Wired Switching - Motorola WS5100 Series Reference Manual

1-18 WS5100 Series Switch System Reference Guide

1.2.3 Wired Switching

The switch includes the following wired switching features:
• DHCP Servers
• DDNS
• VLAN Enhancements
• Interface Management
• DHCP User Class Options
1.2.3.1 DHCP Servers
Dynamic Host Configuration Protocol (DHCP) allows hosts on an IP network to request and be assigned IP
addresses as well as discover information about the network to which they are attached. Configure address
pools for each subnet. Whenever a DHCP client requests an IP address, the DHCP server assigns an IP
address from that subnet's address pool.
When a DHCP server allocates an address for a DHCP client, the client is assigned a lease, which expires
after an pre-determined interval. Before a lease expires, clients (to which leases are assigned) are expected
to renew them to continue to use the addresses. Once the lease expires, the client is no longer permitted to
use the leased IP address. For information on defining the switch DHCP configuration, see
DHCP Server Settings on page
1.2.3.2 DDNS
Dynamic DNS (DDNS) keeps a domain name linked to a changing IP address. Typically, when a user connects
to a network, the user's ISP assigns it an unused IP address from a pool of IP addresses. This address is only
valid for a short period. Dynamically assigning IP addresses increases the pool of assignable IP addresses.
DNS maintains a database to map a given name to an IP address used for communication on the Internet.
The dynamic assignment of IP addresses makes it necessary to update the DNS database to reflect the
current IP address for a given name. Dynamic DNS updates the DNS database to reflect the correct mapping
of a given name to an IP address.
1.2.3.3 VLAN Enhancements
The switch has incorporated the following VLAN enhancements:
• Physical port (L2) is now operated in Trunk Mode or Access Mode.
• A VLAN now allows an AP to receive and send only untagged packets. All tagged packets received by the
AP are discarded. The untagged traffic received is placed in an "access vlan".
• A trunk port can now receive both tagged and untagged packets. Only one native VLAN per trunk port is
supported. All untagged traffic received on is placed into a "native vlan".
• You can now configure a set of allowed VLANs on a trunk port. Packets received on this port that belong
to other VLANs are discarded.
5-3.