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SF.express
Asked: 2017-11-03 23:06:33 +0800 CST

In IPv6 is it required the host's MTU is the same as (or smaller than) the gateway?

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I understand the concept of Path MTU but not sure if it's required that systems in the same network should have the same MTU. For example my host's MTU is 9000 and the gateway's MTU is 1500, is IPv6 supposed to work fine with this configuratoin?

routing

1 Answers

  1. Best Answer

    It depends on what the MRU of the systems is: what the maximum frame size that systems can receive is. There is no way to signal MTU and MRU on ethernet, so if one system sends larger frames than the other system can receive the frames get lost. And if it doesn't get lost it can still cause weird situations when a system receives larger packets than it can send.

    This is not specific to IPv6 as it's a layer 2 issue. The same will happen with any layer 3 protocol. Therefore it is generally strongly recommended to use the same MTU on all systems on an ethernet, unless you know what you are doing.

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