VLAN Interface Command

[tsmarcyes]

Ok, I thought I had the reason for the VLAN interface command down. I thought it was either used for switch management or routing between VLANS? However, now I realized that some communication wont work with out this command which doesnt make sense. If I have a VLAN, then the switch will only switch packets to ports on the same VLAN. The only way, communication would work between VLANS is if I either enabled routing between VLANs with the VLAN Interface command, connected the switch to another multi-layer switch that did do routing between VLANS, or connected the switch to a router which routed between the VLANs.

However, I just got this new 3550 switch in, configured the correct ports with the assigned VLANs, and the only way my cisco ip phone would work is if the VLAN Interface for my voice-ip VLAN was configured. The 3550 is connected to a 4507. Now, can someone tell my why this is? You shouldnt have to configure the VLAN Interface, right?(unless I wanted to route between VLANs, which could be done by the 4507)

[Georg Pauwen]

Hello,

are you using voice VLANs ? If so, be aware that the VLAN defined by the 'switchport voice vlan X' command is not automatically created as is the case with the ' switchport access vlan X' command. That means, you have to define your voice VLAN manually.

Can you post the configuration of your 3550 ?

Regards,

GP

[kamlesh_s1181]

hi,

The only way, communication would work between VLANS is if I either enabled routing between VLANs with the VLAN Interface command,

Your this statement is confusing. Make sure you are using ip routing command along with interface vlan command to configure intervlan.second thing trunk should be up and running to do intervlan between switches.

Best of my knowl----

Kamlesh sharma

[tigerxxxx]

what is "vlan interface" command?

can someone write the syntax for that command? and what it does?

for my understand till now, to work with multiple vlan's

we need to configure trunking (isl/802.1q) between switch to switch, and between switch to the router (again isl/802.1q) and for each vlan need to create a sub interface to work with and encapsulate him with trunking (router-on-a-stick)

and to configure VTP on the all switches.

and to configure a vtp domain name in both.

thanks

[ankurbhasin]

HI tsmarcyes,

You need not create interface vlan for your ip phones on 3550 if you are doing that on your 4000 series switch.

Make sure that when you assigned the ports to the voice vlan on 3550 have you also created that vlan in vlan database. What happens in 3550 is when you create interface vlans that partuclar vlan is also created in vlan databaase.

Just confirm that your voice vlan is created in vlan database and you can simply remove interface vlan you do not need that.

Also make sure you confi this command on your ports

switchport voice vlan ---for voice

switchport access vlan ---for data

run both the command if you connect you computer to the ip phones.

HTH

Ankur

[baileja]

Sounds to me like you either dont have the dot1q trunk interface between your 4506 and 3550 working properly, or your 3550 is running the enhanced image which allows routing.

It would be nice to see your config on both the 3550 and the 4500 to determine the reason. Just a stab at how it should be configured is that on your 4506, you have it running VTP server or transparent with the defined Data and Voice Vlan's. You have a port configured for trunking (which connects to the 3550). On your 3550, you have configured it as a vtp client or transparent and have verified that it has received (or if transparent VTP you have configured) the appropriate VLAN's. You than specified "interface VLAN #" or whatever number for switch management and configured the port that connects to the 4500 as a trunk. Your port connected to the port has the auxillary or voice vlan configured. If this is how your equipment is configured and it still does not work, than look for the line "ip routing" in your 3550 and negate it with "no ip routing".

If still no worky worky, post your config.

Cheers,