From 88c777a8555dd4ea3c26d9c7eed47168315eeef4 Mon Sep 17 00:00:00 2001 From: Martin Quinson Date: Sat, 26 Mar 2016 22:38:44 +0100 Subject: [PATCH] vivaldi: we are not using euclidean distance, actually --- doc/doxygen/platform.doc | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/doc/doxygen/platform.doc b/doc/doxygen/platform.doc index 09e5500d6a..d68200c583 100644 --- a/doc/doxygen/platform.doc +++ b/doc/doxygen/platform.doc @@ -1754,9 +1754,16 @@ complicated in using it, here is an example of it: \endverbatim -Coordinates are then used to calculate latency between two hosts by -calculating the euclidean distance between the two hosts coordinates. -The results express the latency in ms. +Coordinates are then used to calculate latency (in microseconds) +between two hosts by calculating the distance between the two hosts +coordinates with the following formula: distance( (x1, y1, z1), (x2, +y2, z2) ) = euclidian( (x1,y1), (x2,y2) ) + abs(z1) + abs(z2) + +In other words, we take the euclidian distance on the two first +dimensions, and then add the absolute values found on the third +dimension. This may seem strange, but it was found to allow better +approximations of the latency matrices (see the paper describing +Vivaldi). Note that the previous example defines a routing directly between hosts but it could be also used to define a routing between AS. That is for example what is commonly done when using peers (see Section \ref pf_peer). @@ -1766,7 +1773,7 @@ That is for example what is commonly done when using peers (see Section \ref pf_ - + -- 2.20.1