1. A ‘segmentation’ exercise What changes to our ‘segment.c’ device-driver module are needed for offloading of ‘UDP Segmentation’?

2. Ethernet Header Destination MAC-addressSource MAC-address TYPE / LENGTH

3. IP Header VERS Identification Destination IP-address Source IP-address Total LengthTOSHLEN fragment offset IP Header Checksum Protocol ID TTL FLAGS

4. UDP Header Source port-numberDestination port-number UDP Segment Length UDP Checksum

5. UDP Pseudo Header Destination IP-address Source IP-address UDP Length Protocol ID ZERO

6. ‘Partial’ pseudo-header Destination IP-address Source IP-address ZERO Protocol ID ZERO

7. Context descriptor (type 0) IPCSS PAYLEN DTYP =0 MSS IPCSEIPCSOTUCSSTUCSETUCSO TUCMDSTAHDRLEN RSV 63 48 47 40 39 32 31 16 15 8 7 0 Legend: IPCSS (IP CheckSum Start)TUCSS (TCP/UDP CheckSum Start) IPCSO (IP CheckSum Offset)TUCSO (TCP/UDP CheckSum Offset) IPCSE (IP CheckSum Ending) TUCSE (TCP/UDP CheckSum Ending) PAYLEN (Payload Length)DTYP (Descriptor Type) TUCMD (TCP/UCP Command)STA (TCP/UDP Status) HDRLEN (Header Length)MSS (Maximum Segment Size) DEXT=1 (Extended Descriptor)

8. The TUCMD byte IDESNAP DEXT (=1) reserved (=0) RSTSEIPTCP 7 6 5 4 3 2 1 0 Legend: IDE (Interrupt Delay Enable) SNAP (Sub-Network Access Protocol) DEXT (Descriptor Extension) RS (Report Status) TSE (TCP-Segmentation Enable) IP (Internet Protocol) TCP (Transport Control Protocol) always valid valid only when TSE=1

9. Context descriptor (type 1) BASE ADDRESS DTALEN DTYP =1 VLANDCMDSTAPOPTS RSV 63 48 47 40 39 32 31 16 15 8 7 0 Legend: DTALEN (Data Length) DTYP (Descriptor Type) DCMD (Descriptor Command) STA (Status) RSV (Reserved) POPTS (Packet Options) VLAN (VLAN tag) DEXT=1 (Extended Descriptor)

10. The DCMD byte IDEVLE DEXT (=1) reserved (=0) RSTSEIFCSEOP 7 6 5 4 3 2 1 0 Legend: IDE (Interrupt Delay Enable) VLE (VLAN Enable) DEXT (Descriptor Extension) RS (Report Status) TSE (TCP-Segmentation Enable) IFCS (Insert Frame CheckSum) EOP (End Of Packet)) always valid valid only when EOP=1