VLAN scenario

This scenario shows how to assign VLAN IDs to access and trunk interfaces for the following deployment:

In this scenario, VLANs are used to isolate the traffic from different devices.

VLAN 25 carries tagged and untagged traffic from computers connected to switch B.
VLAN 4 carries tagged traffic from computers connected to switch B.
VLAN 6 carries tagged and untagged traffic from computers connected to switch C.
VLAN 17 carries tagged traffic from computers connected to switch C.
VLAN 100 carries untagged traffic from the server.

Procedure

Execute the following commands on switch A and B.

Create VLANs 4 and 25.

switch# config
switch(config)# vlan 4,25

Define LAG 1 and assign the VLANs to it.

switch(config)# interface lag 1
switch(config-lag-if)# no shutdown
switch(config-lag-if)# no routing
switch(config-lag-if)# vlan trunk native 25
switch(config-lag-if)# vlan trunk allowed 4,25

Add ports 1/1/1 and 1/2/1 to LAG 1.

switch(config-lag-if)# interface 1/1/1
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1
switch(config-if)# interface 1/2/1
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1

Execute the following commands on switch A and C.

Create VLANs 6 and 17.

switch# config
switch(config)# vlan 6,17

Define LAG 3 and assign the VLANs to it.

switch(config)# interface lag 3
switch(config-lag-if)# no shutdown
switch(config-lag-if)# no routing
switch(config-lag-if)# vlan trunk native 6 tag
switch(config-lag-if)# vlan trunk allowed 6,17

Add ports 1/1/13 and 1/2/13 to LAG 3.

switch(config-lag-if)# interface 1/1/13
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 3
switch(config-if)# interface 1/2/13
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 3

Execute the following commands on switch A to configure the connection to the server.

Configure interface 1/2/13 as an access interface with VLAN ID set to 100.

switch# config
switch (config)# vlan 100
switch(config-vlan-100)# interface 1/2/32
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# vlan access 100
switch(config-if)# exit

Verify VLAN configuration by running the command show vlan. For example:

switch# show vlan

--------------------------------------------------------------------------------------------------------------
VLAN  Name                              Status  Reason                Type      Interfaces
--------------------------------------------------------------------------------------------------------------
1     DEFAULT_VLAN_1                    down    no_member_port        default
4     VLAN4                             up      ok                    static    lag1
6     VLAN6                             up      ok                    static    lag3
17    VLAN17                            up      ok                    static    lag3
25    VLAN25                            up      ok                    static    lag1
100   VLAN100                           up      ok                    static    1/2/32

Verify that the connection to the DHCP server is sending/receiving data with the command show interface. Check that the Rx and Tx fields are incrementing. For example:

switch# show interface 1/2/32
Interface 1/2/32 is up
 Admin state is up
 Description:
 Hardware: Ethernet, MAC Address: 70:72:cf:3a:8a:0b
 MTU 1500
 Type SFP+LR
 qos trust none
 Speed 10000 Mb/s
 Auto-Negotiation is off
 Input flow-control is off, output flow-control is off
 VLAN Mode: access
 Access VLAN: 100
 
 Rx
            20 input packets              1280 bytes
            0 input error                0 dropped
            0 CRC/FCS
 Tx
            9 output packets             1054 bytes
            0 input error                0 dropped
            0 collision

Verify LAG interface configuration with the command show interface. Check the fields admin state, MAC address, Aggregated-interfaces, VLAN Mode, Native VLAN, Allowed VLAN, Rx count, and Tx count. For example:

switch# show interface lag1
Aggregate-name lag1
 Description :
 Admin state           : up
 MAC Address           : 94:f1:28:21:63:00
 Aggregated-interfaces : 1/1/1 1/2/1
 Aggregation-key       : 1
 Speed 1000 Mb/s
 L3 Counters: Rx Disabled, Tx Disabled
 qos trust none
 VLAN Mode: native-untagged
 Native VLAN: 25
 Allowed VLAN List: 4,25
 Rx
            10 input packets              1280 bytes
            0 input error                0 dropped
            0 CRC/FCS
 Tx
            8 output packets             980 bytes
            0 input error                0 dropped
            0 collision

switch# show interface lag3
Aggregate-name lag3
 Description :
 Admin state           : up
 MAC Address           : 94:f1:28:21:63:00
 Aggregated-interfaces : 1/1/13 1/2/13
 Aggregation-key       : 3
 Speed 1000 Mb/s
 L3 Counters: Rx Disabled, Tx Disabled
 qos trust none
 VLAN Mode: native-tagged
 Native VLAN: 6
 Allowed VLAN List: 6,17
 Rx
            19 input packets              1280 bytes
            0 input error                0 dropped
            0 CRC/FCS
Tx
            15 output packets             1000 bytes
            0 input error                0 dropped
0	Collision

Verify the physical interfaces (1/1/1, 1/2/1, 1/1/13, 1/2/13) with the command show interface. Check that the Rx and Tx fields are incrementing. For example:

switch# show interface 1/1/1
Interface 1/1/1 is up
 Admin state is up
 Description:
 Hardware: Ethernet, MAC Address: 94:f1:28:21:73:ff
 MTU 1500
 Type SFP+LR
 qos trust none
 Speed 1000 Mb/s
 Auto-Negotiation is off
 Input flow-control is off, output flow-control is off
 Rx
            6 input packets              620 bytes
            0 input error                0 dropped
            0 CRC/FCS
 Tx
            4 output packets             422 bytes
            0 input error                0 dropped
0	collision