Re: [DLC]Multicast

Scott,

  Typically when you look at multicast you are looking at the routers
(unless the switch is handling IGMP), the switch typically treat
multi-cast traffic as if were a broadcast.  The Ethernet card is just
handing off the information to the kernel which determines how to
handle the data.

--
Matthew P Kemp



On Mon, Mar 15, 2010 at 1:50 PM, Scott Behrens <[email protected]> wrote:
> I should note I have a more firm understanding from the Switch level.
>
> On Mon, Mar 15, 2010 at 1:40 PM, Scott Behrens <[email protected]> wrote:
>> Matthew,
>>
>> What I am trying to do is just work with multicast from the bottom up.
>>  What happens when the application tries to listen to a multicast
>> address?  What does the linux do with the request?  What does the NIC
>> do once the application tries to join the multicast group?  The
>> switch?
>>
>> I work in the finance industry and one of our clients is using a
>> custom developed multicast tool to do trading.  I want to make sure I
>> got a firm understanding of this in order to facilitate support.
>>
>> Thanks,
>>
>> Scott Behrens
>>
>> On Mon, Mar 15, 2010 at 1:33 PM, Matthew P Kemp
>> <[email protected]> wrote:
>>> Scott,
>>>
>>>  I guess I am trying to understand what you are expecting from the
>>> kernel in regards to multi-casting?  A user space program joins a
>>> multi-cast group, and the appropriate information is sent to the user
>>> space program.  I have written a couple multi-cast applications for
>>> *nix and windows.  Do you have a specific problem you are trying to
>>> troubleshoot, or are you attempting to write a program?
>>>
>>> A couple of links:
>>>
>>> <http://andrew.triumf.ca/pub/linux/multicast-FAQ>
>>> <http://tldp.org/HOWTO/Multicast-HOWTO-6.html>
>>>
>>> --
>>> Matthew P Kemp
>>>
>>>
>>>
>>> On Mon, Mar 15, 2010 at 12:14 PM, Scott Behrens <[email protected]> wrote:
>>>> Guys,
>>>>
>>>> I'm doing general multicast research.  I'm hitting alot of roadblocks
>>>> and I'm not sure where to go for information.  Many of the articles I
>>>> have found our so outdated, that I don't know if the information is
>>>> relative anymore.  I really am trying to nail down on Linux when an
>>>> application tries to listen to a multicast address and what happens on
>>>> the kernel level.  If anyone has good information or even an answer to
>>>> that question please let me know.
>>>>
>>>> Thanks in advance,
>>>>
>>>> Scott Behrens
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