R2511-HP MSR Router Series ACL and QoS Configuration Guide(V5)

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Protocol field value Protocol
4 IPinIP
6 TCP
8 EGP
17 UDP
47 GRE
50 ESP
51 AH
88 EIGRP
Flags field for fragmentation in the IP header
Figure 26 shows the format of the 3-bit flags in an IP packet.
Figure 26 Format of the 3-bit flags
The lower 2 bits of the flags field control IP packet fragmentation. The 3 bits in the flags field are defined
as follows:
• Reserved—Must be 0.
• Do not fragment—0 indicates fragmentation is allowed, and 1 indicates fragmentation is
forbidden.
• More fragments—0 indicates the packet is the last fragment, and 1 indicates it is not the last
fragment.
The 3-bit flags field 001 indicates the IP packet is an IP fragment. The 3-bit flags field 000 indicates the
IP packet is the last IP fragment.