This event had place on Tuesday 19th, November 2019 at 9hrs PDT
You can download the slides of the presentation in PDF format here.
A: The Multicast packets are tunneled to the anchor controller of the client to avoid the reverse path filtering (RPF) check. The anchor then forwards the multicast packets to the infrastructure switch.
A: Yes, you need to enable global Multicast on the WLC to start talking Multicast.
A: They are sent using A-MPDU.
A: Then, no need to enable multicast on that VLAN. You can use either Multicast-multicast or Multicast-unicast.
A: Vlan 30 is the AP vlan
A: That is correct.
A: If it is local mode or central switching the APs will lose connectivity and the whole wireless network will be down.
A: Actually, when you do media stream you specify a Multicast stream and what it does is that you can combine that with Multicast direct to be able to send that traffic in unicast towards APS for specific Multicast groups and that will allow you to do some reliable sending and apply different policies Since traffic will be in unicast.
A: If you have FlexConnect Local Switching, you don't need to enable multicast at the WLC. The traffic will be handled locally at the switch, therefore if you need the multicast communication to happen between different subnets or even different sites, you need to enable multicast in the wired network between the source and the receivers. The WLCs will not participate in the multicast traffic forwarding, therefore its location is not relevant.
A: Yes, since they are part of the Multicast group they all will receive the Multicast traffic. Nevertheless, they do not have any client requesting this traffic they will simply drop this traffic.
A: We used ip pim sparse-dense. This will use Sparse mode if there is a RP (Rendevouz Point) enabled, or Dense Mode if there is not.
A: Yes, this is needed for video stream. But there is some additional steps to make video stream more reliable.Please refer : https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/multicast_broadcast_setup.html#d110100e1461a1635
A: For FlexConnect, all the mcast configuration must happen in the wired network. For example, if you need mcast traffic between clients on different SSIDs/VLANs, you need to enable multicast-routing and pim on both VLANs at the gateway. No wlc config reqd.
A: TP use Multicast unicast, you need to configure the AP Multicast mode and select Unicast. In that way WLC will send multicast traffic to the interested APs using unicast packets. This Multicast mode is not recommended for more than 50 APs. In this mode you do not need to enable multicast between APs and WLC vlans.
A: Exactly. Then you will need PIM enabled all the way between the DC and the client's default gateway.
A: The main difference is that DMs is 802 11 B so the clients need to support 802 11 B. So on video stream, if the AP captures the Multicast packets that are sent from those clients to allow the clients to sleep for longer time they will send the packet after the client come back up. Whereas on Multicast stream we’re just talking about the conversion form Multicast to Unicast
A: The forwarding logics from the controllers to the Aps is most likely the same if you need Multicast routing between the controller and the AP management VLAN.
Nevertheless, for IPv6 you need to consider other things into consideration, such as a logical route advertisement guard to prevent clients from becoming Multicast gateways at the default subnet etc.
The logic about how Ipv6 and Pv4 works is pretty much the same, but MLD and IPv6 have some differences on the way the clients learn or request Multicast traffic, they also need to have different type of packages so you can leverage Multicast to get IP addresses, etc. There are specific things for IPv6 but overall forwarding of the traffic is the same of what we showed on this session
A: In this case the multicast traffic is not forwarded since Multicast is not enabled in the WLC. This scenario is not supported, please refer: "Table 1. Platform Support for Global Multicast and Multicast Mode"
A: Multicast traffic is sent at the highest mandatory data rate. Therefore, the client may be using a higher rate for unicast frames. We usually recommend having only 1 mandatory rate but if you have a multicast heavy deployment, consider enabling two. QoS wise it is treated the same. But there are some optional features that you can enable, for example multicast-direct or 802.11v DMS. The way between the DC and the client's default gateway.
A: AP multicast mode is the multicast method that the controller uses in order to transport the multicast packets over CAPWAP to all or several access points at the same time. The controller performs multicasting in two modes, unicast and multicast. For further details refer: https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/81671-multicast-wlc-lap.html#anc4
The multicast group address is used in case you choose AP multicast mode as "Multicast". When you enable multicast mode on the controller, you must also configure a CAPWAP multicast group address. APs subscribe to the CAPWAP multicast group using IGMP. When you enable multicast mode and the controller receives a multicast packet from the wired LAN, the controller encapsulates the packet using CAPWAP and forwards the packet to the CAPWAP multicast group address.