Repository : ssh://git@diktynna/doc On branches: backup-redmine,main

commit 348bb2d322537016b1187ac6e45afc47915920fd Author: Linus Lüssing linus.luessing@c0d3.blue Date: Fri Apr 19 01:52:56 2024 +0000

doc: batman-adv/Multicast-optimizations

348bb2d322537016b1187ac6e45afc47915920fd batman-adv/Multicast-optimizations.textile | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/batman-adv/Multicast-optimizations.textile b/batman-adv/Multicast-optimizations.textile index 640e1487..8864f640 100644 --- a/batman-adv/Multicast-optimizations.textile +++ b/batman-adv/Multicast-optimizations.textile @@ -10,19 +10,25 @@ In the field observations revealed that a typical multicast session is actually

h2. Overview

-The current multicast optimizations in batman-adv provide a basic infrastructure for multicast awareness. So far, this basic optimization reduces overhead in the following two ways: +The current multicast optimizations in batman-adv provide a basic infrastructure for multicast awareness. So far, this optimization reduces overhead for IPv4/IPv6 packets through the following forwarding decisions:

-h3. Discards IPv4/IPv6 packets with no multicast listener +!batman-adv-multicast-type-decision.png! + +h3. 1) No multicast listener/router: Discard

!{width: 66%;}basic-multicast-no-receiver.png!

-batman-adv detects whether there are any potential IPv4/IPv6 multicast listeners interested in traffic to the given multicast destination address. If not then the packet is never forwarded into the mesh network. +batman-adv detects whether there are any potential IPv4/IPv6 multicast listeners or multicast routers interested in traffic to the given multicast destination address. If not then the packet is never forwarded into the mesh network. + +h3. 2) batman-adv multicast packet + +If all nodes support the [[Multicast-Packet-Type|batman-adv multicast packet]] and encapsulating the IP packet in it, with all its destination node entries included, would fit into a 1280 bytes frame (excluding outer ethernet frame header) then this packet type is chosen for forwarding.

-h3. Forwards IPv4/IPv6 packets with a some multicast listeners via unicasts +h3. 3) batman-adv unicast packet(s)

!{width: 66%;}basic-multicast-multiple-receivers.png!

-If there is an amount of multicast listeners smaller or equal to the (configurable) multicast-fanout parameter (default: 16) then the packet is forwarded via individual unicast transmissions. +If the batman-adv multicast packet type cannot be used and if there is an amount of interested multicast listeners/routers smaller or equal to the (configurable) multicast-fanout parameter (default: 16) then the packet is forwarded via individual unicast transmissions.

h3. Limitations