Transfer Frame Structures Notes: A VC is managed to either contain VC Sub-channels or not Streaming refers to Packets that cross frame boundaries or VCA user octets that need not fill the Information area VCS ID is the identifier field for the VC Sub-channel VCA SDUs carry user specified Octets VCDF SDU is the contents of a frame’s data field VCS Counter provides continuity check for VC Sub-channel Virtual Channel Data Field Contents of this field are based upon the value in the VCS_Flag field: Only present when Streaming_Flag=y Contents based on value in Packet Flag This field is only present when the VCS_Flag=y: VCS_Counter VCS Flag y/n Packets Flag y/n Streaming Flag y/n VCS Flag Value Contents Yes (1) VCS_ID No (0) Spare bits Packet Flag Contents Yes (1) !st Header Pointer No (0) Number of Valid Octets Info Field 1 bit 1 bit 1 bit 1 Bit 4 Bits 5 Bits 8 Bits (optional) 16 Bits (optional) Remainder Of VCDF

Rationale for Specific Field Placement In Frame Structure If included, Insert Zone must be included in all frames of a Master Channel. Can not be encrypted because MC processing precedes Decryption. Insert Zone should contain a size field to allow MC Insert Zone Service to operate without setup by Service Management. If Flagged the Secondary header must follow the Insert Zone ( could be prior to or after Security Header) The Transfer Frame Data Field is place in a position that VC constructer can insert the VCSub-channel (the Data Field) directly into the frame without effecting the VC channel processes. Rationale for Specific Field Placement In Frame Header The three flags (FEC, Insert Zone and Secondary Header) are included within first byte of header to fill out the byte. The order of appearance of the flags could be changed VC ID and SCID Use Fields fill a byte. SCID Use Field is place as the second field in the byte so that it appears just before the SCID Field. The SCID and VC Count Size Fields share a two byte grouping. The placement of the VC Count Size Field follows the SCID so that it appears just before the VC Count Field. The VC Count Field can be zero to seven bytes as identified by the contents of the VC Count Size Field. Rationale for Specific Field Placement In Frame Data Field Header The first byte provides the structural information (bits 0 to 3) and VC Sub-Cannel Identification (bits 4 through 7) The VCS Counter field is required only when the Field contains a VC sub-channel. The next field is required only if streaming data is flagged. This field is either a first header pointer for packets or a count of valid octets for VCA Data.

Transfer Frame Header Structural Components Version ID- is extended to 4bits to accommodate 3 additional frame versions after this one (1100) is codified Destination/Source - Identifies the Spacecraft ID as either the source of the data or the intended recipient FEC Included -- signals the inclusion of the CRC (y/n) Signals the receiving Master Channel process to check Frame’s validity using attached FECF Master Channel Insert Zone contained Flag Virtual Channel Secondary Header contained Flag Frame Length –(N+1) allows for frame to be as large as 65536 octets Virtual Channel ID – accommodates 64 Virtual Channels Spacecraft ID use Field can be used by a Mission to organize its data without requiring multiple SCIDs Spacecraft ID - allows for 8192 names VC Count Size – the contents identify the size of the VC count field– (size can be 0 to 7 octets) VC Count –VC counter that has a minimum size of 0 octet and a maximum size of 7 octets; This counter will need to increment when sequence control is specified for this VC The content of this field can be user defined when sequence control is not specified for this VC This field can be used by the crypto authentication process eliminating the need of a second counter

Packets Octets VCA Service Packet Service VCA SAP VCA SAP VCDF_Service OCF Service VC SH Service VC_OCF_PDU VCDF_PDU Virtual Channel (VC) Formulation Insert Received VCS-PDUs Add VC Header and increment VC Counter Compute and Add Security Header and Trailer Insert OCF Compute CRC and add FEC VC_PDU Virtual Channel_PDU MC Insert Master Channel (MC) Formulation Merge Received VC_PDUs FEC Coding and Randomization Add Attached Sync Marker MC_PDU Master Channel_PDU Physical Channel (PC) Formulation Merge Received MC_PDUs Add Idle as required Physical Channel Symbol Stream

Transfer Frame Assembly Computed and entered in frame 4 Received from OC Service and Inserted into frame Received from SAP and inserted into frame Generated and entered into frame Calculated and entered into frame 1 3 2 5 Transfer Frame Operational Control Field Transfer Frame Data Field (VCF_SDU) Transfer Frame Primary Header Master Channel Insert Zone Virtual Channel Secondary Header Transfer Frame Security Header Transfer Frame Security Trailer Transfer Frame Error Control Field 6-10 Octets “fixed” Variable Variable Variable Variable 4 Octets Variable Mandatory Optional Optional Optional Optional Optional Optional Optional VC Data Field VC Transfer Frame Note: The number within the circles identifies the order of inclusion in the frame formation process

Transmitting (sending) Side Receiving Side VCA Service Packet Service VCA Service Packet Service Packets Octets VCDF_Service VCDF_Service Octets Packets VCS SAP VCA SAP Form VCF_SDU Form VCF_SDU VCA SAP VCS SAP Extract Packets Extract Octets OCF Service Input Sub-layer Select VCF_SDU VC_OCF_SDU VCS_SDU Separate GVCS_Frames Output Sub-layer VCDF_SDU (VC_Frame Data Field) Virtual Channel (VC) Formulation Add VC Header and increment VC Counter Insert Received VC-SDUs Insert OCF Compute and Add Security Header and Trailer Compute and add CRC (optional) VC SH Service VC_Frame VC Service Deliver Received verified VC-Frames Check VC Continuity Perform Security Process Extract OCF Data Sub-layer VC_Frame Data Sub-layer Virtual_Channel_Frame Virtual_Channel_Frame Merge VC Frames MC_Frame Separate VC_Frames Master_Channel_Frame MCF Service Master_Channel_Frame Master Channel (MC) Formulation Merge Received VC_PDUs FEC Coding and Randomization Add Attached Sync Marker Separate VC_Frames MC Insert Delimit Frames using Sync Marker FEC Decoding and Derandomization Validate Frame using CRC when contained Separate MC_Frames Sync& Coding Sub-layer Sync& Coding Sub-layer MC_Frame Link_Transmission_Unit Link Transmission_Unit (ASM+VC_Frame) Physical Layer Merge MC Frames Physical Layer Physical Channel Symbol Stream Physical Channel Symbol Stream Physical Channel (PC) Formulation Merge Received MC_PDUs Add Idle as required Physical Channel (PC) Reception Acquire symbols

Virtual Channel Processing Legend Packets VCA_SDUs VCDF_SDUs Note: -Packet SAP can support multiple users -VCA SAP can only support a single user Packet SAP VCA-SAP VCDF-SAP VC_OCF Service Data Unit Packet Processing Function VCA Processing Function OCF-SAP OCF_SDUs VCF_SDUs Virtual Channel Creation Virtual Channel Processing Security Process Virtual Channel Processing Virtual Channel Processing CRC Creation Virtual Channel Data Unit (VCDU) Master Channel Process Master Channel Process (Virtual Channel Multiplexing) Master Channel Data Unit (MCDU) VCF-SDU = VC Data Field Legend All Channel Multiplexing Optional Process Multiplexer Coding and Sync Sub-Layer Process Physical Channel Replicated Processes

Virtual Channel Processing Legend Packets Note: VCA_SDUs VCDF-SDUs VC-SDUs Packet SAP VCA-SAP VCDF-SAP VC-SAP COP-1 Service Packet Processing Function VCA Processing Function Note: -Security Process may output a report -CRC Validation will output a report to OCF OCF_SDUs OCF-SAP CRC Report VCDF_SDUs VCDF_SDUs Virtual Channel SDU Extraction Virtual Channel Processing Virtual Channel Processing Virtual Channel Processing Security Process Virtual Channel Data Unit (VCDU) CRC Validation Master Channel Process Master Channel Process (Virtual Channel Multiplexing) Master Channel Data Unit (MCDU) Legend All Channel Multiplexing Optional Process Multiplexer Coding and Sync Sub-Layer Process Physical Channel Replicated Processes

Managed Parameters Master Channel--- FEC Code, Inter-frame Idle Allowed/not allowed? Fixed/variable frame length? VC priorities Max Frame Size allowed ASM, Fill type (frame or bits) VC --- Count size Sequence controlled y/n? Sequence count indexing required OCF y/n Security header & trailer sizes Security SA (use VC Count?) VCS/packets/VCA (signaled in frame) VCS --- list allowed data types Streaming data (Packets not required to fit within a single frame) VCS --- Packets/VCA (signaled in frame) Size of Field

Short Uplink Code Performance

Overall Coding Performance (provided by JPL Coding Group) LDPC Rate ½ Block size 16 384 bits Rate ½ Block size 1024 1/2, 1024 LDPC with BCH TED LDPC Rate 4/5 Block size 16384 BCH SEC TED GSFC-LDPC (8176,7156)

Transfer Frame Data Field Primary Header Master Channel Insert Zone Virtual Channel Secondary Header Transfer Frame Security Header Transfer Frame Data Field (VCDF_PDU) Transfer Frame Security Trailer Transfer Frame Operational Control Field Transfer Frame Error Control Field 6-11 Octets Variable Variable Variable Variable Variable 4 Octets Variable Mandatory Optional Optional Optional Optional Optional Optional Optional Transfer Frame Header Version ID Destination or Source ID FEC Included Flag Secondary Header Flag Frame Length Virtual Channel ID SCID Use Field Spacecraft ID VC Count size VC Count Insert Zone Flag 4 bits 1 bit 1 Bit 1 Bit 1 Bit 16 Bits 6 Bits 2 Bits 13 bits 3 Bits 0-56 Bits Virtual Channel Data Field Contents of this field are based upon the value in the VCS_Flag field: Only present when Streaming_Flag=y Contents based on value in Packet Flag This field is only present when the VCS_Flag=y: VCS_Counter VCS Flag y/n Packets Flag y/n Streaming Flag y/n VCS Flag Value Contents Yes (1) VCS_ID No (0) Spare bits Packet Flag Contents Yes (1) !st Header Pointer No (0) Number of Valid Octets Info Field 1 bit 1 bit 1 bit 1 Bit 4 Bits 5 Bits 8 Bits (optional) 16 Bits (optional) Remainder Of VCDF