Multicasting Over Wireless

[hadas]

I m tryng multicast movie from my Desktop PC over Wireless ( Mikrotik RouterBord ) to my Laptop (Apple AirPort) but video discontinuous, over Ethernet works very well , where is problem

[Rémi Denis-Courmont]

802.11 is not suited for bulk multicast. There is no way to fix this, but to use unicast.

[popper]

wireless 802.11 IS perfectly fine with Bulk Multicast, were are you getting this wrong information from ?

given average connections, 11b can safely manage 6Mbit/s, 11g 15Mbit/s, and 11n well in and above the 36Mbit/s + that for instance DVB-*(2)H etc, uses to transmit a full transport stream of channels and related data, Rémi perhaps you could try writing a Multicast tunnel in line with the basic java Mtunnel http://www.cdt.luth.se/~peppar/progs/mTunnel/ for intigrated generic inclusion into VLC and extending its command line for said tunnel point to multipoint etc over the web IPv4/6 TCP/UDP, to help you get a FAR better understanding of multicast and its capabilitys......

hadas, you dont say what the bitrates or the levels or indeed any data refering to this content that plays fine over 100Mbit, but not good over 11,22,66+ Mbit/s generic ethernet packet UDP wireless....

[hadas]

My video bit rate is 2Mbps,
With Wireshark i grab packets on server and client, on client side received packets is about 60% than server transmit. Im trying with Linksys, Mikrotik AP's result same.

[Rémi Denis-Courmont]

wireless 802.11 IS perfectly fine with Bulk Multicast, were are you getting this wrong information from ?

Definitely not. First, packet loss is higher since retransmission is not possible to correct errors. Second many access points, especially the cheaper ones, have very limited bit rates for multicast.

[popper]

take your pick ......and impliment/retro fit it/them internally ASAP into the current VLC multicasting codebase then, they have been around for a very long time now, its way past time something was done to bring the old MBONE (Multicasting backBONE) tunnels etc back into current innovations, or are all the innovators no more.

http://www.nard.net/~tmont/rm-links.html
Last update: October 12, 1998

ftp://ftp.isi.edu/in-notes/rfc2354.txt
Options for Repair of Streaming Media
"....
3 Network Loss Characteristics

If it is desired to repair a media stream subject to packet loss, it
is useful to have some knowledge of the loss characteristics which
are likely to be encountered. A number of studies have been
conducted on the loss characteristics of the Mbone [2, 8, 21] and
although the results vary somewhat, the broad conclusion is clear:
in a large conference it is inevitable that some receivers will
experience packet loss. Packet traces taken by Handley [8] show a
session in which most receivers experience loss in the range 2-5%,
with a somewhat smaller number seeing significantly higher loss
rates. Other studies have presented broadly similar results.

It has also been shown that the vast majority of losses are of single
packets. Burst losses of two or more packets are around an order of
magnitude less frequent than single packet loss, although they do
occur more often than would be expected from a purely random process.

Longer burst losses (of the order of tens of packets) occur
infrequently. These results are consistent with a network where
small amounts of transient congestion cause the majority of packet
loss. In a few cases, a network link is found to be severely
......."