It depends on the switch, but not quite in the manner described by eternal0void. Most consumer switches do not need an IP address set because they are unmanaged. Unmanaged refers to the fact that no configuration can be done to the firmware running on the switch, it is pre-configured usually to simply connect computers.
However, managed switches allow a network administrator to access the firmware running on the switch. Using this firmware a admin can turn on/off ports, look at what ports are in use, set certain ports to only allow specific computers to be connected... There are many different settings that can be made. Normally you are required to connect directly to a switch to configure it, but then can assign it an IP address, and you can connect to it then from a web browser or Telnet.
Consumer Router/Switches commonly have IP addresses set. This is because the router component requires an IP address for it to route IP traffic and the device is usually provides a management interface for the router, sometimes even the switch can be managed.
Itsbomba is correct. It's all about whether the switch is managed or not. If you want to network administer or remote manage the switch, enable port security, update firmware, configure SNMP, etc, then you would want a managed switch. Simply put, the IP gives the switch a network presence allowing it to be remotely managed with a browser. If all you want to do is share a connection, an unmanaged switch should suffice.
It would depend on the type of switch. A conventional switch which merely transmitted packets between connections does not have a control module that could be assigned an IP address, so it does not require an IP address. This is the category most switches fall into, especially switches intended for the home user.
A high-end switch with additional features has a control module with its own IP address assigned, mostly so you can access the control module through the assigned IP address. This type of switch is generally a router with additional ports to allow it to provide switching capabilities as well.
The main point here is that a switch provides a connection between systems on a network, but does not provide any routing functions itself, nor does it have any configuration which may need adjustment. Thus a switch which only provides switching functions does not need an IP address, and usually cannot have one assigned to it.
The IP assignment mode determines if the switch IP information will be manually assigned (static) or be automatically assigned by a Dynamic Host Configuration Protocol (DHCP) server. The default is Static.
Cisco recommends that you select Static and manually assign the IP address for the switch. You can then use the same IP address whenever you want to access the device manager.
If you select DHCP, the DHCP server automatically assigns an IP address, subnet mask, and default gateway to the switch. As long as the switch is not restarted, the switch continues to use this information, and you can use the same IP address to access the device manager.
Note If you manually assign the switch IP address and your network uses a DHCP server, make sure that the IP address that you give to the switch is not within the range of addresses that the DHCP server will automatically assign to other devices. This prevents IP address conflicts between the switch and another device.
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Oddjob Dec, 09 2007 at 08:41 AM
