WO2023181162A1

WO2023181162A1 - Communication device switching method and communication system

Info

Publication number: WO2023181162A1
Application number: PCT/JP2022/013465
Authority: WO
Inventors: 昂平鈴木; 勝也南; 康隆木村; 一成間瀬
Original assignee: 日本電信電話株式会社
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2023-09-28

Abstract

The purpose of the present invention is to provide a communication device switching method and a communication system which are capable of switching communication devices at a low cost without requiring work for implementing redundancy.　The communication device switching method according to the present invention performs switching work by the following procedure. (Step 1) Setting is performed such that a termination device 31 changes an uplink frame to a relay device 35#2 at a relocation destination on the basis of an LLID and receives a downlink frame from both the relay device (35#1) at the relocation destination and a relay device (35#2) at a relocation source. (Step 2) A function of an L2 switch 16 (for automatically learning the transmission source MAC address of an uplink frame and a port that has received the frame and transmitting, to the port, a downlink frame with the termination device as the destination MAC address) is used to cause the downlink frame to automatically pass through the relay device 35#2 at the relocation destination.

Description

Communication device switching method and communication system

The present disclosure relates to a communication device switching method for switching a communication device from one to another, and a communication system that can implement the method.

For example, it may be necessary to switch the current in-office MC (media converter) to another in-office MC due to reasons such as updating equipment. Patent Document 1 discloses a method of performing this switching work without interrupting communication (without interruption).

FIG. 1 is a diagram illustrating a communication device switching method disclosed in Patent Document 1. In Patent Document 1, in a wide area Ethernet (registered trademark) service, an uninterrupted communication device 10 is used to connect a device (internal MC) 15#1 in a source building to a device (internal MC) 15#2 in a destination building. A method for switching to is disclosed. The uninterrupted communication device 10 is a device that performs frame order management using sequence numbers, frame duplication confirmation, frame duplication, frame selection control, and correction control for path delay and delay fluctuation.

Specifically, the MC in the source station is switched to the MC in the destination station in the following steps.
(Step 1)
In-house MC 11 #2, in-office MC 15 #2, switch 16 #2, in-office MC 25 #2, and in-home MC #2 are newly installed in the system. By connecting the uninterrupted communication device 10-1 to two in-home MCs (11#1, 11#2) and the uninterrupted communication device 10-2 to two in-home MCs (21#1, 21#2), , communication is performed simultaneously using both route 1 from the home MC 11#1 to the home MC 21#1 and route 2 from the home MC 11#2 to the home MC 21#2.
(Step 2)
From this state, the home MC 11#1 is turned off. Then, the uninterrupted communication device 10-1 continues communication using the home MC 11#2 without frame loss due to its functions.

In other words, the communication device switching method disclosed in Patent Document 1 prepares two communication paths and uses an uninterrupted communication device to change the path from the source building to the destination building without interruption. The method is to switch.

International publication WO2020/261393 pamphlet

However, the communication device switching method disclosed in Patent Document 1 requires installation of the in-home MC 11#2 and the non-interruption switching device 10-1 opposite to the in-office MC 15#2 of the relocation destination building Tn1 in the user building U1. Similar redundancy is also required for the communication partner user building U2 and station building T2. For this reason, the communication device switching method disclosed in Patent Document 1 has problems in that the cost of the equipment is high and that there is a period when communication is not possible in the opposite building due to redundancy construction.

Therefore, in order to solve the above-mentioned problems, it is an object of the present invention to provide a communication device switching method and a communication system that can switch communication devices at low cost and without redundancy construction.

In order to achieve the above object, a communication device switching method according to the present invention connects an in-home MC (terminal device) in a user building and a plurality of communication devices in a source building and a destination building, such as a PON (Passive Optical Network). It was decided to connect to the in-office MC (relay device) using 1:N time division multiplexing. N is the number of in-house MCs in the source building and the destination building. For example, N=2.

Specifically, the communication device switching method according to the present invention is a communication device switching method for changing a relay device connected to a network via a layer 2 switch from one to the other,
connecting a termination device to both of the relay devices using LLID and time-sharing communication;
At an arbitrary timing, both of the relay devices set the previous setting to discard the downlink frame from the other relay device and send the uplink frame to one of the relay devices using the LLID. changing to a new setting in which the uplink frame is received from the relay device and sent to the other relay device using the LLID, and the layer automatically learns the route of the uplink frame in the new setting. The two switches transmit downlink frames addressed to the terminal device to the other relay device.

Further, the communication system according to the present invention includes two relay devices connected to the network via a layer 2 switch, and a terminal device connected to both relay devices via a splitter using LLID and time-sharing communication. A communication system comprising:
The terminal device discards the downlink frame from the other relay device and transmits the uplink frame to one of the relay devices using the LLID at a timing when the terminal device is about to change the relay device with which it communicates from one to the other. changing the previous setting to a new setting of receiving downlink frames from both of the relay devices and transmitting uplink frames to the other relay device using the LLID,
The layer 2 switch is characterized in that it automatically learns the route of the uplink frame in the new setting and transmits the downlink frame addressed to the terminal device to the other relay device.

In this communication device switching method, the switching operation is performed in the following steps.
(Step 1)
The terminating device changes the uplink frame to the transfer destination relay device using the LLID, and makes settings to accept the downlink frame from both the transfer destination and transfer source relay devices.
(Step 2)
By using the L2 switch function (automatically learns the source MAC address of an upstream frame and the port that received the frame, and sends a downstream frame with the destination MAC address of the terminal device to that port), the downstream frame is Automatically route through the relay device at the relocation destination.

In this communication device switching method, during switching, the terminal device enters a state where it accepts downlink frames from both the transfer destination and transfer source relay devices, and broadcast frames arrive in duplicate. Therefore, it is not possible to switch completely without interruption as in Patent Document 1.
(supplement)
In a state where the terminating device accepts downlink frames from both relay devices, broadcast frames arrive twice, and this is communication not intended by the sender, resulting in a state in which communication is essentially impossible. In the present disclosure, this state in which communication is virtually impossible is treated as a "momentary interruption."

However, as described above, this communication device switching method only requires preparing a transfer destination relay device and an L2 switch and forming a PON configuration (low cost and no redundancy construction required). Although the switching of this communication device switching method is not instantaneous, the period during which broadcast frames arrive at the terminal device in duplicate is only the learning time of the L2 switch, and the effect on the communication system as a whole is small. In this specification, a momentary interruption with a small effect is expressed as a "short momentary interruption."

Therefore, the present invention can provide a communication device switching method and a communication system that can switch communication devices at low cost and without redundancy construction.

The communication device switching method according to the present invention is characterized in that, after changing to the new setting, a completion setting is further performed on the terminal device to discard the downlink frame from one of the relay devices.
Further, the terminal device of the communication system according to the present invention is characterized in that, after changing to the new setting, the terminal device further performs a completion setting for discarding the downlink frame from one of the relay devices.

As the L2 switch learns, downlink frames will arrive at the terminating device via the destination relay device, but the terminating device will be in a state where it accepts downlink frames from both the destination and source relay devices. Therefore, there remains a possibility that duplicate broadcast frames will arrive at the end device. Therefore, in order to completely avoid frame loss, settings are made to end this state at the end.

Note that the above inventions can be combined as much as possible.

The present invention can provide a communication device switching method and a communication system that can switch communication devices at low cost and without redundancy construction.

FIG. 2 is a diagram illustrating a related communication system. FIG. 1 is a diagram illustrating a communication system according to the present invention. FIG. 2 is a diagram illustrating a communication device switching method according to the present invention. FIG. 2 is a diagram illustrating a communication device switching method according to the present invention. FIG. 1 is a diagram illustrating a communication system according to the present invention.

Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. Note that components with the same reference numerals in this specification and the drawings indicate the same components.

FIG. 2 is a diagram illustrating the communication system of this embodiment. This communication system is
two relay devices (35#1, 35#2) connected to the network 50 via layer 2 switches (16#1, 16#2);
A terminal device 31 that connects to both relay devices (35#1, 35#2) via a splitter 33 using LLID and time-sharing communication;
Equipped with
The terminating device 31 discards the downlink frame from the relay device 35#2 at the timing when the communication is to be changed from the relay device 35#1 to the relay device 35#2, and transmits the uplink frame to the relay device 35#1 using the LLID. The "old setting" transmits frames, and the "new setting" receives downlink frames from both relay devices (35#1, 35#2) and sends uplink frames to relay device 35#2 using the LLID. Change to
The layer 2 switches (16#1, 16#2) automatically learn the route of the uplink frame (the source MAC address of the frame and the port that received the frame) in the "new setting" and send it to the terminal device 31. The downlink frame is transmitted to the relay device 35#2.

In this embodiment, for reasons such as system equipment renewal or building relocation, the relay device (e.g., in-office MC) 35#1 in the source building To1 of the wide area Ethernet service is replaced with the relay device (e.g., in-house MC) in the destination building Tn1. , local MC) Consider a situation where you want to switch to 35#2. In the following description, the relay device 35#1 may be referred to as "in-office MC 35 #1," the relay device 35 #2 may be referred to as "in-office MC 35 #2," and the terminal device 31 may be referred to as "in-home MC 31."

This communication system includes, on the switching side, an in-house MC 31, an in-office MC 35 #1 and L2 switch 16 #1 in the relocation source building To1, and an in-office MC 35 #2 and L2 switch 16 #2 in the relocation destination building Tn1, and relays. On the other side via the network 50, there is an in-house MC 21, and an in-office MC 25 and an L2 switch 26 in the office building T2.

This communication system connects an in-home MC 31 and two in-office MCs (35#1, 35#2) through an optical transmission path including a splitter 33 to form a PON. The in-house MC 31 functions as an OLT (Optical Line Terminal), and the in-house MC (35#1, 35#2) functions as an ONU (Optical NetWork Unit). In other words, the in-home MC 31 and the two in-office MCs (35#1, 35#2) are connected 1:2 using LLID and time-division communication. With this configuration, before device switching, the home MC 31 has established 1:1 communication with the home MC 35 #1, but has not established communication with the home MC 35 #2.

The L2 switches (16#1, 16#2) and the switches (rings) of the relay network 50 have the same general and basic functions as before, by referring to the destination MAC address of the received frame and sending it from the appropriate port. It has the ability to send. Furthermore, if the received frame has an unlearned MAC address and port combination, the L2 switches (16#1, 16#2) and the switch (ring) of the relay network 50 change the MAC address and port combination. It has the ability to learn.

In this communication system, while two in-office MCs (35#1, 35#2) are simultaneously connected to one in-home MC 31 in a time-sharing manner, the destination of uplink frames from the in-home MC 31 is transferred to the in-office MC 35. By controlling the change from #1 to in-office MC 35 #2, device switching can be achieved with a short interruption.
Unlike Patent Document 1, the communication device switching method in this communication system does not require an uninterrupted communication device, and does not require the other party to add redundant routes (in-office MC 25 in office building T2 and in-home MC 21 in user building U2). , device switching is completed with only the work on the switching side.

Although the communication device switching method in this communication system cannot switch devices without instantaneous interruptions as in Patent Document 1, it does so by keeping momentary interruptions during switching to a short period of time, while reducing equipment costs and the construction period for equipment installation. device switching is possible.

FIG. 3 is a diagram illustrating a communication device switching method in this communication system. This communication device switching method is a method of changing the relay device connected to the network 50 via layer 2 switches (16#1, 16#2) from one (35#1) to the other (35#2). ,
connecting the terminal device 31 to both relay devices (35#1, 35#2) using LLID and time-sharing communication (step S01);
At any timing, the "previous setting" for discarding the downlink frame from the relay device 35#2 and transmitting the uplink frame to the relay device 35#1 using the LLID is set to the terminal device 31 on both relay devices. (Step S02), changing to a "new setting" that receives downlink frames from (35#1, 35#2) and transmits uplink frames to the relay device 35#2 using the LLID, and "new setting" The layer 2 switch 16#2, which has automatically learned the route of the uplink frame at
I do.

In this communication device switching method, after step S03, in order to complete the device switching, “completion setting” is further performed on the terminal device 31 to discard the downlink frame from the relay device 35#1.

FIG. 4 is a diagram specifically explaining this communication device switching method. Note that, as described above, in this communication device switching method, device switching is completed only by the work on the switching side, so the description of the other party's devices (in-home MC 21, in-office MC 25, L2 switch 26) is omitted in FIG.

<Initial state and final state>
In the initial state, in this communication system, the in-home MC 31 in the user building U1 and the in-office MC 35#1 in the source building To1 communicate on a 1:1 basis. The purpose is to switch this to the final state where the in-home MC 31 and the in-office MC 35#2 of the relocation destination building Tn1 communicate on a 1:1 basis.

<Switching procedure>
[Step S01]
This is the state shown in FIG. 4(A).
A splitter 33 is installed in the middle of the optical transmission path (optical fiber) from the home MC 31 to the office MC 35 #1. If a splitter is not installed on the optical transmission path, a new splitter 33 may be placed immediately before the in-home MC 31 in the user building U1. When communication is interrupted for several seconds, the optical fiber is removed from the home MC 31, and the optical fiber is inserted into the splitter 33 so as to form an optical transmission path as shown in FIG.
Through this optical transmission path, uplink frames sent from the home MC 31 are sent to both home MCs (35#1, 35#2), and downlink frames from both home MCs (35#1, 35#2) are sent to the home MC 31. arrive.
In this state, the home MC 31 operates like an OLT of a normal PON, and similarly, the office MCs (35#1, 35#2) operate like ONUs of a normal PON. That is, the in-home MC 31 and the in-office MC (35#1, 35#2) establish a link-up, and the in-home MC 31 uses time division communication with both in-office MCs (35 #1, 35 #2). Communication will be possible at the same time.
However, at this stage, the in-home MC 31 is configured to discard downlink frames from the in-office MC 35#2 and transmit uplink frames to the in-office MC 35#1 using the LLID ("previous setting"). Therefore, frames are transmitted and received only between the home MC 31 and the office MC 35 #1 (uplink frame path Dup and downlink frame path Ddp). This "previous setting" is a setting for preventing the home MC 31 from receiving duplicate broadcast frames transmitted from both in-house MCs.

[Step S02]
This is the state shown in FIG. 4(B).
The home MC 31 uses the LLID to change the destination of the uplink frame from the home MC 35#1 to the home MC 35#2 at an arbitrary timing (uplink frame route Dus). At the same time, the home MC 31 changes its settings ("new settings") to be able to receive downlink frames from both in-station MCs (35#1, 35#2) (downlink frame routes Ddp and Dds). After this "new setting" becomes effective, broadcast frames arrive twice, causing momentary interruptions due to frame discards. However, the unicast frame can be received by the home MC 31 without loss.

[Step S03]
This is the state shown in FIG. 4(C).
The uplink frame that has passed through the intra-office MC 35#2 passes through the L2 switch 16#2 and a switch (ring) on the way to the terminal specified by the destination MAC address of the frame. The switch 16 #2 and the switch (ring) automatically learn the source MAC address of the frame and the port that received the frame, and send the downlink frame with the destination MAC address of the home MC 31 to the port destined for the home MC 35 #2. It will start sending.
In other words, uplink frames take the uplink frame route Dus by selecting the LLID, downlink frames take the downlink frame route Dds by automatic destination learning, and frames in both the up and down directions pass through the intra-office MC 35 #2.

[Step S04]
This is the state shown in FIG. 4(C).
Up to step S03, the in-office MC 35#1 is in a state of not contributing to communication with the in-home MC 31. Therefore, the in-home MC 31 is finally configured to discard the downlink frame from the in-office MC 35 #1 ("completion setting"). This "completion setting" is a safety setting for preventing duplicate transmission of broadcast frames from both in-house MCs (35#1 and 35#2). The momentary interruption that has continued since step S02 ends here. Since the switching of the in-office MC is completed above, it becomes possible to remove the in-office MC 35#1 of the relocation source building To1.

<Effects of the present invention>
In the present invention, unlike Patent Document 1, the work is completed only by communication between the in-office MC on the device switching side and the in-home MC. Therefore, there is no need to introduce an uninterrupted communication device to the user on the opposite side, or to prepare a communication device or an optical cable optical path for redundancy.

10#1, 10#2: Uninterrupted communication device 11#1, 11#2: In-home MC
15#1, 15#2: Internal MC
16#1, 16#2:

L2 switch

21, 21#1, 21#2: Home MC
25, 25#1, 25#2: Internal MC
26: L2 switch 31: Home MC
35#1, 35#2: Internal MC
50: Relay network

Claims

A communication device switching method for changing a relay device connected to a network via a layer 2 switch from one to the other,
connecting a termination device to both of the relay devices using LLID and time-sharing communication;
At an arbitrary timing, both of the relay devices set the previous setting to discard the downlink frame from the other relay device and send the uplink frame to one of the relay devices using the LLID. changing to a new setting in which the uplink frame is received from the relay device and sent to the other relay device using the LLID, and the layer automatically learns the route of the uplink frame in the new setting. A communication device switching method in which two switches transmit a downlink frame addressed to the terminal device to the other relay device.
2. The communication device switching method according to claim 1, further comprising performing a completion setting on the terminal device to discard a downlink frame from one of the relay devices after changing to the new setting.
two relay devices connected to the network via a layer 2 switch,
a terminating device that connects to both of the relay devices via a splitter using LLID and time-sharing communication;
A communication system comprising:
The terminal device discards the downlink frame from the other relay device and transmits the uplink frame to one of the relay devices using the LLID at a timing when the terminal device is about to change the relay device with which it communicates from one to the other. changing the previous setting to a new setting of receiving downlink frames from both of the relay devices and transmitting uplink frames to the other relay device using the LLID,
The communication system is characterized in that the layer 2 switch automatically learns the route of the uplink frame in the new setting and transmits the downlink frame addressed to the terminal device to the other relay device.
4. The communication system according to claim 3, wherein the terminal device further performs a completion setting for discarding a downlink frame from one of the relay devices after changing to the new setting.