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Internet Protocol Formats. IP (V4) Packet. byte 0 byte1 byte 2 byte 3. Version IHL Serv. Type Total Length. data ... – up to 65 K including heading info. Identifcation flags Fragment Offset.
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IP (V4) Packet byte 0 byte1 byte 2 byte 3 Version IHL Serv. Type Total Length data ... – up to 65 K including heading info Identifcation flags Fragment Offset TTL Protocol Header Checksum source address destination address options... Unused Padding
IP (V6) Packet byte 0 byte1 byte 2 byte 3 Version Traffic Class (16)Flow Label (20 bits) data – up to 65K Payload Length Next Hops source address destination address
UDP Header byte 0 byte1 byte 2 byte 3 Source Port Destination Port Length Checksum data.... This sites in the data portion of the IP packet. LIterally, its the next layer.
TCP Header byte 0 byte1 byte 2 byte 3 Source Port Dest. Port Sequence Number Acknowlegement Number U A P R S FWindow Offset Reserved Checksum Urgent Pointer options... Unused Padding Data ....... Like UDP... All this sits inside the data area of an IP packet
ICMP (basic) byte 0 byte1 byte 2 byte 3 Type Code Checksum
ICMP Type 3 – Dest. Unreachable byte 0 byte1 byte 2 byte 3 Type Code Checksum Unused Internet Header + 64 bits of original datagram
ICMP Types 8 (echo) 0 (echo Reply) byte 0 byte1 byte 2 byte 3 Type Code Checksum Identifier Sequence Number Data ....
ICMP Timestamp and Reply (Types 13,14 ) byte 0 byte1 byte 2 byte 3 Type Code Checksum Identifier Sequence Number Original Timestamp Timestamp @dest receipt Timestamp @ dest. reply