A brief analysis of the technical difficulty of "number portability"

According to the Ministry of Industry and Information Technology, my country officially launched a new "number portability" service process on December 1, 2018. In the new process, users only need text messages to complete inquiries and applications, without having to go to the outlets of various operators in person.

At present, the "number portability" service is still in the trial operation stage, and only five pilot provinces and cities can handle it: Tianjin, Hainan, Jiangxi, Hubei and Yunnan.

According to the plan of the Ministry of Industry and Information Technology, it will take at least until 2020 for "number portability" to be promoted nationwide.

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What is "number portability"?

As the name suggests, number portability means changing networks with your number. In other words, changing networks without changing your number.

Number Portability

For example, if you currently have a China Mobile number starting with 139, after you apply for "number portability", the number remains the same, but the operator affiliation changes - the service package becomes China Telecom or China Unicom, and the network and services used also become China Telecom or China Unicom. This is number portability.

Number portability is both an act and a service name. From a professional perspective, it should be called "number portability".

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"Number portability" is also called "number portability"

In fact, this business is very old. If you count on your fingers, it has a history of at least twelve years in China.

As early as October 2006, the then Ministry of Information Industry (the predecessor of the current Ministry of Industry and Information Technology) issued Document No. 630 - "Notice of the Ministry of Information Industry on Protecting Mobile Phone Users' Right to Choose Tariff Plans", which mentioned the "number portability" or "number portability" policy for the first time.

Although the idea of ​​number portability was proposed very early, the pace of its implementation has been very slow.

• It was not until November 22, 2010 that the first batch of number portability pilot projects were launched in Tianjin and Hainan.
• Later, four years later, on September 20, 2014, the second batch of number portability pilot projects were launched in Jiangxi, Hubei and Yunnan.
• Now, 2018 is almost over, and these five pilot provinces and cities are still the same, with no changes.

This business is not unique to China; it actually also exists internationally, and it was created earlier.

For example, in the United States, number portability services were mentioned as early as in the Telecommunications Act promulgated in 1996.

In November 2002, the US Federal Communications Commission (FCC) intended to push it forward, but was jointly opposed by mobile operators.

After years of negotiation, it was not until November 24, 2003, seven years after it was proposed, that it was officially implemented in the United States.

By the way, this "number portability" service is also related to Xiaozaojun. In 2008, I was in charge of a new project of an operator in Romania, and I tested this service (Romania requires all operators to support number portability), and I suffered a lot from it.

Why do we say "seriously affected"? Because this business is really a big "pitfall".

On the surface, number portability is just changing operators and reusing existing numbers, which doesn't seem complicated.

In fact, number portability is a very maddening business.

First, there is the issue of number analysis.

I have mentioned before that the most important step in making a phone call is number analysis.

We configure a series of rules in the communication system to analyze and match the called numbers.

For example, check whether the called number is an emergency call special service number (such as 110, 120), whether it is an international roaming number (such as country code 0091, 0087, our country is 0086), whether it is a supplementary service number (by dialing a fixed number, you can activate or cancel a certain service). . .

Different number analysis results correspond to different system processing methods and are sent to different destinations.

For example, if a China Mobile number A starting with 139 dials a number B starting with 138, it will be analyzed as a China Mobile number and processed according to the operator's internal call process. If a China Unicom number starting with 185 is dialed, it will be analyzed as a foreign network number and routed to the gateway office, then sent to China Unicom, and finally the call will be connected.

If you want to port your number, it will be troublesome.

For example, A, whose phone number starts with 139, calls B, whose phone number starts with 138. B is a user who has applied for number portability. Although the number starts with 138, it cannot be processed according to China Mobile's internal call process, otherwise it will be sent to the wrong destination.

China Mobile's core network system must make special arrangements for B numbers and handle them separately.

If there is only one exception, it is fine. But the problem is that if this service is open to users, there will be tens of thousands of exceptions. In this case, the number analysis will become very large, which will burden the system capacity.

Even if the system capacity is sufficient, it will affect the efficiency of number analysis to a certain extent and increase the waiting time for call establishment.

In addition, the number of such numbers is constantly increasing, and each time one is added, a new one must be configured on the system, which will bring a lot of maintenance workload.

Therefore, equipment vendors are often forced to transform and upgrade their systems to meet functional requirements while minimizing implementation difficulty and cost. This is especially true for accounting and billing systems, which require more transformation and are more troublesome.

Number portability can also cause confusion for users.

In the past, when Xiaozaojun configured this service in Romania, he encountered this problem: it was cheap for operator A's number to call operator A's number; but it was very expensive for operator A's number to call operator B's number.

If a user of operator A calls a friend, A looks at the number segment of the other party and thinks it is the same operator segment, and the rate is 1 yuan per minute, but in fact, the friend has switched to another network, and the rate should be 2 yuan per minute. Then, the calling user will complain and be dissatisfied.

There were countless problems like these caused by number portability. We had meetings every day to discuss these trivial issues.

Moreover, the number portability service has greatly increased the difficulty of troubleshooting. This is because when we handle faults, we can no longer quickly determine the user attributes of the complainant by the number segment as before. Different user attributes mean completely different troubleshooting processes and ideas, which is very frustrating.

So, we communications engineers are very disgusted with this business.

In fact, for number owners, number portability is not necessarily a convenient thing.

Now is the era of mobile Internet. Everyone is online, and mobile phone numbers are our online ID cards. We use mobile phone numbers to register for many services.

If you apply for "number portability", although the number has not changed, different Internet service providers will have different handling methods for different operator numbers.

For example, when sending SMS verification codes or service codes, different operators have different ways of sending them. The service provider will not intelligently determine whether you are a number portability user, but will simply determine based on the number segment. In this case, many of your services will easily fail or become abnormal. In the end, it is still you who are affected.

In fact, from today's perspective, the "number portability" service has long deviated from its original intention.

When it was first launched in 2006, it was due to the historical background and reasons.

At that time, because the strength of major operators was very uneven, the difference in tariffs between operators became larger and larger. Especially in 2008, after the 3G licenses were issued, China Unicom's WCDMA standard was the most mature and popular, and mobile phones were also easy to buy. Many users wanted to use WCDMA, but did not want to change their original 138/139 (China Mobile) numbers, so there was a strong demand for "number portability" services.

Things are different now. Dual-SIM dual-standby phones and even full-network phones are very common, and the problem of difficulty in buying mobile phones has basically been solved.

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Moreover, after the issuance of 4G licenses, China Mobile abandoned TD-SCDMA and switched to TDD-LTE, and the network quality has been significantly improved (at least the technical gap is not as large as that of 3G). In addition, after several years of market competition, the three major operators have now reached very similar tariff standards. Therefore, the demand for users to "port their numbers" has dropped significantly.

It can also be seen from the data that according to statistics, as of the end of December 2016, in the five pilot areas, the number of users who have applied for number portability is only 450,000. Compared with the existing users of hundreds of millions, this number is nothing.

Therefore, Xiaozaojun believes that although this service can help break the monopoly barriers and facilitate users to make independent choices, it is not very urgent and necessary. The promotion of this service has a low cost-effectiveness, brings limited convenience to users, and brings a lot of trouble to network maintenance, and the cost is also high.

Instead of dealing with this complicated service, it is better to bring more practical benefits to users in terms of reducing charges and improving signal quality, so as to retain old users and attract new ones.