Dot1q Trunk from Cisco IOS  switch to Force10 S25

Posted on 2012-08-20
Last Modified: 2012-08-21
Dot1q Trunk from Cisco IOS  switch to Force10 S25

I am configuring a dot1q trunk from a Cisco IOS box to a Force10 S25. The trunk is meant to pass VLANs 101, 102, and 103 using VLAN 104 as the default VLAN for the trunk.

Cisco configuration:
Int fas0/16
Switchport trunk encapsulation dot1q
Switchport mode trunk
Dot1q native vlan 104
No shut

Force10 Configuration:
Int gi0/21
Portmode hybrid
Int vlan 104
Untag gi0/21
Int vlan 101
Tag gi0/21
Int vlan 102
Tag gi0/21
Int vlan 103
Tag gi0/21

Show int switchport    gives me
Name: GigabitEthernet 0/21
Description: XCON_CSS
802.1QTagged: Hybrid
Vlan membership:
Q       Vlans
U       104
T       101-103

Native VlanId:    104.

I see the expected mac addresses on VLANs 101,102,103 but cannot seem to get layer 3 traffic to pass through. Any hints ?

Question by:vbrick57
    LVL 6

    Expert Comment

    I don't know if you just omitted it, but the int gi0/21 and the int vlan command need a no shut after them.

    As far as layer 3 traffic goes, can you ping the subnets within each respective VLAN (Local Traffic)?


    Author Comment

    Thanks for the response - Yes the vlans are 'no shut' I forgot to include that in post. Regarding layer 3, there is no response whatsoever to a ping on any of the VLANs on the Force10 side to the subnets on the Cisco side.
    LVL 6

    Accepted Solution

    Can you ping anything on the default vlan? These should be untagged.


    Author Closing Comment

    Thanks for your help Sebastian. I discovered today that this is not an issue between Cisco and Force10. The trunks are working fine when I test directly off the Force10. Somewhere after than I am losing layer 3 connectivity. I will go through my configs and try to locate the problem.  Thanks for the quick thoughts!

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