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OSN3500 devices The GSCC single board is an intelligent system control board, which manages the single boards of the devices in cooperation with the network management system and realizes the mutual communication among the devices.The GSCC single board supports the functions and features of master control, official business, communication and system power monitoring. It consists of a communication and control module, an overhead processing module, and a power supply module.The functional versions of the GSCC single board are N4 and N6.For the differences in the packet system performance indicators supported by N4GSCC and N6GSCC, please refer to Packet System Performance.
System Grouping Performance Indicators Item Performance Indicators Protection
- For the number of distributed MPLS APS supports, the MPLS Tunnel APS shares resources with the MPLS PW APS.
- For the number of centralized MPLS APSs supported, the MPLS Tunnel APS, MPLS PW APS, MPLS-TP Tunnel APS, and MPLS-TP PW APS share resources with the MRPS (one MRPS ring occupies 2 APS resources).
- N4GSCC: 1K
- N6GSCC: 4K
- N4GSCC: 1K
- N6GSCC: 4K
- N4GSCC: 1K
- N6GSCC: 1K
- N4GSCC: 1K
- N6GSCC: 1K
- N4GSCC: 16
- N6GSCC: 32
MRPS ring protection supports intersecting ring protection. When two rings intersect, an intersection point containing the two farthest nodes is established, and when one of the nodes fails, services can cross the ring from the other node. This intersection point is not an actual physical node and is called a virtual intersection point. When this ring intersects more than one ring, it is necessary to establish a virtual intersection point from that ring to each ring.
- Number of network elements supported: 32
- Number supported on a single ring: 8
- For the number of distributed MPLS OAMs supported, the MPLS Tunnel OAM, MPLS PW OAM, and ETH OAM share resources.
- For the number of centralized MPLS OAMs supported, MPLS Tunnel OAM, MPLS PW OAM, MPLS-TP Tunnel OAM, MPLS-TP PW OAM, and ETH OAM share resources with MRPS OAM.
- N4GSCC: 2K
- N6GSCC: 8K
- N4GSCC: 2K
- N6GSCC: 8K
- N4GSCC: 2K
- N6GSCC: 2K
- N4GSCC: 2K
- N6GSCC: 2K
- N4GSCC: 32
- N6GSCC: 64
An MRPS ring network occupies 2 OAM resources, while MRPS OAMs are automatically created when creating an MRPS ring network and do not need to be created manually.
- N4GSCC: 4K
- N6GSCC: 8K
- Unidirectional:
- N4GSCC: 4K
- N6GSCC: 16K
- Bidirectional:
- N4GSCC: 2K
- N6GSCC: 8K
- Bidirectional Tunnel and unidirectional Tunnel jointly occupy the number of Tunnel, one bidirectional Tunnel is equivalent to two unidirectional Tunnel.
- MPRS ring protection needs to occupy Tunnel resources, and an MRPS ring network occupies 4xN (N is the number of nodes on the ring) Tunnel resources, and the Tunnel resources are automatically allocated when configuring MRPS ring protection.
- N4GSCC: 8K
- N6GSCC: 16K
Problem Description
On a certain day, during the process of replacing the single master control by the user, the "interrupt mode" is used to download, and the service is flashed off for 16S. Users require OSN3500 single master board download test in the experimental environment.
Alarm message
TU_AIS. T2000 version is V2R6C03, OSN3500 version is 5.21.13.47.
Processing
The download process is analyzed as follows:
1, the download process in the initialization of the network element step, the master data is cleared, enter the state of Ann. At this time, the configuration is not issued to the single board, the service is not interrupted
2, after the creation of the single board and dynamic port to create MSP ring protection group, and then issued the check command, at this time, the configuration will be issued to the single board, the business began to interrupt
3, SDH services are downloaded in packets, T2000 sends OSN3500 devices in the amount of 200 crosses per packet, and each packet is validated once after the download of services is completed, and the next packet is downloaded after the host gives feedback on the success of the download. With the successful verification of each packet of services, the SDH services involved start to recover. When all SDH services are downloaded, all SDH services are restored.
4. The download order of cross-connections is randomized. There is no guarantee in the network management code that the one with the small cross-ID is downloaded first.
See the attachment for details
Root Cause
And user exchanges, T2000 "interrupt mode" download for 5.0 platform equipment business interruption time is relatively long. Through the download test, the following conclusions:
During the download of OSN3500, if the conventional mode is adopted, the SDH service interruption time has a certain degree of randomness. After downloading the ring multiplexing segment, linear multiplexing segment and other protections, the SDH service begins to be downloaded. the SDH service is downloaded in packets and verified in packets. Each packet is estimated to be around 200 items (estimated value, for reference only), and all SDH services are restored after the last packet is downloaded and verified successfully. Through several download attempts found that the interruption time of SDH service ranges from ten seconds to several minutes, and the download order of the network management is random. Theoretically speaking, if the download mode of OSN3500 is changed to "non-interrupt mode", the SDH service will not be affected. That is to say, if the download mode is changed to "non-interrupt mode", the interruption time of SDH service is <=50mS.
There are several conditions for unaffected services:
1. The versions of host and service board must be matched.
2. The business configuration of the network management shall be consistent with the current configuration of the network element.
3. All protection groups on the network element must not be in the inverted state.
4、During the download process, the network element should not have other abnormalities such as reset and fiber breakage.
The risk of operational failure during the network management download process is high. The program to restore the business in the way of network management download is mainly for failure recovery, and the most common application scenario is the master control to replace the single board. It is recommended that the master control master and backup dual allocation can effectively reduce the probability of download operation, which will greatly reduce the risk brought about by the network management download.
Suggestions and Summary
Due to the increasingly stringent assessment of service interruption by operators, it is required to replace the main control board so that the service will not be affected. For Metro equipment, it is recommended to improve the download mechanism to achieve SDH service interruption time <=50mS;
For OSN equipment single master control in addition to improve the download mechanism to achieve SDH service interruption time <= 50mS. In the market configuration in accordance with the master double match to do.
This chapter of related technical information and SDH equipment troubleshooting process by Shenzhen Optical Transmission Network Technology Co. ( www.opticaltrans.com), reproduced please retain! Huawei SDH Optical Transmission Equipment,SDH Transmission Equipment Sales
