Clarification on trunking on this 'cascaded' switch

Answered Question
May 22nd, 2009
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Imagine I have the following:


Switch1 (all ports on Vlan1)

fa0/10 ---connected to-----fa0/10Switch2



Switch2 (all ports on Vlan2)


If I want hosts from Vlan2 to communicate with switch1 Vlan1 hosts, I would need to do:

switch1

int fa0/10

switchport mode trunk

switchport allowed vlan 2


and do the same on switch2.


Is that correct?

Correct Answer by John Blakley about 8 years 4 days ago

That's correct, but you'd need to create a vlan 2 on the vlan 1 switch and vice versa. The vlan's need to match on both switches. Then configure your int fa0/10 like your example.


You *may* need to change your line to allow vlan 1 also (but it's native by default, so you may not):


switchport allowed vlan add 1,2


HTH,

John

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Correct Answer
John Blakley Fri, 05/22/2009 - 08:14
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That's correct, but you'd need to create a vlan 2 on the vlan 1 switch and vice versa. The vlan's need to match on both switches. Then configure your int fa0/10 like your example.


You *may* need to change your line to allow vlan 1 also (but it's native by default, so you may not):


switchport allowed vlan add 1,2


HTH,

John

Leo Laohoo Sun, 05/24/2009 - 14:52
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John's right. Aside from creating the VLAN 2 SVI, if your switch is the 2900/3500, 2950/3550, X4013+, you need to create VLAN 2 on the VLAN database.

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