diff mbox series

[1/6] Better documentation of mcast_to_unicast option

Message ID 20200412235038.377692-2-rouca@debian.org
State Accepted
Delegated to: stephen hemminger
Headers show
Series iproute improve documentation of bridge | expand

Commit Message

=?UTF-8?q?Bastien=20Roucari=C3=A8s?= April 12, 2020, 11:50 p.m. UTC
From: Bastien Roucari├Ęs <rouca@debian.org>

This option is useful for Wifi bridge but need some tweak.

Document it from kernel patches documentation

Signed-off-by: Bastien Roucari├Ęs <rouca@debian.org>
---
 man/man8/bridge.8 | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Stephen Hemminger April 20, 2020, 4:43 p.m. UTC | #1
On Mon, 13 Apr 2020 01:50:33 +0200
roucaries.bastien@gmail.com wrote:

> +.BR mcast_to_unicast
> +works on top of the multicast snooping feature of
> +the bridge. Which means unicast copies are only delivered to hosts which
> +are interested in it and signalized this via IGMP/MLD reports
> +previously.
> +
> +This feature is intended for interface types which have a more reliable
> +and/or efficient way to deliver unicast packets than broadcast ones
> +(e.g. WiFi).
> +
> +However, it should only be enabled on interfaces where no IGMPv2/MLDv1
> +report suppression takes place. IGMP/MLD report suppression issue is usually
> +overcome by the network daemon (supplicant) enabling AP isolation and
> +by that separating all STAs.
> +
> +Delivery of STA-to-STA IP mulitcast is made possible again by
> +enabling and utilizing the bridge hairpin mode, which considers the
> +incoming port as a potential outgoing port, too (see
> +.B hairpin
> +option).

It probably doesn't make difference but seems like inconsistent usage
of Bold and BoldRoman macros

.B mcast_to_unicast
works on top of the multicast snooping feature of

.BR hairpin "option)."
diff mbox series

Patch

diff --git a/man/man8/bridge.8 b/man/man8/bridge.8
index b9bd6bc5..ff6f6f37 100644
--- a/man/man8/bridge.8
+++ b/man/man8/bridge.8
@@ -383,6 +383,32 @@  there is no MDB entry. By default this flag is on.
 Controls whether a given port will replicate packets using unicast
 instead of multicast. By default this flag is off.
 
+This is done by copying the packet per host and
+changing the multicast destination MAC to a unicast one accordingly.
+
+.BR mcast_to_unicast
+works on top of the multicast snooping feature of
+the bridge. Which means unicast copies are only delivered to hosts which
+are interested in it and signalized this via IGMP/MLD reports
+previously.
+
+This feature is intended for interface types which have a more reliable
+and/or efficient way to deliver unicast packets than broadcast ones
+(e.g. WiFi).
+
+However, it should only be enabled on interfaces where no IGMPv2/MLDv1
+report suppression takes place. IGMP/MLD report suppression issue is usually
+overcome by the network daemon (supplicant) enabling AP isolation and
+by that separating all STAs.
+
+Delivery of STA-to-STA IP mulitcast is made possible again by
+enabling and utilizing the bridge hairpin mode, which considers the
+incoming port as a potential outgoing port, too (see
+.B hairpin
+option).
+Hairpin mode is performed after multicast snooping, therefore leading to
+only deliver reports to STAs running a multicast router.
+
 .TP
 .BR "neigh_suppress on " or " neigh_suppress off "
 Controls whether neigh discovery (arp and nd) proxy and suppression is