VLAN interface IP

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Hi all,

There is an IP address for the VLAN interface. VLAN is basically a group of
computer sharing the same network address and subnet mask. The VLAN
interface IP is like an address of no where. What is the purpose of the VLAN
interface IP?

Thanks



Re: VLAN interface IP
Only two reasons:

1) If the switch is capable of doing layer 3 routing, then this can be
the default gateway for that vlan

2) Management.  For telnet, etc... or for routing protcols (again Layer
3 switching)

Otherwise, for layer 2, the vlan does not need an IP.

a wrote:
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Re: VLAN interface IP
a wrote:
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Hi,

It's only for management purpose. (ping, access and configuration of
your switch whith telnet/ssh/http)

Re: VLAN interface IP

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If it's a layer 3 switch than the vlan interface ip address becomes the
default gateway for that subnet.



Re: VLAN interface IP
I think the so-called layer 3 switch is the integration of router and switch
in the same box, right?
So, the vlan interace ips are always the default gateway for the VLANs under
the same switch. Am I right?

Is it for the VLAN
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Re: VLAN interface IP

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yes.


yes but the vlan might just be getting trunked through the switch to another
that has access ports in that vlan.

switch1--core switch--switch2--switch3

switches 1,2 and 3 might be assigned different vlans so vlan 3 (for switch3)
needs to be trunked through switch2.   For switch3 hosts to talk to switch1
hosts they use their default gateway which are vlan interfaces on the core
switch.  This example isn't necessarilly a good design I'm just showing how
vlan interfaces are layer-2 adajacent to hosts uysing them but not
necessarilly on their directly attached switch.

BernieM

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Re: VLAN interface IP

switch1--core switch--switch2

simplified example of the same thing.  switches 1 and 2 are layer 2 switches
while core switch is layer 3 and has vlan interfaces for the vlans on
switches 1 and 2.

BernieM

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