1. Internet Protocol Formats

2. IP (V4) Packet byte 0 byte1 byte 2 byte 3 data... – up to 65 K including heading info Version IHL Serv. Type Total Length Identifcation flags Fragment Offset TTL Protocol Header Checksum source address destination address options... Unused Padding

3. IP (V6) Packet byte 0 byte1 byte 2 byte 3 data – up to 65K Version Traffic Class (16) Flow Label (20 bits) Payload Length Next Hops source address destination address

4. UDP Header byte 0 byte1 byte 2 byte 3 Source PortDestination Port Length Checksum data.... This sites in the data portion of the IP packet. LIterally, its the next layer.

5. options... Unused Padding U A P R S F Window TCP Header byte 0 byte1 byte 2 byte 3 Sequence Number Source PortDest. Port Acknowlegement Number Offset Reserved Checksum Urgent Pointer Data....... Like UDP... All this sits inside the data area of an IP packet

6. ICMP (basic) byte 0 byte1 byte 2 byte 3 Type CodeChecksum

7. Unused ICMP Type 3 – Dest. Unreachable byte 0 byte1 byte 2 byte 3 Type CodeChecksum Internet Header + 64 bits of original datagram

8. ICMP Types 8 (echo) 0 (echo Reply) byte 0 byte1 byte 2 byte 3 Type CodeChecksum Identifier Sequence Number Data....

9. Identifier Sequence Number ICMP Timestamp and Reply (Types 13,14 ) byte 0 byte1 byte 2 byte 3 Type CodeChecksum Original Timestamp Timestamp @dest receipt Timestamp @ dest. reply