Metrodata Limited

Ethernet over satellite at up to 110Mbps

This application shows how a pair of LH1000 units can be used to interface to HSSI satellite modems to offer Ethernet over satellite at up to 110Mbps.

ATM over satellite at between 52Mbps and 155Mbps

This application shows how a pair of Access Processor units can be used to interface to ASI satellite modems to offer ATM over satellite at up to 155Mbps.

IP over satellite at up to 100Mbps

This application shows how a pair of PA1000 units can be used to interface routers with Packet over Sonet (POS) interfaces to HSSI satellite modems to offer IP over satellite at up to 100Mbps.

Frame Relay Multi-casted over satellite at up to 100Mbps

This application shows how a PA1000 unit can be used at the head end to interface to a HSSI satellite modem to offer multi-casted Frame Relay over satellite at up to 100Mbps, using Ipricot Frame relay receivers.

Analysing your options for high data rate over satellite as a service provider or end-user

Metrodata has a history of successfully deploying high data rate over satellite solutions, and this web page analyses the different options for deploying satellite links between 52Mbps and 155Mbps, whether these are symmetric full duplex, asymmetric, or uni-directional. There are 4 main protocols that can be used to transport data over satellite links:

• IP
• Frame Relay
• ATM
• Ethernet
  

Historically IP has been used, but this has traditionally been limited to 52Mbps as this corresponds to the maximum speed of a HSSI router interface. Above 52Mbps the option has only been a 155Mbps POS interface, but supporting 155Mbps over satellite is only possible over a small number of the installed base of satellite transponders.

Many satellite service providers have moved from IP to a Frame Relay based multicast network as this offers cost savings with the satellite capacity, but the network is still limited to the 52Mbps limit of HSSI router interfaces. It is more than likely that the same network could operate at 60Mbps or higher with small changes to the satellite modem settings, but the HSSI router interface limitation remains.

Apart from the core satellite infrastructure (transponders, antenna sizes, power levels), the key criteria for supporting higher data rates are the satellite modems.

Maximum data rates of satellite modem interfaces

There are 3 satellite modem manufacturers that support ASI at high data rates:

• Newtec - 110Mbps
• Radyne Comstream - 240Mbps on the Modulator and 160Mbps on the Demodulator
• Tandberg - Prekor System (please note the Prekor System does not work with the Metrodata Access Processor ASI UNI module)

There are 2 satellite modem manufacturers that support HSSI at high data rates:

• Newtec - 110Mbps
• Comtech EFDATA - 70Mbps

ECL is not widely available commercially on satellite modems, but Metrodata can interface to ECL up to 155Mbps.

Some satellite modems are starting to have Ethernet interfaces, but these often have speed restrictions and they also tend to operate at layer 3 which partitions the user network and can cause maintenance problems.

Please note, these maximum data rates are guidelines only. If you require exact details of these modems please contact the manufacturers directly or through your local distributor.

Maximum data rates of router interfaces

Here are the maximum data rates of the high speed router interfaces:

• HSSI - 52Mbps
• Fast Ethernet - 100Mbps
• ATM OC-3/STM-1 - 155Mbps
• POS OC-3/STM-1 - 155Mbps

Choosing your high data rate over satellite solution

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Please note that the Access Processor and PA1000 products can connect directly to leased lines meaning that the router does not need to be located in the Earth station.

All of the above equipment can be used in point-to-point satellite applications, however the Access Processor can also perform multi-casting using ATM over satellite, whilst the PA1000 can be used at the head end of a Multi-casted Frame Relay based satellite network.