From 16d2551857f26a309a873d904a47a767ee0875d6 Mon Sep 17 00:00:00 2001 From: Jesse Gross Date: Fri, 4 Feb 2011 13:54:58 -0800 Subject: [PATCH] vlan-test: Add examples of vlan problems to man page. --- utilities/ovs-vlan-test.8.in | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/utilities/ovs-vlan-test.8.in b/utilities/ovs-vlan-test.8.in index d3cd0316..82b4cf7d 100644 --- a/utilities/ovs-vlan-test.8.in +++ b/utilities/ovs-vlan-test.8.in @@ -16,6 +16,25 @@ test, configure Open vSwitch to tag traffic originating from \fIvlan_ip\fR and forward it out the target interface. Then run the \fBovs\-vlan\-test\fR in client mode connecting to an \fBovs\-vlan\-test\fR server. \fBovs\-vlan\-test\fR will display "OK" if it did not detect problems. +.PP +Some examples of the types of problems that may be encountered are: +.IP \(bu +When NICs use vlan stripping on receive they must pass a pointer to +a vlan group when reporting the stripped tag to the networking core. +If there is no vlan group in use then some drivers just drop the +extracted tag. Drivers are supposed to only enable stripping if a +vlan group is registered but not all of them do that. +. +.IP \(bu +Some drivers size their receive buffers based on whether a vlan +group is enabled, meaning that a maximum size packet with a vlan tag +will not fit if a vlan group is not configured. +. +.IP \(bu +On transmit some drivers expect that vlan acceleration will be used +if it is available (which can only be done if a vlan group is +configured). In these cases, the driver may fail to parse the packet +and correctly setup checksum offloading and/or TSO. . .SS "Client Mode" An \fBovs\-vlan\-test\fR client may be run on a host to check for VLAN -- 2.30.2