Telecommunication test network - MSSN (MultiService Switching Network)

Content:

Introduction:

The three AxD 305 of the telecommunication test network was donated by Ericsson Hungary to the Dept. of Telecommunications and Media Informatics in 2009 for educational purposes. The equipments (network elements) are located in the nodes of a telecommunication network and they are able to handle simultaneously (network, switch, gateway, circuit emulation functions) the traffic mixture (voice, data, video) arriving through the lines of diverse telecommunication technologies (TDM (ISDN/PSTN, PCM, STM), IP, POS, etc.). This is the origin of its name: MSS - MultiService Switching.
One of the main functions of the received configuration is to connect the existing TDM exchanges (LE (Local Exchange), PABX (Private Automatic Branch Exchange)) to an IP network which provides interconnection between the exchanges, i.e. the implementation of the Media Gateway function.

General hardware structure of MSS (Block diagram, mechanical structure):

Block diagram of the hardware structure of MSS can be seen in the following figure (functional units are signed with the ID used also in the user interface of the AxD): 

Functional structure:


   <--  User -------><------------ MSS ---------------->

  +-----+            +--------+  +-----+  +----+   +---+
  |PABX |---- TDM ---| - ET - |--|     |--| CP |---| MT|
  +-----+            +LI----SP+  |     |  +----+   +---+
                                 |     |  +----+
   +----+            +--------+  |     |--| CP |
   | LE |---- SDH ---|   ET   |--|  SC |  +----+
   +----+            +--------+  |     |
                     +--------+  |     |
          IP, POS ---|   ET   |--|     |
                     +--------+  +-----+

               |
         external, user side
          interfaces

Mechanical structure:
                             Subrack
                     +----------------------+
                     |       Fans           |
                     +----------------------+
                     |       Boards         |
                     +----------------------+
                     .                      .
                     .                      .    9 Slots
                     .                      .
                     +----------------------+
                     |       Boards         |
                     +----------------------+
A short review of the functional elements can be read in the following: (A detailed review can be found in the index and in the manufacturer documentation available in the laboratory.)

Comparing the block diagram of MSS to the general scheme of the SPC/TDM exchanges a considerable similarity can be pointed out. The large difference lies in the connected devices: while a SPC exchange connects telephones, MSS connects exchanges and trunks.

Services, applications

The manufacturer of the equipment implemented many services and developed many applications on the above delineated platform. The MSSs of the telecommunication test network provides the following services and applications:

Scheme of the test network build up with MSSs (MSSN)

Leaving the introduction of network services to other equipments of the laboratory here we will focus on the introduction of the above delineated applications. So the following subnetwork (MSSN - MultiService Switching Network) was deployed in the laboratory rooms using the three Ericsson AXD-305 MSS in the telecommunication test network:

The 3 MSSs are distributed in the B.211, B.212, and B.213 laboratory rooms of the department. The motivation of this distribution:

Details of the network elements. This type of VoIP networks have three main elements: (A more detailed block diagram and review can be read in the index.)

In order to demonstrate the operability of the network some trunks, links, and connections was previously configured.

The detailed exposition of the configuration, as well as the manufacturer documentation of AxD are available only in the laboratory, and only for educational purposes. Copying of these documents is strictly forbidden!