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Switches Vlan

orkinos
orkinos used Ask the Experts™
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I have 2x HP ProCurve 3400cl switches.

switch1 is my old switch and vlan configured on it Vlan 1,Vlan 2.......Vlan 20.
switch2 is brand new switch and Vlan is Defaulft Vlan1(only one vlan).

I know I need to Vlan configure .But if i connect them together like above configuration(switch1 is with vlan other not).What can happen?
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I believe on the procurve series you are going to need to configure your trunk groups to carry the vlans - I am not entirely certain how the new switch will respond, however, it is likely you will need to define vlans on both switches before communication can occur. In the event you have specific questions for your switch, I have included the link to the config /user guide for your series of switch from HP.

http://ftp.hp.com/pub/networking/software/6400-5300-4200-3400-MgmtCfg-Oct2006-59906050.pdf
Top Expert 2011
Commented:
If you connect them without a trunk, only PC's in vlan 1 will be able to communicate between the switches.
1) connect sw2 to accesport on sw1:
If you connect the new switch to a port on the old switch configured as untagged in some vlan, then this old vlan is distributed via new switch same way as an unmanaged sw would do.
2) connect to a port with several vlans configured, some tagged , one untagged in some vlan.
If you connect the new switch to such a port, then only the untagged vlan in old switch is carried to all ports in new sw.
===
What you would end up doing is make the same pattern of Tagging on both sides of link
so if sw1/port1====sw2/port4 and you want to carry vlan 1.....vlan20
sw1:
vlan1
UNTAG 1
exit
vlan 2
TAG 1
exit
.....
vlan 20
TAG 1
exit
-- -- -- --
SW2:
vlan 1
UNTAG 4
exit
vlan 2
TAG 4
exit
....
vlan 20
TAG 4
exit

HTH