19 Januari 2015

network interface booting sequence

Network technologies have advanced a lot. Cross UTP cable is just so ancient. I just knew that cross cable is not necessary to connect two computers via UTP cable directly. Plug it, set the network, and voila done.

However when there is a service that bind to the network address, a chaos occurs. Since the cable only powered when both the computer up, to establish client server set up, we must turn the client first and then the server. Thus when the service in the server up, it detects that network is already up, and set up the networking accordingly. My experience with the setup was with postgresql. When the server up, but without internet connection, the service will be up without support to the inactive network interface. Only after the connection is up and the postgresql is restarted, the service is correctly set up.

This problem can be easily tackled by adding a network device such as a hub. However turning on the client first will also do.

That is if we work with LAN, what about WLAN? To be frankly, I have no idea. WLAN controllers software often work in GUI level. Yes, you can definitely set it up on lower level. Meanwhile services usually boot first, so it must be trickier to arrange the sequence. I think it must be easier to plug a LAN cable to an infrastructure, and let the clients connect there :).