Same VLAN on diffrent Switches have diffrent settings

[RafPfe]

Hi everybody

I have a question:

We have 2 switches, which have both some vlans, which have the same ID.

When I will show the IPs of the VLAN, I choose: show ip interface brief.

Now, for example, we have a vlan 2 on both switches.

on switch1, the IP-Adress is: 172.xxx.xxx.xx1

on switch2, the IP-Adress is 172.xxx.xxx.xx2

Why they don't have the same IP?

Is there a better solution, to list the VLANS with IP?

Thank you so much

[Karsten Iwen · Accepted solution]

The command is the right one to list the IPs on the switches. I typically use "show ip int brief | e una" to avoid unnecessary output.

For the IPs itself. In general, all devices on one subnet need different IP addresses. If two devices have the same IP, there would be an IP address conflict. This leads to the question why you think that both switches should have the same address. If these devices are the default-gateway for other devices on the network and you want to have one IP that can "live" on either device for redundancy, then you need a First-Hop-Redundancy-Protocol (FHRP). HSRP and VRRP are the typical choices for this in many networks:

https://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9234-hsrpguidetoc.html

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipapp_fhrp/configuration/xe-3se/3850/fhp-xe-3se-3850-book/fhp-vrrp.html

[paul driver · Accepted solution]

Hello
Devices that have ip addressing CANNOT be duplicated, they need to be different.
You don’t state what the switches are being used for but it could be these two switch's are performing the intervlan routing for a LAN a such they may share the same vlan ID and logical virtual ip address (FHRP) but their ip addressing will be different.

Or it could be these two switches are sharing the vlan but have different ip address for remote management.

[RafPfe]

Thanks Karsten

Thanks Paul.

So the IP output is not the Gateway for this VLan?

May I explain more: 

We have 2 locations, on each side a C6832-X-LE and both have this vlan.

the previous networker has left our company without any lists or visio, so we must do that now.

How can I find the Gateway adress from this Vlan with the ip range? They are both /30, but I don't know the GW.

Sorry for this.

Thanks in advance

[Jon Marshall · Accepted solution]

It sounds like that is the link connecting the two sites and each end has an IP address from the 172.x.x.0/30 subnet ie. there is no gateway as in that subnet there are only two useable IPs (172.x.x.1 and 172.x.x.2). 

I suspect the vlans/IP subnets in each site are routed across this link. 

Jon