A user level matches a certain command level. After logging in to a switch, a user can run only the commands of which the levels are the same as or lower than the user level. For example, a user at level 2 can run only the commands at levels 0, 1, and 2.
By default, the command level ranges from 0 to 3, and the user level ranges from 0 to 15. An administrator can change the command level as required so that users of different levels can execute commands correspondingly.
The administrator at user level 15 can run the following command to increase command levels:
Run the command-privilege level level view view-name command-key command with the command-key parameter specified.
Run the command-privilege level rearrange command to increase command levels in batches.
If the levels of commands have not been changed using the command-privilege level level view view-name command-key command, the levels of all level-2 and level-3 commands will be increased to level 10 and level 15 after the preceding command is executed, whereas the levels of level-0 and level-1 commands are unchanged.

You can find OSN 7500 on Thunder-link.com.

At the ROADM station consisting of the OptiX OSN 6800 V1R2, the signal flow in the wavelength add direction is as follows: L4G->M40V->WSM9->OAU->FIU. After the internal logical fiber connections are complete at the NE, create the single-station optical cross-connections and select the automatic optical power adjustment function. Then, the T2000 prompts that the creation is successful. The OAU board, however, reports the MUT_LOS alarm. No alarm is generated on other boards.

1, choose the received broadcast data sent by OLT;
2, ranging from OLT response and power control command; and make the corresponding adjustment;
3, the user's Ethernet data cache, and in the OLT distribution of the sending window to the uplink direction.

In the DWDM network, clock is the key factor that ensures the synchronous communication between the SC1/SC2 and the SCC. There is only one clock source at the source end in the entire network. The communication between the OSC board at other stations and the SCC must be synchronous with the clock at the source end. Otherwise, the R_SLIP alarm is generated.
During the networking commissioning, port 1 of the OSC is connected to the upstream NE and port 2 is connected to the downstream NE normally. By default, the OSC sends the line clock at port 1 to the SCC. In a certain situation, when port 2 of the OSC is connected to the upstream NE and port 1 is connected to the downstream NE, you need to configure the east clock as the clock that is sent back to the SCC manually. It is recommended, however, that you do not change the clock source that the OSC sends back the SCC.

More blog:
What’s the alarm on the OptiX OSN 1800II board restarts after power-off
Warning of Failed Cascading on the MA5616 Equipped with the JDSU GE Optical Module

1 Creating NEs, Optical Fibers, and Topology Subnets
Network services and protection schemes can be configured only after NEs, optical fibers, and topology subnets are created.
 
2 Configuring the Equipment Level Protection
The OptiX OSN 3500 equipment supports various equipment level protection schemes, including the TPS, 1+1 board protection, board level protection, and port protection.
 
3 Configuring the Protection Subnet
The OptiX OSN 3500 equipment supports various network level protection schemes, including the linear MSP and ring MSP.
 
4 Configuring Clocks
A clock is the basis for the normal running of NEs. You must configure clocks for all NEs prior to configuring services. In addition, you need to configure clock protection for complex networks.
 
5 Configuring Orderwire
You can configure orderwire for NEs by using the U2000.
 
Will update the topic configuration in several weeks, hope can help you!
 
Here is the content for Creating NEs, Optical Fibers, and Topology Subnets
Network services and protection schemes can be configured only after NEs, optical fibers, and topology subnets are created.

1. star mode.
When between OLT and ONU by point-to-point configuration and each ONU directly by a special optical link with the OLT connected, in the middle there is no optical branching device consisting of a star structure. Because of this configuration there is no loss of optical splitter is introduced, so the transmission distance is far greater than the point to multipoint configuration. But the application of fiber waste is serious, can not reflect the advantages of GPON technology, less practical application.
2. way tree mode.
Tree topology is point to multipoint configurations of the basic structure, this structure using the a series of cascade distribution point (DP) of the signal splitter, passed to multiple users, but also on the distribution node uplink signal combined together give OLT. 1:N type splitter distribution points, in the important customer access, may use 2:N light to achieve the trunk fiber protection. In the application of the local network, considering the fiber network layout complex, generally use a light, for multistage, suggested control within three class.
3. Bus mode.
Bus structure is the basic structure of point to multipoint configuration. This topology, in fact, is the topology of the OLT and distribution points, and the distribution point to the ONU is still the star structure. This structure uses a series of distribution points in order to distribute the signal from the bus to the ONU to send the signal to the OLT, and can send the signal of each ONU to the bus to send back to OLT. This approach is generally used in monitoring and control system, optical device for 1:2 is divided into light, light 5:95 or 10:90 and 20:80 multiple choice, recommend the use of 10:90 light splitter, actual use in optical power calculation principles prevail, there is generally no more than 7.

When an SSN3PSXCSA (Ver.B) board is used to replace another cross-connect board, after theSSN3PSXCSA (Ver.B) board is inserted into the subrack, the state of the original active cross-connect board is abnormal and NE services are interrupted. After about 40s, the state of the original active board is back to normal and services recover.
[Problem Description]Fault symptoms:
When an SSN3PSXCSA (Ver.B) board is inserted into the slot of the standby cross-connect board, the ACT indicator of the active cross-connect board turns from steady green to off and services are interrupted. The NE may report the PLL_FAIL alarm of service boards.
Trigger conditions:
Use an SSN3PSXCSA (Ver.B) board to replace another kind of cross-connect board. This problem does not occur if the original active cross-connect board is an SSN3PSXCSA board.

When the board is connected ONTs, the ONTs respond to the management messages or PLOAM messages sent by the OLT. By reporting interruptions, the board GMAC instructs the CPU to process these messages. The CPLD codes of the GPBD board have a bug. As a result, useless interruptions will be reported to the CPU and the CPU always responds to these interruptions. When the system TICK interruption is generated (once 10 ms), the interruption that cannot be processed in time will be buffered in the system workQ queue. This process repeats. After the queue overflows (the depth of the workQ queue is 64), the operating system automatically resets the board.

In the DWDM network, clock is the key factor that ensures the synchronous communication between the SC1/SC2 and the SCC. There is only one clock source at the source end in the entire network. The communication between the OSC board at other stations and the SCC must be synchronous with the clock at the source end. Otherwise, the R_SLIP alarm is generated.
During the networking commissioning, port 1 of the OSC is connected to the upstream NE and port 2 is connected to the downstream NE normally. By default, the OSC sends the line clock at port 1 to the SCC. In a certain situation, when port 2 of the OSC is connected to the upstream NE and port 1 is connected to the downstream NE, you need to configure the east clock as the clock that is sent back to the SCC manually. It is recommended, however, that you do not change the clock source that the OSC sends back the SCC.

At the moment, a few companies access technology, which is in general used is flawed: Traditional Huawei SDH and Huawei MSTP have good business bearing capacity with high cost, and mainly used to high-end business enterprise customers who are very concerned about quality; xDSL access to multi-service bearing with low potential, and only can be used to small voice and low rate of broadband of low-end application; in middle-end, there will present the DDN, PDH, Ethernet mixed with a variety technologies, these techniques in many business bearing capacity, reliability and maintainability, etc, all have their own limitations, and it is difficult to meet the demand of the whole business of access in the new period. At this situation, build a enterprise access network to meet the needs of most corporate customers, capable of carrying a comprehensive enterprise with various business, to maintain, easy to manage has become the priority of the operators.
Along with the light into the copper retreated In-depth development of the process, the PON network bandwidth upgrade, business hosting and passive network maintenance and other advantages of gradually is accepted by the operator.Recently, some global mainstream operators began to access GPON technology was applied to enterprises, makes the GPON has been the star of the access plan of the enterprise technology.

Uniform switching architecture: OptiX OSN 3500 devices adopt a unified exchange architecture to meet the needs of existing users for traditional business, while addressing the growing group of business requirements. OptiX OSN device uses the "unified exchange" architecture, to achieve a unified scheduling of packet services and TDM business, to build a flexible application mode: pure grouping mode, pure TDM mode and mixed mode (+TDM). Between the three modes can be through business board level expansion, to achieve a smooth transition, thus always to best fit model meet the demands of the business operators and network development, convenient operators follow industrial chain development and maturity of distributed smooth investment. Based on the unified fabric architecture, OptiX OSN equipment using packet transport technology, realizing
According to the high statistical multiplexing service, effectively reduce the transmission cost of each bit service; while inheriting the advantages of SDH and TDM to provide business Native bearing, ensure the high quality transmission of voice service. Based on the unified fabric architecture, OptiX OSN equipment can be used as a packet transmission products are compatible with the TDM service, realize the unification of the 2G, 3G, customer dedicated network load, reduce network overlap. Hybrid network based on the unified exchange "architecture, operators can set up end to end packet networks, packet and SDH, network and router realize L2+L3 unified bearing and build a complete packet delivery solutions, realize the bearer network from TDM to all IP harmonious evolution.

SDH optical transmission medium of the transmission network is, of course, fiber, the single-mode optical fiber with a large bandwidth, easy to upgrade and expansion and low cost advantages, international has agreed that digital synchronous optical line system using only single mode fiber as transmission medium. There are 3 transmission "windows" in the optical fiber transmission, which is suitable for the transmission wavelength range, 850nm, 1310nm, 1550nm. In which the 850nm window is only used for multi-mode transmission, only 1310nm and 1550nm are used for the single mode transmission window.
The distance of the optical signal transmission in the optical fiber is affected by the dispersion and loss, and the dispersion will cause the transmission of the digital pulse in the optical fiber, which can reduce the signal quality. When the code interference between the transmission performance degradation to a certain extent (for example 10-3), transmission system will not work the, the loss of the optical signals in the optical fiber transmission with power transmission distance decreased, when the optical power is reduced to a certain degree, transmission system cannot work.
In order to extend the transmission distance of the system, it is mainly to reduce the dispersion and loss. 1310nm optical transmission window is called the 0 dispersion window, the optical signal transmission dispersion in this window is minimal, the 1550nm window is called the minimum loss window, the attenuation of the optical signal transmission in this window is minimized.

Huawei OSN6800 is a 40G/100G level DWDM, with 17 service slots, support 360G Cross-Connect capacity. OSN6800 Subrack comes with two PIU (Power Interface Unit), one AUX (System Auxiliary Interface Board), other system board and service board are configurable. Thunder-link.com also offers typical configuration bundle line, to meet your different requirement on various scenarios. In addition, Thunder-link.com provides self configuration page, where you can configure your own OSN6800 by selecting boards and items yourself. With our professional technical support to rich your experience.

Short for DSLAM is Digital Subscriber Line Access Multiplexer, called Digital Subscriber Line Access Multiplexer in Chinese.DSLAM is all sorts of bureau of DSL system end equipment, belong to the last mile access equipment (the last mile), its function is to accept all of the DSL line, funnel flow, the equivalent of a layer 2 switches.Broadband Access services BRAS (Broadband Remote Access Server - Broadband Remote Access service equipment), to provide Broadband Access services, and to achieve a variety of business and forwarding, can satisfy the different network users demand for transmission capacity and bandwidth utilization, is the core of the Broadband user Access equipment.

The Echo Life HG8245, an optical network terminal (ONT), is a high-end home gateway in Huawei FTTH solution.
By using the GPON technology, ultra-broadband access is provided for home and SOHO users. The HG8245 provides
two POTS ports, four GE/FE auto-adapting Ethernet ports and one WiFi port. The HG8245 features high-performance
forwarding capabilities to ensure excellent experience with VoIP, Internet and HD video services.

Features
Port: 2POTS+4GE+1USB+WiFi.
Plug-and-play (PnP): Internet, IPTV and VoIP services can be deployed by one click on the NMS and on-site configuration
is not required.
Remote diagnosis: Remote fault locating is implemented by the loop-line test of POTS ports, call emulation and PPPoE
dialup emulation initiated by the NMS.
High speed forwarding: GE line rate forwarding in the bridge scenario and 900 Mbit/s forwarding in the NAT scenario.
Green energy-saving: 25% power consumption is saved with highly integrated system on chipset (SOC) solution, in which, a single chip integrates with PON, voice, gateway and LSW modules.

Applications & Benefits
High-performance forwarding capability provides an optimal terminal solution and future oriented service supporting capabilities for FTTH deployment.
Plug-and-play makes service provisioning easier and more quickly.
Abundant remote diagnosis helps to locate failure more quickly and reduce OPEX.

the OptiX OSN 3500 is mainly used at the convergence layer and backbone layer of the metropolitan area network (MAN). The network application scenarios are described as follows:
In TDM networking, can be networked with the other OptiX transmission equipment (the OptiX OSN 9560, OptiX OSN 9500, OptiX OSN 7500 II, OptiX OSN 7500, OptiX OSN 3500 II, OptiX OSN 2500, OptiX OSN 1500, OptiX OSN 500, and OptiX OSN 550) to optimize the carrier's investment.
With the packet switching technology, can constitute a packet data transmission network with the other OptiX transmission equipment (the OptiX OSN 7500 II, OptiX OSN 7500, OptiX OSN 1500, OptiX OSN 500, OptiX OSN 550, OptiX PTN 910, OptiX PTN 950, OptiX PTN 1900, OptiX PTN 3900, and OptiX RTN 900) to meet the requirement for bearing IP services.
Can be flexibly networked with WDM equipment and Metro equipment.
Can transparently transmit services over third-party Layer 2 networks, allowing end-to-end configuration and management.

Summary: In MA5600T V8R6 and V8R7, during the management message (OMCI and PLOAM messages) interaction when the H802GPBD board is connected ONUs, there is a possible that the CPLD logic bug is triggered. As a result, the board resets.
Product Model: MA5600T Product Family: Optical access
[Issue Description]
Trigger conditions:
ONUs are in the auto-discovery stage and the management message interaction increases.
ONUs repeatedly go online and offline, and the management message interaction increases.
ONUs are repeatedly powered on and powered off, and the management message interaction increases.
The possibility of board reset increases with the normal management message interaction.
Fault symptom:
The H802GPBD board resets at random when it is connected to ONTs.
Identification method:
Query the CPLD version of the H802GPBD board.
MA5600T(config)#display version 0/12
Send message for inquiring board version successfully, board executing...
Main Board: H802GPBD
---------------------------------------
Pcb Version: H802GPBD VER B
Mab Version: 0000
Logic Version: (U50)000(U25)008(U26)008(U49)018
--U49 is the CPLD logic and 018 is the logic version. Versions earlier than 018 has the issue of misinforming interruptions.
Main CPU :
CPU Version: (U48)MPC8349
APP Version: 672(2011-7-19)
BIOS Version: (U57)651
Enter the transparent transmission channel of the board to query the GMAC statistics.
Commands for querying the GMAC information are as follows:
MA5600T(config)#diagnose
MA5600T(diagnose)%%su
MA5600T(su)%%transparent on <frameid>/<slotid>
MA5600T(su)%%user
MA5600T(su)%%gmac show st 0
MA5600T(su)%%transparent off

MA5600T(su)%%gmac show stat 0 ------payload--------------------------------------------------------------- DownGemCnt: 13830616 UpGemCnt: 16303424 Down NVld Gem: 0 Up Misync Cnt: 0 UGemReceivedIdle: 833932 ------DARB & RSM & PED------------------------------------------------------ DarbSendEthCnt: 13828216 RsmSendEthCnt: 12579847 DarbSendOmciCnt: 2400 RsmSendOmciCnt: 2400 DarbSendTdmCnt: 0 RsmSendTdmCnt: 0 DarbInsertIdleCnt: 9687041 RsmInsertInvalidCnt: 0 DarbInsertInvalidPortID: 0 RsmDropInvalidPortID: 0 PedCrcErrEth: 2 PedPLIErrDropOmci: 0 PedPLIErrDropTdm: 0 PedSendEthCnt: 12579847 PedSendTdmCnt: 0 PedSendOmciCnt: 2400 PedRecOverSizeEthCnt: 0 PedRecUnderSizeEthCnt: 0 ------OMCI------------------------------------------------------------------ DomciInsertCnt: 2400 UomciSendCnt: 2400 UomciCrcErrSendCnt: 0 ------PLOAM----------------------------------------------------------------- DownPloamCnt: 9297 UpPloamCnt: 23783 UploamDropForCrcCnt: 0 UploamDropForFullCnt: 0 UploamNoMsgCnt: 16058 ------SPI4.2---------------------------------------------------------------- SPI4DnReceiveCnt: 13828216 SPI4UpSendPktCnt: 12579847 SPI4DnDropCnt: 0 SPI4DnFifofullDrop: 0 SPI4DnPLIErrCnt: 0 SPI4DnTDMErrCnt: 0 SPI4DnETHErrCnt: 0 ---------------------------------------------------------------------------- GMAC_ENTER_SERVICE: 10636691 -----The number of interruptions here is larger than 10 million, but the total number of interruptions on the following related PON ports is only larger than 20,000. Therefore, the issue is caused by excessively frequent interruptions. GMAC_ENTER_GMAC0_SERVICE: 8276
GMAC_ENTER_GMAC1_SERVICE: 8539
GMAC_ENTER_GMAC2_SERVICE: 3556 GMAC_ENTER_GMAC3_SERVICE: 1829 GMAC_ENTER_GMAC4_SERVICE: 2 GMAC_ENTER_GMAC5_SERVICE: 2 GMAC_ENTER_GMAC6_SERVICE: 2 GMAC_ENTER_GMAC7_SERVICE: 2 GMAC_INT_PLOAM: 18271 GMAC_INT_OMCI: 3661
GMAC_INT_ALARM: 344
GMAC_INT_LACKBAND: 0
[Root Cause]
When the board is connected ONTs, the ONTs respond to the management messages or PLOAM messages sent by the OLT. By reporting interruptions, the board GMAC instructs the CPU to process these messages. The CPLD codes of the GPBD board have a bug. As a result, useless interruptions will be reported to the CPU and the CPU always responds to these interruptions. When the system TICK interruption is generated (once 10 ms), the interruption that cannot be processed in time will be buffered in the system workQ queue. This process repeats. After the queue overflows (the depth of the workQ queue is 64), the operating system automatically resets the board.
[Impact and Risk]
The possibility of board reset increases with the number of ONTs connected to the board or the number of automatically discovered ONTs.
[Measures and Solutions]
Workarounds:
Reduce the management message interaction between OLT and ONU.
Clear the automatically discovered ONTs of the board. Enable these ONTs to go online or remove them to reduce the management message interaction.
Query the optical path status to check whether the management message interaction increases because ONTs repeatedly go online and offline due to optical path error codes.
Solution:
Upgrade the IO board package file for MA5600T V800R006C00SPC127 and later versions.
Upgrade the IO board package file for MA5600T V800R007C00SPC317 and later versions.
Upgrade the IO board package file for MA5600T V800R008C01SPC307 and later versions.

[Rectification Scope and Time Requirements]
None
[Pre-Warning Expiration]
The version is upgraded to V800R006C00SPC127 or V800R007C00SPC317 or V800R008C01SPC307, and the corresponding IO board package file is also upgraded.
Query the CPLD logic version of the H802GPBD board. If the version is 018 or later, this issue is resolved.

At first only a 10 g ring need to build form a complete set of otns is temporarily input is large, use its OTN devices (Huawei OSN 6800/8800) bearing ring of SDH in the long channel is to embody the value, particularly as the LTE/big customer special line/broadband business all at the same time from the county to the core engine, built its OTN equipment is equivalent to at least 10 g (GE) built a * 40 thoroughfare, when we in the later build two plane SDH equipment directly go wavelength division, and 10 g SDH equipment do not need to consider the dispersion, the attenuation, because the channel wavelength division has already in place, when new OLP, now as long as the fiber resource abundance and fiber attenuation can meet with OLP protection, simply add 1 piece of OLP veneer in equipment, add a pair of OLP protection period need to spend 6 db attenuation.Bearing on its OTN, for A certain period of A county town gathered node and the core node in the SDH equipment with 10 G plate, the OTN county gathering node and to end the core node configuration LSX board (OSN6800), if not the LSX SDH plate will need to use 10 line plate color, A color plate is support g. 691 agreement, this kind of plate directly in 6800 of us on the partial wave veneer, but for now, this solution is not directly connected LSX veneer maintenance convenient.

Procedure on the OSN 6800
1. Check whether the insertion loss between the TDC and RDC optical interfaces is normal before the DCM is replaced with another DCM. The permitted maximum insertion loss between the TDC and RDC optical interfaces = Maximum gain of TN11OAU101 (31 dB) - Nominal gain (set on the T2000).
In the NE Explorer, select the OAU board and then choose Configuration > WDM a.Interface from the Function Tree.
b.On the right of the user interface, select By Board/Port (Channel).
c.On the Basic Attributes tab page, click Query to query the nominal gain of the OAU board in the Nominal Gain(dB) field.
2. If the insertion loss between the TDC and the RDC optical interfaces is very high, that is, if the insertion loss exceeds the adjustment range of the TN11OAU101, the TN11OAU101 reports the VOA_ADJUST_FAIL. In this case, check whether the fiber insertion loss is very high and whether the TDC and RDC optical interfaces on the TN11OAU101 are clean.

Create a GPON ONT line profile, named ftth, and bind it to the DBA profile ftth_dba.
huawei(config)#ont-lineprofile gpon profile-name ftth
huawei(config-gpon-lineprofile-1)#tcont 4 dba-profile-name ftth_dba
huawei(config-gpon-lineprofile-1)#gem add 11 eth tcont 4
huawei(config-gpon-lineprofile-1)#gem add 12 eth tcont 4
huawei(config-gpon-lineprofile-1)#gem add 13 eth tcont 4
huawei(config-gpon-lineprofile-1)#gem add 14 eth tcont 4
huawei(config-gpon-lineprofile-1)#commit
huawei(config-gpon-lineprofile-1)#quit

Huawei OSN3500 is a STM-64 level MSTP, It have 15 service slots and can MAX support 12*STM-64 interface. OSN3500 Subrack comes with two PIU (Power Interface Unit), one AUX (System Auxiliary Interface Board), others system board and service board are configurable. Thunder-link.com also offers typical configuration bundle line, to meet your different requirement on various scenarios. In addition, Thunder-link.com provides self configuration page, where you can configure your own OSN3500 by selecting boards and items yourself. With our professional technical support to rich your experience.

HUAWEI STM-4 (622M) optical interface board supports the implementation of sending and receiving STM-4 signal, STM-4 signal of the photoelectric conversion is completed, the overhead byte extraction and insertion, and reporting to the alarm on the line. STM-4 optical interface board SDH board are: SL4, SL4A, SLD4, SLD4A, SLQ4, SLQ4A, each type of plate distance distance, according to customer demand, the corresponding configuration panel.

1. Adding an ONT offline: Before installing an ONT, manually add an ONT to the OLT and configure the ONT. After the ONT goes online, the OLT authenticates the ONT and issues configurations to the ONT.
2. Adding an ONT online: After an ONT is installed, the OLT discovers the online ONT and adds and configures it. The automatic discovery of an ONT applies when an ONT is added online. In this scenario, the installation time of an ONT is uncertain because the OLT periodically searches for online ONTs.
3. The automatic discovery of an ONT connecting to 10G GPON ports is disabled by default.
4. In 10G GPON interface mode, run the port ont-auto-find command to enable the automatic discovery of an ONT.
5. In 10G GPON interface mode, run the display ont autofind command to query the automatic discovery of an ONT.

The OptiX OSN 8800 V100R008C10SPC200 does not support hardware tributary SNCP on the TN54THA and TN53TSXL boards. If hardware tributary SNCP is configured on a TN54THA or TN53TSXL board, array violation will occur on the board, causing the board to insert an incorrect s-code to the cross-connect board on the NE. As a result, bit changes occur on the chip page of the cross-connect board. Consequently, the cross-connect board reports a HARD_BAD alarm.

our company supply Huawei PRODUCT.



Thunder-link

The TN12OAU1 can be created as OAU1 on the NMS. The former can substitute for the latter at type 01,02,03,05, without any software upgrade. After substitution, the TN12OAU1 functions as the TN11OAU1.
The TN13OAU1 can be created as OAU1 on the NMS. The former can substitute for the latter at type 01,03,05, without any software upgrade. After substitution, the TN13OAU1 function as the TN11OAU1. The TN13OAU1 board occupies one physical slot and two logical slots while the TN11OAU1 board occupies two physical slots. After the substitution, the remaining one physical slot cannot be used to house any other board.
The TN13OAU1 can be created as 12OAU1 on the NMS. The former can substitute for the latter at type 01,03,05, without any software upgrade. After substitution, the TN13OAU1 functions as the TN12OAU1. The TN13OAU1 board occupies one physical slot and two logical slots while the TN12OAU1 board occupies two physical slots. After the substitution, the remaining one physical slot cannot be used to house any other board.

Multiplexing section overhead processor sets MSOH (Section Overhead Multiplex) bytes to the received STM-N signal, including K1, K2, D4-D12, S1, M1, E2, and B2 bytes. If Los R, R lof or MS AIS alarms are detected in the downlink signal flow is set b6-b8 K2 bytes of 110, sent MS RDI warning echo to the distal end. If in the downlink signal flow detected B2 error, M1 is used to send MS_REI bytes back to the remote alarm.