lunes, 28 de noviembre de 2011

Network in Nachos

Here we are going to show you a little introduction of how networking works in NachOS.

In Nachos we have two main classes: 
The network class
The postoffice class

Network

The network class is not directly used by the user. It is the Link between nachOS and sockets TCP/IP.
It has four methods:


  • Send: Sends a packet to a NachOS machine.
  • Receive: If there is a packet, it receives it. If not, it returns with a 0.
  • CheckPktAvail: It activates regularly to verify if a packet arrives.
  • SendDone: When it receives the packet, it calls a manager  in order to organize it.


For communication, NachOS uses PacketHeader and MailHeader.

They both contain:
To (Destination of the packet)
From (Origin of the packet)
Length (Size of the packet)

Postoffice


Example of postoffice

  • Sends a packet to a given address
  • Waits for a message and prints it once received
  • Sends another packet to the same address
  • Waits for a message and prints it once received


Now we are going to explain some other important files in the network folder and we are going to show you some code

  • nettest.cc  (nachos/code/network)


Here is where we run the routines of the network test.



  • post.h, post.cc  (nachos/code/network)


They help to synchronize the data sent and received. (like a messenger)

Here we show you some code 

Post.h


       Post.cc



  • network.h, network.cc (nachos/code/machine)


They are a physical network hardware emulation. 

Network.h


        Network.cc




References:


bit.ly/vtlhRr





1 comentario:

  1. Esto lo pongo como el +1 por contenido extra en el blog.

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