6505/7609 Switchports Disappear

Unanswered Question
Jun 7th, 2007

Hello. We have a 7609 with VLAN204 (layer2 and a layer3 vlan interface: 192.168.100.1) with an access port in VLAN204 (g3/29: switchport access vlan 204). We also have a 6506 with a VLAN102 (layer2 and layer3 vlan interface: 192.168.100.148) with an access port in VLAN102 (g1/12: switchport access vlan 102). When we connect a CAT5 cable between g3/29 on the 7609 and g1/2 on the 6506, no IP connectivity exists between them (i.e. can't ping between the two). When doing a "show vlan", the access ports on both switches do NOT exist in their respective VLANs. If we unplug the cable, the ports reappears as access ports in the respective VLANs on the respective switches. We're running "vtp mode transparent" on both and on the 6506, we've got "no spanning-tree vlan 102"; we didn't do a "no spanning-tree 204" on the 7609... The port interfaces show the same Ethernet negotiation (1000/Fullduplex) and the in/out bytes match inversely on each unit. If we place a switch between them (in this case, a small Linksys 8-port), they come up, don't disappear from the VLANs and pass IP traffic between them. Any thoughts? It's reproducible and consistently behaves the same and does so on both units so I have to think it is by design, but if someone could shed light on "what" this design is, I'd be appreciative! -jess

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ycae Thu, 06/07/2007 - 21:50

Hi,

Are you sure that your port in in access mode? It could be that the port is in trunk desirable or trunk auto mode which would explain why the ports are disappearing from the vlan table.

Try to add the line on the ports:

switchport mode access

Yves

jessedupont307 Fri, 06/08/2007 - 06:42

Yves,

Thanks for the reply, I appreciate it. Here is the config for each port:

GigabitEthernet 1/12

Description (desc here)

no ip address

switchport

switchport access vlan (vlanid)

I will add the line you suggested and post after with results.

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