Multiple VLANs on the Same Port on Cisco Catalyst 3508G XL Aggregation Switch

[selahattin_cilek]

On my old Catalyst 2508G-XL, I am trying to achive this:

Ports 1-2 -> Port Group 1, Trunked with a newer HP Switch

Ports 3-4 -> Port Group 2, Trunked with a newer HP Switch

Port 6-7-8 -> Port Group 3, Trunked with pfSense Router (Load Balanced LAGG, VLAN 1 - VLAN 2)

This is my configuration:

3508G-XL#show running-config
Building configuration...

Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname 3508G-XL
!
enable secret 5 ***************************************
!
!
!
!
!
!
ip subnet-zero
ip name-server 192.168.0.1
!
!
!
interface GigabitEthernet0/1
 port group 1 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/2
 port group 1 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/3
 port group 2 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/4
 port group 2 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/5
 switchport trunk allowed vlan 1,2,1002-1005
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/6
 port group 3 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/7
 port group 3 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface GigabitEthernet0/8
 port group 3 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable
!
interface VLAN1
 ip address 192.168.0.3 255.255.252.0
 no ip directed-broadcast
 no ip route-cache
!
ip default-gateway 192.168.0.1
no cdp run
snmp-server engineID local 000000090200000AF4E6AC80
snmp-server community private RW
snmp-server community public RO
!
line con 0
 transport input none
 stopbits 1
 speed 115200
line vty 0 4
 login
 transport input none
line vty 5 15
 login
 transport input none
!
end

Here is my problem:

I have an old Lenovo T400 laptop. Its Intel 82567LM Ethernet card supports VLAN tagging. And there are two VLANs defined: VLAN 1, VLAN 2.

VLAN 1 address -> 192.168.0.2/22

VLAN 2 address -> 10.0.0.2/8

I want to connect this laptop to Port 5 on the switch. I want both VLANs to work on the same port so that I can use this laptop for multiple purposes.

How should I configure Port 5 so that the Lenovo T400 can communicate on both VLANs?

[selahattin_cilek]

After a lot of trial&error, I finally got it to work!

It seems putting the port in access mode will not do the trick. What needs to be done is to put it in trunk mode:

interface GigabitEthernet0/5
 port group 4 distribution destination
 switchport trunk encapsulation dot1q
 switchport mode trunk
 no cdp enable

This is identical to the configuration of the other ports exccept for the port group number.

I also had to configure the laptop's Intel card:

VLAN_MAIN -> Untagged

VLAN_INFO -> ID 2

Now it works like a charm.

[Seb Rupik]

Hi there,

Since you do not have a port-channel to your laptop you can lose the port group command. Also you should specifify the VLANs you want to trunk to the laptop. The switchport should look like this:

!
interface GigabitEthernet0/5
  switchport trunk encapsulation dot1q
  switchport trunk allowed vlan 1,2
  switchport mode trunk
  no cdp enable
!

cheers,

seb.

[selahattin_cilek]

Thank you very. I'll give that a try and keep you informed.

But what do you mean by "your laptop you can lose the port group command"? What can go wrong with the current configuration?

[selahattin_cilek]

That worked too. But this time, when I tried to ping my laptop's DHCP-assingned IP, I got this:

# ping -S 192.168.0.1 192.168.0.109
PING 192.168.0.109 (192.168.0.109) from 192.168.0.1: 56 data bytes
64 bytes from 192.168.0.109: icmp_seq=0 ttl=128 time=0.298 ms
64 bytes from 192.168.0.109: icmp_seq=0 ttl=255 time=1.100 ms (DUP!)
64 bytes from 192.168.0.109: icmp_seq=1 ttl=128 time=0.191 ms
64 bytes from 192.168.0.109: icmp_seq=1 ttl=255 time=1.037 ms (DUP!)
64 bytes from 192.168.0.109: icmp_seq=2 ttl=128 time=0.200 ms
64 bytes from 192.168.0.109: icmp_seq=2 ttl=255 time=1.059 ms (DUP!)
64 bytes from 192.168.0.109: icmp_seq=3 ttl=128 time=0.198 ms
64 bytes from 192.168.0.109: icmp_seq=3 ttl=255 time=1.042 ms (DUP!)
64 bytes from 192.168.0.109: icmp_seq=4 ttl=128 time=0.233 ms
64 bytes from 192.168.0.109: icmp_seq=4 ttl=255 time=1.065 ms (DUP!)
64 bytes from 192.168.0.109: icmp_seq=5 ttl=128 time=0.206 ms
64 bytes from 192.168.0.109: icmp_seq=5 ttl=255 time=1.033 ms (DUP!)
^C

That did not happen with the previous configuration.

And it does not happen with the other DHCP-assigned IP:

# ping -S 10.0.0.1 10.0.0.4
PING 10.0.0.4 (10.0.0.4) from 10.0.0.1: 56 data bytes
64 bytes from 10.0.0.4: icmp_seq=0 ttl=128 time=0.235 ms
64 bytes from 10.0.0.4: icmp_seq=1 ttl=128 time=0.244 ms
64 bytes from 10.0.0.4: icmp_seq=2 ttl=128 time=0.244 ms
64 bytes from 10.0.0.4: icmp_seq=3 ttl=128 time=0.225 ms
64 bytes from 10.0.0.4: icmp_seq=4 ttl=128 time=0.235 ms
64 bytes from 10.0.0.4: icmp_seq=5 ttl=128 time=0.252 ms
64 bytes from 10.0.0.4: icmp_seq=6 ttl=128 time=0.249 ms 
...

What is happening?