02-05-2008 02:27 AM - edited 03-05-2019 08:56 PM
I am having a problem with dot1q between a 6509 running CatOS 6.1, and a 3524XL.
Both sides are using vlan1 as the native vlan. The trunk ooks properly formed, and vlan pruning is also functioning properly.
I cannot ping form the 3524 to the default GW conigured on the switch. From a router in vlan 1, the arp entry for the IP configure on the switch shows incomplete. Using ISL everything works fine.
I am testing this 3524 using dot1q because I have a 2950 that supports only dot1q, and have the same problem with it.
Config:
#module 1 : 2-port 1000BaseX Supervisor
set udld enable 1/2
set trunk 1/1 on isl 1-1005,1025-4094
set trunk 1/2 nonegotiate dot1q 1-1005,1025-4094
interface GigabitEthernet0/2
switchport trunk encapsulation dot1q
switchport mode trunk
end
MilA3cat1> (enable) sh trunk 1/2
* - indicates vtp domain mismatch
Port Mode Encapsulation Status Native vlan
-------- ----------- ------------- ------------ -----------
1/2 nonegotiate dot1q trunking 1
Port Vlans allowed on trunk
-------- ---------------------------------------------------------------------
1/2 1-1005,1025-4094
Port Vlans allowed and active in management domain
-------- ---------------------------------------------------------------------
1/2 1-9,115,117,120,700
Port Vlans in spanning tree forwarding state and not pruned
-------- ---------------------------------------------------------------------
1/2 1,700
MilA3cat1> (enable)
mil1sw04#sh int gi 0/2 switchport
Name: Gi0/2
Switchport: Enabled
Administrative mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1-9,115,117,120,700
Pruning VLANs Enabled: 2-1001
Priority for untagged frames: 0
Override vlan tag priority: FALSE
Voice VLAN: none
Appliance trust: none
mil1sw04#
ISL trunks for fine.I am currently testing with a 3524 using dot1q
Any ideas?
Thanks,
Joe
02-11-2008 07:29 AM
If two switches are in different VTP domains and trunking is desired between them, you must configure the trunk mode as ON or NONEGOTIATE on both sides in order to allow the trunk to come up without DTP negotiation agreement. In other words, this setting forces the link to be a trunk link.
02-11-2008 07:50 AM
The trunk port on the Cat6509 side is already set to nonnegotiate.
The switches are in the same VTP domain as well.
The trunk seems to come up fine. It's just that I cannot access the IP configured for management, which is vlan 1.
04-21-2008 02:16 AM
Just in case someone stumbles across this.
Someone had configured:
set dot1q-all-tagged enable
on the 6509. This causes all native (untagged)packets to be dropped, so any communication over vlan 1, which is our management vlan, were dropped. This explains why all other vlan traffci was uneffected.
resolution is: set dot1q-all-teagged disable
which is the default.
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