Can't get any connection from cisco switch to HP when the port is tagged.

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Jan 26th, 2012
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I have connected a cisco switch ( SG 200-08) to a HP switch, everythings works fine when hade have the HP port as untagged, but I can't get out when I tag the HP port.

Maybe this is a HP problem but we can tag other ports on it to other switches.

Is it some setting on the Cisco switch i need to do?

I have put 7 ports as access and one as trunk.

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viswamin Thu, 01/26/2012 - 23:43
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What kind of encapsulation do you use on that truck link which connects the HP and Cisco Switch?

Can you post the interface configurations of the trunk links (both Cisco and HP).


gill.lantz Fri, 01/27/2012 - 02:21
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Thank you for your answers.

I new on this, is it a easy way to find out the interface configurations of the trunk links?

eugen: I have tried to disable autonegotiation but it din't help.

I don't want to replace the cisco switch, but it is common that there is problem when people mix different brands.

Another question: is tagged different things on cisco and for example HP.

Tagged on HP is the same as Trunk on cisco...or did I misunderstand?

ebarticel Fri, 01/27/2012 - 04:45
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Tagged is a IEEE 802.1Q encapsulation term. When dot1q encapsulation is enabled the switch inserts the vlan id into the data link frame.

I don't know what type of HP switch you have but I will post this extract from HP site

Q: Does the HP ProCurve Switch 2124 support 802.1Q/802.1p?
The HP ProCurve Switch 2124 allows 1522 byte size packets tagged  with an 802.1Q tag but does not decode the VLAN ID. The switch does not  participate in VLAN tagging or VLAN priorities. The packets will be  forwarded without any problems.

What that is saying is that HP switch will act as a Cisco switch in transparent mode.

One solution is to have a vlan that is only on HP switch.


PS. Also read this post to understand the difference between terms in Cisco an HP lingo

gill.lantz Fri, 01/27/2012 - 04:59
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Thanks for your answer.

What do you mean by HP in a transparent mode.

If the HP switch is in transparent mode (not tagged?) it will act as a Cisco switch?

Is it easier to have a HP switch instead of the cisco switch in this case?, i guess this is the wrong place to ask if the best thing is to buy a HP switch? ;-)

(cisco is known for it´s quality so I really want this one, but it seems to be to much trouble)

I'm new to this world and english isn't my native language, ( if the questions seems stupid :-))

ebarticel Fri, 01/27/2012 - 05:48
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For the switches to form a trunk the native vlan has to be the same on both switches.

HP and Cisco have native Vlan 1 by default.

The Cisco switch does not tagg the native vlan

The HP switch taggs its native vlan.

Can you log into HP switch? If you can then look under Vlan 1 and see the tagg number it uses for it.

You then need to untagged Vlan 1.

On the port connected to Cisco switch you need to set the mode to tagged and not trunk (tagged  on HP is same as trunk on Cisco).

If you can configure these two the switches should become friends

Native Vlan (in this case Vlan 1 is used to carry traffic for all Vlans in your network). Thats is way is important to have same native vlan configured on both switches.

Hope this helps


gill.lantz Fri, 01/27/2012 - 07:32
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Thanks for your help I will look at this on monday when I'm back at work. :-)

ebarticel Thu, 01/26/2012 - 23:48
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Did you disable autonegotiation on Cisco switch? Usually if it is set to auto it won't form a trunk link with non-Cisco switch

Also as Vijay mention we like to have more information

Hope it helps


gill.lantz Fri, 01/27/2012 - 05:28
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I don't think I can see the  interface configurations.

We have tried to connect with Putty but we can't get a connection.


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