06-12-2007 01:27 AM - edited 03-05-2019 04:38 PM
Hi
I have some confuse about vlan
Can one vlan have more subnet or more ip address ?
thanks
06-12-2007 01:32 AM
Hi,
The best practice is that VLAN = IP subnet, although there can be work arounds to have multiple IP subnets with a single VLAN (a simple example is to use secondary IPs).
HTH, please do rate all helpful replies,
Mohammed Mahmoud.
06-12-2007 01:38 AM
Hi
i don't understand how benefit to do this
ex. vlan 2 have three ip interface 192.168.1.254, 192.168.2.254, 192.168.3.254
i think one vlan should have only one ip interface
please explain me
Thanks
06-12-2007 02:30 AM
When you want redundancy for the network.
example:
L3 has three alternate way for the destination ,that scenario on the SVI interface
can configure three Ip ,if the link fails which has 1st ip traffic will automatically fallback to 2nd link which has secondary ip
------------------------------------
interface Vlan1
ip address 192.168.1.254 255.255.255.0 secondary
ip address 192.168.2.254 255.255.255.0
06-12-2007 09:41 AM
Usually the reason I've seen multiple IPs on a VLAN is IP migration or address exhaustion- if you're moving from one scheme to another, and can't touch every device at once. Let's say you're migrating from 1.1.1.0 / 27 to 2.2.2.0/24.
The old config was:
int vl 1
ip address 1.1.1.1 255.255.255.224
You would drop on this config:
int vlan 1
ip address 2.2.2.1 255.255.255.0
ip address 1.1.1.1 255.255.255.224
And now users on the old address scheme can still get to the rest of the network, until you have time to go touch their PCs and reconfigure.
You might do this when you need more IP address range within a physical cable plant, and can't accomplish this easily with downstream switches that don't support multiple VLANs or trunks, etc.
06-12-2007 05:56 PM
thanks for all comment :)
08-29-2020 05:48 AM
can i assign Multiple ip's to one single Vlan such as Configure VLAN10 with Ip's 192.168.1.0/30, 192.168.2.0/30, 192.168.3.0/30.
08-29-2020 07:16 AM
Yes you can, using secondary addresses, as shown in mtechnology's post. NB: there are some issues in doing this, such, as by default, DHCP will only provide addresses to the primary address network.
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