SS7 or SMPP? Sometimes the Right Protocol Can Make All the Difference

5 min read

Sometimes, the right tool can make all the difference. We’re not just talking about obvious distinctions, like trying to hammer a screw. The same principle applies to even quite fine differences — try slicing bread with an ordinary kitchen knife rather than a serrated breadknife.

In our world of telecommunications, there are many protocols for connections and interworking from which to choose. Most operators will use a mix, but without a clear strategy for when to use each option.

Are there any advantages of using one over the other to achieve specific goals?

This is important, because each protocol type has different properties and conditions attached that affect the way they operate. At GMS, we tend to prioritise SMPP and SS7 (and the SS7-compatible SIGTRAN), but there are features of each that mean we want to implement them in different ways, and for different purposes.

What is our goal?

Naturally, as a messaging protection specialist, GMS uses these protocols slightly differently than other telecom entities. While aggregators and enterprises have developed techniques and practices which minimise delivery costs, we base our recommendations around how to best promote the transparency of messaging. (This isn’t just important for the MNO. It is also very important for enterprises paying good money with an understanding that their one-time passcode (OTP) SMS will be properly delivered.)

This means that we often make choices by considering the availability of metadata that would be useful to messaging protection. To start with, we need to keep a few things in mind about the protocols and infrastructure we use.

  • It is not hard for people to mask IP addresses, or gain access to an SMSC application, making it harder to gain accurate information about message originators.
  • Should undelivered SMS messages be stored on the operator’s SMSC (in order to attempt redelivery) the sender is unaware when there is a problem, nor of the reason for non-delivery.
  • When using SMPP, the sender of the message must often rely on intermediate connections, and delivery via the operator’s SMSC. It is therefore difficult to attribute responsibility or hold anyone to account in the case of manipulated messages.

Advantages of SS7

Let’s talk about one protocol in particular: the near-ubiquitous Signalling System 7 (SS7). Technically speaking, we can often improve transparency by employing SS7 (and SIGTRAN) for specific traffic types.

Although it is an older protocol, SS7 retains a number of strengths to recommend it when thinking about optimising and monetising a mobile network. For one, it is the central protocol for 2G and 3G networks, used both for internal data exchange within the network, and for interconnections between operators. Its flexibility — including SIGTRAN and SS7↔Diameter interoperability — further ensures compatibility with other networks.

The technical implementation of SS7 also has a lot to recommend it. Signalling interconnections are established end-to-end. Messages do not travel via the SMSC, nor are messages stored anywhere during transit.

Finally, the sender typically must ensure their connections are set up correctly, to guarantee the proper signalling exchange. This relieves the MNO of some of the responsibility for guaranteeing delivery — less is reliant on their network or setup.

Delivery is also more transparent and reliable. The sender can customise their profile settings; for example, to arrange for redelivery (for a specified validity period) should the first attempt fail.

The additional available data further aids analysis, making it possible to immediately trace the cause of failed delivery. Furthermore, provided the operator’s network configuration permits it, the inclusion of IMSI and SRI data makes routing more efficient and reliable, since it is easier to correctly target numbers ported via MNP.

In summary:

SS7 advantages SMPP limitations
End-to-end visibility of SMS traffic – we can track where message failure/blocking occurs Limited visibility: end-to-end tracking is not possible
Easier to detect grey routes, manipulations and manipulators by tracking GTs, Sender-IDs and other metadata Manipulation control is more difficult, and it is harder to detect culprits
Simple to perform GMS Messaging Protection activities (e.g. testing and grey route detection) without any platform access MNO support is required with each test, especially identifying message originators; only the last sending hop is identifiable
The sending partner (aggregator or enterprise) can be informed immediately about failures or delays in message delivery The sending partner receives no information about delays or possible causes – they will only become aware after all retries are made by the MNO’s SMSC
100% clear error handling Fake error reports can be configured
Easy to design and implement monetisation rules. We can design rules and provide suggestions based on testing, without accessing the MNO platform Monetisation rules are difficult to implement — typically, a large number of local aggregators are connected via SMPP, making it difficult to apply monetisation rules only for specific LAs
No message storage is required during transit Storage is required on every hop involved
Clear identification of international/national traffic via Global Titles IP-only data leads to too much ambiguity in international/national traffic identification

The right tool for the job

As a result of this, the SS7 protocol can be thought of as a preferred — even necessary — protocol component for A2P SMS monetisation services. It offers ease and universality of connection, while also providing a wealth of data that lets GMS and our MNO partners track and fix issues. This includes possible manipulations to metadata, letting us trace grey routes and unscrupulous actors.

Does this mean we deprecate SMPP entirely? Not at all. In fact, using both protocols can be incredibly useful for segregating traffic types at a technical level and, as a result, correctly monetising that traffic. Additionally, it is often hard for local aggregators — in contrast to international hubs — to access the Global Titles necessary to use SS7 connections.

By refusing SMPP connections, an operator would unfairly penalise these entities, while also losing any traffic they might bring in, cutting off their nose to spite their face.

The important thing to remember is that protocols are tools, each with their own strengths and weaknesses. In our particular line of work, GMS has found many to be useful — and yet the key is knowing when and how to use each available tool. Our experience has taught us much about the best technical configurations for maximising transparency and revenue potential across the whole value chain.

To learn more about the different strengths and weaknesses of these protocols, and how to incorporate them into a structured and strategic monetisation program, contact our experts.

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