Documentation/networking/udplite.txt

2                       The UDP-Lite protocol (RFC 3828)
6   UDP-Lite is a Standards-Track IETF transport protocol whose characteristic
7   is a variable-length checksum. This has advantages for transport of multimedia
12   For in-depth information, you can consult:
14    o The UDP-Lite Homepage:
15 	http://web.archive.org/web/*/http://www.erg.abdn.ac.uk/users/gerrit/udp-lite/
18    o The UDP-Lite HOWTO on
19        http://web.archive.org/web/*/http://www.erg.abdn.ac.uk/users/gerrit/udp-lite/
20 	files/UDP-Lite-HOWTO.txt
22    o The Wireshark UDP-Lite WiKi (with capture files):
30   Several applications have been ported successfully to UDP-Lite. Ethereal
31   (now called wireshark) has UDP-Litev4/v6 support by default.
32   Porting applications to UDP-Lite is straightforward: only socket level and
39   UDP-Lite provides a connectionless, unreliable datagram service and hence
40   uses the same socket type as UDP. In fact, porting from UDP to UDP-Lite is
50   With just the above change you are able to run UDP-Lite services or connect
51   to UDP-Lite servers. The kernel will assume that you are not interested in
65       Of each packet only the first 20 bytes (plus the pseudo-header) will be
66       checksummed. This is useful for RTP applications which have a 12-byte
72       This option is the receiver-side analogue. It is truly optional, i.e. not
82   The calls to getsockopt(2) are analogous. Being an extension and not a stand-
86   A detailed discussion of UDP-Lite checksum coverage options is in section IV.
97         for UDP-Lite header fields and protocol constants
99   For testing purposes, the following can serve as a `mini' header file:
106   Ready-made header files for various distros are in the UDP-Lite tarball.
153   of UDP-Lite packets is determined by the size of the send buffer. The
156   net.core.wmem_default or via setting the SO_SNDBUF socket(7)
158   by net.core.wmem_max.
160   Given a payload size larger than the send buffer size, UDP-Lite will
166   UDP-Lite packet is split into several IP packets, of which only the
175   UDP-Lite will ship the 1536 bytes in two separate packets:
180   The coverage packet covers the UDP-Lite header and 848 bytes of the
183   length. The kernel always re-adjusts the coverage length to the packet
186   As an example of what happens when one UDP-Lite packet is split into
192   +-+-----------+--------------+--------------+--------------+
194   +-+-----------+--------------+--------------+--------------+
199   The UDP-Lite module generates one 1032 byte packet (1024 + 8 byte
213     Fragment 1: 1280 bytes carrying  1232 bytes of UDP-Lite data
214     Fragment 2: 1280 bytes carrying  1232 bytes of UDP-Lite data
215     Fragment 3:  948 bytes carrying   900 bytes of UDP-Lite data
218   fragment only 598 (= 3062 - 2*1232) bytes are checksummed.
221   are (annoyingly) rare: UDP-Lite is designed for optimising multimedia
226   V) UDP-LITE RUNTIME STATISTICS AND THEIR MEANING
229   level.  Live statistics about UDP-Lite are available in /proc/net/snmp
232                             netstat -svu
234   This displays UDP-Lite statistics variables, whose meaning is as follows.
241    InErrors:        Number of erroneous UDP-Lite packets. Errors include:
258   There is packet match support for UDP-Lite as well as support for the LOG target.
261   udplite 136     UDP-Lite        # UDP-Lite [RFC 3828]
264               iptables -A INPUT -p udplite -j LOG
271   The UDP-Lite patch was developed at