The error is caused by the fact that there is an overhead of two bytes for varying length and a one-byte overhead for null.
造成这个错误的原因是,变化的长度占用 2 字节,null 占用 1 字节。
2
Importantly, each layer USES a single, interleaved parity byte to provide error monitoring across a particular segment, along the end-to-end SONET path.