> Group multicast addresses are there i.e. mac address with the first bit
set
> to one. example: 11:22:33:44:55:66 is a group multicast address.
for details, look at tcp/ip illustrated(stevens n wright) pg 341.
> What I think is that there are no such thing as MAC multicast, correct
me
> if I am wrong , thanks. I think when MAC address of a packet with a
> multicast address is sent to a physical subnet, it should be
> FF:FF:FF:FF:FF:FF , ie. for all to receive.
this is a special case of multicast MAC address
> >I want to implement packet forwarding using MAC multicast. Basically,
what
> >I want to acheive is the following: a frontend machine accept packets
from
> >client side and forwards the packets to more than one backend machines.
You need to have hardware switching capability for best results. I guess u
probably have a data switch as ur frontend, with backends directly
connected to its different interfaces. Look into the switch manuals to
understand how to enable it to perform the hardware multicast forwarding.
If, instead, you have a regular multihomed host, I'd suggest following
choices:-
1. Use IP multicasting instead. Matter of fact I think that's the easiest
possibility.
2. Or maybe you have a single driver controlling all the interfaces. Then
this driver could have the added functionality to forward between these
interfaces based on the multicast MAC address. Normally such is not the
case. Drivers generally leave the forwarding capability to the network stack
or the hardware switch.
3. Use vlans. Let all your backends be on a single vlan. Broadcast to this
vlan.
Vivek.
--
*********************************************************
What is evil to thee does not subsist in the ruling principle of another;
nor yet in any turning and mutation of thy corporeal covering.
Where is it then? or is it really there?...it? what??
- Marcus Aurelius and Vivek in The Meditations and My Interpretations
:-)
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"atul" <atul.gupta@wipro.com> wrote in message
NHBBJCIOGDENKEIHCAJGEEJNCDAA.atul.gupta@wipro.com">news:NHBBJCIOGDENKEIHCAJGEEJNCDAA.atul.gupta@wipro.com...
> Group multicast addresses are there i.e. mac address with the first bit
set
> to one. example: 11:22:33:44:55:66 is a group multicast address.
> To send the packet to more than one backend machines (which are hidden
from
> client either through router/server frontend machine in your case) you
have
> to run some application at your frontend machine which can retrieve the
> header information from the client and forwards the packet to all machines
> in any particular group.
> You can take some idea how ARP packets are sent, ARP cache is built.
> -----Original Message-----
> From: linux-net-owner@vger.kernel.org
> [mailto:linux-net-owner@vger.kernel.org]On Behalf Of Tace
> Sent: Thursday, May 15, 2003 5:56 PM
> To: linux-net@vger.kernel.org; Ronghua Zhang
> Cc: kernelnewbies@nl.linux.org
> Subject: Re: packet forwarding using MAC multicast
>
>
> Hi,
> What I think is that there are no such thing as MAC multicast, correct
me
> if I am wrong , thanks. I think when MAC address of a packet with a
> multicast address is sent to a physical subnet, it should be
> FF:FF:FF:FF:FF:FF , ie. for all to receive.
>
> Tace
>
> On Thu, 15 May 2003 16:58:01
> Ronghua Zhang wrote:
> >I want to implement packet forwarding using MAC multicast. Basically,
what
> >I want to acheive is the following: a frontend machine accept packets
from
> >client side and forwards the packets to more than one backend machines.
> >The easiest way is simply forwarding packet once for each backend. But
> >this will consume too much bandwidth, that's why I resort to multicast.
> >But I have no idea how to let the MAC layer send a packet to a multicast
> >address, Anybody can shed some light on this? Thanks.
> >
> >ronghua
> >-
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> >
>
>
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