killertop ~ # lsmod | egrep 'sky|8021q'
8021q                  16129  0 
sky2                   46950  0 
killertop ~ # vconfig set_name_type VLAN_PLUS_VID_NO_PAD
Set name-type for VLAN subsystem. Should be visible in /proc/net/vlan/config
killertop ~ # vconfig add eth0 100
Added VLAN with VID == 100 to IF -:eth0:-
killertop ~ # ip a a 10.191.251.251/24 dev vlan100
killertop ~ # ip a l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:21:9b:ee:ee:94 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::221:9bff:feee:ee94/64 scope link 
       valid_lft forever preferred_lft forever
7: vlan100@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
    link/ether 00:21:9b:ee:ee:94 brd ff:ff:ff:ff:ff:ff
    inet 169.254.86.184/16 brd 169.254.255.255 scope global vlan100
    inet 10.191.251.251/24 scope global vlan100
    inet6 fe80::221:9bff:feee:ee94/64 scope link 
       valid_lft forever preferred_lft forever
killertop ~ # ping 10.191.251.1
PING 10.191.251.1 (10.191.251.1) 56(84) bytes of data.
From 10.191.251.251 icmp_seq=2 Destination Host Unreachable
From 10.191.251.251 icmp_seq=3 Destination Host Unreachable
From 10.191.251.251 icmp_seq=4 Destination Host Unreachable
From 10.191.251.251 icmp_seq=6 Destination Host Unreachable
From 10.191.251.251 icmp_seq=7 Destination Host Unreachable
From 10.191.251.251 icmp_seq=8 Destination Host Unreachable
From 10.191.251.251 icmp_seq=10 Destination Host Unreachable
From 10.191.251.251 icmp_seq=11 Destination Host Unreachable
From 10.191.251.251 icmp_seq=12 Destination Host Unreachable
From 10.191.251.251 icmp_seq=14 Destination Host Unreachable
From 10.191.251.251 icmp_seq=15 Destination Host Unreachable
From 10.191.251.251 icmp_seq=16 Destination Host Unreachable