Network Technologies DVB-ASI to IP Data Flow Block Diagrams, Forward Error Correction FEC

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ASI-IP-GTW User's Manual

1.1.1.34 UDP Mode

To allow interoperability with legacy equipment, the ASI-IP-GTW can stream video over IP without using the RTP protocol encapsulation. This is also called UDP mode or UDP only. UDP mode is manually configured on the transmitting ASI-IP-GTW unit, and automatically detected on the receiving ASI-IP-GTW.

Note: FEC relies on information in the RTP protocol, and will not be available in UDP mode. FEC is explained in 5.4.1.

5.4 Data Flow Block Diagrams

The following figure shows the data flow between two ASI-IP-GTW over an IP network.

Figure 35. Data flow between two units

5.4.1 Forward Error Correction (FEC)

Unfortunately, real networks are not perfect and packet losses occur. In order to cope with packet losses, the ASI-IP-GTW has implemented Pro- MPEG FEC according to Pro-MPEG Code of Practice #3 rev. 2. Pro- MPEG FEC is carried out on RTP packets. The mechanism is based on the insertion of additional data containing the result of an XOR (exclusive OR)-operation of packets over a time window.

The generation of FEC packets is based on the use of a matrix. The matrix size is defined by the number of columns (L) and the number of rows (D). The FEC packets are calculated as an XOR operation over the packets in a column and the packets in a row. Figure 36 shows an example of the FEC scheme. Three packets are lost and corrected.

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Contents DVB-ASI to IP Gateway This page is intentionally left blank Important notice Rev Date SW ver CommentPage Table of Contents Options 12.1 Who Should Use this Manual IntroductionPurpose of this Manual Contact Information What Equipment is Covered by this ManualSoftware versions Summary of FeaturesRole of the ASI-IP-GTW in a Typical System Page Indicator Colour Description Guided TourUser Interface Front Panel DescriptionConstruction Hardware OptionsSoftware Options Functionality Max value DescriptionIntroduction Installing the EquipmentInstalling the Equipment Equipment access To fix the equipmentTo cable the equipment VentilationTo connect the equipment ASI portPower Cable and Protective Earth PowerAC Power Supply USA Nema 5-15P Protective Earth /Technical EarthUK BS Pin placement Specification Optional DC Power SupplyConnecting the Video Gateway to the AC Power Supply ASI ports Signal ConnectionsIntroduction DVB ASI output Ethernet data portDVB ASI input LEDs Ethernet management portPowering Up/Down Before Powering upPowering Up Powering DownOperating the Equipment Changing the IP address of the unitLooking at the WEB interface Overall statusMain tab Sub-tab Description SnmpStatus Device Info Product type ASI-IP-GTWNetwork MainAdvanced 1.22 SFPDevice info page, Network and SFP sub-page Time settings Shows the sub-page for time setting used for alarm reportsAlarms SnmpSnmp tab Ping Ping tabPage Shows the sub-page for user security password protection SecurityMain Input ConfigurationIP TX Input Status IP TX ParametersIP TX Status FEC Settings IP TX FECPage Static MAC setting Ethernet SettingsVlan settings Ping Settings Ping page of an IP transmitterOutput Configuration IP RXIP RX Status Output StatusIP RX Parameters FEC sub-page of an IP receiver Page Ethernet sub-page of an IP receiver Ping page of an IP receiver Advanced Tab Advanced TabPage Transmitted Network streams NetworkData Network Interface Status Shows the Network page for a unit configured to IP-RX mode Received Network streamsSaving a Configuration Save/LoadLoading a Configuration Save/Load page when saving configurationOptions 1PPS/10MHz interface modulesSeparate 10MHz/1PPS module 2 1PPS interfaceOperating the 1PPS/10MHz interface module Shows the layoutLED descriptions LED description for separate 1PPS/10MHz interface moduleRIPv2 functionality Shows the layout of the RIP-2 screenPage Functional Description IP Transmit ModeEquipment Description Management IP Receive ModeIP Bi-directional Mode Page Alarm Severity level Description Overview of Video over IP Protocol mappingUDP Mode Data Flow Block DiagramsForward Error Correction FEC Page Maintenance Preventive Maintenance and Fault-findingPreventive Maintenance Preliminary Checks Fault-findingFault finding Philosophy PSU LED Unlit / Power Supply Problem Alarm LED lit / Alarm condition Fans Not Working / OverheatingStep Action If the result of action is Yes Check Fan RotationAlarm Description Error source Progress Bitrate estimationGeneral Disposing of this EquipmentTo return the unit Appendix a Glossary Page Page Page Appendix B Technical Specification DVB ASI portAlarm relay and maintenance port specification Ethernet data portEthernet management port ProtocolsAC Mains Input DC Mains inputPhysical Details Safety Environmental ConditionsCompliance1 Electromagnetic Compatibility EMCCE Marking Interface to public telecommunication systemAppendix C References Appendix D Upgrade of Features Ex. http//192.168.0.100/upgradeFeature upgrade Feature upgrade dialogue Upgrade SW Appendix E Upgrading SoftwareSW load progress Layer 3 Routing Appendix F Quality of service Setting Packet priorityMpls ASI-IP-GTW Configuration Layer 2 priority