Motorola WS5100 manual Wired Switching, 1.2.3.1DHCP Servers, 1.2.3.2DDNS, 1.2.3.3GRE Tunneling

1-16WS5100 Series Switch System Reference Guide

flow having UPSD enabled. After the AP acknowledges the trigger frame, it transmits the frames in its UPSD power save buffer addressed to the triggering switch.

UPSD is well suited to support bi-directional frame exchanges between a voice STA and its AP

1.2.3 Wired Switching

The switch includes the following wired switching features:

•DHCP Servers

•DDNS

•GRE Tunneling

•VLAN Enhancements

•Interface Management

•Multiple WLAN Support

1.2.3.1DHCP Servers

Dynamic Host Configuration Protocol (DHCP) allows hosts on an IP network to request and be assigned IP addresses, and discover information about the network to which they are attached. Configure address pools for each subnet, and whenever a DHCP client in that subnet requests an IP address, the DHCP server assigns an IP address from the address pool configured for that subnet.

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 5-3.

1.2.3.2DDNS

Dynamic DNS (DDNS) is a method of keeping 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.

1.2.3.3GRE Tunneling

GRE tunnelling extends a WLAN across a Layer 3 network using standards based GRE tunneling technology.

•GRE tunnels need to be explicitly provisioned on the switch as well as the tunnel termination device present at the other end of the Layer 3 network.

•One or more WLANS on the switch are then mapped to the GRE tunnel interface. The configuration is very similar to mapping WLANs to VLANs.

•All IP packets received from MUs on the WLAN are encapsulated in GRE and sent across the Layer 3 network. The tunnel termination device at the other end decapsulates the GRE header and routes the inner IP packet to its original destination.