Packet Layout
Revision as of 14:02, 17 November 2006 by Cube Linden (talk | contribs)
Packet Layout Visualization
+-+-+-+-+-------+---------------+---------------+---------------+ |Z|R|R|A| | |E|E|E|C| Packet ID (28 bits) | |R|L|S|K| | +-+-+-+-+-------+---------------+---------------+---------------+ | | : :
Header
- Byte 0, 4 most significant bits: Packet Information
- LL_ZERO_CODE_FLAG 0x80 -- Packet data is run length encoded, such that series of 1 to 255 zero bytes are encoded to take 2 bytes.
- LL_RELIABLE_FLAG 0x40 -- This packet was sent reliably (implies please ack this packet)
- LL_RESENT_FLAG 0x20 -- This packet is a resend from the source.
- LL_ACK_FLAG 0x10 -- This packet contains appended acks.
- Bytes 0, (4 least significant bits) to byte 3: (for a total of 28 bit) Packet ID, assigned by circuit
- Everything beyond this is potentially zerocoded for compression
- Bytes n thru n+(frequency size)
- 1/2/4 byte ID of the message the packet contains
Body
- Bytes n thru n+(data length)
- Body of packet, possibly zero coded.
Zero Coding
Appended Acks
- Bytes n+(data length) thru acks
- Rest of packet is fill with as many acks as will fit from reliable messages
See also: libsecondlife documentation