Repository : ssh://git@open-mesh.org/doc
On branches: backup-redmine/2019-09-17,master
commit 616a76bc8ac4e1f4add9211a5c562d569fd3a84d Author: Sven Eckelmann sven@narfation.org Date: Tue Sep 17 10:27:24 2019 +0000
doc: batman-adv/Multicast-optimizations-tech
616a76bc8ac4e1f4add9211a5c562d569fd3a84d batman-adv/Multicast-optimizations-tech.textile | 34 ++++++++++++------------- 1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/batman-adv/Multicast-optimizations-tech.textile b/batman-adv/Multicast-optimizations-tech.textile index 7d5da78..f534c53 100644 --- a/batman-adv/Multicast-optimizations-tech.textile +++ b/batman-adv/Multicast-optimizations-tech.textile @@ -2,7 +2,7 @@ h1. Multicast Optimizations – Technical Description
Prior Readings:
- * [[multicast-optimizations|Multicast Optimizations]] +* [[multicast-optimizations|Multicast Optimizations]]
h2. Multicast Listener Announcements
@@ -60,9 +60,9 @@ Optimization for IPv4 or IPv6 multicast packets is performed by considering a fe
If the total number of nodes interested in a group is:
- * ... 0, then this frame can be safely dropped. - * ... 1, then this frame is encapsulated in and forwarded via a batman-adv unicast packet to the according destination. - * > 1, then this frame is encapsulated in a batman-adv broadcast packet and forwarded via classic flooding to all nodes. +* ... 0, then this frame can be safely dropped. +* ... 1, then this frame is encapsulated in and forwarded via a batman-adv unicast packet to the according destination. +* > 1, then this frame is encapsulated in a batman-adv broadcast packet and forwarded via classic flooding to all nodes.
The latter case is the general fallback to broadcast, which is also used when the the multicast optimization is turned off.
@@ -99,22 +99,22 @@ batman-adv currently detects IPv6 multicast routers by searching for ff02::2 all
h2. Limitations
- * groups with more listeners (+routers) than #multicast-fanout (default: 16) don't get optimized - * optimization for routable IPv4 multicast in bridged scenarios is not supported yet - * optimization for link-local IPv4 (224.0.0.0/24) or all-nodes IPv6 multicast (ff02::1) is only done if no node announces BATADV_MCAST_WANT_ALL_UNSNOOPABLES, that is no node configures a bridge on batman-adv. - * no awareness for source-specific multicasts - * multcast packets over VLANs are always flooded +* groups with more listeners (+routers) than #multicast-fanout (default: 16) don't get optimized +* optimization for routable IPv4 multicast in bridged scenarios is not supported yet +* optimization for link-local IPv4 (224.0.0.0/24) or all-nodes IPv6 multicast (ff02::1) is only done if no node announces BATADV_MCAST_WANT_ALL_UNSNOOPABLES, that is no node configures a bridge on batman-adv. +* no awareness for source-specific multicasts +* multcast packets over VLANs are always flooded
h2. Next Steps / Roadmap
- * optimization for groups with two or more members: - ** many-to-some: implement batman-adv multicast packet type supporting a list of destination addresses (to reduce ICMPv6 overhead like Neighbor Solicitation Messages, Router Solicitation Messages, MLD Reports, ...) - ** some-to-many / streaming: implement path tracking and use these patches (see [[Multicast-ideas-updated]]) - * integrate bridge's "Multicast Router Discovery":https://tools.ietf.org/search/rfc4286 to properly support scopes greater than link-local - * implement some faster listener roaming mechanism for bridged in hosts (for instance announce (multicast-address, source address) pairs and use general TT roaming mechanism) - * implement source-specific multicast in Linux bridge and batman-adv - * multicast TT announcements and forwarding have to be performed per VLAN - * ... +* optimization for groups with two or more members: +** many-to-some: implement batman-adv multicast packet type supporting a list of destination addresses (to reduce ICMPv6 overhead like Neighbor Solicitation Messages, Router Solicitation Messages, MLD Reports, ...) +** some-to-many / streaming: implement path tracking and use these patches (see [[Multicast-ideas-updated]]) +* integrate bridge's "Multicast Router Discovery":https://tools.ietf.org/search/rfc4286 to properly support scopes greater than link-local +* implement some faster listener roaming mechanism for bridged in hosts (for instance announce (multicast-address, source address) pairs and use general TT roaming mechanism) +* implement source-specific multicast in Linux bridge and batman-adv +* multicast TT announcements and forwarding have to be performed per VLAN +* ...
h2. Further Readings