Differences between current version and revision by previous author of DCCP.
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| Newer page: | version 53 | Last edited on Wednesday, May 30, 2007 4:09:28 pm | by IanMcDonald | |
| Older page: | version 37 | Last edited on Tuesday, October 4, 2005 8:53:13 am | by BruceBarnett | Revert |
@@ -1,30 +1,28 @@
[Acronym] for __D__atagram __C__ongestion __C__ontrol __P__rotocol.
DCCP is a transport level protocol (like [TCP] and [UDP]) which aims to solve many different congestion issues. This is useful for applications that don't need the data reliability/re-transmission of [TCP], but want a session and want congestion control unlike [UDP].
-DCCP is currently at draft
[RFC] status.
+DCCP is a series of proposed standard
[RFC]s (4340-4342)
The main reference page on the web for DCCP is here:
-http://www.icir
.org/kohler
/dcp
/
+http://www.read
.cs.ucla.edu
/dccp
/
There is also a [writeup at LWN|http://lwn.net/Articles/149756/].
!!DCCP stack for Linux
-Much of this page is shifting to http://developer
.osdl.org/shemminger/wiki
/index.php/DCCP - please update both webpages at present until [OSDL] becomes a production machine
.
+Much of this page is shifting to http://linux-net
.osdl.org/index.php/DCCP - that page is considered the definitive reference for the DCCP implementation for Linux
.
-There
is a [GPL] version of DCCP being produced at
present for
the [LinuxKernel]. This is being maintained by ArnaldoMelo at present. The history of this is that it draws from the code of Patrick ~McManus, Lulea and the [WAND] group
that IanMcDonald is part of. The status of this is that it has been
accepted by LinusTorvalds into his
2.6.14 tree.
+DCCP
is present in
the [LinuxKernel]. This is being maintained by ArnaldoMelo at present. The history of this is that it draws from the code of Patrick ~McManus, Lulea and the WandGroup
that IanMcDonald is part of. It was
accepted into the LinuxKernel
by LinusTorvalds in
2.6.14. It continues to evolve rapidly at time of writing (preparatory 2.6.20) and it usually pays to get the latest code from a [Git]
tree.
The core DCCP stack was written by ArnaldoMelo using the Linux [TCP] implementation as a model, with DCCP being used as a way to identify code in the [TCP] implementation that could be made generic and shared with other INET transport level implementations. This resulted in the generalisation of code related to the minisockets representing both TCP_SYN_RECV/DCCP_RESPOND and TCP_TIME_WAIT/DCCP_TIME_WAIT status, code related to established/timewait/listen sockets (inet_lookup, inet_lookup_established, etc), the interface to get sock information (tcp_diag), and many other functions and data structures, with more expected to be generalised and eventually used by [SCTP] and any other INET transport protocols that may be introduced in the future.
-The [CCID]3 code was, as IanMcDonald mentioned, drawn from the [WAND] group
, that in turn got it initially from the Lulea [FreeBSD] codebase and made it work in the core DCCP stack written by Patrick ~McManus. It was modified by ArnaldoMelo to fit Linux standards wrt list handling and several other aspects.
+The [CCID]3 code was, as IanMcDonald mentioned, drawn from the WandGroup
, that in turn got it initially from the Lulea [FreeBSD] codebase and made it work in the core DCCP stack written by Patrick ~McManus. It was modified by ArnaldoMelo to fit Linux standards wrt list handling and several other aspects.
The [CCID] modular infrastructure was written to fit the [CCID]3 existing interface, but will probably be changed in the near future in the effort to have a generic CA (Congestion Avoidance) infrastructure shared with [TCP] (and others, who knows), continuing work on the existing [TCP] CA infrastructure put in place by Stephen Hemminger.
-To have a look at the theoretical performance of [CCID]3 see http://wand.net.nz/~iam4
/dccp/xcalc
.sxc
- the codebase currently assumes
s=256, unless you override with an option.
-
-The code is maintained in [Git] at: http://www.kernel.org/git/?p=linux/kernel/git/acme/net-2.6.git;
a=summary and there is a mailing list for DCCP work which is dccp at vger dot kernel dot org. Discussion also occurs on the main Linux networking mailing list - netdev at vger dot kernel dot org
.
+To have a look at the theoretical performance of [CCID]3 see http://wand.net.nz/~perry
/max_download
.php
- the codebase currently calculates
s using
a weighted average
.
!!TcpDump support
TcpDump now has DCCP support in the tree. There is TcpDump support available at http://wand.cs.waikato.ac.nz/~iam4/dccp/tcpdump8.diff for older versions. This applies to many versions and at least the weekly build from CVS of tcpdump dated 22nd August 2005. Remember to run tcpdump(8) with a -s0 parameter to capture all data (or some other value) as the default size gets the base DCCP header, but not the options, in many cases.
@@ -57,31 +55,44 @@
The above listing was with the ttcp test.
!!Netcat support
-A patch for [NetCat] is available at
http://oops.ghostprotocols.
net:81/dccp/netcat-
.7
.1.dccp.patch or http:
//wand
.net.nz/~iam4/dccp
/netcat-.7.1.dccp.patch
-. The version of NetCat that this is used against is .71 from http://netcat.sf.net and was used on 8th September for, what we believe to be, the first public transmission of DCCP over the InterNet.
+See
http://linux-
net.osdl
.org
/index
.php
/DCCP#
netcat_support
!!Mailing List Archives
http://www1.ietf.org/mail-archive/web/dccp/current/index.html - A discussion of the DCCP protocol by the IETF
http://www.mail-archive.com/dccp@vger.kernel.org/ - a discussion of the Linux implementation of DCCP
+!!To do & testing
+There is a [Todo list|http://linux-net.osdl.org/index.php/TODO#DCCP] also which tracks the issues needing working on.
+There is a [DCCPTesting|http://linux-net.osdl.org/index.php/DCCP_Testing] page which also talks about the status of testing in [DCCP].
-!!To do & testing
+For sample code have a look at the applications ported or you can contact IanMcDonald
-There is
a [DCCPToDo
] list also which tracks the issues needing working on
. The
[WLUG
] wiki is currently
the master maintainer
for this
.
+There are
a couple of ttcp implementations for DCCP available for the 2.6
[LinuxKernel
]:
+* http://wand
.net.nz/~iam4/dccp/ttcp_new.c that works with earlier versions of
[DCCP
]
+* http://wand.net.nz/~iam4/dccp/ttcp_acme.c that works with later versions of [DCCP] that require
the service option to be set (gives ERRNO of 22 otherwise). This has had include files altered slightly from [ArnaldoMelo]s version (just
for TFRC) and should be compiled like
+<pre>
+gcc ttcp_acme.c -o ttcp_acme -I ~~/linuxsrc/dccpwork/include/
+</pre>
+change is:
+<pre>
+-#include <netinet/tfrc.h>
++// #include <netinet/tfrc.h>
++#include <linux/tfrc
.h>
+</pre>
-There is a [DCCPTesting] page which also talks about the status of testing in [DCCP].
+!!FAQ
-There is sample code at
http://wand.
net.nz/~iam4/dccp/sample/ that uses the mmap interface for the 2
.4 kernel, and a ttcp implementation for DCCP at http:
//wand
.net.nz
/~iam4/dccp/ttcp_new.c that works with the 2.6 kernel
+See [FAQ|
http://linux-
net.osdl
.org
/index
.php
/DCCP#FAQ]
For more details, ask IanMcDonald from the WandGroup.
See also:
* KernelDevelopment
----
CategoryProtocols
