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Does router do fragmentation?
Fragmentation is done by the network layer when the maximum size of datagram is greater than maximum size of data that can be held a frame i.e., its Maximum Transmission Unit (MTU). It is done by network layer at the destination side and is usually done at routers.
What are the problems involved in IP fragmentation process?
IP fragmentation can cause excessive retransmissions when fragments encounter packet loss and reliable protocols such as TCP must retransmit all of the fragments in order to recover from the loss of a single fragment. Thus, senders typically use two approaches to decide the size of IP packets to send over the network.
When does fragmentation occur in an IP network?
Fragmentation occurs when an IP datagram traverses a network which has a maximum transmission unit (MTU) that is smaller than the size of the datagram.
How are fragments of IPv4 packets reassembled?
The fragments are reassembled by the receiving host . The details of the fragmentation mechanism, as well as the overall architectural approach to fragmentation, are different between IPv4 and IPv6 . RFC 791 describes the procedure for IP fragmentation, and transmission and reassembly of IP packets.
Which is the fragment flag in the IP header?
The Identification field along with the foreign and local internet address and the protocol ID, and Fragment offset field along with Don’t Fragment and More Fragment flags in the IP protocol header are used for fragmentation and reassembly of IP packets.
Is it possible to select an IP datagram size to avoid fragmentation?
It is not possible to select a particular IP datagram size to always avoid fragmentation, as the MTU for different transmission It is possible, though, for a given path to choose a size that will not lead to fragmentation. This is called Path MTU Discovery and is discussed in the RFC 1191.