What Is Multicast Tunneling; What Is Igmp - Dell PowerConnect 7048P Manual

What Is Multicast Tunneling?

If Multicast traffic is to be routed through a part of a network that does not
support multicasting (routers which are not multicast capable) then the
multicast packets are encapsulated in an IP datagram and sent as a unicast
packet. When the multicast router at the remote end of the tunnel receives
the packet, the router strips off the IP encapsulation and forwards the packet
as an IP Multicast packet. This process of encapsulating multicast packets in
IP is called tunneling.

What Is IGMP?

The Internet Group Management Protocol (IGMP) is used by IPv4 systems
(hosts, L3 switches, and routers) to report their IP multicast group
memberships to any neighboring multicast routers. The PowerConnect 7000
Series switch performs the multicast router role of the IGMP protocol, which
means it collects the membership information needed by the active multicast
routing protocol.
The PowerConnect 7000 Series switch supports IGMP Version 3. Version 3
adds support for source filtering, which is the ability for a system to report
interest in receiving packets only from specific source addresses, as required to
support Source-Specific Multicast [SSM], or from all but specific source
addresses, sent to a particular multicast address. Version 3 is designed to be
interoperable with Versions 1 and 2.
Understaning IGMP Proxy
IGMP proxy enables a multicast router to learn multicast group membership
information and forward multicast packets based upon the group
membership information. The IGMP Proxy is capable of functioning only in
certain topologies that do not require Multicast Routing Protocols (i.e.,
DVMRP, PIM-DM, and PIM-SM) and have a tree-like topology, as there is no
support for features like reverse path forwarding (RPF) to correct packet route
loops.
The proxy contains many downstream interfaces and a unique upstream
interface explicitly configured. It performs the host side of the IGMP protocol
on its upstream interface and the router side of the IGMP protocol on its
downstream interfaces.
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Managing IPv4 and IPv6 Multicast