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| -rw-r--r-- | doc/source/devel/protocol.rst | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/doc/source/devel/protocol.rst b/doc/source/devel/protocol.rst index a8c3c71..274016e 100644 --- a/doc/source/devel/protocol.rst +++ b/doc/source/devel/protocol.rst @@ -15,8 +15,10 @@ values are reserved for future use and must be ignored by current implementation Handshake format ~~~~~~~~~~~~~~~~ -For historical reasons, all multi-byte values mentioned in the handshake specification are transmitted in Little Endian byte order -unless specified otherwise. +For historical reasons, there are two different TLV encodings: all multi-byte values mentioned in the handshake specification +may be transmitted either in big endian or in little endian byte order. As fastd versions before v17 only understand the old +little endian format, fastd will always transmit its handshake as little endian to maintain compatiblity, but it can also +understand and correctly handle the new big endian format to support future fastd versions which will use the new format. The initial ``0x01`` byte together with the next three bytes form the 4-byte handshake header; the rest of the packet after the header consists of a list of TLV records. The second header byte is reserved and must |