1. Protocolo IP Profa. Ana Cristina Benso da Silva Disciplina: Redes de Computadores
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5. Frame IP Version HLEN Service Type Total Length Identification Flags Fragment Offset Time to Live (TTL) Protocol Header Checksum Source IP Address Destination IP Address IP Options (if any) Padding 0 4 8 16 19 24 31 Data
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26. Fragmentação - exemplo R1 R2 MTU = 1500 bytes MTU = 1000 bytes MTU = 1500 bytes 1 Datagrama Origem 3000 bytes 3 fragmentos de 1000 bytes 3 fragmentos de 1000 bytes ID = 12345, DF = 0 MF = 0 Offset = 0, len = 3000 ID = 12345, DF = 0 MF = 1 Offset = 0, len = 1000 ID = 12345, DF = 0 MF = 1 Offset = 1000, len = 1000 ID = 12345, DF = 0 MF = 0 Offset = 2000, len = 1000 ID = 12345, DF = 0 MF = 1 Offset = 0, len = 1000 ID = 12345, DF = 0 MF = 1 Offset = 1000, len = 1000 ID = 12345, DF = 0 MF = 0 Offset = 2000, len = 1000
27. Fragmentação com DF = 1 R1 MTU = 1500 bytes MTU = 1000 bytes 1 Datagrama Origem 3000 bytes 0 fragmentos Retorno ICMP ID = 12345, DF = 1 MF = 0 Offset = 0, len = 3000 ID = 12345, DF = 1 MF = 0 Offset = 0, len = 3000 Datagrama Descartado !!! ICMP – Destination Unreachable Fragmentation Neede and DF = 1 ICMP – Destination Unreachable Fragmentation Neede and DF = 1 Recebido pela origem do datagrama Se Offse t == 0 icmp