Motorola Series Switch WS5100 - Manual (Page 206)

5-36 WS5100 Series Switch System Reference Guide
DHCP and ARP are tunneled through the home switch. The IP address for the MU is assigned from the VLAN
to which the MU belongs (as determined by the home switch).
The current switch for the MU is the switch in the mobility domain to which it is currently associated to, and
keeps changing as the MU continues to roam amongst. The current switch is also responsible for delivering
data packets from the MU to its home switch and vice-versa.
Key aspects of Layer 3 Mobility include:
• Seamless MU roaming between switches on different Layer 3 subnets, while retaining the same IP
address.
• Static configuration of mobility peer switches.
• Layer 3 support does not require any changes to the MU. In comparison, other solutions require special
functionality and software on the MU. This creates numerous inter-working problems with working with
MUs from different legacy devices which do not support Layer
• Support for a maximum of 20 peers, each handling up to a maximum of 500 MUs.
• A full mesh of GRE tunnels can be established between mobility peers. Each tunnel is between a pair of
switches and can handle data traffic for all MUs (for all VLANs) associated directly or indirectly with the
MU.
• Data traffic for roamed MUs is tunneled between switches by encapsulating the entire L2 packet inside
GRE with a proprietary code-point.
• When MUs roam within the same VLAN (L2 Roaming), the behavior is retained by re-homing the MU to
the new switch so extra hops are avoided while forwarding data traffic.
• MUs can be assigned IP addresses statically or dynamically.
• Forward and reverse data paths for traffic originating from and destined to MUs that have roamed from
one L3 subnet to another are symmetric.
CAUTION: An access port is required to have a DHCP provided IP address before
attempting layer 3 adoption, otherwise it will not work. Additionally, the access port must
be able to find the IP addresses of the switches on the network.
To locate switch IP addresses on the network:
• Configure DHCP option 189 to specify each switch IP address.
• Configure a DNS Server to resolve an existing name into the IP of the switch. The access
port has to get DNS server information as part of its DHCP information. The default DNS
name requested by an AP300 is “Symbol-CAPWAP-Address”. However, since the default
name is configurable, it can be set as a factory default to whatever value is needed.
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