Motorola Series Switch WS5100 - Manual (Page 205)

Switch Services 5-35
• Whenever the cluster protocol is disabled, a member switch forgets the learned cluster license as well
as peer information needed to compute license totals.
• If the switch start-up configuration is removed, a member switch forgets the learned cluster license as
well as peer information needed to compute license totals.
• If adding a new switch (with zero or non-zero installed license) to a group with at least one license
contributing switch down, the new group member will receive a different cluster license value.
For example, for a cluster of three switches (S1 = 6, S2 = 6 and S3 = 6 licenses), the group license count
is 18. If S1 goes down, the license count is still 18, since the license calculation is not initiated if a
member switch goes down. If S4 (with zero licenses) is introduced, S4 becomes part of the group (can
exchange updates and other packets), but has license count of 12 (NOT 18), even though S2 and S3 still
show a license count of 18. This should be an indicator a new member has been introduced during a
period when the redundancy group is not operating with all its license contributing members.
5.5 Layer 3 Mobility
Refer to the following sections to configure Layer 3 Mobility:
• Configuring Layer 3 Mobility
• Defining the Layer 3 Peer List
• Reviewing Layer 3 Peer List Statistics
• Reviewing Layer 3 MU Status
5.5.1 Configuring Layer 3 Mobility
Layer 3 mobility is a mechanism which enables a MU to maintain the same Layer 3 address while roaming
throughout a multi-VLAN network. This enables transparent routing of IP datagrams to MUs during their
movement, so data sessions can be initiated while they roam (in for voice applications in particular). Layer 3
mobility enables TCP/UDP sessions to be maintained in spite of roaming among different IP subnets.
A mobility domain comprises of a network of switches among which an MU can roam seamlessly without
changing its IP address. Each switch in the mobility domain needs to be configured to be part of the same
mobility domain (using a mobility domain string identifier) such that MUs roaming between these switches
can retain their Layer 3 address and thus maintain application-layer connectivity.
When a MU enters a mobility domain by associating with a switch, it is first assigned a home switch. The
home switch is responsible for assigning a VLAN for the MU and communicating the MU's mobility-related
parameters to the other switches in the mobility domain. The home switch does not change for the remainder
of the MU's presence in the mobility domain. All data packets transmitted/received by the MU including