Switchport VLANs and Devices

[Sidgarth]

Hi Everyone!

I'm relatively new to networking at a business level and hope you can help.

Currently I have 3 VLANs configured on a Cisco Catalyst 2960x:

-VLAN 1: normal data <- I know it is good practice to move the default VLAN to something other than "1" but it is what it is...

-VLAN 6: voip 

-VLAN13: IP Cameras

I want to focus on VLAN13. Currently the one of the ports on the switch have the config below:

switchport trunk allowed vlan 1,13

switchport trunk voice vlan 6

srr-queue bandwidth share 1 30 35 5

priority-queue out

mls qos trust cos

spanning-tree portfast

The other cameras port settings are

switchport trunk allowed vlan 1,13

switchport mode trunk

srr-queue bandwidth share 1 30 35 5

priority-queue out

mls qos trust cos

spanning-tree portfast

Could you please clear up some things? :) 

1. The camera is not a switch or AP so does it even need trunk settings (mode trunk, trunk allowed)?

if yes

a. because the cameras communicate over vlan13 can I remove vlan1?

2. it doesnt make sense for "trunk voice" be set seeming I am not using it at all.

Thanks in advanced 

[Leonid Voronkin]

1) It depends on cameras settings.

a) You should to clarify it. It seems vlan 1 maybe uses for cameras management and vlan 13 for video transferring.

2) I think you don't need it

[Sidgarth]

How does "switchport trunk allowed vlan #" work in conjunction with "switchport mode trunk"? Like, would there be a time when you only need one of the other?

[Giuseppe Larosa]

Hello @Sidgarth ,

to verify if both Vlan1 and Vlan13 are in use you can type the following command

show mac address-table interface gi0/5

if you see a MAC address learned in Vlan1 and one learned in vlan13 you will have a proof that the current configuration is needed .

Please note that this true even if you see the same MAC address learned in Vlan1 and Vlan 13.

Of course no voice vlan is needed here.

Hope to help

Giuseppe

[Richard Burts]

The original poster asks a question whether there would be a time that you would need only one of switchport mode trunk and switchport trunk allowed but not both? If you want a switchport to operate as a trunk you will always need switchport mode trunk. By default a trunk will carry all vlans that are on the switch. You would not need switchport trunk allowed if you want all vlans to be carried on this trunk. You do need it if you want to be selective about what trunks are carried.

[pieterh]

"switchport trunk voice vlan 6"

are you sure????? the command is : "switchport voice vlan 6"
it is used for IP-phoned using CDP or LLDP to retreive what vlan to use for voice data 

it enables an ACCESS port to process vlan-tagged packets for the voice vlan
and this would be my first encounter that it is used on trunks!

[Giuseppe Larosa]

Hello @pieterh ,

you are right I think it is a typing error of the original poster

Best Regards

Giuseppe

[pieterh · Accepted solution]

then I'll try to combine the individual answers  for the original poster:

1) As Leonid Voronkin mentions : it could be the camera needs a (vlan) trunk port connection

the the port must be configured as a trunk 

2)  @Sidgarth : How does "switchport trunk allowed vlan #" work in conjunction with "switchport mode trunk"?
switchport trunk configures the port to add vlan tags to packets so the receiving end knows for what vlan the packet is destined

switchport trunk allowed vlan limits the vlans to the list provided; without this list it is ALL vlans

3) a normal data port should have the config
- switchport mode access
- switchport access vlan 1 (this is by default)
- switchport voice vlan 6
with this you can connect pc BEHIND the IP-phone on the same switchport

4) a normal camera port should have the config
- switchport mode access
- switchport access vlan 13
(- switchport voice vlan 6 ! only needed when you connect a camera BEHIND the IP-phone -> rarely used) 

[Sidgarth]

Thank you for clarifying Richard!