Hello Hari, 
In case of device that has 2 logical ports, port-1 with vlan_id=0 and port-2 with vlan_id=3

using vif --list give me followed output:


Vrouter Interface Table

Flags: P=Policy, X=Cross Connect, S=Service Chain, Mr=Receive Mirror
       Mt=Transmit Mirror, Tc=Transmit Checksum Offload, L3=Layer 3, L2=Layer 2
       D=DHCP, Vp=Vhost Physical, Pr=Promiscuous, Vnt=Native Vlan Tagged
       Mnp=No MAC Proxy

vif0/0      OS: sproute0 (Speed 10, Duplex 1)
            Type:Physical HWaddr:00:00:00:00:00:00 IPaddr:0
            Vrf:0 Flags:L3L2Vp MTU:1514 Ref:3
            RX packets:299  bytes:109103 errors:0
            TX packets:683  bytes:498998 errors:0

vif0/1      OS: vhost0
            Type:Host HWaddr:08:00:27:01:02:03 IPaddr:0
            Vrf:0 Flags:L3L2 MTU:1514 Ref:3
            RX packets:679  bytes:508336 errors:0
            TX packets:299  bytes:109103 errors:0

vif0/2      OS: pkt0
            Type:Agent HWaddr:00:00:5e:00:01:00 IPaddr:0
            Vrf:65535 Flags:L3 MTU:1514 Ref:2
            RX packets:5  bytes:350 errors:0
            TX packets:1  bytes:70 errors:0

vif0/3      OS: veth_wan (Speed 10000, Duplex 1)
            Type:Physical HWaddr:aa:35:41:da:e0:59 IPaddr:0
            Vrf:0 Flags:TcL3L2Vnt MTU:1514 Ref:3
            RX packets:1  bytes:42 errors:0
            TX packets:1  bytes:42 errors:0

vif0/4      OS: port-1 (Speed 65535, Duplex 255)
            Type:Physical HWaddr:00:90:0b:3a:dc:58 IPaddr:0
            Vrf:0 Flags:L3L2Vnt MTU:1514 Ref:3
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/5      OS: port-2 (Speed 65535, Duplex 255)
            Type:Physical HWaddr:00:90:0b:3a:dc:59 IPaddr:0
            Vrf:0 Flags:L3L2Vnt MTU:1514 Ref:3
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/6      OS: port-3 (Speed 65535, Duplex 255)
            Type:Physical HWaddr:00:90:0b:3a:dc:5a IPaddr:0
            Vrf:0 Flags:L3L2Vnt MTU:1514 Ref:2
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/7      OS: port-4 (Speed 65535, Duplex 255)
            Type:Physical HWaddr:00:90:0b:3a:dc:5b IPaddr:0
            Vrf:0 Flags:L3L2Vnt MTU:1514 Ref:2
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/8      OS: NULL Vlan(o/i)(,S): 0/0 Bridge Index: 0 Parent:vif0/3
            Type:Virtual(Vlan) HWaddr:aa:35:41:da:e0:59 IPaddr:0
            Vrf:1 Flags:PL3L2Mnp MTU:1514 Ref:7
            RX packets:1  bytes:42 errors:0
            TX packets:1  bytes:42 errors:0

vif0/10     OS: NULL Vlan(o/i)(,S): 0/0 Bridge Index: 0 Parent:vif0/4
            Type:Virtual(Vlan) HWaddr:00:90:0b:3a:dc:58 IPaddr:0
            Vrf:2 Flags:PL3L2Mnp MTU:1514 Ref:1
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/12     OS: NULL Vlan(o/i)(,S): 3/3 Bridge Index: 0 Parent:vif0/5
            Type:Virtual(Vlan) HWaddr:00:90:0b:3a:dc:59 IPaddr:0
            Vrf:3 Flags:PL3L2Mnp MTU:1514 Ref:6
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/4350   OS: pkt3
            Type:Stats HWaddr:00:00:00:00:00:00 IPaddr:0
            Vrf:65535 Flags:L3L2 MTU:9136 Ref:1
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0

vif0/4351   OS: pkt1
            Type:Stats HWaddr:00:00:00:00:00:00 IPaddr:0
            Vrf:65535 Flags:L3L2 MTU:9136 Ref:1
            RX packets:0  bytes:0 errors:0
            TX packets:0  bytes:0 errors:0


--------------------------------------

So that looks to 
vif0/12 is logic interface for vif0/5 (port-2) with vlan_id=3
vif0/10 is logic interface for vif0/4 (port-1) with vlan_id=0

next is that I can use vif0/10 with vlan_id=0 correctly (with no interface modification) because vlan_id=0, 
as  a second step I was created logical interface with wlan_id=3 eth0.3 and vconfig add eth0 3.
using this interface I am unable to get any IP address or even connectivity