Rail – G.703 Contra Clocking over MPLS Railway signalling project
Many railway networks around the world are upgrading to become a Digital Railway. Part of this digital upgrade involves moving towards an IP based communications system away from the old legacy SDH/PDH systems. The national telecommunications operators are also moving in the same direction.
This can present a challenge: the majority of the signalling equipment installed over the last 20-30 years has been based on SSI (solid state interlocking). The interconnection communications bus uses 64K CONTRA G.703. This bus type is native to the legacy SDH/PDH but has no direct equivalent in the IP world.
The PacketBand Plus Contra product has been developed to help with the migration from PDH to a MPLS transport network. It uses circuit emulation with a contra clocking interface to deliver SSI over IP. The product meets the stringent delay requirements for a mission-critical rail infrastructure network.