[Olsr-users] Olsr Multicast Streaming Question

[Erik Tromp]

>     destination: set to the "01:00:5e:" multicast address, 
>       instead of all-ones.

For BMF, this may or may not be a good idea. BMF uses (local, layer 2)
broadcast as underlying medium. Using "01:00:5e" as the first three bytes
in the Ethernet destination address may incorrectly trigger multicast
snooping/optimization algorithms of the layer 2 infrastructure equipment.


>  - If BMF sends out with source addresses of captured frames,
>    this is to be corrected. I think BMF uses tap tunnel (instead 
>    of tun). Using tun saves some bytes also.

BMF transparently encapsulates all packets. The receiver sees the originally
sent packet,
with the original source address.

BMF uses tun, not tap. See the function 'CreateLocalEtherTunTap' in
NetworkInterfaces.c

Best regards,
Erik
 

-----Oorspronkelijk bericht-----
Van: (spam-protected)
[mailto:(spam-protected)] Namens Teco Boot
Verzonden: woensdag 5 januari 2011 9:13
Aan: NaTo ClubSilom
CC: (spam-protected)
Onderwerp: Re: [Olsr-users] Olsr Multicast Streaming Question

Couple of remarks:
 - You use 224.0.0.1 multicast address. This is for link-local. 
   BMF supports forwarding such packets, but IMHO it is better
   to use a more appropriate address (such as 239.x.x.x)
 - I assume you use WLAN cards, in ad hoc mode. Then,
   NodeC and NodeD could receive packets from NodeA every now
   and then. Did you check this? (inspect olsr links)
 - On BMF and other multicast plugins: more cleanup is needed 
   on Ethernet address handling. The p2pd plugin has code for 
   setting correct addresses:
     source: the address of sending interface
     destination: set to the "01:00:5e:" multicast address, 
       instead of all-ones. (But I just saw the version in 
       stable repository has a bug, to be corrected soon).
       IP Broadcast packets should keep using all-ones.
 - If BMF sends out with source addresses of captured frames,
   this is to be corrected. I think BMF uses tap tunnel (instead 
   of tun). Using tun saves some bytes also.

Regards, Teco.


Op 4 jan 2011, om 17:53 heeft NaTo ClubSilom het volgende geschreven:

> Hello I'have a senior project in comscience major . The topic is about
performance measurements in olsr multicast network.
> 
> My Topology Have 4Node : NodeA : 192.168.1.1/24,NodeB : 
> 192.168.1.2/24,NodeC :192.168.1.3,NodeD :192.168.1.4
> 
> all Node is run on Ubuntu 10.04 and olsrd 0.6.1 with bmf 1.7.0
> 
> Topology looklike
>                                                     -   NodeC
>                                            -         
>                                     -   
> NodeA --------- NodeB 
>                                     - 
>                                            -
>                                                     -   NodeD
> 
> I use VLC for streaming multicast 224.0.0.1 from NodeA To NodeC and 
> NodeD via NodeB . I don't understand why stream packet arrived to NodeC
And NodeD have a source macaddress is NodeA not NodeB and port is vlc port
not bmf port.
> 
> Sorry I'm not good in english
> 
> Regards
> NaTo
> --
> Olsr-users mailing list
> (spam-protected)
> http://lists.olsr.org/mailman/listinfo/olsr-users


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