Users Guide

Working with Proxy IGMP and Proxy Remote Subscription
The controller is always aware of the client's location, so the controller can join multicast group(s) on behalf of
that mobile client. This feature, called Proxy IGMP, allows the controller to join a multicast group and
suppresses the client’s IGMP control messages to the upstream multicast router. (The client's IGMP control
messages will, however, still be used by controller to maintain a multicast forwarding table.) The multicast
IGMP traffic originating from the client will instead be sent from the controller’s incoming VLAN interface IP.
The IGMP proxy feature includes both a host implementation and a router implementation. An upstream
router sees a controller running IGMP proxy as a host; a client attached to the controller sees the controller as
router. When you enable Proxy IGMP, all multicast clients associated with the controller are hidden from the
upstream multicast device or router.
The newer IGMP proxy feature and the older IGMP snooping feature cannot be enabled at the same time, as both
features add membership information to multicast group table. For most multicast deployments, you should enable
the IGMP Proxy feature on all VLAN interfaces to manage all the multicast membership requirements on the
controller. If IGMP snooping is configured on some interfaces, there is a greater chance that multicast information
transfers may be interrupted.
IGMP proxy must be enabled or disabled on each individual interface. To use the IGMP proxy, ensure that the
VLANs on the controllers are extended to the upstream router. Enabling IGMP proxy enables IGMP on the
interface and sets the querier to the controller itself. You must identify the controller port from which the
controller sends proxy join information to the upstream router, and identify the upstream router by upstream
port so the controller can dynamically update the upstream multicast router information.
IGMPv3 Support
ArubaOS 6.4 supports IGMPv3 functionality that makes Dell controllers aware of the Source Specific Multicast
(SSM) and is used to optimize bandwidth of the network. The SSM functionality is an extension of IP multicast
where the datagram traffic is forwarded to receivers from only those multicast sources to which the receivers
have explicitly joined. By default, the multicast group range of 232.0.0.0 through 232.255.255.255 (232/8) is
reserved for SSM by IANA (Internet Assigned Numbers Authority).
The IGMPv3 snooping functionality is configured at the edge of the network. The devices that support IGMP
snooping listen for the IGMP messages that the host sent to join an IP multicast group. These devices record
details of all the hosts and also about the IP multicast group in which a particular host has joined. These devices
forward IP multicast traffic to the hosts that have joined the specific multicast group.
The IGMP proxy and IGMP snooping functionalities cannot be enabled on the same VLAN simultaneously.
Configuring SSM Range
You can configure the SSM range by using the CLI and WebUI.
In the WebUI
1. Navigate to Configuration > Network > IP > Multicast Routing page of the WebUI.
2. In the IGMP tab, enter values for SSM Range in the SSM Range Start-IP and SSM Range Mask-IP text
boxes.
3. Click Apply.
The proxy operation will be downgraded to IGMPv2 if any lower version clients are present and reverts back to v3
mode if the controller finds no lower version client joins (reports) for a specified interval of time. In the downgraded
proxy operation the SSM semantics is not applicable for the particular VLAN.
Dell Networking W-Series ArubaOS 6.4.x | User Guide IP Mobility | 707