binding to tap interface

[daggs]

Greetings,

after yet again another llbvirt which messed up my vms to the point that 
downgrade doesn't fixes it, I'm toying again with using scripts to setup and 
launch my vms.
my main problem in the past was the network.
my router is in side the vm, I need to bring up a virtual switch, connect the 
router and another vm to it and connect the host and the router vm.
all using tap interfaces.
here is what I setup:
dagg@NCC-5001D ~/workspace/virt_nix_scripts $ brctl show virt_switch
bridge name     bridge id               STP enabled     interfaces
virt_switch             8000.12c886c96cc5       no              vsw_router
                                                        vsw_streamer
dagg@NCC-5001D ~/workspace/virt_nix_scripts $ ip a
5: veth: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state 
DOWN group default qlen 1000
    link/ether 4e:13:0a:ec:01:b5 brd ff:ff:ff:ff:ff:ff
6: virt_switch: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc noop state DOWN group 
default qlen 1000
    link/ether 12:c8:86:c9:6c:c5 brd ff:ff:ff:ff:ff:ff
8: vsw_streamer: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast 
master virt_switch state DOWN group default qlen 1000
    link/ether 86:8f:a9:e5:a3:4d brd ff:ff:ff:ff:ff:ff
9: vsw_router: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast 
master virt_switch state DOWN group default qlen 1000
    link/ether 4a:a0:ea:44:8b:c6 brd ff:ff:ff:ff:ff:ff

and now I'm missing the proper nic config in the qemu line however I was never 
able to configure it properly.
what is the proper nic params?

Thanks,

Dagg.