Cisco 3750 and HP 1810-8G trunking

[Adam Hudson]

I'm trying to get a trunk working between my 3760 switch and an HP 1810-8G switch. I understand after reading the posts below that "trunking" for HP is akin to an etherchannel on the Cisco side of things, I don't want that. I want a link that carries multiple VLANs on it.

http://itpeopleworld.blogspot.com/2011/12/cisco-and-hp-procurve-trunk-8021q.html

http://www.petenetlive.com/KB/Article/0000741.htm#S2

In the pictures attached I've tagged the ports for the VLANs I want them in (40,70,100) with 100 being my management VLAN. The HP VLAN carrying port should be port 1.

For the port on the cisco switch it's plugged into, here's my config:

interface GigabitEthernetx/x/x
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 40,70,100
 switchport mode trunk
 switchport nonegotiate

I doesn't matter whether or not I have the "switchport nonegotiate" in there or not, it still doesn't work.

Also attached is my "Setup Network" page. I have my switch IP and gateway in the management gateway because that's how my other switches are setup.

My problem:The HP switch and anything attached can't get to the rest of the network. I can't ping the HP switch or even anything statically assigned an IP and attached to the HP switch.

The port it's plugged into is showing Up and Up for status.

Any help is appreciated.

[burleyman]

You could have done this using VLAN 100 if you wanted as well.

If you look above when you ran the Show trunk on the Cisco switch it showed VLAN 1 as being the native VLAN on the Cisco switch even though you config did not specifically say that it is by default. The HP switch does not "see" that so on the Cisco side you had to specifically "say" that so the HP switch understands.

If you want to use VLAN 100 than on the Cisco switch tell it VLAN 100 is the native VLAN and on the HP side untag VLAN 100 and it should work just fine.

Mike

[burleyman]

Maybe a better explanation.

The Cisco side had this based on the show trunk command output

VLAN 1 showed as native so that would have been untagged

VLAN 40, 70 ,100 you had configured as allow so those would have been tagged.

on the HP side for port 8 you had this.

VLAN 1, 40, 70 as Tagged

VLAN 100 as untagged

So as you can see on the Cisco side VLAN 1 was untagged and the the HP side you had it Tagged and that is why it would not work.

Mike

[Jon Marshall]

I don't know is the short answer but I doubt it because that would mean you always needed a separate connection to the switch to manage it which would be a bit daft.

I think we sorted out the management with the native command on the 3750 ie. I believe the HP expects the management vlan to be untagged but the doc didn't say anything about which vlan you could use.

Jon

[Adam Hudson]

Jon, it's working now. But not ideally the way I'd like it.

I think my mind was heading in the same direction as yours with your second paragraph. It looks like the management port needs to be the (cisco term) "trunk" port if you want to manage the switch with an IP address. Meaning when I set more of these up they'll all have to be set 'switchport trunk native vlan 1'

To test, I tried setting Port 1 the exact same way as Port 8, except setting VLAN 1 "untagged" and VLAN 100 "tagged". Then I set my trunk port on my Cisco switch to 'switchport trunk native vlan 1' and I cannot ping the IP of the HP switch.

[Jon Marshall]

Adam

Not sure I understand.

We had it working using vlan 100 so why can't you use that vlan.

Jon

[Adam Hudson]

I totally can and will use VLAN 100. I think I was still trying to think of the switch in some Cisco context instead of the topsy turvy way HP does.
 

[Jon Marshall]

Okay well as long as it supports untagged traffic on the management vlan which it seems to do it looks like it is all working does it ?

There is a section in that document on STP so you may want to have a look at it as ideally you want your client ports (but not your trunk) to be the equivalent of portfast although that may be the default.

If they aren't then that could affect DHCP and in addition you don't want the switch generating TCNs whenever a client ports changes state.

Jon

[Adam Hudson]

Jon, you bring up a good point with STP. Do you have a link to the document are you looking at?

[Jon Marshall]

Adam

I have been using the document Daniel linked to earlier in this thread.

Jon

[devils_advocate]

The good thing about Cisco is that are largely consistent between their switch models when it comes to things like this, the Cisco IOS is pretty much the same throughout the catalyst range.

Unfortunately the same cannot be said of HP, the GUI's are not consistent and they seem to work in slightly different ways depending on which switch you buy so its much more difficult to learn them.

[devils_advocate]

If port 8 is connected to the Cisco (you said port 1 was above?) then you have a native vlan mismatch.

The default native vlan is 1 on the Cisco side and as you have untagged Vlan 100 in port 8 on the HP side, its a mismatch.

Whatever port uplinks to the Cisco needs to be:

Untagged - Vlan 1
Tagged - Vlan 40,70,100

The rest of the ports simply need to be Untagged in whatever Vlan you want them to be a member of.

If you have changed the VLAN ID of the Managenent address on the switch to be Vlan 100 then I think (and I could be wrong) that the switch will start to tag its management frames so having Vlan 100 tagged on the Uplink should work fine.

[Jon Marshall]

There is no native vlan mismatch.

Vlan 100 is being used as the management vlan on the Cisco and "switchport trunk native vlan 100" has been added to the 3750 trunk link.

Jon

[devils_advocate]

I must have missed that post, the last one I saw showed the native as 1 on the Cisco side.

Something in my memory tells me that the HP tags management frames if you change the management vlan to something other than 1.

Now I am doubting myself but I remember having a nightmare when trying to get the management vlan to work on a HP!

[Jon Marshall]

You may well be right as I have never used HP.

But when Adam set vlan 100 as untagged on the port connecting to the 3750 and we set the native vlan to be 100 on the 3750 he could ping the HP switch.

I would have thought you could use any vlan but like I say you have experience with these switches so I may be misunderstanding something here.

Jon

[devils_advocate]

I have worked with HP's in the past and they can take some time to get your head round.

Ignore the term trunk on the HP as it means Link Aggregation, not Trunking as in an 802.1q trunk.

Basically, you have Untagged and Tagged.

An access Port on a Cisco is equivalent to an Untagged port on a HP.
All the ports which connect to hosts on the HP should be untagged in the Vlan you want them to be a member of.

The port which uplinks to the Cisco (i.e the 802.1q trunk) needs to be untagged in one Vlan (i.e the native, which by default is  VLAN1) and Tagged in all other Vlans that you want to carry across the Trunk.

The Cisco side if configured fine looking at the config above.

Lets assume you want to use Port 1 as your uplink, i.e you connection to the Cisco and the rest of the 7 ports need to be part of Vlan 40.

So, Port 1 would be Untagged in Vlan 1 (as this is the native, no vlan tag applied) and Tagged in Vlans 40, 70 and 100.

Ports 2-7 would be Untagged in Vlan 40.

Simple as that.

The CLI on the HP is easier to use in my opinion but its backwards to the Cisco in that you have to go into the Vlan itself and then select the ports to tag/untag as opposed to the Cisco where you do the config on the port itself.

Yours would be (for my assumption above)

#vlan 1
#untagged 1
#vlan 40
#tagged 1
#untagged 2-7

#vlan 70
#tagged 1
​#untagged 2-7

#vlan 100
#tagged 1
​#untagged 2-7