty-four; and

identifying said AAL service type as an AAL service type three-four if said first two-bit portion of said first data cell corresponds to a value representing a single segment message segment type and a first four bit sequence number portion of said first data cell is equal to a binary one.

13. The method of claim 11, wherein step (D)(2) further comprises the step of:

(c) determining if said AAL service type is an AAL service type one, including the steps of;

determining a first three-bit sequence count value for said first data cell;

determining a second three-bit sequence count value for a second data cell if said AAL service type is not identified; and

identifying said AAL service type as an AAL service type one if said second three bit sequence count value is one greater than said first three-bit sequence count value.

14. The method of claim 10, further comprising the step of:

repeating said step (D) for all channels that are identified as active and whose AAL service type has not been identified.

15. The method of claim 10, wherein step (D)(2) includes the step of:

determining if said AAL service type is an AAL service type three-four, including the steps of;

identifying said AAL service type as an AAL service type three-four if a first two-bit portion of said first data cell corresponds to a value representing one of a beginning of message segment type and a continuation of message segment type and if a first six-bit portion of said first data cell is equal to a binary forty-four; and

identifying said AAL service type as an AAL service type three-four if said first two-bit portion of said first data cell corresponds to a value representing a single segment message segment type and a first four bit sequence number portion of said first data cell is equal to a binary one.

16. The method of claim 10, wherein step (D)(2) includes the step of:

determining if said AAL service type is an AAL service type one, including the steps of;

determining a first three-bit sequence count value for said first data cell;

determining a second three-bit sequence count value for a second data cell if said AAL service type is not identified; and

identifying said AAL service type as an AAL service type one if said second three bit sequence count value is one greater than said first three-bit sequence count value.

17. A method for automatically identifying an ATM application layer (AAL) service type used by data cells on a first channel identified as active, comprising:

(A) receiving at least a first data cell associated with the first active channel, said at least first data cell having contents; and

(B) identifying said AAL service type using the contents of said at least first data cell wherein said identifying includes the steps of;

(1) determining if a first three-bit portion of said first data cell is equal to one of a binary value of one and a binary value of three; and

(2) identifying said AAL service type as an AAL service type five if said first three-bit portion of said first data cell is equal to one of a binary value of one and a binary value of three.

18. The method of claim 17, wherein step (B) further comprises the step of:

(3) determining if said AAL service type is an AAL service type three-four, including the steps of;

identifying said AAL service type as an AAL service type three-four if a first two-bit portion of said first data cell corresponds to a value representing one of a beginning of message segment type and a continuation of message segment type and if a first six-bit portion of said first data cell is equal to a binary forty-four; and

identifying said AAL service type as an AAL service type three-four if said first two-bit portion of said first data cell corresponds to a value representing a single segment message segment type and a first four bit sequence number portion of said first data cell is equal to a binary one.

19. The method of claim 17, wherein step (B) further comprises the step of:

(3) determining if said AAL service type is an AAL service type one, including the steps of;

determining a first three-bit sequence count value for said first data cell;

determining a second three-bit sequence count value for a second data cell if said AAL service type is not identified; and

identifying said AAL service type as an AAL service type one if said second three bit sequence count value is one greater than said first three-bit sequence count value.

20. The method of claim 17, further comprising the step of:

repeating said steps (A) and (B) for all channels that are identified as active and whose AAL service type has not been identified.

23. The method of claim 17 wherein identifying said AAL service type for the first active channel further comprises comparing a portion of the contents of said at least first data cell to a pre-defined characteristic of a data cell of said AAL service type.

24. The method of claim 17 wherein (B) further comprises:

(1) determining whether said at least first data cell is of a first AAL service type; and

, if said at least first data cell is not of said first AAL service type,

(2) determining whether said at least first data cell is of a second AAL service type.

25. The method of claim 17 wherein identifying said AAL service type for the first active channel further comprises:

(1) comparing a portion of the contents of said at least first data cell to a pre-defined characteristic of a data cell of a first AAL service type; and

, if said at least first data cell is not of said first AAL service type,

(2) comparing a portion of the contents of said at least first data cell to a pre-defined characteristic of a data cell of a second AAL service type.

26. The method of claim 25 further comprising:

(3) comparing a portion of the contents of said at least first data cell to a pre-defined characteristic of a data cell of a third AAL service type, if said first data cell is not of said first AAL service type or of said second AAL service type.

27. The method of claim 25 wherein said first AAL service type is AAL service type five and said second AAL service type is AAL service type three-four.

28. The method of claim 26 wherein said third AAL service type is AAL service type one.

21. A method for automatically identifying an ATM application layer (AAL) service type used by data cells on a first channel identified as active, comprising:

(A) receiving at least a first data cell associated with the first active channel, said at least first data cell having contents; and

(B) identifying said AAL service type using the contents of said at least first data cell wherein step (B) includes the step of;

determining if said AAL service type is an AAL service type three-four, including the steps of;

identifying said AAL service type as an AAL service type three-four if a first two-bit portion of said first data cell corresponds to a value representing one of a beginning of message segment type and a continuation of message segment type and if a first six-bit portion of said first data cell is equal to a binary forty-four; and

identifying said AAL service type as an AAL service type three-four if said first two-bit portion of said first data cell corresponds to a value representing a single segment message segment type and a first four bit sequence number portion of said first data cell is equal to a binary one.

22. A method for automatically identifying an ATM application layer (AAL) service type used by data cells on a first channel identified as active, comprising:

(A) receiving at least a first data cell associated with the first active channel, said at least first data cell having contents; and

(B) identifying said AAL service type using the contents of said at least first data cell wherein step (B) includes the step of;

determining if said AAL service type is an AAL service type one, including the steps of;

determining a first three-bit sequence count value for said first data cell;

determining a second three-bit sequence count value for a second data cell if said AAL service type is not identified; and

identifying said AAL service type as an AAL service type one if said second three bit sequence count value is one greater than said first three-bit sequence count value.