Re: serial-line protocols

[Raj Malhotra <ral.mal () gmail com>]

Hi, 

                                                                
----------------------------------
----------------------------------
|       ROUTER             | -------PPP fiber link---|     ROUTER              |
----------------------------------                               
                                                                 
----------------------------------
       |                      |
------------------           ------------------  
| switch       |          | switch       |
------------------           ------------------

We are not allowed to touch the left part of the diagram for any type
of deployment
due to policies. We can deploy only on the outgoing link which is PPP.
If we deploy any of the optical taps, the tap only splits the light
wave to give us a portion
of the raw data going on the link. Our NIDS has an ethernet interface
and hence we need
a protocol converter to convert from PPP to ethernet frames. 
How does the protocol converter detect the IP frames before it can
encapsulate it into
an ethernet frame and send out.

Raj