From: Vadim Kochan <vadi...@gmail.com>
Add more explanation about VLAN reordering and what it affects.
Signed-off-by: Vadim Kochan <vadi...@gmail.com>
---
man/man8/ip-link.8.in | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
index df2fcce..b9137fb 100644
--- a/man/man8/ip-link.8.in
+++ b/man/man8/ip-link.8.in
@@ -313,7 +313,31 @@ the following additional arguments are supported:
- specifies the VLAN Identifer to use. Note that numbers with a leading " 0 "
or " 0x " are interpreted as octal or hexadeimal, respectively.
.BR reorder_hdr " { " on " | " off " } "
-- specifies whether ethernet headers are reordered or not.
+- specifies whether ethernet headers are reordered or not (default is
+.BR on ")."
+
+.in +4
+If
+.BR reorder_hdr " is " on
+then VLAN header will be not inserted immediately but only before passing to
the
+physical device (if this device does not support VLAN offloading), the similar
+on the RX direction - by default the packet will be untagged before being
+received by VLAN device. Reordering allows to accelerate tagging on egress and
+to hide VLAN header on ingress so the packet looks like regular Ethernet
packet,
+at the same time it might be confusing while the packet sniffing as the VLAN
header
+does not exist within the packet.
+
+VLAN offloading can be checked by
+.BR ethtool "(8):"
+.in +4
+.sp
+.B ethtool -k
+<phy_dev> |
+.RB grep " tx-vlan-offload"
+.sp
+.in -4
+where <phy_dev> is the physical device to which VLAN device is bound.
+.in -4
.BR gvrp " { " on " | " off " } "
- specifies whether this VLAN should be registered using GARP VLAN
Registration Protocol.
@@ -1065,7 +1089,8 @@ IEEE 802.15.4 device wpan0.
.SH SEE ALSO
.br
.BR ip (8),
-.BR ip-netns (8)
+.BR ip-netns (8),
+.BR ethtool (8)
.SH AUTHOR
Original Manpage by Michail Litvak <m...@owl.openwall.com>
--
2.4.2
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