document auto-recognition of device capabilities

1 files changed, 8 insertions, 19 deletions

diff --git a/share/man/man4/vlan.4 b/share/man/man4/vlan.4
index cbd7074..d6157ef 100644
--- a/share/man/man4/vlan.4
+++ b/share/man/man4/vlan.4
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 25, 2001
+.Dd November 14, 2002
 .Dt VLAN 4
 .Os
 .Sh NAME
@@ -72,16 +72,8 @@ The
 .Nm
 driver supports physical devices that do
 the VLAN demultiplexing in firmware.
-The
-.Cm link0
-flag should be set on a
-.Nm
-interface
-.Pq Em not on its parent
-using
-.Xr ifconfig 8
-in that case to indicate that hardware support for
-the 802.1Q VLANs is present in its parent.
+Devices that have hardware support for
+802.1Q VLANs are automatically recognized by their interface capabilities.
 .\"
 .Ss "Selecting the Right Network Interface Card to Run VLANs Through"
 By now, the only NICs that have both hardware support and proper
@@ -151,16 +143,13 @@ supports long frames only if the card is built on a newer chip
 (Cyclone and above).
 .El
 .Pp
-Note:
-Unless marked as having native support for
-.Nm ,
-the above drivers don't inform the
+The
 .Nm
-driver about their long frame handling capability.
-Just increase the MTU of a
+driver automatically recognizes devices that support oversized frames
+for
 .Nm
-interface if it appears to be lower than 1500 bytes after
-attaching to a parent known to support long frames.
+use and calculates the appropriate frame MTU based on the
+capabilities of the parent interface.
 .Sh SEE ALSO
 .Xr ifconfig 8
 .Sh BUGS