Switches, Hubs, and Modems
cancel
Showing results for 
Search instead for 
Did you mean: 

VLAN not functioning as expected.

Wullie Buntin
Occasional Visitor

VLAN not functioning as expected.

First post on the HP forums folks so be gentle with me ;-)

Right we currently have 3 HP switches in house that replaced our aging Cisco 2950 and 3550 switches. Our core swwtch is a 5412zl and our 2 others are 5406zl. I reckon that the VLAN we are having an issue with resides on the core switch.

Below is the config for the VLAN

vlan 100
name "VLAN100"
untagged A1-A3
no ip address
exit

Now the 3 ports that are used for the VLAN house a Sonciwall firewall the uses 2 ports as it is in hardware failover mode and a Riverbed Steelhead appliance.

Now when these devices are connected to the HP switch i cannot ping past the Riverbed appliance. If i change the ports to be tagged rather than untagged then all seems to function normally but the way we have our network configured, as per the attached Visio drawing is that it shouldn't be able to.

Can anyone shed any light as to why we can't get this to work??
2 REPLIES
RicN
Valued Contributor

Re: VLAN not functioning as expected.


Hello and welcome to the forums.

As to your question on the tagged/untagged status I can not tell from your visio drawing what the correct mode should be, but the tagging status really only depends on the other side of the link.

That is, is the other device 802.1Q compatible and does it expect to see frames from a certain vlan to enter with the 802.1Q tag attached or not.

If you get your configuration to work with tagging the switch ports than it could mean that your devices is VLAN aware and also does tag their outgoing frames.

Does that make any sense to you?
Pieter 't Hart
Honored Contributor

Re: VLAN not functioning as expected.

Like Rick says,
for vlan tagging both sides of the link better be matched (no different from speed/duplex).

when an untagged packet comes in the port. it's internally added a tag. Then within the switch it is propagated within vlan100.
- to tagged ports for vlan100 (packet is forwarded with tag)
- to untagged ports for vlan100 (tag is stripped before it's sent out)

when a tagged packet for vlan-100 is comming into this port it may also be accepted and forwarded.
for tagged packets with another vlan-number than 100 other lines in the switch config need to be examined.

But it's not really clear what's the issue here.
>>>Now when these devices are connected to the HP switch i cannot ping past the Riverbed appliance<<<
seems allright to me!
You may need to look in the appliance config to see if this is allowed, not in the vlan config.

>>>I reckon that the VLAN we are having an issue with resides on the core switch.
<<<
I assume the three devices in question connected to this coreswitch?