User's Manual Part 2

Chapter 9
Configuring Motrix Roaming
This chapter contains information on configuring the Motrix Roaming Service on the
MSR2000.
Motrix Protocol Overview
Motrix is the roaming service MSR2000 provides to support the seamless roaming of
wireless clients across different mesh network subnets. Such support is necessary
because every MSR2000 is a layer-3 router and each BSS within the mesh network is
associated with a single layer-3 subnet. These subnets are interconnected via IP routing
functions of the MSR2000. When a client joins the network on one router’s BSS, it would
have an IP that belongs to that BSS’s subnet. If the client subsequently roams to
another router’s BSS, the Motrix service enables the client to retain its connectivity to the
network using its previous IP address (which would actually belong to a different
subnet). Without motrix, the client would have to change its IP address and thus lose all
of its existing connections.
To support inter-subnet roaming, each participating access router must enable the
Motrix service and have the same BSS settings (SSID, authentication, etc) configured.
We emphasize "access router" here because it is not necessary for a MSR2000
configured only for backhaul or client to enable the Motrix service.
Motrix is designed to function with all 802.11-conforming clients without special client-
side support. When a client decides to leave its currently associated router and attempts
to associate with a new router, it sends to the new router an IEEE802.11 re-association
request to make roaming succeed. Upon observing the request, the Motrix service on
the new router will communicate with the Motrix service running on other participating
routers and set up the roaming support that routes the client traffic through the new
router.
Note: There are some clients that do not send re-association requests as according to
the 802.11 standard. These non-conforming clients always send association requests
regardless of whether they are first associating to an AP when they switch from one AP
to another. Motrix currently can not provide roaming support for these clients without
additional configurations (see the following section “Support for non-conforming or static
IP clients”). The appendix section of this manual contains a list of clients that have
verified to be 802.11-conforming clients as well as a list of non-conforming clients.
It is also
highly recommended that the participating clients use dynamic IP addressing
(DHCP). If the clients must be configured with static IP addresses or the client it is non-
conforming, (see above) please refer to the following section “Support for non-
conforming or static IP clients”
MSR2000 CLI Configuration Guide
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