Switch Port Access

[Chetan Kumar]

Hi

Please refer the below Senario ,

Code: Select all

Switch 1 ------ Switchport mode access ----- Switch 2
    |                                            |
    |                                            |
PC1 in VLAN 2                              PC 2 in VLAN3

In this senario you ca see that PC 1 is configured in VLAN 2 & PC 2 is configured in VLAN3 & the cable that connect between Switch 1 & Switch 2 is configured as a Access Port.

Then can PC 1 communicate with PC 2 if they are in different VLAN.
If No then Why ?


Regards
Chetan Kumar

[j_blakley]

I would say YES. Here's why.

If you have a port on the edge (switch 1) configured as an access port, that automatically means that the traffic coming through that port is now untagged. It's native VLAN is now 2 on that port. When you put the uplink that connects to switch 2 as an access port on both ends, you've configured those as untagged as well, and the same thing goes for PC2 as an access port.

The only thing is that both computers would have to be on the same subnet. If they're on different subnets, then you'd need a router in between to route the vlans.

I tested this in GNS, and I can't get it to work. In theory it should work, but best practice anyway would be to have your switch interconnected links as trunk ports.


HTH,
John

[Chetan Kumar]

Hi

As per theroy it should work , But to get result we should test the same on praticle devices.
But Thanks for you reply.


Regards
Chetan Kumar

[Edison Ortiz]

With Cisco switches, you will receive Vlan mismatch messages with CDP but your design will work.

Theory put on practice:

Rack1SW2#sh ver | i IOS
Cisco IOS Software, C3560E Software (C3560E-UNIVERSALK9-M), Version 12.2(44)SE6, RELEASE SOFTWARE (fc1)

Rack1SW1#sh ver | i IOS
Cisco IOS Software, C3560E Software (C3560E-UNIVERSALK9-M), Version 12.2(44)SE6, RELEASE SOFTWARE (fc1)

On Switch 1
interface GigabitEthernet0/15
switchport access vlan 112
switchport mode access

interface Vlan112
ip address 1.1.1.1 255.255.255.0

On Switch 2
interface GigabitEthernet0/15
switchport access vlan 122
switchport mode access


interface Vlan122
ip address 1.1.1.2 255.255.255.0

Rack1SW2#ping 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/9 ms
Rack1SW2#
Rack7Pod1>1
[Resuming connection 1 to sw1 ... ]

*Mar 9 17:47:11.859: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/15 (112), with Rack1SW2 GigabitEthernet0/15 (122).
Rack1SW1#ping 1.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/8 ms
Rack1SW1#

[Chetan Kumar]

Hi Edison

Thanks for you an helpful explanation & sharing the praticle result.

So i was thinking correct , If i configured access port between both switches then it won't see the vlan tag ,Ir work with native vlan .
Different VLAN can communicate in mention senario.


Regards
Chetan Kumar