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Tag: Osmocom

HNBAP and RANAP support in Osmocom.org

HNBAP and RANAP support in Osmocom.org

Sysmocom is in the process of adding 3G support to OpenBSC. This is done in the nature of using an existing hNodeB Femtocell that exposes the Iuh interface. The binary protocol for Iuh (and related protocols) is defined using the Abstract Syntax Notation One (ASN.1) and the aligned packed encoding rules (APER) are used to encode/decode the data. After exploring several options LaForge picked the one that adds APER support to Lev Walkin’s ASN1 compiler, simplifies the 3GPP ASN.1 input…

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Adding menu items in redmine (e.g. a link to contact information)

Adding menu items in redmine (e.g. a link to contact information)

The Osmocom project is switching from a list of separate trac projects to a single instance of redmine. One German legal requirement is to publish contact information (Impressum) and it needs to be easily discoverable. The easiest seems to be to add this to the top level menu of our redmine. This way it will be available on all pages and just one (or two on mobile to open the menu) clicks away. The below can be placed in a…

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osmo-pcap capture on the edge and store in the center

osmo-pcap capture on the edge and store in the center

Imagine you run a GSM network and you have multiple systems at the edge of your network that communicate with other systems. For debugging reasons you might want to collect traffic and then look at it to explore an issue or look at it systematically to improve your network, your roaming traffic, etc. The first approach might be to run tcpdump on each of these systems, run it in a round-robin manner, compress the old traffic and then have a…

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OpenCore and Python moving to Github

OpenCore and Python moving to Github

Some Free Software projects have already moved to Github, some probably plan it and the Python project will move soon. I have not followed the reasons for why the Python project is moving but there is a long list of reasons to move to a platform like github.com. They seem to have a good uptime, offer checkouts through ssh, git, http (good for corporate firewalls) and a subversion interface, they have integrated wiki and ticket management, the fork feature allows…

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Build or buy a GSM HLR? Is there an alternative?

Build or buy a GSM HLR? Is there an alternative?

The classic question in IT is to buy something existing or to build it from scratch. When wanting to buy an off the shelves HLR (that actually works) in most cases the customer will end up in a vendor lock-in: The vendor might enforce to run on a hardware sold by your vendor. This might just be a dell box with a custom front, or really custom hardware in a custom chasis or even requiring you to put an entire…

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osmo-pcu and a case for Free Software

osmo-pcu and a case for Free Software

Last year Jacob and me worked on the osmo-sgsn of OpenBSC. We have improved the stability and reliability of the system and moved it to the next level. By adding the GSUP interface we are able to connect it to our commercial grade Smalltalk MAP stack and use it in the real world production GSM network. While working and manually testing this stack we have not used our osmo-pcu software but another proprietary IP based BTS, after all we didn’t…

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Cisco probeless monitoring protocol

Cisco probeless monitoring protocol

The Cisco probeless monitoring protocol (pmp) is a proprietary protocol used by the Cisco ITP. This protocol is used to forward M3UA/MTPL3 messages to another server. The data is being sent on port 33500 using UDP. Previously I used okteta to study the file format and this time I used Pages and HexFiend. To understand the basic structure one needs to start somewhere. The first assumption for a telco protocol is DER or TLV encoded data. In wireshark one could…

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The state of mobile telecommunication protocol design and the way ahead

The state of mobile telecommunication protocol design and the way ahead

I have been implementing various ETSI/3GPP specifications for more than a decade. At GMIT we provided implementation feedback for DVB-H and OMA BCAST. With the Osmocom project and Sysmocom I have several years of implementing GSM (and UTRAN) specifications on my back. In general GSM is a great engineering project. It lead to the creation of the ETSI, they adopted the English language for their specifications and they applied the information hiding principle. The group speciale mobile managed to create…

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Speeding up my SIP/MGCP Smalltalk Parsers

Speeding up my SIP/MGCP Smalltalk Parsers

When creating the MGCP and SIP implementation I didn’t want to do string splitting/scanning myself but follow the grammar of the two RFCs. I decided to use the PetitParser framework. PetitParser is a parsing combinator. Which mostly mean you create small parsers and combine them with things like a sequence (parse this, than that and expect the input to be fully consumed). For a long time this approach was just okay but I recently started to use the code on…

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Using GNU autotest for running unit tests

Using GNU autotest for running unit tests

This is part of a series of blog posts about testing inside the OpenBSC/Osmocom project. In this post I am focusing on our usage of GNU autotest. The GNU autoconf ships with a not well known piece of software. It is called GNU autotest and we will focus about it in this blog post. GNU autotest is a very simple framework/test runner. One needs to define a testsuite and this testsuite will launch test applications and record the exit code, stdout and…

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