Add a section about RSTP support.

1 files changed, 33 insertions, 17 deletions

diff --git a/share/man/man4/if_bridge.4 b/share/man/man4/if_bridge.4
index 23090f9..5f222fe 100644
--- a/share/man/man4/if_bridge.4
+++ b/share/man/man4/if_bridge.4
@@ -35,7 +35,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 8, 2006
+.Dd January 20, 2007
 .Dt IF_BRIDGE 4
 .Os
 .Sh NAME
@@ -95,17 +95,6 @@ interfaces that are part of the bridge.
 For unicast traffic, the bridge learns which MAC addresses are associated
 with which interfaces and will forward the traffic selectively.
 .Pp
-The
-.Nm
-driver implements the IEEE 802.1D Spanning Tree protocol (STP).
-Spanning Tree is used to detect and remove loops in a network topology.
-The bridge can log STP port changes to
-.Xr syslog 3
-by enabling the
-.Va net.link.bridge.log_stp
-variable using
-.Xr sysctl 8 .
-.Pp
 All the bridged member interfaces need to be up in order to pass network traffic.
 These can be enabled using
 .Xr ifconfig 8
@@ -130,6 +119,32 @@ This can be used to multiplex the input of two or more interfaces into a single
 stream.
 This is useful for reconstructing the traffic for network taps
 that transmit the RX/TX signals out through two separate interfaces.
+.Sh SPANNING TREE
+The
+.Nm
+driver implements the Rapid Spanning Tree Protocol (RSTP or 802.1w) with
+backwards compatibility with the legacy Spanning Tree Protocol (STP).
+Spanning Tree is used to detect and remove loops in a network topology.
+.Pp
+RSTP provides faster spanning tree convergence than legacy STP, the protocol
+will exchange information with neighbouring switches to quickly transition to
+forwarding without creating loops.
+.Pp
+The code will default to RSTP mode but will downgrade any port connected to a
+legacy STP network so is fully backward compatible.
+A bridge can be forced to operate in STP mode without rapid state transitions
+via the
+.Va proto
+command in
+.Xr ifconfig 8 .
+.Pp
+The bridge can log STP port changes to
+.Xr syslog 3
+by enabling the
+.Va net.link.bridge.log_stp
+variable using
+.Xr sysctl 8 .
+.Pp
 .Sh PACKET FILTERING
 Packet filtering can be used with any firewall package that hooks in via the
 .Xr pfil 9
@@ -234,8 +249,8 @@ ifconfig_fxp0="up"
 .Ed
 .Pp
 Consider a system with two 4-port Ethernet boards.
-The following will cause a bridge consisting of all 8 ports with Spanning Tree
-enabled to be created:
+The following will cause a bridge consisting of all 8 ports with Rapid Spanning
+Tree enabled to be created:
 .Bd -literal -offset indent
 ifconfig bridge0 create
 ifconfig bridge0 \e
@@ -302,6 +317,10 @@ This version of the
 driver has been heavily modified from the original version by
 .An Jason R. Thorpe
 .Aq thorpej@wasabisystems.com .
+.Pp
+Rapid Spanning Tree Protocol (RSTP) support was added by
+.An Andrew Thompson
+.Aq thompsa@FreeBSD.org .
 .Sh BUGS
 The
 .Nm
@@ -310,6 +329,3 @@ network devices, with exactly the same interface MTU size as the bridge device.
 .Pp
 Only wireless interfaces in hostap mode can be bridged due to the 802.11
 framing format, bridging a wireless client is not supported yet.
-.Pp
-The bridge implements version IEEE 802.1D 1998 of the Spanning Tree Protocol so
-newer features in IEEE 802.1D 2004 such as RSTP are not available.