Signaling frequency detection for a communications network

• US 5,537,098 A
• Filed: 03/16/1995
• Issued: 07/16/1996
• Est. Priority Date: 04/14/1993
• Status: Expired due to Fees

• Current Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Patrick, Michael W., Daly, James A.
• Primary Examiner(s): Bowler, Alyssa H.
• Assistant Examiner(s): Rinehart, Mark H.
• Application Number:
  US08/406,261
• Time in Patent Office: 488 Days
• Field of Search: 340/825.05, 370/1611, 370/85.5, 370/85.1, 370/85.15, 364/131, 364/148, 364/149, 364/DIG. 1, 395/200.12, 395/200.19, 395/200.20
• US Class Current: 370/452
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion

Abstract

An apparatus is provided for detecting the signaling frequency of communications signals transported on the trunk and lobe circuits of a token ring. The communications signals including Differentially Manchester Encoded data signals. The apparatus includes an internal trunk circuit and a plurality of ports including an input port for connecting to an input trunk segment, and an output port for connecting to an output trunk segment, and a plurality of lobe ports for connecting to the lobe circuits. Means are provided for sensing the frequency of the data signals at each of said plurality of ports. The sensing means including means for taking multiple successive timing samples, and grouping the samples into quality groups.

Claims

1. An apparatus for detecting signaling frequencies in a communications network, comprising:

a token ring communications network, the token ring communications network including nodes for transmitting and receiving communications signals and a signaling medium for transporting the communications signals, the signaling medium including lobe circuits for connecting to the nodes and a trunk circuit having trunk segments for connecting to the lobe circuits in a ring configuration,

a plurality of ports including an input port connected to an input trunk segment of said trunk segments, and an output port connected to an output trunk segment of said trunk segments, and a plurality of lobe ports connected to the lobe circuits;

an internal trunk circuit for connecting said plurality of ports to each other;

means, connected to each of said plurality of ports, for sensing a frequency of the communications signals at each of said plurality of ports; and

a controller, connected to each of said means for sensing, said controller responsive to said frequency of the communications signals, sensed at each of said plurality of ports, said controller connecting a particular one of said plurality of ports to said internal trunk circuit, while said frequency of the communications signals at said particular port are within a valid predetermined frequency range.

2. The apparatus as in claim 1 wherein said means for sensing extracts frequency samples from the data signals at predetermined time intervals.

3. The apparatus as in claim 2 further including means for disconnecting said particular port from said internal trunk circuit if said first predetermined number of successive frequency samples at said particular port include more than a second predetermined number of frequency samples having a frequency outside said valid predetermined frequency range.

4. The apparatus as in claim 3 wherein said first predetermined number is eight and said second predetermined number is three.

5. A method for detecting signaling frequencies in a communications network, comprising:

transmitting and receiving communications signals by nodes of the communications network, the communications network configured as a token ring;

transporting the communications signals over a signaling medium of said token ring, the signaling medium including a plurality of lobe circuits for connecting to the nodes and a trunk circuit having trunk segments for connecting to the plurality of lobe circuits;

connecting an input trunk segment of the trunk segments to an input port of a controller;

connecting an output trunk segment of the trunk segments to an output port of said controller;

connecting separately each one of the plurality of lobe circuits to one lobe port of a plurality of lobe ports of said controllers, said controller including an internal trunk circuit for connecting said input port, said output port and said plurality of lobe ports to each other;

sensing a frequency of the communications signals at said input port, said output port and said plurality of lobe ports as frequency samples;

classifying each of the communications signals as a valid communications signals or as an invalid communications signals, said valid communications signals having the frequency samples within a permitted frequency range, and said invalid communications signals having the frequency sample outside said permitted frequency range; and

connecting said input port, or said output port, or said plurality of lobe ports to said internal trunk circuit if the communications signals at said input port, or said output port, or said plurality of lobe ports are designated as said valid communications signals.

6. The method as in claim 5 further including the steps of

grouping a plurality of successive ones of said frequency samples into a group,

counting the number of said valid samples and counting the number of said invalid samples in said group to determine a relative quality of said communications signals, said relative quality of said communications signals proportional to the number of said valid frequency samples and the number of said invalid frequency samples in said group,

designating the communications signals said valid communications signals if the number of said valid frequency samples is greater than a first predetermined number, and

designating the communications signals as said invalid communications signals if the number of said invalid frequency samples is greater than a second predetermined number.

7. The method as in claim 6 further including the step of disabling the connection of of said input port, said output port, or said plurality of lobe ports to said internal trunk circuit if respectively, said frequency of the communications signals at said input port, or said output port, or any of said plurality of lobe ports is substantially different than said frequency of the communications signals at said input port.

8. A method for detecting signaling frequencies, comprising:

transmitting and receiving communications signals by nodes of a token ring communications network;

transporting the communications signals over a signaling medium, the signaling medium including a plurality of lobe circuits for connecting to the nodes, each of the plurality of lobe circuits for connecting to one of the nodes, and a trunk circuit having trunk segments for connecting to the lobe circuits;

connecting an input trunk segment of the trunk segments to an input port of a controller;

connecting an output trunk segment of the trunk segments to an output port of said controller;

connecting separately each one of the plurality of lobe circuits to one lobe port of a plurality of lobe ports of said controller;

sensing, respectively, a frequency of the communications signals at said input port, said output port, and said plurality of lobe ports as frequency samples;

classifying each of said frequency samples as valid samples or as invalid samples, said valid samples having a first frequency within a permitted frequency range and said invalid samples having a second frequency outside said permitted frequency range;

designating the communications signals as valid communications signals if the number of said valid samples of the communications signals is greater than a first predetermined number;

designating the communications signals as invalid communications signals if the number of said invalid samples of the communications signals is greater than a second predetermined number;

connecting, respectively, said input port, or said output port, or any of said plurality of lobe ports to an internal trunk circuit of said controller if, respectively, the communication signals at said input port, or said output port, or any of said plurality of lobe ports are designated as said valid communications signals, said internal trunk circuit for connecting said input port, said output port, and said plurality of lobe ports to one and another; and

establishing an internal signaling frequency of said internal trunk circuit, said internal signaling frequency being substantially the same as said frequency sensed at a majority of said input port, said output port, and said plurality of lobe ports.

9. The method as in claim 8 further including the steps of

if there is no majority of said plurality of ports having the same frequency, establishing said internal signaling frequency of said internal trunk circuit the same as said frequency sensed at said input port.

10. A method for detecting signaling frequencies of communications signals of a communications network, comprising:

connecting a token ring to a multi-access unit, the multi-access unit having a plurality of ports and an internal trunk, said plurality of ports including an input port connected to an input segment of the token ring, an output port connected to an output segment of the token ring, and a plurality of lobe port connected to lobe circuits of the token ring, said plurality of ports for providing signaling continuity of the token rings, and said internal trunk for connecting said plurality of ports to each other;

sensing a frequency of the communications signals at each of said plurality of ports;

determining if said frequency of the communications signals sensed at each of said plurality of ports is within a valid permitted range of frequencies; and

enabling, in response to said frequency being within said valid permitted range of frequencies, signaling continuity between the token ring and said internal trunk via any of said plurality of ports having said frequency within said valid permitted range of frequencies.

11. The method of claim 10 further including:

establishing said frequency of said internal trunk circuit to a majority frequency, said majority frequency being said frequency detected at a majority of said plurality of ports.