Generic Stream Encapsulation: Difference between revisions

Revision as of 12:22, 9 April 2011

Revision as of 14:29, 9 April 2011

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GSE also provides additional features that increase the protocol flexibility and applicability. Some key GSE functions/characteristics are:

#* Support for multi-protocol encapsulation ([[IPv4]], [[IPv6]], [[MPEG]], [[ATM]], [[Ethernet]], [[IEEE 802.1Q|802.1pQ]] [[VLAN]]s, etc.)

#* Transparency to network layer functions, including [[IP]] [[encryption]] and IP [[Van Jacobson TCP/IP Header Compression|header compression]].

#* Support of several addressing modes. In addition to the 6-byte [[MAC]] address (including [[multicast]] and [[unicast]]), it supports a MAC address-less mode, and an optional 3-byte address mode.

#* A mechanism for fragmenting [[IP]] [[datagrams]] or other [[network layer]] [[Packet (information technology)|packets]] over [[baseband|Base Band]] frames to support [[Link adaptation|ACM]]/[[Variable Coding and Modulation|VCM]].

#* Support for [[hardware]] [[Firewall (computing)|filtering]].

#* Extensibility: additional [[link protocol]]s can be included through specific protocol type values (e.g. [[Layer 2]] security, IP Header Compression, etc.).

== Protocol Outline ==

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If the last fragment of a paylod frame is lost, the decapsulator can not directly detect that fact. It never sees the GSE frame with the End flag set and containing the CRC-32. For this situation, the decapsulator must choose a suitable time-out based on the data-rate and application.

== GSE-based IP Service OfferingsImplementations ==

=== Products Supporting GSE ===

Since GSE packets are directly inserted into base-band frames of the

modulation scheme, GSE products come in the form of "GSE Routers" or

"GSE Modems", which - from the outside - act very much like a DSL

Router or DSL Modem used by consumers. More generically these devices

are also referred to as "GSE Encapsulators". These products have a standard

IP network interface (most often [[Ethernet]] or a similar [[LAN]]

interface) to collect IP traffic which is to be forwarded over the

uni-directional link on the other end. To optimise the packaging into

base-band frames, these devices typically generate complete base-band

frames with the GSE packets as payload, which are then transferred to

the [[DVB-S2]], [[DVB-T2]] or [[DVB-C2]] modulator throuhg a second

interface.

Here is a (very likely incomplete) list of GSE en- and decapsulators:

* [http://www.newtec.eu/ Newtec]

** [http://www.newtec.eu/products/professional-equipment/elevation/modems/ip-satellite-modem-el470/ EL470 IP Satellite Modem]

** [http://www.newtec.eu/products/professional-equipment/elevation/demodulators/ip-satellite-demodulator-el970/ EL970 IP Satellite Demodulator]

* [http://www.work-microwave.de/ WORK Microwave GmbH]

** [http://www.work-microwave.de/dvb-s_s2.html#modems Challenge Series Satellite High Speed DVB-S2 IP Modem SK-IP]

* [http://www.gcs-salzburg.at/ gcs Global Communication & Services GmbH]

** [http://www.gcs-salzburg.at/odg.html.en ODG-200 Open DVB Gateway]

** [http://www.gcs-salzburg.at/bsr.html.en BSR-200 Broadband Satellite Receiver]

* [http://www.advantechwireless.com/ Advantech Wireless Inc.]

** [http://www.advantechwireless.com/catalogue/products/amt75e-dvb-ss2-high-speed-broadcast-modem-2/ AMT 75e DVB-S/S2 High Speed Broadcast Modem]

* [http://www.comtechefdata.com/ Comtech EF Data Corporation]

** [http://www.comtechefdata.com/products/Advanced-VSAT-Series/pcdm-840.asp CDM-840 Remote Router]

* [http://www.transplaneta.com/ K.S.Transplaneta Ltd.]

** [http://www.transplaneta.com/products/ip-encapsulator dpi4502 DVB2 (S2/T2/C2) compliant IPv4 / IPv6 Encapsulator]

* [http://dveo.com/ Computer Modules, Inc.]

** [http://dveo.com/broadcast-systems/ip-over-dvb-encapsulator.shtml DVB Rocket™/S2]

=== GSE-based IP Service Offerings ===

There are many IP-over-satellite service offerings, including for

instance [[ASTRA2Connect]] from [[SES Astra]] or [[Tooway]] from

[[Eutelsat]]. Little detail is however known about the protocols used

since the receivers are provided as part of the service by the

operators and very little technical detail is disclosed.

== References ==