User's Manual

Layer-3 (L3) mobility allows a client to roam without losing its IP address and sessions. If WLAN access
parameters are the same across these networks, clients connected to APs in a given Cloud Network Manager
network can roam to APs in a foreign Cloud Network Manager network and continue their existing sessions using
their IP addresses. You can configure a list of Virtual Controller IP addresses across which L3 mobility is
supported.
The HP Cloud Network Manager Layer-3 mobility solution defines a Mobility Domain as a set networks, with the
same WLAN access parameters, across which client roaming is supported. The Cloud Network Manager network
to which the client first connects is called its home network. When the client roams to a foreign network, an AP in
the home network (home AP) anchors all traffic to or from this client. The AP to which the client is connected in the
foreign network (foreign AP) tunnels all client traffic to or from the home AP through a GRE tunnel.
Figure 7: Routing of traffic when the client is away from its home network
When a client first connects to Cloud Network Manager network, a message is sent to all configured Virtual
Controller IP addresses to see if this is an L3 roamed client. On receiving an acknowledgment from any of the
configured Virtual Controller IP addresses, the client is identified as an L3 roamed client. If the AP has no GRE
tunnel to this home network, a new tunnel is formed to an AP (home AP) from the home network of the client.
Each foreign AP has only one home AP per Cloud Network Manager network to avoid duplication of broadcast
traffic. Separate GRE tunnels are created for each foreign AP / home AP pair. If a peer AP is a foreign AP for one
client and a home AP for another, two separate GRE tunnels are used to handle L3 roaming traffic between these
APs.
If client subnet discovery fails on association due to some reason, the foreign AP identifies its subnet when it
sends out the first L3 packet. If the subnet is not a local subnet and belongs to another network, the client is treated
as an L3 roamed client and all its traffic is forwarded to the home network through a GRE tunnel.
Configuring L3-mobility
To configure a mobility domain, you have to specify the list of all Cloud Network Manager networks that form the
mobility domain. To allow clients to roam seamlessly among all the APs, specify the VC IP for each foreign
subnet. You may include the local Cloud Network Manager or VC IP address, so that the same configuration can
be used across all Cloud Network Manager networks in the mobility domain.
HP Cloud Network Manager | User Guide Wireless configuration | 76