network device comes up only after 20s after command prompt shows up

Reproduction:
1. Boot with kvm -net,model=rtl8139 (i.e. with a RTL 8139 network card)
2. Wait for command prompt to appear
3. Do "ifconfig"
4. Wait 10-20 seconds
5. A red line will show up (by itself) saying that eth-pci(0,3,0) got available.
6. Do "ifconfig" again

Actual result:
In step 3, only the looback interface is shown. Trying to set up the interface will (most likely) fail, too.
In step 6, in addition to the loopback interface, the interface eth-pci(0,3,0) shows up, as not configured.

Expected result:
The interface is there right after boot, when the commandline interface shows up (in fact, even when jnode.ini runs).
Step 3 shows the same result as step 6.

Importance:
Will probably prevent to configure the interface in jnode.ini.

Additional comments:
lsantha thinks that this is caused by DHCP.