The Service Broker / SCIM market

The concepts of SCIM or Service Broker were introduced in 3GPP IMS specifications, but so far have never been adequately defined (I had the opportunity to address this topic several times).

However, this does not mean that there are no SCIM or Service Broker products (or product components) on the market!

Light Reading has just issued a report called Combining Telco Services: The Network Service Broker Opportunity. As they provide a list of vendors they have surveyed for their report, I decided to have a look at what these companies actually provide by looking at documentation available on their web sites. In this post I will summarize my findings, which are only based on my (potentially erroneous or biased) interpretation of usually high level product descriptions.

Call Control / IN Centric Service Broker / SCIM

Most of these products are presented as equally applicable to Intelligent Networks and IMS, which in some cases might mean that the product is an Intelligent Network one that has been upgraded to support SIP, or that the supplier hopes that what is good for IN will also be good for (telephony-centric) IMS.

As described by Aepona, their Service Broker is primarily a proxy Service Switching Function (SSF) between the switch and multiple IN servers (thus permitting service invocation in multiple servers, what a switch is usually unable to do). As an IMS "SCIM", it performs a similar function between the S-CSCF and multiple ASs. Because of its dual SIP/IN nature, the Service Broker can also serve as a gateway between IMS and IN (the "IM SSF" entity in 3GPP IMS specifications).

The description of the AppTrigger's Ignite Application Session Controller (ASC) includes a "SCIM+". Like Aepona's Service Broker, ASC sits between the network and the "application cloud". IMS is explicitly listed along legacy TDM networks that can appear below the ACS, but the figure on the web page does not show IMS at all, only entities of a fixed IP access network. The product supports Parlay X, MAP/CAMEL and SIP. It also supports SIP to IN interworking (IM SSF).

OpenCloud is the supplier of a JAIN SLEE platform, a standardized Java service execution platform that was initially targeted at new generation IN services (IN services implemented in Java on an open platform and possibly using non-call related service capabilities like location or SMS as part of their logic). Such a platform can also support SIP and Diameter interfaces and can therefore be positioned as a SIP AS platform as well. On their page, Opencloud speak about a Service Interaction SLEE (SIS) for IN, and another one for IMS. The SIS supports service interaction and composition. The SIS can also offload an IN server by supporting some IN logic itself (logic as it is based on an IN service platform).

jNetX is another supplier of a JAIN SLEE platform. I was not able to find any information about a SCIM or Service Broker on their site, but if they have one it is very likely to be similar to what Aepona, AppTrigger and Opencloud offer.

I could not find a precise description of Tekelec's TekSCIM Service Mediator. However, as it is supposed to provide a seamless experience to TDM and IMS users, and its IMS role is to manage and simplify complex service interactions, I assume this is more or less the same type of product.

These products often have a clear interest in a TDM IN context, and I think this should be the primary reason why an operator might be interested in them. On the other hand, I am more doubtful about their value in an IMS context, even for the support of telephony services, and this for the following reasons:

- An IMS S-CSCF has the capability to chain several ASs in SIP signalling, so such a feature supported by a SCIM/SB would be functionally redundant.

- Call control Service Interaction Management is an important issue that has never been addressed in a satisfactory generic manner in IN networks, more especially when implemented in a standalone box outside of application servers. Why would this change now and more especially in an IMS context?

- Unless it is used to emulate the TDM network, IMS is a very different type of network, and SIP has nothing to do with INAP or CAP. What is good and necessary for TDM is not obviously good and necessary in IMS.

- Providing added value call control services in IMS is necessary, but it is not what operators will make money with. A SCIM/SB centered around voice-centric call control is by no means the magic box that will solve all operators' IMS related problems.

- The interest of an IM SSF function is questionable. IN platforms are often old and costly, and operators often have to fully rely on the supplier of the platform for developing new services. Is it interesting for operators to extend the life of these platforms for many years by positioning them in their long term IMS strategy? On the contrary, many would prefer to replace their IN servers by new application servers able to control TDM calls as well as IMS ones, and this is exactly what the ongoing 3GPP IMS Centralized Services (ICS) initiative is trying to achieve.

TCAP / Web Services Gateway

Convergin's Accolade WCS SCIM seems to be a gateway supporting translation between TCAP and web services. It is not clear to me if this is only this and if it is limited to TCAP (leaving the task of supporting CAP, MAP or INAP to the application) or if it also supports a direct translation of these protocols to web services.

The first thing to say is that this does not correspond at all to what someone can expect from a product called "SCIM".

The second thing to say is that, whether the name is appropriate or not, this component can be very interesting in an IMS context, when it is associated to an IP-centric service platform, which lacks native support of legacy SS7-based protocols to access legacy service capabilities in the TDM network. This is typically the case of J2EE platforms supporting SIP servlets for IMS, which are offered by well known companies like IBM, Oracle or Sun.

These platforms are ideal to implement innovative IMS applications which can combine usage of SIP, HTTP, Diameter and web services, thus permitting convergence between the Internet, Enterprise IT and the new Telco domains. So far, the lacking capability has been the possibility to conveniently connect with the legacy TDM telco world (OSA/Parlay gateways have not proved to be simple and cost effective enough).

I do not think that such a product would allow a J2EE server to become a suitable platform to implement classical IN services. On the other hand, they could permit to implement new TDM-centric services that make use of IMS enablers like presence or instant messaging, or IMS-centric services that need to use TDM capabilities like starting a pure TDM call.

Consequently, this is not a surprise if Convergin seems to be in business with the J2EE suppliers I mentioned.

SIP-level Orchestration Engine

This is the approach adopted by suppliers of J2EE platforms (IBM, Oracle/BEA, Sun?), which usually clearly distinguish between the need to orchestrate web services, using a standard like BPEL, and the need to orchestrate services invoked through SIP requests. Differences may lie in both semantical and performance aspects.

In this context, the SCIM/SB corresponds to the concept of application router, defined in JSR 289, the latest SIP servlets specification. The original mechanism specified for invoking SIP servlet applications, based on servlet mapping rules that are quite similar to web servlet mapping rules in the fact that they rely on a quite simplistic analysis of incoming SIP messages, has proved to be inadequate for a proper selection and composition of IMS services hosted by a J2EE platform. The application router permits to replace the servlet mapping rules by an intelligent component tailored to the needs of the operator.

The intelligence itself is not standardized, and this is therefore an important differentiation area for suppliers or for operators who may decide to specify and possibly implement their own application router.

The service invocation and chaining logic may take into account subscription information (which services the user is subscribed to) as well as other information related to the user, such as presence, service preferences (e.g. the user wants this service to be executed at certain times) or calendar information.There might also be more or less sophisticated rules related to the composition of services.

The ideas for a SCIM I exposed on this blog fit in this context, with the concern to remain as simple as possible and avoid too much intelligence, complexity and processing delays in this component. I think that the suppliers of J2EE platforms are trying to offer the possibility for more sophisticated rules, adding both more potential and more risks to the concept.

Global Orchestration Engine

This seems to be the case for the Alcatel-Lucent Service Broker, implemented by Bell Labs, which is part of the Alcatel Lucent Service Delivery Platform (SDP). The component supports both SIP and web services interfaces, and examples given illustrate access to user subscription information, service preferences, presence, as well as access to other services like IPTV through web services.*

This Service Broker therefore seems to be an integrated equivalent to the combination of a web services orchestration engine and a SIP application dispatcher as proposed by J2EE suppliers.

A potential reason for this difference is that Alcatel Lucent provide their own SIP servlets container, which is a standalone component that needs to be integrated with a third party J2EE platform for converged services. The service broker would therefore permit integration with J2EE web containers (integration which is much tighter in J2EE platforms supporting both web and SIP servlets) and would transfer web services orchestration to the Alcatel Lucent SIP-centric component as well.

Such an approach might offer advantages, more especially in terms of performance, but could also come with associated complexity, a lack of compliance to web services orchestration standards, and the gain obtained through a tighter integration of different orchestrations may also lead to less flexibility for the operator. However, this would be an aspect to investigate.

Service Management Mediation

Leapstone's CCE ServiceBroker is a tool that applies both to legacy networks and IMS. It aims at making easier the management and provisioning of packaged services, including subscriber management and live management of composition and interaction rules between blended services.

From an IMS perspective, this means that the operator may use serviceBroker to define service composition rules and to generate appropriate data for an HSS (Initial Filter Criteria) and a SCIM, as well as for other network databases.

As such, ServiceBroker appears to be a management complement associated to what is usually called a SCIM or Service Broker. More generally, this is a service and subscriber management mediation tool as can already be found on the
market, but enriched with IMS-specific service composition requirements.

Such a tool is very important but also requires ad-hoc adaptations in order to fit in specific environments, considering that management interfaces are usually vendor-specific. Concerning the SCIM/SB, this is even worse as this component is not standardized and leaves room for very different implementations, as can be seen in this post.

Other SCIMs / Service Brokers

Considering the list provided by Light Reading, I was not able to find anything about the Ericsson and Huawei implementations of the concept.

Conclusions

The concept of SCIM / Service Broker, which is part of IMS specifications but has never been specified, leaves room to multiple interpretations and very different products claiming this label can be found on the market.

You can basically find two mainstream interpretations:

- The SCIM / SB is a standalone component that takes care of classical call control and IN issues related to the support of multiple application servers and complex interactions between call control services. The concept is primarily aimed at legacy networks and is also promoted as being equally applicable (and important) for IMS. The telephony context is clear and while everyone can have its own opinion on the interest of such a product for IMS, I will assume that no-one can seriously claim that this component will help an operator finding new sources of revenue with IMS (the key term here is "leveraging", applied to TDM and IMS in the context of telephony).

- The SCIM / SB is a component part of a service delivery platform, and its aim is to complement what the IMS core network component called S-CSCF can do for the composition and "blending" of several services. Such a SCIM / SB can be specialized in SIP-level orchestration (a dedicated engine will do the equivalent for web services) or can address both SIP and web services orchestration.

The first interpretation is closer to the initial motivation for introducing the concept in 3GPP specifications, while the second is closer to what the real IMS need actually is.

A major architecture difference between the two interpretations is that the first one is a standalone product standing between the IMS core network and application servers, while the second is an added-value component of a more comprehensive product usually called service delivery platform in the telecom context (an application server in its own right).

The description I made of a SCIM on this blog is essentially one of the second category. However, since then I thought a little bit about what a standalone SCIM / SB could be, in the terms of which value it could provide to a SCIM / SB embedded in a service platform can do.

I cannot divulge here the content of these thoughts, as they are being discussed with a customer company of Arismore, but to make it short I think there is a lot of added-value a standalone SCIM / Service Broker could add to a service platform -embedded one, while being very different from what the market has to offer right now. More especially, such a product would have no relationship to IN and call control.

If you are knowledgeable in some of the products I surveyed in this post, do not hesitate to contact me in order to correct or complement it. I will gladly compile and post feedbacks, including those that make a point against my assertions.

Christophe