Catalyst Switch Setup

[Lakeram Harrypersaud]

I have two 3750 that are stacked and which i will be using as a core. I also have six 2960 which will be connecting to the core. I have three vlans, i.e. vlan 1, vlan 2 and vlan 3. All these Cisco switches will be in vlan 1 but there is a Nortel switch which is on a voice network and which has vlan 2 and 3 and which will also be trunked to the core. My question is how do i setup the 2960 to the core?

Should i just add this command to each 2960 switch but with a different ip address so i can manage it and create a trunk port to the core?

interface Vlan1

ip address 10.1.1.211 255.255.0.0

Any help will be greatly appreciated?

Thanks,

Lake

[Collin Clark]

Lake-

That should work just fine for a basic configuration. Make sure VLAN 1-3 are on the trunk. Good luck!

[Lakeram Harrypersaud]

Thanks for the quick reply. Just to confirm. I take it you mean my theory is correct?

Thanks,

Lake

[Jon Marshall]

Lake

Yes your theory is correct although a couple of points -

1) you should not use vlan 1 for data traffic or management

2) if you only had vlan 1 on the 2960 switches then you wouldn't need to trunk these switches to the 3750s, you could simply use an access port.

However following on from point 1)

3) you should use a different vlan from vlan 1 for user ports on your 2960 switches.

4) you should use a different vlan from vlan 1 and from 3) for managing your switches.

So generally you would have at least 2 vlans on your access switches one for data and one for management. Then you would need to trunk back to the 3750s to allow both vlans. You would route these vlans on the 3750 switches.

Jon

[Lakeram Harrypersaud]

Does that mean i need a management ip address to manage the switches and that if i am in the data vlan i won't be able to connect to the switches?

Thanks,

Lake

[Jon Marshall]

Lake

No, you can still connect to the switch from the data vlan because it will be routed onto that vlan by th 3750 switches.

So your 2960 would have a management IP from for example vlan 2. On the 3750 you would also have a vlan interface for vlan 2. Then on the management switch you would add -

ip default-gateway x.x.x.x  <-- where x.x.x.x is the IP address assigned to the vlan 2 interface on the 3750.

Jon

[Lakeram Harrypersaud]

I really appreciate all your help but i am a litttle confused.

Do i need a dedicated switch for management?

If possible can you please send me a template of a similar setup?

Thanks,

Lake

[Jon Marshall]

Lake

No, you don't need a dedicated switch for management. But it is recommended to have a dedicated vlan for management. So lets say you have vlan 10 for users on your 2960s and vlan 11 for managing all your Cisco switches.

On each 2960 -

1) create vlan 10 and 11 in the vlan database (note if you are using VTP server/client you may only need to do this on the VTP server)

2960(config)# vlan 10

2960(config-vlan)# name v10

same for vlan 11

do this on each of your 2960 switches and also the 3750

2) create the L3 vlan interface for management on the 2960 switches. Lets say vlan 11 has a subnet of 192.168.5.0/24

on the 2960s

int vlan 11

ip address 192.168.5.2 255.255.255.0  <-- use a different IP from the 192.168.5.0/24 subnet for each 2960

3) create the L3 vlan interface for both vlan 10 and vlan 11 on the 3750 -

int vlan 10

ip address 192.168.6.1 255.255.255.0

int vlan 11

ip address 192.168.5.1 255.255.255.0

4) for clients in vlan 10 they will have a default-gateway of 192.168.6.1 ie. the L3 vlan interface on the 3750.

5) on the 2960 switches add this command -

ip default-gateway 192.168.5.1  <-- this is the same for all 2960 switches

6) make sure the 2960 switches are connected to the 3750 stack with a L2 trunk or etherchannel trunk.

With the above you should be able from a client in the user vlan 10 to connect to any of the switches using their vlan 11 ip address.

Jon

[Lakeram Harrypersaud]

That means i have to go into each port on all switches and add vlan 10 and 11 except on the ports that will be trunked?

Is this correct?

Thanks,

Lake

[Jon Marshall]

Lake

There won't actually be any ports for the management vlan other than the trunk links.

For vlan 10 ports yes you need to assign these into vlan 10. Don't forget the "interface range ..." command where you can select a range of ports and apply the same config to each port. It saves a fair amount of time.

Jon

[Lakeram Harrypersaud]

Thank you very much

Is this the correct command to create a trunk port on both 3750 and 2960?

vlan 5 is my data vlan

int fa0/23

switchport trunk encap dot1q

switchport mode trunk

switchport trunk native vlan 5

switchport trunk allowed vlan 2,3,5,10

Thanks,

Lake

[Jon Marshall · Accepted solution]

Lake

Couple of things -

1) you don't need to allow the native vlan on the trunk link. Also you should not have a L3 vlan interface for the native vlan on any switches because the native vlan should be a vlan with no ports assigned to it and therefore never needs to be routed.

2) the rest is fine but you may well find the "switchport trunk encapsulation .." is not there on the 2960 switches. Don't worry, the 2960s only support 802.1Q so that is why there is no need to set the encapsulation.

Jon

[Lakeram Harrypersaud]

I truly appreciate all your help.  Thank you very, very much.

Regards,

Lake

[Lakeram Harrypersaud]

Jon,

I forgot to mention that the trunk ports need to be aggregated i.e. etherchannel. Can you please verify whether these commands are correct for the 3750 switch and then i add the commands to the 2960?

Each 2960 switch will be connecting to a port on each 3750 so if one 3750 switch goes down the other connection will up.

Now for the connection to the second 2960 switch i repeat the commands using a port channel?

interface Port-channel1
switchport
switchport trunk encapsulation dot1q
switchport mode trunk

interface GigabitEthernet1/48
description xxxxxxxxxxxxxxx
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk allowed vlan 2,3,5,10
channel-group 1 mode on
!
interface GigabitEthernet2/48
description xxxxxxxxxxx
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk allowed vlan 2,3,5,10
channel-group 1 mode on

Thanks,

Lake

[Jon Marshall · Accepted solution]

Lake

to configure a L2 etherchannel you first configure the physical ports ie.

3750(config)# int range gi1/48 ,  2/48

3750(config-range)# channel-group 1 mode on

this will automatically create the port-channel. From then on you should apply the rest of the config to the port-channel ie.

int port-channel1

switchprort

switchport trunk enapsulation dot1q

switchport mode trunk

switchport trunk allowed vlan 2,3,5,10

when you configure the port-channel it automatically propogates the config to the switchports in that etherchannel.

Jon