VLAN & Inter-VLAN Routing

Example: Create VLAN and set untagged or tagged VLAN member on the interface.
Topology :

Procedure :

Steps 1. Check IP interface before adding IP address to VLAN interface.

Caution:  IP address has to be removed from physical interface

admin@sonic:~$ show ip interfaces 
Interface    IPv4 address/mask    Admin/Oper
-----------  -------------------  ------------
Ethernet0    192.168.1.1/24       up/up
docker0      240.127.1.1/24       up/down
eth0         188.188.98.25/16     up/up
lo           127.0.0.1/8          up/up
             10.1.0.1/32
admin@sonic:~$ sudo config interface ip remove Ethernet0 192.168.1.1/24

i.e Since there is IP address on physical interface "Ethernet0",  we have to remove IP address from it.

Steps 2. Create VLAN1 and VLAN2 on the switch

admin@sonic:~$ sudo config vlan add 1       
admin@sonic:~$ sudo config vlan add 2

Steps 3. Let the Ethernet48 as VLAN1 untag member.

admin@sonic:~$ sudo config vlan member add -u 1 Ethernet48

Steps 4. Let the Ethernet52 as VLAN2 tag member.

admin@sonic:~$ sudo config vlan member add 2 Ethernet52

Caution: please make sure the port name is correct. Otherwise it does not work.

Since there's no warning messages for wrong command.

i.e use "show vlan brief" to double check above settings.

admin@sonic:~$ show vlan brief     
+-----------+----------------+------------+----------------+-----------------------+    
|   VLAN ID | IP Address     | Ports      | Port Tagging   | DHCP Helper Address   |    
+===========+================+============+================+=======================+    
|         1 |                | Ethernet48 | untagged       |                       |    
+-----------+----------------+------------+----------------+-----------------------+    
|         2 |                | Ethernet52 | tagged         |                       |    
+-----------+----------------+------------+----------------+-----------------------+

Example: Inter-VLAN routing 

Steps 1. Configure IP addresses on VLAN1 and VLAN2

admin@sonic:~$ sudo config interface ip add Vlan1 192.168.1.2/24       
admin@sonic:~$ sudo config interface ip add Vlan2 192.168.2.1/24

Caution: Vlan1 and Vlan2 are the Names of VLAN interface.   So, "V" must be capital.

Steps 2. Check the VLAN setting and IP addresses

admin@sonic:~$ show vlan brief     
+-----------+----------------+------------+----------------+-----------------------+    
|   VLAN ID | IP Address     | Ports      | Port Tagging   | DHCP Helper Address   |    
+===========+================+============+================+=======================+    
|         1 | 192.168.1.2/24 | Ethernet48 | untagged       |                       |    
+-----------+----------------+------------+----------------+-----------------------+    
|         2 | 192.168.2.1/24 | Ethernet52 | tagged         |                       |    
+-----------+----------------+------------+----------------+-----------------------+

admin@sonic:~$ show ip int 
Interface    IPv4 address/mask    Admin/Oper
-----------  -------------------  ------------
Vlan1        192.168.1.2/24       up/up
Vlan2        192.168.2.1/24       up/up
docker0      240.127.1.1/24       up/down
eth0         188.188.98.30/16     up/up
lo           127.0.0.1/8          up/up
             10.1.0.1/32

Steps 3. Check the native VLAN (PVID)

admin@sonic:~$ sudo bridge vlan 
port	vlan ids
docker0	 1 PVID Egress Untagged

Bridge	 1
	 2

dummy	 1 PVID Egress Untagged

Ethernet48	 1 PVID Egress Untagged

Ethernet52	 1 PVID Egress Untagged
	 2

Steps 4. Save the setting to config_db.json

admin@sonic:~$ sudo config save -y

Steps 5. Check VLAN setting on config_db.json

admin@sonic:/etc/sonic$ sudo vi config_db.json
{

    ...
    "VLAN": {
        "Vlan1": {
            "members": [
                "Ethernet48",
            ],
            "vlanid": "1"
        },
        "Vlan2": {
            "members": [
                "Ethernet52",
            ],
            "vlanid": "2"
        },        
    },
    "VLAN_MEMBER": {
        "Vlan1|Ethernet48": {
            "tagging_mode": "untagged"
        },
        "Vlan2|Ethernet52": {
            "tagging_mode": "tagged"
        }
    },
     "VLAN_INTERFACE": {
        "Vlan1|192.168.1.2/24": {},
        "Vlan2|192.168.2.1/24": {}
    },   
    ...
}