TCP Enhancement PDF Print E-mail

The majority of TCP Enhancement Products take an Ethernet Interface from a Router, Switch or Server and then apply their TCP Enhancement and output as Ethernet again. In order for this to be usable over Satellite, therefore, you need to convert Ethernet to Serial. This is because most Satellite Modems have Serial Interfaces.

In the past, people have used Routers to do this Ethernet to Serial Conversion but now with the Metrodata LH1000 and WC X.21/V.35 there is a more cost effective and scalable solution. These 2 products are designed for the satellite market and have features that are optimised for Asymmetric Operation and working with Satellite Modems. They also support high maximum rates for each interface, thereby offering scalability not available on Routers or equivalent Serial to Ethernet Converters.

With the WC X.21/V.35 you can support data rates up to 20Mbps, and with the LH1000 you can support data rates up to 68Mbps. We are also looking at higher data rates for TCP Enhancement Products.

EIA530 Ethernet Converters

Metrodata specialise in EIA530 for Satellite Applications. We have a number of different products support EIA530 Satellite Modems. Where possible we support EIA530 up to 20Mbps. This is not the maximum of EIA530, it is just that we haven't found anything faster than 20Mbps that we can plug into. We'd be interested if anyone has anything running EIA530 over 20Mbps, and if you would like to test it with our EIA530 Module.

Metrodata WC-Serial - The product offers conversion of X.21, V.35 or EIA530 (via Cisco Compatible cables) to Fast Ethernet (10/100baseT). It supports up to 20Mbs, and has a built in 2 port Ethernet Swtich. Its a more cost effective Serial to Ethernet converter than a Router, and has the added benefit of being faster than a Cisco Serial Interface and faster than comparable Serial to Ethernet converters. It takes its clock from the Serial Interface of the Satellite Modem, and therefore requires little configuration. Because it requires no data rate config it can therefore be used at any speed up to 20Mbps.

Metrodata WC X.21/V.35 - This product converts EIA530 to Ethernet (10/100BaseT). It supports up to 20Mbps, and has a built in 4 Port Ethernet switch. Its a more cost effective Serial to Ethernet converter than a Router, and has the added benefit of being faster than a Cisco Serial Interface and faster than comparable Serial to Ethernet converters. It takes its clock from the Serial Interface of the Satellite Modem, and therefore requires little configuration. Because it requires no data rate config it can therefore be used at any speed up to 20Mbps.

Metrodata LH1000 - This device was developed for Intelsat. It interfaces HSSI to Ethernet at up to 68Mbps. It also has a second Serial interface which supports X.21, EIA530, V.35, RS422 which can run up to 20Mbps. With the LH1000 it is possible to support an Asymmetric Satellite service with HSSI used for the higher rate and EIA530 used for the lower rate. This can be a more cost effective solution than buying 2 x HSSI Satellite Modems.

HSSI Ethernet Converter

HSSI stands for High Speed Serial Interface. Metrodata actually developed the first HSSI to G.703 Converter in 1994 for Intelsat. They had received one of the first Cisco HSSI Routers [The 4000 Series] and wanted to see if it was compatible with their G.703 Satellite Modems. As the link was running at E2 or 8.448Mbps we used a Metrodata product called the FM4850. This testing is covered in the Intelsat Document on Internet Over Satellite, called ITLAN-003.

HSSI Interfaces on Satellite Modems can go as high as 90Mbps, but typically HSSI is only used up to 51.84Mbps or STS-1. This is the "theoretical" maximum speed of HSSI [also known as EIA/TIA612]. This is more down to Cisco, and the fact that their HSSI Modules won't go any faster than 52Mbps. The other problem with running HSSI at high speeds is that the line driving capability is drastically reduced the higher the data rate.

Metrodata LH1000 - This device was developed for Intelsat. It interfaces HSSI to Ethernet at up to 68Mbps. It also has a second Serial interface which supports X.21, EIA530, V.35, RS422 which can run up to 20Mbps. With the LH1000 it is possible to support an Asymmetric Satellite service with HSSI used for the higher rate and EIA530 used for the lower rate. This can be a more cost effective solution than buying 2 x HSSI Satellite Modems.