Internet Minimum MTU: 576 Bytes

最新推荐文章于 2024-09-23 21:02:19 发布

转载最新推荐文章于 2024-09-23 21:02:19 发布 · 1.9k 阅读

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本文深入探讨了IP网络中路由器处理数据包大小的机制，特别是最大传输单元（MTU）的概念。解释了为什么每个路由器都需要能够处理IP数据包，这些数据包的大小不能超过连接网络的最大MTU。强调了576字节作为最小MTU值的重要性，以及其背后的逻辑。此外，阐述了即使主机连接到MTU大于576字节的本地网络，选择使用576字节MTU的原因，旨在确保在网络传输过程中无需进一步的数据包分割。

文章出处：http://blog.chinaunix.net/space.php?uid=10392839&do=blog&id=1988876

Each router must be able to fragment as needed to handle IP datagrams upto the size of the largest MTU used by networks to which they attach. Routersare also required, as a minimum, to handle an MTU of at least 576 bytes. Thisvalue is specified in RFC 791, and was chosen to allow a “reasonable sized”data block of at least 512 bytes, plus room for the standard IP header andoptions. Since it is the minimum size specified in the IP standard, 576 byteshas become a common default MTU value used for IP datagrams. Even if a host isconnected over a local network with an MTU larger than 576, it may choose touse an MTU value of 576 anyway, to ensure that no further fragmentation will berequired by intermediate routers.