Remove an old bug item - this is not client only anymore.

Add a section describing how we "violate" the standard by allowing larger
MTUs and why this is a good thing.

share/man/man4/pppoe.4

@@ -1,4 +1,4 @@
-.\"	$NetBSD: pppoe.4,v 1.28 2004/12/08 18:33:32 peter Exp $
+.\"	$NetBSD: pppoe.4,v 1.29 2006/04/28 08:15:30 martin Exp $
 .\"
 .\" Copyright (c) 2002 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd October 1, 2003
+.Dd April 28, 2006
 .Dt PPPOE 4
 .Os
 .Sh NAME
@@ -299,9 +299,20 @@ The
 .Nm
 device appeared in
 .Nx 1.6 .
-.Sh BUGS
-This implementation is client side only.
+.Sh DEVIATIONS FROM STANDARD
+The PPPoE standard,
+.Li RFC2516 ,
+requires a maximal MTU of 1492 octets. This value is the maximum conservative
+value possible, based on the PPPoE header size and the minimum frame size
+ethernet interfaces are required to support.
 .Pp
+In practice most modern ethernet interfaces support bigger frames, and
+many PPPoE services allow the use of (slightly) larger MTUs, to avoid
+the problems described above.
+.Pp
+This implementation allows MTU values as large as possible with the actual
+MTU of the used ethernet interface.
+.Sh BUGS
 It is important to specify
 .Dq Li netmask 0xffffffff
 to