RE: Huawei / ALLT / SVC since 2010
Like with most Telco Equipment Manufacturers (TEM), Huawei has also a sales and integration organization that is selling 3rd party products (like in the Sandvine/Telefonica case). Due to their relations with customers sometimes they will sell those other products - either as a part of a larger project or even just in a response to an RFP. Most TEMs will prefer, once they have their own product, to sell it, unless the customer insists on something else.
These market changes show that Huawei now has a DPI product (or function) that is good enough, and the pure players/standalone DPI vendors need to show the market that they are [still] ahead of TEMs in value and cost. Especially when they are compared to embedded DPI and optimization features in other network products (Cisco, NSN, Ericsson).
Same goes for NSN, that resells/used to resell both Allot and Sandvine.