Ring node device and method of connecting terminal to ring node device

Abstract

A ring node device includes a main Resilient Packet Ring (RPR) card and a queued RPR card. Upon detection of disconnection of a communication link between the main RPR card and an L2/L3 switch, the ring node device exercises control to switch from the main RPR card to the queued RPR card and carries out communication with the L2/L3 switch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic for explaining the drawback of a conventional Resilient Packet Ring (RPR) connecting method;

FIG. 2 is a schematic for explaining the concept and salient features of an RPR connecting method according to an embodiment of the present invention;

FIG. 3 is a functional block diagram for explaining the concept of an RPR card redundant structure;

FIG. 4 is a functional block diagram of the structure of a station shown in FIG. 3;

FIG. 5 is a diagram for explaining an operation of the RPR card redundant structure in an initial state;

FIG. 6 is a diagram for explaining an egress operation of the RPR card redundant structure;

FIG. 7 is a diagram for explaining an ingress operation of the RPR card redundant structure;

FIG. 8 is a functional block diagram for explaining the operation performed by the RPR card redundant structure at the time of occurrence of a failure;

FIG. 9 is a diagram for explaining the operation performed by the RPR card redundant structure at the time of occurrence of the failure; and

FIG. 10 is a diagram for explaining the operation performed by the RPR card redundant structure once the failure has occurred.

Claims

1. A ring node device included in a ring network, the ring node device allocated with an identifier for identifying the ring node device from other devices on the ring network, the ring node device comprising: a first connecting unit and a second connecting unit, the first connecting unit and the second connecting unit employing Resilient Packet Ring (RPR) technique, the first connecting unit and the second connecting unit being allocated with same identifier as that of the ring node device, the first connecting unit and the second connecting unit being input with a first signal from the ring network for sending the first signal to a terminal and input with a second signal from the terminal for sending the second signal to the ring network;a second controlling unit that controls the second connecting unit so that the second connecting unit does not output the first signal to the terminal; anda second masking unit that masks the second signal before the second signal is input into the second connecting unit.

2. The ring node device according to claim 1, wherein the second controlling unit controls the second connecting unit so that the second connecting unit does not output the second signal to the ring network.

3. The ring node device according to claim 1, further comprising a detecting unit that detects disconnection of communication link between the first connecting unit and the terminal, wherein upon the detecting unit detecting the disconnection, the second controlling unit controls the second connecting unit so that the second connecting unit outputs the first signal to the terminal, and the second masking unit unmasks the second signal.

4. The ring node device according to claim 3, further comprising: a first controlling unit that controls the first connecting unit, upon the detecting unit detecting the disconnection, so that the first connecting unit does not output the first signal to the terminal; anda second masking unit that masks, upon the detecting unit detecting the disconnection, the second signal before the second signal is input into the first connecting unit.

5. The ring node device according to claim 2, wherein the second controlling unit includes a selecting unit that selects whether the second signal output from the first connecting unit be output to the ring network or the second signal output from the second connecting unit be output to the ring network.

6. The ring node device according to claim 1, wherein the RPR ring network includes a first ring network and a second ring network such that a signal transmission direction of the second ring network is in opposite direction of a signal transmission direction of the first ring network,the first connecting unit and the second connecting unit being input with first signals from both the first ring network and the second ring network,the ring node device further comprising a selecting unit that selectively outputs the second signal output from the first connecting unit and the second connecting unit to any one of the first ring network and the second ring network.

7. The ring node device according to claim 3, further comprising: a first storage unit that configured to store therein identifiers of the terminal and a transmission terminal in the RPR ring network that transmits the first signal to the terminal when the first signal passes via the first connecting unit; anda second storage unit configured to store therein identifiers of the terminal and a transmission terminal in the RPR ring network that transmits the first signal to the terminal when the first signal passes through the second connecting unit; anda deleting unit that deletes from the first storage unit the identifier of the terminal upon the detecting unit detecting the disconnection.

8. The ring node device according to claim 7, wherein the second storage unit stores therein the identifier of the receiving terminal upon the masking unit unmasking the second signal.

9. The ring node device according to claim 1, further comprising: a first storage unit that stores therein information about a transmission path in the RPR ring network of the first signal that passes via the first connecting unit; anda second storage unit that stores therein information about a transmission path in the RPR ring network of the first signal that passes via the second connecting unit,wherein the same transmission path is stored in the first storage unit and the second storage unit regardless of whether the second controlling unit controls the second connecting unit and whether the second masking unit masks the second signal.

10. A method of connecting a terminal device to a ring node device included in a ring network, the ring node device allocated with an identifier for identifying the ring node device from other devices on the ring network, the ring node device including a first connecting unit and a second connecting unit, the first connecting unit and the second connecting employing Resilient Packet Ring (RPR) technique, the first connecting unit and the second connecting unit being allocated with the same identifier as that of the ring node device, the method comprising: inputting a first signal received via the ring network to both the first connecting unit and the second connecting unit for sending the first signal to the terminal;controlling the second connecting unit so that the first signal is not output to the terminal;masking a second signal received from the terminal before the second signal is input into the second connecting unit; andoutputting the second signal output from any one of the first connecting unit and the second connecting unit to the ring network.

11. The method according to claim 10, wherein the controlling includes controlling the second connecting unit so that the second connecting unit does not output the second signal to the ring network.

12. The method according to claim 10, further comprising detecting disconnection of communication link between the first connecting unit and the terminal, wherein, upon detecting the disconnection at the detecting, the controlling includes controlling the second connecting unit so that the second connecting unit outputs the first signal to the terminal, andthe masking includes unmasking the second signal.

13. The method according to claim 12, further comprising: controlling the first connecting unit, upon detecting the disconnection at the detecting, so that the first connecting unit does not output the first signal to the terminal; andmasking, upon detecting the disconnection at the detecting, the second signal before the second signal is input into the first connecting unit.

14. The method according to claim 11, wherein the controlling unit includes selecting the second signal from the first connecting unit for outputting to the ring network or the second signal output from the second connecting unit for outputting to the ring network.

15. The method according to claim 10, wherein the RPR ring network includes a first ring network and a second ring network such that a signal transmission direction of the second ring network is in opposite direction of a signal transmission direction of the first ring network,the inputting includes inputting first signals from both the first ring network and the second ring network to both first connecting unit and the second connecting unit,the method further comprising selecting any one of the second signal output from the first connecting unit and the second connecting unit for outputting to any one of the first ring network and the second ring network.

16. The method according to claim 12, further comprising: storing in a first storage unit identifiers of the terminal and a transmission terminal in the RPR ring network that transmits the first signal to the terminal when the first signal passes via the first connecting unit, storing in a second storage unit identifiers of the terminal and a transmission terminal in the RPR ring network that transmits the first signal to the terminal when the first signal passes through the second connecting unit; anddeleting from the first storage unit the identifier of the terminal upon detecting the disconnection at the detecting.

17. The method according to claim 16, wherein the storing includes storing in the second storage unit the identifier of the receiving terminal upon the second signal is unmasked at the masking.

18. The method according to claim 10, further comprising: storing in a first storage unit information about a transmission path in the RPR ring network of the first signal that passes via the first connecting unit; andstoring in a second storage unit information about a transmission path in the RPR ring network of the first signal that passes via the second connecting unit,wherein storing includes storing the same transmission path in the first storage unit and the second storage unit regardless of whether the controlling controls the second connecting unit and whether the masking masks the second signal.