HP and Cisco – VLANs and Trunks Confusion!

KB ID 0000741 Dtd 09/01/13

Problem

When I first started in IT, I went and did my Cisco CCNA. So I learned that to connect Cisco switches and pass VLAN traffic between them, I needed to create a 'Trunk' to pass the VLAN traffic. Fast forward a few years, and I now work for an HP reseller. Very early on I came to realise that what HP called a 'trunk' was very different from what I had been taught. Below is an article I did a while ago about setting up HP Trunks.

HP Networking 'ProCurve' - Trunking / Aggregating Ports

I was in some HP/Wireless training last week and once again I was struggling with their terminology, so today I lined up a bunch of switches on the test bench and worked out the differences.

Below you will find the following scenarios;

Scenario 1 Configuring Cisco Catalyst Switches with VLANs.

Scenario 2 Configuring HP Switches with VLANs.

Scenario 3 Setting up HP Switches with Trunked VLANs

Scenario 4 Setup VLANs via HP Trunks and Cisco Port Channels

Setting up VLANs on older Cisco Switches

Solution

Scenario 1 Configuring Cisco Catalyst Switches with VLANs.

Cisco VLANS

In 'Ciscoland' All ports are either in access mode or trunk mode, the access mode allows the port to communicate with the VLAN. The trunk mode carries the VLAN traffic to another switch (or device). So to replicate the diagram above, this is what you would need to do. (Note: For older switches like the 3550XL the VLAN commands are a little different see here)

Switch01>  Switch01>enable  Password: xxxxxxxx  Switch01#configure terminal  Enter configuration commands, one per line. End with CNTL/Z.  Switch01(config)#vlan 10  Switch01(config-vlan)#name Admin  Switch01(config-vlan)#exit  Switch01(config)#vlan 20  Switch01(config-vlan)#name Data  Switch01(config-vlan)#exit  Switch01(config)#int f0/2  Switch01(config-if)#switchport mode access  Switch01(config-if)#switchport access vlan 10  Switch01(config-if)#exit  Switch01(config)#inf f0/16  Switch01(config-if)#switchport mode access  Switch01(config-if)#switchport access vlan 20  Switch01(config-if)#exit  Switch01(config)#int f0/23  Switch01(config-if)#switchport mode trunk  Switch02(config-if)#switchport trunk allowed vlan 1,10,20  Switch01(config-if)#exit  Switch01(config)#exit  Switch01#write mem  Building configuration...  [OK]  Switch01#        Switch02>  Switch02>enable  Password: xxxxxxx  Switch02#configure terminal  Enter configuration commands, one per line. End with CNTL/Z.  Switch02(config)#vlan 10  Switch02(config-vlan)#name Admin  Switch02(config-vlan)#exit  Switch02(config)#vlan 20  Switch02(config-vlan)#name Data  Switch02(config-vlan)#exit  Switch02(config)#int f0/2  Switch02(config-if)#switchport mode access  Switch02(config-if)#switchport access vlan 10  Switch02(config-if)#exit  Switch02(config)#inf f0/15  Switch02(config-if)#switchport mode access  Switch02(config-if)#switchport access vlan 20  Switch02(config-if)#exit  Switch02(config)#int f0/1  Switch02(config-if)#switchport mode trunk  Switch02(config-if)#switchport trunk allowed vlan 1,10,20  Switch02(config-if)#exit  Switch02(config)#exit  Switch02#write mem  Building configuration...  [OK]  Switch02#

Scenario 2 Configuring HP Switches with VLANs.

Cisco VLANS

With HP switches the terminology is different, here switch ports are either tagged members or untagged members of a VLAN.

What's the difference between tagged and untagged? If a port is a tagged member it passes the VLAN information with the traffic it sends. If it is untagged it sends the VLAN traffic without adding in the VLAN tag. So you would only make a port a tagged member if the device that is plugged into it is VLAN aware, i.e. another switch, router, or machine with a VLAN aware NIC. (Note: The VLAN tag is the ID that gets inserted into the head of a network packet). So to do exactly the same as we did in scenario 1, but with HP switches, you would do the following:

BE AWARE: Any single port can only be untagged on one VLAN. Out of the box all ports are untagged on VLAN 1 (or the default VLAN), so if you untag a port into VLAN 20 (for example) it will automatically remove the 'vlan 1 untagged' property for that port.

Switch01> enable  Password:xxxxx  Switch01# configure terminal  Switch01(config)# vlan 10 name Admin  Switch01(config)# vlan 20 name Data  Switch01(config)# vlan 10  Switch01(vlan-10)# untagged 6  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# untagged 16  Switch01(vlan-20)# exit  Switch01(config)# vlan 10  Switch01(vlan-10)# tagged 13  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# tagged 13  Switch01(vlan-20)# exit  Switch01(config)# write mem  Switch01(config)#    Switch02> enable  Password:xxxxx  Switch02# configure terminal  Switch02(config)# vlan 10 name Admin  Switch02(config)# vlan 20 name Data  Switch02(config)# vlan 10  Switch02(vlan-10)# untagged 4  Switch02(vlan-10)# exit  Switch02(config)# vlan 20  Switch02(vlan-20)# untagged 20  Switch02(vlan-20)# exit  Switch02(config)# vlan 10  Switch02(vlan-10)# tagged 23  Switch02(vlan-10)# exit  Switch02(config)# vlan 20  Switch02(vlan-20)# tagged 23  Switch02(vlan-20)# exit  Switch02(config)# write mem  Switch02(config)#

Scenario 3 Setting up HP Switches with Trunked VLANs

HP Trunked VLANS

Remember with HP a Trunk is adding together lots of links, (if you're a Cisco head think of port-channeling). So here we create a trunk, then use that trunk to pass tagged VLAN traffic across the switches.

Switch01> enable  Password:xxxxx  Switch01# configure terminal  Switch01(config)# vlan 10 name Admin  Switch01(config)# vlan 20 name Data  Switch01(config)# vlan 10  Switch01(vlan-10)# untagged 6  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# untagged 16  Switch01(vlan-20)# exit  Switch01(config)# trunk 21,23 Trk1 LACP  Switch01(config)# vlan 10  Switch01(vlan-10)# tagged Trk1  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# tagged Trk1  Switch01(vlan-20)# exit  Switch01(config)# write mem   Switch01(config)#

    Switch02> enable  Password:xxxxx  Switch02# configure terminal  Switch02(config)# vlan 10 name Admin  Switch02(config)# vlan 20 name Data  Switch02(config)# vlan 10  Switch02(vlan-10)# untagged 4  Switch02(vlan-10)# exit  Switch02(config)# vlan 20  Switch02(vlan-20)# untagged 20  Switch02(vlan-20)# exit  Switch01(config)# trunk 21,23 Trk1 LACP  Switch01(config)# vlan 10  Switch01(vlan-10)# tagged Trk1  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# tagged Trk1  Switch01(vlan-20)# exit  Switch02(config)# write mem  Switch02(config)#

Scenario 4 Setup VLANs via HP Trunks and Cisco Port Channels

HP Trunked VLANS to Cisco Catalyst

Now we have gone full circle, we know what all the differences are, the final part is to get them to talk to each other. So I'll set up a two cable HP Trunk, and connect it to Cisco LACP port channel, and then finally add in the VLAN traffic.

Switch01> enable  Password:xxxxx  Switch01# configure terminal  Switch01(config)# vlan 10 name Admin  Switch01(config)# vlan 20 name Data  Switch01(config)# vlan 10  Switch01(vlan-10)# untagged 6  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# untagged 16  Switch01(vlan-20)# exit  Switch01(config)# trunk 21,23 Trk1 LACP  Switch01(config)# vlan 10  Switch01(vlan-10)# tagged Trk1  Switch01(vlan-10)# exit  Switch01(config)# vlan 20  Switch01(vlan-20)# tagged Trk1  Switch01(vlan-20)# exit  Switch01(config)# write mem   Switch01(config)#

    Switch02>  Switch02>enable  Password: xxxxxxx  Switch02#configure terminal  Enter configuration commands, one per line. End with CNTL/Z.  Switch02(config)#vlan 10  Switch02(config-vlan)#name Admin  Switch02(config-vlan)#exit  Switch02(config)#vlan 20  Switch02(config-vlan)#name Data  Switch02(config-vlan)#exit  Switch02(config)#int f0/2  Switch02(config-if)#switchport mode access  Switch02(config-if)#switchport access vlan 10  Switch02(config-if)#exit  Switch02(config)# interface range fa0/23 - 24  Switch02(config-if-range)# spanning-tree portfast trunk  %Warning: portfast should only be enabled on ports connected to a single  host. Connecting hubs, concentrators, switches, bridges, etc... to this  interface when portfast is enabled, can cause temporary bridging loops.  Use with CAUTION

Switch02(config-if-range)# channel-protocol lacp  Switch02(config-if-range)# channel-group 1 mode active  Creating a port-channel interface Port-channel 1  Switch02(config-if-range)# interface port-channel 1  Switch02(config-if)# switchport mode trunk  Switch02(config-if-range)#switchport trunk allowed vlan 1,10,20  Switch02(config-if)#exit  Switch02(config)#exit  Switch02#write mem  Building configuration...  [OK]  Switch02#

Setting up VLANs on older Cisco Switches

Here's an example using the older vlan database commands.

Switch01>  Switch01>enable  Password:   Switch01#  Switch01#vlan database  Switch01(vlan)#vlan 10 name Admin  VLAN 10 modified:  Name: Admin  Switch01(vlan)#vlan 20 name Data  VLAN 20 modified:  Name: Data  Switch01(vlan)#exit  APPLY completed.  Exiting....  Switch01#configure terminal  Enter configuration commands, one per line. End with CNTL/Z.  Switch01(config)#int f0/2  Switch01(config-if)#switchport mode access   Switch01(config-if)#switchport access vlan 10  Switch01(config-if)#exit  Switch01(config)#int f0/16  Switch01(config-if)#switchport mode access  Switch01(config-if)#switchport access vlan 20  Switch01(config-if)#exit  Switch01(config)#int f0/23  Switch01(config-if)#switchport mode trunk  Switch01(config-if)#switchport trunk encapsulation dot1q   Switch02(config-if-range)#switchport trunk allowed vlan 1,10,20  Switch01(config-if)#exit  Switch01(config)#exit  Switch01#write mem  Building configuration...    Switch01#

 

Related Articles, References, Credits, or External Links

Thanks to Valentin Bajramifor the feedback

Author: Migrated

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