Cisco IE-3400H-24T Layer 3 VLAN Configuration

[ZF1]

Hello, 

I have a Cisco IE-3400H-24T, with a number of ports connected to a 120.95.11.x network and other ports connected to a 192.168.1.x network. I have assigned these ports in the VLAN configuration as VLAN20 for 120.95.11.x and VLAN10 for 192.168.1.x. I have also assigned IP address 192.168.1.1 to VLAN10 and 120.95.11.5 to VLAN20 in the SVI settings. 

Most of the devices are communicating between subnets just fine, but I have one that is giving me an issue. I have many questions:

Will SVI configuration enable layer 3 communication and implicitly route VLAN10 & VLAN20 together?

Do I need to use static routing to perform this successfully?

VLAN20 is the same IP address as the router (120.95.11.5) is this problematic? Should VLAN20 be set for 120.95.11.1?

[Flavio Miranda]

@ZF1 

 You need to enable "inter-vlan routing". Not sure where exactly it is on this switch but it should be on the IPV4 config probably under configuration tab.

On CBS350 it looks like this

[liviu.gheorghe]

I'm not sure that's the case. The IE-3400 is running IOS XE and from what I recall, ip routing is enabled by default.

[liviu.gheorghe]

Hello @ZF1 ,

The router will enable IP routing by default once you configure an IP address on the SVI's.

You do not need to configure any static routes to enable routing between host from vlan 10 and vlan 20. If the hosts have the correct default gateway configured - 192.168.1.1 for VLAN10 and 120.95.11.5 for VLAN20 - the hosts will be able to communicate.

You will need a default gateway configured in order to enable hosts from vlan 10 and 20 to communicate with other networks.

Not sure what you mean by the last sentence. Vlans is a layer 2 concept so it doesn't have an IP address - this happens at layer 3 - the SVI.

[ZF1]

I do not have a button for enabling IPv4 routing. When I setup each port I set it to access the appropriate VLAN which was configured in SVI.

I think it is the 3rd party device itself. Everything else is communicating between the 2 networks but this one device. 

I've tried setting the switchport mode to "trunk" and "access" with the appropriate VLAN numbers, but no success. I am still playing around in the Cisco switch settings while I am waiting to hear back from the manufacturing regarding the problematic device. 

[liviu.gheorghe]

What is the "3rd party device" you are referring to? Can you share your topology with us in order to better understand your issue?

[ZF1]

The image attached is a very simplified version of the system, but it gets the point across. The left network has a PLC that is able to communicate with other devices in the 120.95.11.x network AND it can also communicate with multiple remote I/O devices in the right network (192.168.1.x). It is just the one variable frequency drive the PLC has a hard time with. 

Also, the gateway in the PLC is set to 120.95.11.5 and the gateway in the remote I/O devices & drive is set to 192.168.1.1. 

The worst part is that the PLC shows the drive as "running", but when you open the properties page I receive a "communications lost" error. At this point I am leaning toward this being an issue with the drive firmware, but I wasn't sure if there were avenues in the switch I have not realized. 

[liviu.gheorghe]

Ok, I see what you are talking about now.

Is there any way you can do a icmp ping from the PLC to the VFD or from the VFD to The PLC. I want to be sure that the layer 3 connectivity is ok. If a ping is not an option, telnet or ssh between the PLC and VFD is just as good.

[ZF1 · Accepted solution]

I finally received a reply from the VFD manufacturer. They found that there is a bug in their firmware. While I wait for the new firmware (hopefully there is a fix without new hardware), I have temporarily moved the VFDs to the 120 network and everything is working. 

Thanks for your support!