e057f8367c
Let's just see on a diagram how the receiver can detect that the
window is large enough for the remote sender to fill the link. Here
it seems that a first criterion is that data are accumulating in
the rxbuf, indicating that the next hop doesn't consume them fast
enough. On the diagram it's visible when blue arrows (incoming data)
are more frequent than the magenta ones on average (outgoing data),
which happens when silence moments are less frequent and don't allow
the reader to catch up. It's also visible that there are two phases
alternating in the transfer:
- measure round trip time (i.e. how long it takes to restart
sending after a WU was sent after a long silence)
- measure the lowest rxbuf size during the previous round trip
It's worth noting that a window size change only has *observable* effect
after two RTT: the first RTT is to restart sending (opening or enlarging
the window), the second RTT to measure the lowest rxbuf size over the
period.
By turning the advertised window into an offset and comparing it to
the received quantity, it's possible to measure the RTT of the whole
chain (including the client possibly producing the data). Note that
when multiple streams compete for BW this can become tricky. Limiting
the window to available buffers and counting the number of sending
streams on a connection could work (i.e. split total buffers into
1+#senders, first one being used for tx).
HAProxy
HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.
Installation
The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.
Getting help
The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.
The issue tracker is only for bug reports or feature requests.
Documentation
The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.
Please refer to the following files depending on what you're looking for:
- INSTALL for instructions on how to build and install HAProxy
- BRANCHES to understand the project's life cycle and what version to use
- LICENSE for the project's license
- CONTRIBUTING for the process to follow to submit contributions
The more detailed documentation is located into the doc/ directory:
- doc/intro.txt for a quick introduction on HAProxy
- doc/configuration.txt for the configuration's reference manual
- doc/lua.txt for the Lua's reference manual
- doc/SPOE.txt for how to use the SPOE engine
- doc/network-namespaces.txt for how to use network namespaces under Linux
- doc/management.txt for the management guide
- doc/regression-testing.txt for how to use the regression testing suite
- doc/peers.txt for the peers protocol reference
- doc/coding-style.txt for how to adopt HAProxy's coding style
- doc/internals for developer-specific documentation (not all up to date)
License
HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.