[Olsr-dev] Rounting

[fboehm]

Hi Scolfield,

I don't think your question is stupid and your considerations are quite 
helpful in understanding IP networking basics.

OLSR runs as a daemon and it only processes OLSR messages coming in on a 
specific port. This means this process is listening to this port. But 
the OLSR daemon only manipulates the IP routing table in the network 
subsystem (netfilter) of the Linux kernel according to the information 
in the OLSR messages and some additional calculations (the routing 
algorithm). But the OLSR daemon doesn't handle any user traffic.

The forwarding (routing) of the network traffic is done by the network 
subsystem (netfilter) where all the routes come into play that the OLSR 
daemon created modified or deleted.

Regards,
Franz


Am 2011-05-17 01:34, schrieb scolfield:
> Hello again,
>
> My question may be a little or very stupid. Consider below packet:
>
> ------ -------- ---------------------------
> | IP | UDP | OLSR Messages |
> ------ -------- ---------------------------
>
> The OLSR messages came from 698 port number and so, OLSR daemon begin 
> processing this
> messages. My first question is, can I affirm that the OLSR daemon is a 
> protocol that
> belongs a application layer? Because it is started as daemon and not 
> loaded as kernel
> module. I know that the OLSR is a routing protocol that determine 
> which is a better path
> from origin to destine. And so, the data user application can flow on 
> this better path.
>
> My second question is, consider the data user application over TCP. 
> The packet format is:
>
> ------ -------- ---------------------------------
> | IP | TCP | User Data Application |
> ------ -------- ---------------------------------
>
> OLSR evaluate the IP header and detect that protocol and destine port 
> is different of UDP/698?
> So, OLSR will not process and simply look at the routing table, look 
> the next hope and forward it?
> It is OLSR protocol that perform this?
>
> User Data Application                                             
>   User Data Application
>           ||                                                           
>                       ||
>           \/                                                           
>                      \/
>     TCP/UDP                                                           
>           TCP/UDP
>           ||                                                           
>                       ||
>           \/                                                           
>                      \/
>          IP                                                           
>                      IP
>           ||                                                           
>                       ||
>      MAC/PHY                                                           
>          MAC/PHY
>           ------------------------------ Routers with OLSR 
> ----------------------------
>
> In computer networks lessons, the basic that we learn is that routers 
> may only to see for
> until layer 3, and not above it. But, the OLSR utilize the UDP 
> protocol, and this confused me.
>
> Can anyone "to remove" my doubts (questions)? I know that my questions 
> maybe is a
> little strangers. But, please, I would like to considers my questions.
>
> Thanks for any help,
> --
> scolfield
>
>
>


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