S5. What is packet fragmentation and how is it handled in IPv4 vs IPv6? Flashcards
What is packet fragmentation?
Packet fragmentation is the process in which large packets of data are broken down into smaller pieces to fit within the MTU of a network path
Why is packet fragmentation necessary?
Different networks and links may support different MTU sizes, and a packet larger than the MTU needs to be fragmented to ensure that it can be transmitted without being dropped
What is MTU?
Maximum Transmission Unit, the maximum size of a data packet that can be sent over a network path
What happens when a packet exceeds the MTU?
It gets dropped
How does fragmentation work in IPv4?
In Ipv4, fragmentation can occur both at the source and along the routers between the source and the destination. When a router receives a package larger than the MTU, it fragments the package and forwards each fragment separately.
How are fragmented IPv4 packets reassembled?
IPv4 headers include information used to manage fragmentation and reassembly. Each fragment carries a copy of the original header with modifications indicating its position in the original packet. The destination host can then use these headers to reassemble the fragments back into the original packet.
How does fragmentation work in IPv6?
In IPv6 routers do not perform fragmentation, instead it is handled solely by the source node. The source node ensures that each fragment is small enough to traverse the entire path without requiring any further fragmentation. This approach reduces the processing burden on intermediate routers and improves overall network performance.
Is IPv4 or IPv6 more efficient in terms of fragmentation?
IPv6 puts the responsibility for fragmentation on the source node, resulting in more streamlined and efficient handling of packet fragmentation. IPv4 allows intermediate routers to fragment packets, which can lead to inefficiencies and additional processing.
