Cisco 500 series Administration Manual page 277

Configuring IP Information
Management and IP Interfaces
Cisco 500 Series Stackable Managed Switch Administration Guide
The IP address assignment rules for the switch are as follows:
• When in Layer 2 system mode, unless the switch is configured with a static
IP address, it issues DHCP queries until a response is received from the
DHCP server.
• If the IP address on the switch is changed, the switch issues gratuitous ARP
packets to the corresponding VLAN to check IP address collisions. This rule
also applies when the switch reverts to the default IP address.
• The system status LED changes to solid green when a new unique IP
address is received from the DHCP server. If a static IP address has been
set, the system status LED also changes to solid green. The LED flashes
when the switch is acquiring an IP address and is currently using the factory
default IP address 192. 1 68. 1 .254.
• The same rules apply when a client must renew the lease, prior to its
expiration date through a DHCPREQUEST message.
• With factory default settings, when no statically-defined or DHCP-acquired
IP address is available, the default IP address is used. When the other IP
addresses become available, the addresses are automatically used. The
default IP address is always on the management VLAN.
Layer 3 IP Addressing
In Layer 3 system mode, the switch can have multiple IP addresses. Each IP
address can be assigned to specified ports, LAGs, or VLANs. These IP addresses
are configured in the IPv4 Interface page in Layer 3 system mode. This provides
more network flexibility than the Layer 2 system mode, in which only a single IP
address can be configured. Operating in Layer 3 system mode, the switch can be
reached at all its IP addresses from the corresponding interfaces.
A predefined, default route is not provided in Layer 3 system mode. To remotely
manage the switch, a default route must be defined. All DHCP-assigned default
gateways are stored as default routes. In addition, you can manually define default
routes. This is defined in the IPv4 Static Routes page.
All the IP addresses configured or assigned to the switch are referred to as
Management IP addresses in this guide.
If the pages for Layer 2 and Layer 3 are different, both versions are displayed.
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