CASE STUDY: EFR GmbH

About EFR GmbH

EFR GmbH is a systems provider for utilities companies based in Germany. It offers the long-wave services for:

• Energy Management
• Lighting control
• Feed-in management
• Smart Grid -services
• Data services

Since 1995 EFR GmbH long-wave transmitters offer a nationwide solution, cost-effective and independent of individual power supply networks. Over one million radio receivers in Germany are controlled from the EFR GmbH transmitters.

Product Background

The Mongoose Web Server Library is integrated and enables connectivity for the Secure Smart Grid Hub (SGH-S), a highly secure smart meter communication gateway for modern measuring systems, network management with all-IP connectivity via ethernet, cellular and broadband PLC.

We ran a short Q&A session with Kristóf Havasi, Development Team Leader at EFR GmbH to get his feedback on working with Mongoose Web Server Library.
Here are the main takeaways from it:

The decision

Q: Can you share a little about why you chose Mongoose Web Server Library and the process that led there?

A: The main factors for us to chose to integrate Mongoose Web Server Library into our flagship product were:

• Support for multiple needed protocols (HTTP(S), SNTP, SocksV5), with this the number of dependencies could be minimized
• Out of the box support for both openSSL and mbedTLS
• Relatively wide adoption with an active community
• Small memory and CPU footprint
• Dual license option
• Availability of technical support
• Mainline unit-tests which are regularly executed via GitHub actions
• Mainline integration with fuzzing service

The results

Q: What changed for you after you integrated Mongoose Web Server Library?

A: We had a typical case, where we removed a parallel, self-implemented HTTP server part of a configuration process with the help of Mongoose Web Server. The commit, which took care of this change, touched 14 relevant files with 168 added and 1169 deleted lines. This included the reduction of the config-server to a single-threaded programm with ca. 170 LOC in a single file.

Another successful use-case for Mongoose Web Server was the deployment in a "socat" like scenario, where we had to act as a TLS Proxy / man-in-the-middle between two communication partners. In this special case we have two separated TLS channels and the payload needs to be "repackaged" in our "proxy" program. Here the implementation profited from the event-based API, offering out-of-the-box events for transmission and timing. With this support e.g. custom timing restrictions were achieved without much hassle.

Working with Mongoose Web Server Library

Q: What you'd like others to know about working with Mongoose Web Server Library?

A: We regard Mongoose Web Server as a high-quality library, which helped us out several times with its flexible API and numerous features. If we encounter a bug, I tend to push my developers to check in our own business logic, because Mongoose has proven to do reliably the tasks which it claims to do.