Joining procurve switches together

[amaze_it]

Apologies as i'm sure this may well have been answered in the past - but i can't find a definitive answer!

We have a Procurve 5412zl which is our core network switch.  It has approximately 5 VLANs configured as well as being the default gateway router for the network.  We have a range of devices connected, mainly cisco aeronet and Mitel IP phones.  client devices are connected to the network through the IP phones.

We have now reached capacity on the switch, so we have purchased a 5406zl2 switch to extend the network.  I've purchased 2 x J9536A modules (1 for each switch), and connecting them using 2 x 10GB SFP+ cables.

I want to connect them using LACP to allow a 20GB trunk between the two switches, but i'm struggling to work out how to set this up (switch programming has never been my strong point!).  All the info i've read mentions using STP in case of the LACP failing and causing a broadcast storm, but i can't do that due to the IP phones not working when enabled.  The main confusion points are:

1. Do I setup all the VLANs on the second switch as well?  The second switch is likely to mainly only be VoIP phones with PC/mac connected to them; although there will the be possibility that i will need to add some additional Cisco Aeronets to it at some point - these have 4 different VLANs configured on them, one of which only has access to a firewall port for internet access and hence no IP address for the VLAN.

2. can i safely configure this without STP?  as the VoIP devices are highly likely to move around on ports, only very few will be definitely never have them connected and so will be safe to have STP enabled.

3. I'm assuming i will need to add a default route on the 2nd switch to point to the IP address of the first switch to deal with all the routing? 

if someone could provide an example config for my situation, that would be really appreciated!  I'd love to spend a while playing around with it, but i have about 7 days to install, configure and test this solution before it goes live (nothing like plenty of notice....)

Any help would be really appreciated!

[Uma_Maheswar]

Answer 1 : You must create required vlans on the second switch

Answer 2: Yes, STP is not needed. But ensure you connect cables physically once the configuration is completed

Answer 3: new switch default gateway would be your core switch Ip for routing. Do not enable IP Routing on the new switch. But at least assign one ip for the management vlan

Core configuration
=-=-=-=-=-=-=-=-=

Core#Config

(Config)# trunk ethernet a21-a22 trk1 lacp
(Config)# vlan 10 tag trk1
(Config)# vlan 20 tag trk1
(Config)# vlan 20 tag trk1

New 5406
=-=-=-=
Core#Config

(Config)# ip default-gateway x.x.x.x (Core switch ip)

(Config)# trunk ethernet a21-a22 trk1 lacp

(Config)# vlan 10
(Config)# vlan 20
(Config)# vlan 30
(Config)# exit

(Config)# vlan 10 tag trk1
(Config)# vlan 20 tag trk1
(Config)# vlan 20 tag trk1

[amaze_it]

thanks you for the exmaple - really appreciated.

just to clarify - if i have vlan 0 as the default (untagged) Data LAN on the first switch, with VLAN 1 (tagged) as the Voice VLAN, do i need to add VLAN 0 to the trunk as well?  I assume the VLAN numbers should be exactly the same across both switches?

[Uma_Maheswar · Accepted solution]

Vlan numbers must be same...

And when you create a trunk, by default Trk1 will be untagged to Vlan 1 (Primary vlan)

Now you tag rest of the vlans as required and it must work.

[amaze_it]

thank you for your advice!

we have got our cisco aeronets configured to use a set number of ports for a guest wifi - these ports are tied into a VLAN with no ip address to prevent access to other VLANs - and a firewall port has been tagged with the same VLAN id which generates the IP address for these clients and provides internet access.  If I add another access point using a port on the new switch, will this still work or will i need additional config to consider for this?

[Uma_Maheswar]

it must work without any additional configuration

if you would like to test, enable dhcp on that vlan on the second switch. It must receive an IP from firewall (unless you specified any vendor specific options). It proves enough that you are done with configuration.

To enable dhcp on vlan

(Config)# vlan 10
(vlan-10)# ip address dhcp-bootp

You can disable once the testing is over

no ip address dhcp-bootp

[amaze_it]

Thank you very, very much - your help is truly appreciated!

I will do some testing and update my post so that it may help someone in a similar situation to me in the future :)

[Uma_Maheswar]

My Pleasure..

[amaze_it]

ok - well that hasn't worked very well!

Configured as discussed - setup the VLANs on the new switch, tagged trk1 in all of them (except VLAN1 which is untagged), and set the default gateway to the IP of the current switch.  tagged the ports on the new switch for the voice and Data VLANs as per the other switch, but the phones don't seem to be picking anything up and are just hanging on DHCP:Discovery - normally we get another screen indicating the VLAN for the voice network, so this is indicating that the switch is clearly not passing the info through ok?

[Uma_Maheswar]

Assign an ip for the vlans on the new switch and check if you could ping Gateway from all the vlans.

Share the configs here , from both the switches

[amaze_it]

Thanks for the quick reply.  I have tried as you suggested, and turned on DHCP for one of the other VLANs - it does indeed pick up an IP fine; so i'm starting to suspect it's specifically to do with the phones.  I noticed that when i set up the trk port it's automatically added "spanning-tree Trk1 priority 4" to both configs - i've tried the global spanning tree disable command but it's still there.  Could this be the cause (bearing in mind my previous information about the IP phones)?

[amaze_it]

i've attached the config for both switches (ip addresses removed) - any help would be appreciated. 

The phones are clearly struggling to get DHCP as they are reporting "DHCP Timeout" and then restarting when connected to the new switch.

[Uma_Maheswar]

You missed on Tagging "Trk1" on Core Switch for Vlan 2

[amaze_it]

can't believe i missed that....you are indeed correct.  added to VLAN2 on main switch and phone immediately came online.

Thanks you once again :)

[Uma_Maheswar]

Cheers...