Cisco 200 Series Administration Manual page 152

Configuring IP Information
Management and IP Interfaces
Cisco Small Business 200 Series Smart Switch Administration Guide
When a VLAN is configured to use dynamic IP addresses, the switch issues DHCP
requests until it is assigned an IP address from a DHCP server. The management
VLAN can be configured with a static or dynamic IP address. The IP subnets to
which these IP addresses belong are known as directly connected/attached IP
subnets.
The IP address assignment rules for the switch are as follows:
• Unless the switch is configured with a static IP address, it issues DHCP
queries until a response is received from a 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.
• When no statically defined or DHCP-acquired IP address is available, the
default IP address is used. When the other IP addresses becomes available,
the addresses are automatically used. The default IP address is always on
the management VLAN.
The Internet Protocol version 6 (IPv6) is a network-layer protocol for packet-
switched internetworks. IPv6 was designed to replace IPv4, the predominantly
deployed Internet protocol.
IPv6 introduces greater flexibility in assigning IP addresses because the address
size increases from 32-bit to 128-bit addresses. IPv6 addresses are written as
eight groups of four hexadecimal digits, for example
FE80:0000:0000:0000:0000:9C00:876A:130B. The abbreviated form, in which a
group of zeroes can be left out, and replaced with '::', is also acceptable, for
example, ::-FE80::9C00:876A:130B.
IPv6 nodes require an intermediary mapping mechanism to communicate with
other IPv6 nodes over an IPv4-only network. This mechanism, called a tunnel,
enables IPv6-only hosts to reach IPv4 services, and allows isolated IPv6 hosts and
networks to reach an IPv6 node over the IPv4 infrastructure.
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