Adding a switch to the existing network

[mahesh18]

Hi Everyone,

On flat layer 2 network we have wall jacks in the meeting rooms.

Sometimes we get request from users for additional Lan connections there.

Then we  connect  the unmanged Dlink layer 2 switch to the wall jack at the meeting room then say 10 users connect to the Dlink switch and this switch

has connection to the wall jack.

Connection from wall jack goes to the Cisco switch and this cisco switch has this port config

int gi0/1

switchport mode access

switchport access vlan 10

spanning tree portfast

switchport port security

switchport port security max 4

BPDU is enabled globally enabled on this  switch.

This switch is VTP client mode.

Now we are replacing  the unmanaged switch with the Cisco switch.

This switch will not sit in one place as  per user requirement it will be used where ever needed.

So i can config the switch as per our normal config template.

New switch config

I want to manage this switch remotely so i need to assign IP address.

Config the new switch as VTP client and assign the same domain name  so it can learn all the vlans right.

I can config the port connecting the new cisco switch to existing switch as trunk port and allow  the required vlans on trunk.

This is simple way.

Second Way

Can i config this new switch as vtp transparent mode  and manually  config the required vlans which are  needed?

Is it possible to connect this new switch to existing switch without configuring as trunk port?

i mean is this config possible

switchport access vlan 15

spanning tree portfast

switchport mode access

This way new switch can carry single vlan to existing uplink switch.

Regards

MAhesh

[Reza Sharifi · Accepted solution]

Hi Mahesh,

If you are connecting a new switch to your existing switch and if the new switch has only one vlan, you can simply configure the uplink port as an access port.  If you have multiple vlans on the new switch, then you need to configure the link between the 2 switches as trunk port.  Usually, between switches configure the port as trunk and add the vlan to it.  In the feature when you add more vlans, you simply add them to the trunk.  If you have limited amount of vlan, you can simply configure the new switch in transparent mode and be done with it.  VTP is not needed unless you are dealing with a lots of vlans.

HTH

Reza

[mahesh18]

Hi Reza,

I can config the uplink port as access port and connect it to existing switch.

But existing switch has BPDUguard enabled globally.

When i connect new switch to existing switch as access port will port not be errdisabled as it now connect to new switch?

Regards

Mahesh

[Leo Laohoo · Accepted solution]

Mahesh,

I have a strange feeling you need to enable Auto Smart Port (ASP).

Basically, if you plug a client to an ASP-enabled Cisco switch, the switch will immediately default the interface and apply the configuration required.

Not easy but very achievable.  You may need to create a Cisco TAC Case for this.

Alternatively, you can deploy wireless. 

[Reza Sharifi · Accepted solution]

Hi Mahesh,

Yes, it will put the port in errordiable because you have BPDU guard and that usually applies to access ports.  You would need to disable it for that port and then configure it as trunk.

HTH

Reza

[devils_advocate · Accepted solution]

I agree with Reza in that you should configure an access port otherwise you have a trunk port which affectively terminates on a wall jack which is a risk, especially if its a risk you don't need to take.

Leo made a good point though with wireless being an option. To be honest, in my opinion I don't see what companies need lots of wall jacks in meeting rooms. There are unlikely to be any desktop machines in the room, just people bringing in laptops for meetings. Laptops have Wireless NIC's. You could save yourself the risk and hassle of a switch which is 'carried round from room to room' but just sticking a wireless AP in each meeting room.

[mahesh18]

Hi,

We are also working on to use wi fi as option  currently  i will configure the port as access port connecting to new switch..

Thanks everyone for their advice.

Best regards

Mahesh