Some FAQ about Huawei OptiX OSN 7500 OSN3500 OSN 2500 and OSN1500

When engineers configure and management Huawei MSTP Equipment, there are many questions, below are some questions and answers that is we concluded.

Why Is the Query Result hpuneq or bipsd Although bipsd Is Sent in the SNCP Protection Mode?

Answer: The bipsd parameter is sent in the lower-order SNCP or PP protection mode. While querying the return result, we find that the value is hpuneq or bipsd. The two protection modes defined in the system occupy the same bit and are not differentiated in the callback parameter. As a result, both the two conditions are displayed.

Instructions on Parameters of the cfg-set-sncpattrib Command

Answer: OptCondition: b3sd, hptim, b3exc, hpuneq, lptim, lpslm, lpuneq, bipexc, bipsd, null;

A） For higher-order sncp, only b3sd, hptim, b3exc and hpuneq are valid.

B） For lower-order sncp, only bipexc and bipsd are valid.

C） For PP, lptim, lpslm, lpuneq, bipexc and bipsd are valid.

The host does not report an error for any parameter of “b3sd, hptim, b3exc, hpuneq, lptim, lpslm, lpuneq, bipexc, bipsd, null;” that is invalid for the current SNCP (or PP). In this case, the optional conditions in query operation are null.

When a Line Generates B2SD, AIS Is Inserted by Default, Which Results in Download Protection Switching or Service Interruption.

Answer: If a line generates b2sd, the PP or SNCP switching will occur and the switching state is sf. If the SNCP switching is not configured, the service will be interrupted. This is because that the specification of OSN3500 and OSN 2500 is to insert AIS (which should have been AUAIS) by default when a line generates b2sd. As a result, the corresponding channel is all “1”s and is unavailable. To prevent switching in this case, please disable b2sd with the cfg-set-alm2ais command.

Why Does Transient Happen to Timescale during the MS Switching Event?

Answer: The system clock has a frequency of 50 MHz, so the us counter divides 50 frequencies based on the system clock. The overflow value is not 0xffffffff,, but 0x051eb851.When the timescale goes to 0x051eb851, transient happens to it. 

The Switching Time Is Improperly Long under the Intersection of SNCP and MS

Answer: Both the MS and SNCP should be switched within 50 ms. In special networking, the switching time may be longer than 50 ms. In this case, we should analyze the networking and the fault.

SNCP is configured on one node. Therefore, when the NE at the intersection node is powered off, the two SNCP services are interrupted and the SNCP protection group still uses the working channel. After MS switching, the SNCP protection channel reports 1-second anti-jitter delay, so the switching takes a longer time.

Recommendation: The working and protection channels for the SNCP service run along different routes.

What are the main differences between N1 and N2 boards?

Answer: The board types of N1 and N2 boards are as follows:

N1 series boards: SSN1SEP1, SSN1SEP, SSN1SLQ1, SSN1SL1, SSN1SLQ4, SSN1SLD4, SSN1SL4, SSN1SL16

N2 series boards: SSN2SLQ1, SSN2SL1, SSN2SLQ4, SSN2SLD4, SSN2SL4, SSN2SL16, http://www.thunder-link.com/SSN4SL64LE642LC_p332.html?search=SL64SSN2SL64

The basic naming rules of the N1/N2 boards is that the chip name of Huawei is used for N1 boards (e.g., SD543 that is currently in use) and TSOT1610G is used for N2 boards.

The N2 boards support the TCM function while the N1 boards do not.

The N2 boards support service configuration and alarm of the Au3 level and higher-order path overhead maintenance of the AU3 level. The N1 boards do not support these functions.

As to loopback, the N2 boards support optical interface inloop and outloop, while the N1 boards support optical interface inloop and outloop and VC4 path inloop.

Both N1 and N2 boards support the reverse insertion of the AUAIS in inloop case but not in the outloop case.