# How to set a point-to-point connection

## bogdancalin

Hello,

I have the next situation: I have to send data between 2 branches using 2 Linux servers and a point to point connection (fiber of satellite).

The issue is that the data (IP packages between these 2 locations) is bigger than the bandwidth existing and I need to "cut" the IP header between these 2 servers.

Can anyone help me with this?

Many thanks,

Bogdan.

----------

## Kingmilo

I'm not sure I understand your question, but I use rsync to send data between 2 linux servers.. .

----------

## erik258

 *Quote:*   

> The issue is that the data (IP packages between these 2 locations) is bigger than the bandwidth existing and I need to "cut" the IP header between these 2 servers. 

 

I'm not sure I understand either.  If I do understand, when you say 'bandwidth' you actually mean MTU, right?  Your packets are too big to be transmitted over the P-to-P?  This is distinct from the bandwidth of the conneciton - which is probably quite high if the connection is useful for connecting servers.  Bandwidth is the sum of the information in all of those packets per unit time; in other words bytes per second.  The maximum size of each of these individual packets - including the headers and such - is defined by the MTU (maximum transmission unit) or the MSS (maximum segment size).  

You can't cut anything off an IP header, not without changing the internet protocol.  But you don't need to.  You just need to tell the endpoints of the P-to-P not to send too big of packets through.  The endpoints will then deal with fragmenting the packets - splitting them up between multiple packets, which decreases the amount of data in the packet, not the size of the header.  

If that sounds right to you, you can learn how it can be done with iptables at http://lartc.org/howto/lartc.cookbook.mtu-mss.html  This configuration is used often for DSL connections which also often have an MTU smaller than the standard ethernet MTU of 1500.  I have a feeling it will also work perfectly for you.

----------

## bogdancalin

Hi,

I need to send 16 E1 over 2 MB (that means a compression of 16:1). I use G723 voice codec but the big issue is the IP Header which takes in this case most of the IP packet size. Each packet contains info of 20-50 ms of voice and it need to be send in real time.

I'm not so good in Linux, but I start to learn.

Do you consider that virtual serial connection or a connection where the IP Header to be insignificant comparable with IP data can be realized between the 2 servers? I need from 2MB up to 10MB p-t-p connection.

Many thanks again,

Bogdan.

----------

## John R. Graham

If I'm understanding you correctly, you're asking whether you can force an IP network that is not under your control to not use IP protocols, or to use a modified version of the IP protocol.  That's not possible.

You're best bet is to combine your smaller packets into larger ones so that the header overhead is less.  Of course, this means that the audio you're trying to deliver will be more than 20-50ms off of real time, but that's the tradeoff.

If I've misunderstood you, please clarify.

- John

----------

