Re: Communicating with the domU from dom0 without Network

[Ligesh <xen@lxlabs.com>]

On Tue, Aug 08, 2006 at 03:56:56PM +0100, Keir Fraser wrote:
> 
> That's not how TCP/IP works and a statement like 'serial ports do not allow
> multiple simultaneous streams' is not true since a serial port is part of a
> physical link layer so you can implement whatever protocol you like over the
> top (just as you can with e.g. an Ethernet port).
> 

 You have to build a network stack over serial port where every packet has a header with the destination port.  You can simulate the entire tcp/ip stack over the serial port, but this is again a non-trivial effort. What I meant was out-of-box, as in, you just do an open("/dev/ttyS0", "r"), and read and write, you won't get multiple connections; you will have to ensure the co-operation of the kernel, where it will have to create virtual network ports that will allow simultaneous connections to exist.

 Anyway, ultimately my proposal is that multi-stream message passing system that is not depended on the ip address would be highly desirable. You can actually implement it over the serial port or even the virtual network card itself--by using the mac addresses to identify the machines. This would make writing system management softwares much easier. Since the future seems to point at virtualization getting ubiquitous, this almost becomes a necessary feature.

--
:: Ligesh :: http://ligesh.com