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02-19-2019 03:54 AM - edited 03-08-2019 05:23 PM
I'm sorry if this has already been addressed, but I couldn't find an answer to my question.
I have a pretty standard setup: a few subinterfaces on a router connected to a trunk port on a switch (G0/24). All other ports on the switch have an access VLAN as well as a voice VLAN. However, I apparently fat-fingered the configuration and left G0/24 as an access port. I didn't notice because my phone still registered with the distant end CUCM. How did this happen if G0/24 was not configured as a trunk port?
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02-19-2019 06:17 AM
Wee last section of this and then i confirmed it one of my voice ports below
https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/voice-vlan
#sh int g1/0/6 tru
Port Mode Encapsulation Status Native vlan
Gi1/0/6 off 802.1q not-trunking 1
Port Vlans allowed on trunk
Gi1/0/6 2016,2048
Port Vlans allowed and active in management domain
Gi1/0/6 2016,2048
Port Vlans in spanning tree forwarding state and not pruned
Gi1/0/6 2016,2048
#sh run int g1/0/6
Building configuration...
Current configuration : 526 bytes
!
interface GigabitEthernet1/0/6
description Voice and Data
switchport access vlan 2016
switchport mode access
switchport voice vlan 2048
switchport port-security maximum 2
switchport port-security violation restrict
switchport port-security aging time 1
switchport port-security aging type inactivity
switchport port-security
auto qos trust dscp
spanning-tree portfast
spanning-tree bpduguard enable
service-policy input AutoQos-4.0-Trust-Dscp-Input-Policy
service-policy output AutoQos-4.0-Output-Policy
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02-19-2019 04:18 AM
what vlan was left on the port when it went to access , there had to be one available even as access port was it voice ?
was the phone actually able to ping the CUCM at this stage if vlan was not there or even its gateway , how long did you wait for registration to fail?
did you collect any logs from the router when it happened or outputs to check ?
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02-19-2019 04:23 AM
G0/24 had a voice vlan and access vlan configured. The registration went through just fine - I was even able to dial out. Unfortunately, I didn't think to collect logs before I changed G0/24 to a trunk port as originally intended.
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02-19-2019 04:29 AM
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02-19-2019 04:33 AM
No, G0/24 was set only as an access port:
switchport mode access switchport access vlan 49 switchport voice vlan 48
When I realized the error, I defaulted G0/24 and changed it to:
switchport trunk encapsulation dot1q switchport mode trunk
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02-19-2019 04:44 AM
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02-19-2019 04:51 AM
But how would the router know which subinterface to use if it's only receiving untagged traffic?
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02-19-2019 04:55 AM
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02-19-2019 04:57 AM - edited 02-19-2019 04:59 AM
Yeah, I think i'll need to recreate the situation and do a packet capture. I know access ports process tagged voice packets, but I didn't think they transmitted tagged packets. I suppose they need to for a Cisco phone to know what vlan is the voice vlan.
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02-19-2019 06:17 AM
Wee last section of this and then i confirmed it one of my voice ports below
https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/voice-vlan
#sh int g1/0/6 tru
Port Mode Encapsulation Status Native vlan
Gi1/0/6 off 802.1q not-trunking 1
Port Vlans allowed on trunk
Gi1/0/6 2016,2048
Port Vlans allowed and active in management domain
Gi1/0/6 2016,2048
Port Vlans in spanning tree forwarding state and not pruned
Gi1/0/6 2016,2048
#sh run int g1/0/6
Building configuration...
Current configuration : 526 bytes
!
interface GigabitEthernet1/0/6
description Voice and Data
switchport access vlan 2016
switchport mode access
switchport voice vlan 2048
switchport port-security maximum 2
switchport port-security violation restrict
switchport port-security aging time 1
switchport port-security aging type inactivity
switchport port-security
auto qos trust dscp
spanning-tree portfast
spanning-tree bpduguard enable
service-policy input AutoQos-4.0-Trust-Dscp-Input-Policy
service-policy output AutoQos-4.0-Output-Policy
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02-19-2019 08:21 AM
