Does IPv6 abandon TCP/IP fragmentation?
Why does IPv6 abandon TCP/IP fragmentation?

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IPv6 does not abandon fragmentation at all. What's new is that IPv6 routers do not fragment anymore. Fragmentation must be done by the source host. It will find the optimal packet size by trying the largest possible first and then reduce the packet size if it gets "packet too big" ICMPv6 messages from routers. These messages include the maximum packet size for the next hop. This was done so that routers are efficient in forwarding packets and don't need to deal with fragmentation jobs.

For more information, read my response on IPv4 and IPv6 fragment reassembly in routers. Hope this helps.

This was first published in February 2009