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#

 

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Thanks to Valentin Bajramifor the feedback

Author: Migrated

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