IP Multicast
A virtual router supports IP multicast so that it can
participate in multicast protocols (IGMP and PIM) and forward multicast
traffic from a source to multiple receivers.
IP multicast is a set of protocols that network appliances
use to send multicast IP datagrams to a group of interested receivers
using one transmission rather than unicasting the traffic to multiple
receivers, thereby saving bandwidth. IP multicast is suitable for
communication from one source (or many sources) to many receivers,
such as audio or video streaming, IPTV, video conferencing, and
distribution of other communication, such as news and financial
data.
A multicast address identifies a group of receivers that want
to receive the traffic going to that address. You should not use
the multicast addresses reserved for special uses, such as the range
224.0.0.0 through 224.0.0.255 or 239.0.0.0 through 239.255.255.255.
Multicast traffic uses UDP, which does not resend missed packets.
Palo Alto Networks® firewalls support IP multicast and Protocol
Independent Multicast (PIM) on a Layer 3 interface that you configure
for a
virtual router on
the firewall.
For multicast routing, the Layer 3 interface type can be Ethernet,
Aggregate Ethernet (AE), VLAN, loopback, or tunnel. Interface groups
allow you to configure more than one firewall interface at a time
with the same Internet Group Management Protocol (IGMP) and PIM
parameters, and with the same group permissions (multicast groups
allowed to accept traffic from any source or from only a specific
source). An interface can belong to only one interface group.
The firewall supports IPv4 multicast—it does not support IPv6
multicast. The firewall also does not support PIM Dense Mode (PIM-DM),
IGMP proxy, IGMP static joins, Anycast RP, GRE, or multicast configurations
on a Layer 2 or virtual wire interface type. However, a virtual
wire interface can pass multicast packets. Also, a Layer 2 interface
can switch Layer 3 IPv4 multicast packets between different VLANs
and the firewall will retag the VLAN ID using the VLAN ID of the
egress interface.
You must enable multicast for a virtual router and enable PIM
for an ingress and an egress interface in order for the interfaces
to receive or forward multicast packets. In addition to PIM, you
must also enable IGMP on egress interfaces that face receivers.
You must configure a Security policy rule to allow IP multicast
traffic to a predefined Layer 3 destination zone named multicast or
to any destination zone.
