Subnet issues

[unnikannanvj]

Hi Team

Suppose that an IP address is assigned to a device, not an interface of the device.

How would subnetting be done in this case?

Thank you.

Unni

[John Blakley]

I'm not sure I understand the question...

The address would still be part of an overall subnet regardless if it's per interface or per device. For example, if you had a device that had three nics, you may need a different address on each nic, but if you have a printer, it only uses a single address for the whole node.

HTH,
John

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[Peter Paluch]

Unni, John,

To add my two cents, in IP, there is no such thing as "IP address per device". In the IP addressing paradigm, addresses are always assigned to interfaces, never to entire devices. If the device has just one network interface, the address will be assigned to that interface, sometimes giving the impression that it is the device's address. In reality, though, IP addresses are always a property of network interfaces, and are therefore directly related to the network into which respective network interfaces connect to.

Best regards,

Peter

[Joseph W. Doherty]

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Posting

As Peter has noted, you normally assign IPs to interfaces, although something like a routing protocol's explicit router-ID might be considered an "IP address" assigned to the device and not an interface.

As to assigning a subnet mask, it really depends on whether the IP address is routable, and whether it will create a conflict with other interface IPs on the device as Cisco devices often "complain" (or not accept) if they see multiple interfaces within the same subnet.