Classifying Frames to a VLAN

As per the IEEE standards, rules are defined for classifying the frames in a VLAN. VLAN classification is accomplished by associating a VLAN ID with each port on the switch. Optionally, frames can be classified according to the protocol identifier contained within the frame. Frame classification priority begins with a VLAN Tag, followed by MAC-based, protocol-based, and finally port-based classification, where the VLAN is recognized by the port VLAN Identifier (PVID). The device supports port-based and protocol-based classification.

Port-Based Classification

For port-based (or PVID-based) classification of frames, the following prerequisites must be met:

VLAN must be configured (in the configuration below, this is VLAN 4)
PVID for the interfaces must be configured
Acceptable frame types must be configured.

Port-based classification requires the association of a specific VLAN ID—the port VLAN Identifier (PVID)—with each port. In port-based classification, the VLAN ID associated with an untagged or priority-tagged frame is determined based on the port on which the frame arrives.

Note:

A port can be a member of only one port-based VLAN.

Note:

If PVID value has not been explicitly configured for a port, PVID assumes a default value of 1.

Execute the following commands to configure PVID for interface P5 as VLAN 4.
perform the following:
- Enter the Global Configuration Mode.
```
iS5comm# configure terminal
```
- Enter the Interface Configuration Mode for port gigabitethernet 0/5.
```
iS5comm(config)# interface gigabitethernet 0/5
```
- Configure the PVID that is to be assigned to untagged / priority-tagged frames.
```
iS5comm(config-if)# switchport pvid 4
```
- Exit from the Interface Configuration Mode
```
iS5comm(config-if)# end
```

Review the VLAN-related configuration.

iS5comm# show vlan id 4

Vlan database

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

Vlan ID             : 4

Member Ports        : Gi0/1, Gi0/2, Gi0/3, Gi0/4

Untagged Ports      : None

Forbidden Ports     : None

Name                :

Status              : Permanent

Egress Ethertype    : 0x8100

Service Loopback Status   : Disabled----------------------------------------------------

View the VLAN port configuration table of Port Gi0/5 by executing the following show command.

perform the following:

iS5comm# show vlan port config port gigabitethernet 0/5

Vlan Port configuration table

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

Port Gi0/5

Bridge Port Type                    : Customer Bridge Port

Port Vlan ID                        : 4

Port Acceptable Frame Type          : Admit All

Port Mac Learning Status            : Enabled

Port Ingress Filtering              : Enabled

Port Mode                           : Hybrid

Port Gvrp Status                    : Enabled

Port Gmrp Status                    : Enabled

Port Gvrp Failed Registrations      : 0

Gvrp last pdu origin                : 00:00:00:00:00:00

Port Restricted Vlan Registration   : Disabled

Port Restricted Group Registration  : Disabled

Mac Based Support                   : Disabled

Subnet Based Support                : Disabled

Port-and-Protocol Based Support     : Enabled

Default Priority                    : 0

Filtering Utility Criteria          : Default

Port Protected Status               : Disabled

Ingress EtherType                   : 0x8100

Egress EtherType                    : 0x8100

Egress TPID Type                    : Portbased

Allowable TPID 1                    : 0x0

Allowable TPID 2                    : 0x0

Allowable TPID 3                    : 0x0

Reflection Status                   : Disabled

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

Unicast packets should only reach host B as a tagged VLAN 4 packet (see above the Port Vlan ID shown as 4)that is sent by host A.

Port and Protocol-Based Classification

Groups of protocols can be defined and then bound to a port. After the protocol group is bound to a port, every packet originating from a protocol in the group is mapped to a VLAN that is configured in the protocol-based groups. Then, all tagged and untagged frames will be forwarded based on the protocol-to-VLAN mapping.

Execute the following commands to configure protocol-based VLAN classification.
perform the following:
- Enter the Global Configuration Mode.
```
iS5comm# configure terminal
```
- Define a group ID for a specific encapsulation and protocol value combination.
```
iS5comm(config)# map protocol ip enet-v2 protocols-group 10
```
Note: ip stands for an Ethernet V2 frame that has an IPv4 packet. The protocol number is 0x0800.

Note: enet-v2 stands for the standard IEEE 802.3 frame format.
- Exit from the Interface Configuration Mode
```
iS5comm(config)# exit
```

View the configuration details by executing the following show command.

perform the following:

show vlan protocols-group

Protocol Group Table

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

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

Frame Type      Protocol             Group

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

Enet-v2         IP                 10

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

Map the protocol group 10 to the VLAN identifier 4 and to the specified interface Gi0/7.
perform the following:
- Enter the Global Configuration Mode.
```
iS5comm# configure terminal
```
- Go to port interface gigabitethernet 0/7.
```
iS5comm(config)# interface gigabitethernet 0/7
```
```
iS5comm(config-if)# switchport map protocols-group 10 vlan 4
```
Note:
In this example, the interface GI0/7 is assigned to protocol-based group 10 which is mapped to VLAN 4.
```
iS5comm(config)# exit
```
```
iS5comm# show protocol-vlan
```
```
Port Protocol Table
```
```
--------------------------------------
```
```
Port           Group          Vlan ID
```
```
--------------------------------------
```
```
Gi0/7          10             4
```
```
--------------------------------------
```
Note:
From the above shown Port protocol table, we can see that the IP packets received on the interface GI0/ 7 have VLAN ID of 4.