Whether the interruption of both the working and protection LSPs adversely affects services if OLP is configured between any two WDM NEs on a ring consisting of three WDM NEs


If another protection scheme such as ODUk SNCP or client 1+1 is configured at the service layer, services will not be interrupted. If no other protection is configured at the service layer, services will be interrupted.

Other related questions:
Common questions about extended ECC on WDM NEs
Question: How many NEs can be interconnected using automatically extended ECC at a site? Analysis: At many sites, all NEs are interconnected using automatically extended ECC. As a result, there is a large number of NEs using this function for interconnection, and NEs are frequently unreachable by the NMS. Answer: 1. If an Ethernet is used to establish an extended ECC channel for communication, at most four extended ECC channels are required. With manually extended ECC, a server can be connected to at most 7 clients, and each client can be further connected as a server. Hubs (or switches) can be cascaded, which is related to the network scale limit only. The basic principle applies to each product and is related to the platform. 2. The method of cascading metro WDM devices using ETHERNET1 and ETHERNET2 ports does not apply to a long-haul WDM system. For long-haul WDM devices, the ETHERNET2 port is not used for ECC communication. In addition, you are advised to cascade at most eight network ports in a metro WDM system.

Whether an SS bit mismatch in the AU pointer during WDM product interconnection causes an AU_LOP alarm
Question: According to SDH principles, in AU-4 and TU-3 frame structures, the SS bit of the AU pointer is fixed at 10. When Huawei SDH NE is interconnected with equipment of other vendors and receives the SS bit of a value rather than 10 from the peer end, the corresponding channel of a line board on the SDH NE reports the AU_LOP alarm. As a result, services fail to be provisioned or are interrupted. Do WDM devices have this issue? Answer: 1. OTU boards (except OCU boards) on WDM NEs transparently transmit the SS bit and do not detect it. 2. OCU boards on WDM NEs process the SS bit. The normal value of the bit is 10. When the SS bit is set to 00, 01, or 11, an AU_AIS is inserted and services are impaired. The board does not report an alarm because it does not detect the AU_AIS signal on its WDM side. According to a test in which the test instrument is Agilent OmniBer 817 and is used to send STM-16 data, the H1 SS bit can be modified when the payload is set to Framed and Structed, and Column is set to All in the overhead setup settings. The test instrument reports an AU_AIS or PDH LOF alarm when the SS bit is set to 00, 01, or 11, and does not report alarms when the SS bit is set to 10. This issue is related to the chip processing mode. Because OCU boards use the same chip, they have this issue.

Whether the IP address of a WDM NE varies according to the NE ID
If the IP address of an NE is not changed before you change the NE ID, the IP address of the NE varies according to the NE ID. The association between the NE ID and IP address will be automatically released once you manually change the NE IP address. In other words, the NE IP address will not vary according to the NE ID after the NE IP address is manually changed.

Whether fibers of NG WDM NEs support automatic discovery
This function is unavailable on optical-layer boards.

Synchronization modes between NMS time and NE time on WDM products
Synchronization modes between NMS time and NE time: With the time synchronization function, the NE time is kept consistent with the NMS time. This allows the NMS to record the correct time at which alarms occur and the correct time at which abnormal events are reported by NEs. When NEs report alarms and abnormal events to the NMS, the NMS records the time of alarms and events based on the NE time. If the NE time is incorrect, the generation time of alarms recorded on the NMS is also incorrect, which may cause troubles in fault locating. The same case happens to the generation time of abnormal events that are recorded in the NE security log. To ensure the accuracy of NE time, the NMS provides two time synchronization modes with the following servers: the NMS server and the standard NTP server. Note: The Web LCT improves the accuracy of NE time by synchronizing the NE time with the NMS time. If synchronization with the NMS server is applied, all NEs use the NMS server time as the standard time, and can be synchronized with the NMS server manually or automatically. The NMS time refers to the time of the workstation where the NMS server resides or system time of the NMS server. This synchronization mode is easy and applies to a network with relatively low requirement on time accuracy. If synchronization with the standard NTP server is applied, all NEs and the NMS are synchronized with the standard NTP server automatically. The standard NTP server can be the NMS server or a dedicated time server. This synchronization mode makes the NE time and NMS time accurate to 1/1000,000,000 seconds and applies to a network that has a high requirement on time accuracy.

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