フリー問題

問題文

An operator writes a fixed size for the largest packet a tunnel that carries IPv6 over IPv4 will take. Which band of fixed sizes is promised to work with any far end, and how does the upper layer read the tunnel where the size is found rather than written?

選択肢

1. Anything from 1280 through 1480 bytes is promised to work, and a larger fixed size is barred unless the far end has been shown to take packets of it, while a tunnel whose size is found reads to the upper layer as a link whose size is the one discovered below it with the wrapper counted
2. Anything from 576 through 1500 bytes is promised to work, and a larger fixed size may be written at will because the far end will cut the packet up, while a tunnel whose size is found reads to the upper layer as a link whose size is the one discovered below it with the wrapper counted
3. Anything from 576 through 1500 bytes is promised to work, and a larger fixed size may be written at will because the far end will cut the packet up, while a tunnel whose size is found reads to the upper layer as a link whose size is the one discovered below it less the size of the wrapper
4. Anything from 1280 through 1480 bytes is promised to work, and a larger fixed size is barred unless the far end has been shown to take packets of it, while a tunnel whose size is found reads to the upper layer as a link whose size is the one discovered below it less the size of the wrapper