Cost Effective Replacement of IP/DVB Encapsulators PDF Print E-mail

Satellite Service Delivery

In Satellite networking, point-to-multi-point architectures have been used for some times as a cost effective way of delivering outbound satellite services to end-users. Mainly this is due to the fact that the receiver equipment can be cheaper than a carrier class modulator/demodulator and router combination. Most IP/DVB Receivers have an Ethernet interface so they can be directly connected to a Router Ethernet Port or LAN Switch.

Typically the Headend/Receiver equipment utilises IP encapsulated in MPEG Frames. This can lead to an increased cost within the network as you need an expensive IP/DVB Encapsulator at the headend of the network. Most IP/DVB Encapsulators are overkill for a simple transmit of IP/Data, as they have features and functionality that justifies their high cost.

The ability to transmit to multiple receive sites, where the End User strips off the traffic they don't want and receives only their traffic is also available using Frame Relay. In fact some of the largest Satellite Service Providers use Frame Relay already as a way of reaching multiple customers from a single Transponder. Each Receive Site has a specific Frame Relay DLCI, which they use to identify their traffic and discard other users traffic. This use of Frame Relay has always had restrictions placed upon it until now.

These restrictions are basically interfacing problems due to the use of Cisco's HSSI Interface on Routers. With the Metrodata PA1000 its possible to use an OC-3/STM-1 POS Interface on the Router and still use HSSI on the Satellite Modem.

However, with the Metrodata PA1000 this increased cost can be a thing of the past.

Another method of delivery is using Frame Relay over Satellite. This is usually deployed as a Carrier Class infrastructure where separate HSSI Modulator/Demodulators are used, as well as Cisco HSSI Routers. This means that a threshold is placed on the maximum outbound data rate by the Cisco HSSI Router of 51.84Mbps.

It is possible to operate the Frame Relay infrastructure at speeds in excess of 51.84Mbps by utilising the Metrodata PA1000 as an interface converter between the HSSI Satellite Modem and the Router. This eliminates the requirement for HSSI on the Router and therefore takes away the speed restriction of 51.84Mbps.

With the introduction of Low Cost IP Receivers that support Frame Relay DLCIs, the PA1000 can be used instead of an expensive IP/DVB Encapsulator. This is a win-win situation, as you retain the ability to use low cost receive equipment, reduce the cost of your headend equipment and in some cases increase the possible outbound data rate, using the same transponder.

Frame Relay Receivers

With a PA1000 in place at the headend its possible to connect to a Newtec HSSI Modulator and transmit up to 100Mbps outbound. This uses HDLC on the Satellite Link and therefore transparently passes Frame Relay DLCI information. With a Frame Relay Receiver at the receive site its possible to strip out the end users traffic easily and effectively. So where are the benefits?

Mostly these are in the Service providers infrastructure, as they save money on the Headend. But consider for a second the implications of putting more over the satellite link, you get more customers per transponder. More revenue.

Low Data Rate (LDR) Over Satellite PDF Print E-mail


The Metrodata Access Processor platform supports sub 64kbps data rates on EIA530 or HSSI interfaces. These interface modules can be configured in 1bps increments from 8kbps and as such, the Access Processor can be used to transport multiple 8kbps and 128kbps data rates over a single EIA530 or HSSI satellite modem connection. The Access Processor can also be used to connect any "odd" data rates such as 266.67kbps as well and is completely flexible in terms of clocking and data rate (as it supports Asymmetric, Symmetric and Simplex systems, can the clocking can be slaved off the satellite modem).


With the Metrodata DC3000 it is possible to transport Nx64kbps satellite services over an E1 (2.048Mbps) leased line or digital microwave radio. As such this device could have as low a data rate as 64kbps, which would be 1 timeslot.

High Data Rate (HDR) Over Satellite PDF Print E-mail
  1. Ethernet over satellite at up to 110Mbps
  2. ATM over satellite at between 52Mbps and 155Mbps
  3. IP over satellite at up to 100Mbps
  4. Frame Relay Multi-casted over satellite at up to 100Mbps

Please read the detailed information below to select which solution is most appropriate to your requirements.

Ethernet over satellite at up to 110Mbps

Ethernet over satellite 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

ATM over satellite at up to 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.


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

Satellite Modem Maximum Router Metrodata Product
Interface Manufacturer Data Rate Interface
HSSI Comtech EFDATA 70Mbps OC-3/STM-1 ATM Access Processor
HSSI Comtech EFDATA 70Mbps OC-3/STM-1 POS PA1000
HSSI Comtech EFDATA 70Mbps 100baseT Ethernet LH1000
HSSI Newtec 100Mbps OC-3/STM-1 ATM Access Processor
HSSI Newtec 100Mbps OC-3/STM-1 POS PA1000
HSSI Newtec 110Mbps 100baseT Ethernet LH1000
ASI Newtec 100Mbps OC-3/STM-1 ATM Access Processor
ASI Radyne Comstream 155Mbps OC-3/STM-1 ATM Access Processor

{sbdnicertables tableid=infotable headeroff=2}

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.

ATM Over Satellite PDF Print E-mail

Metrodata Access Processor platform offers a comprehensive solution for offering ATM over satellite applications.

Interface between ATM equipment and satellite modems, from narrowband to broadband, from 8kbps to 155Mbps, supporting symmetric, asymmetric and uni-directional applications, we've got your ATM over satellite solutions covered with the Access Processor platform!

ATM over Satellite Applications

ATM over Satellite applications showing the wide range of ATM switch and satellite modem interfaces supported by the Access Processor

Satellite capacity can be exactly matched by slaving clocking off the satellite modems completely eliminating bit slips using the following ATM cell bearing serial satellite modem interfaces on the Access Processor :

  • EIA530 (up to 20Mbps)
  • HSSI (up to 100Mbps)
  • ASI (up to 155Mbps)

Standard ATM switch interfaces can also be supported including:

  • E1 (2Mbps)
  • E3 (34Mbps)
  • DS3 (45Mbps)
  • OC-3 / STM-1 (155Mbps)

Using the above interface options the Access Processor platform is an extremely flexible platform for your ATM over satellite applications.

Either click for the Access Processor product page, or select one of the following links:

Satellite Backhaul PDF Print E-mail

Metrodata has been involved in satellite backhaul for a number of years see Metrodata's satellite backhaul history.

Metrodata specialise in solutions for integrating satellite and terrestrial networks, supplying many product features that resolve specific satellite backhaul, reachback or longhaul problems.

Where you have a requirement to take a connection from a satellite modem, and transport it over fiber, wide area network (WAN) circuits, microwave radio or free space optics then we can help. Typical examples include extending your satellite service from a teleport to the customer site, or integrating your satellite service from your head-end teleport into your terrestrial network infrastructure.

Access Processor platform being used to backhaul satellite services

The diagram above shows the Access Processor product being used in a typical satellite backhaul application at either end of a terrestrial infrastructure, i.e. extending the service from the satellite earth station (supporting EIA530, HSSI, ECL, ASI or G.703 satellite modems) over a terrestrial infrastructure (e.g. a leased line, microwave link, free space optics link, or fibre) to the customer equipment (e.g. a router, ATM switch or broadcast video equipment (which can be delivered as EIA530, HSSI, or ASI).

Metrodata's flagship product for resolving satellite backhaul problems is the Access Processor range, which supports the following satellite modem interfaces:

  • HSSI (up to 100Mbps with 1bps granularity, can also slave off satellite modem for exact clocking)
  • ECL (up to 100Mbps with 1bps granularity, can also slave off satellite modem for exact clocking)
  • EIA530 (up to 20Mbps with 1bps granularity, can also slave off satellite modem for exact clocking)
  • ASI (up to 52Mbps with 1bps granularity, can also slave off satellite modem for exact clocking)
  • G.703 (T1 1.544Mbps, E1 2.048Mbps, E2 8.448Mbps, E3 34.368Mbps and DS3 44.736Mbps)

Often our equipment is used to backhaul over transatlantic DS3 and OC-3 circuits, however these might just as easily be local leased lines or fiber optic links. The following terrestrial infrastructures are supported:

  • EIA530 (Nx56kbps, Nx64kbps)
  • E1 (2Mbps)
  • E2 (8Mbps)
  • E3 (34Mbps)
  • DS3 (45Mbps)
  • OC-3 / STM-1 (155Mbps), also used for fibre solutions (multimode, singlemode shorthaul, singlemode longhaul)

Metrodata provide a number of unique technical solutions to satellite backhaul applications, supporting all of the common satellite modem interfaces, matching the data rate flexibility of satellite modems, and supporting the following network topologies:

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