From 5e4aa5b8519cfc1b3b4e2d816c1cbe040eada681 Mon Sep 17 00:00:00 2001 From: Jeff Lucovsky Date: Sat, 2 May 2020 10:09:12 -0400 Subject: [PATCH] doc: Improve tos description This commit improves the description of the `tos` keyword by emphasizing that the value used should adhere to the guidelines in RFC2474. Instead of specifying the DSCP value directly, right shift the DSCP value and use that. --- doc/userguide/rules/header-keywords.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/doc/userguide/rules/header-keywords.rst b/doc/userguide/rules/header-keywords.rst index d1d2d7b887..f407af7f05 100644 --- a/doc/userguide/rules/header-keywords.rst +++ b/doc/userguide/rules/header-keywords.rst @@ -259,6 +259,13 @@ field. The tos keyword can be have a value from 0 - 255. This field of the IP header has been updated by `rfc2474 `_ to include functionality for `Differentiated services `_. +Note that the value of the field has been defined with the right-most 2 bits having +the value 0. When specifying a value for tos, ensure that the value follows this. + +E.g, instead of specifying the decimal value 34 (hex 22), right shift twice and use +decimal 136 (hex 88). + +You can specify hexadecimal values as with a leading `x`, e.g, `x88`. Format of tos:: -- 2.47.2