Multicast Routing; B.2.2 Multicast Routing; Figure B-1. Multicast Mapping (Ip To Mac - Comtech EF Data CME-5200 Installation And Operation Manual

CME-5200 Digicast Media Router ASI Receiver
IP Routing Support
Unicast is supported by the ASI-R as it would be in any routed network. Packets received
by the ASI-R are routed to the Ethernet if they meet the subnet criteria or the ASI-R is
configured to route non-local packets to a default gateway.
The ASI-R uses Classless Inter-Domain Routing (CIDR) notation in which a 'slash'
followed by a decimal number is used to represent the number of bits for the mask; e.g.,
/32 is 255.255.255.255 and /24 is 255.255.255.0.
As stated previously, part of the route configuration is a MAC address that is assigned for
delivery of the packet when it is encapsulated into MPE. The MAC address typically
identifies the remote receiver (physical device); e.g., satellite terminal, DTV terminal, or
cable receiver.
B.2.2

Multicast Routing

Multicast routing provides point-to-multipoint delivery of IP datagrams. Routes for
multicast IP packets are configured according to the following:
•
•
•
Multicast IP addresses are related to multicast MAC addresses as follows:
•
Several examples of the relationship are:
•
•
•
first byte of the six-byte MAC address is a '0'. For example, 0x00 11 22 33 44 55
is a Unicast address.
IP Addresses, which fall into class D (224.0.0.0 to 239.255.255.255)
Medium Access Control (MAC) Addresses, which identify the frames as
multicast. The least-significant bit of the first byte of the six-byte MAC address
is a '1'. For example, 0x01 00 5E 00 00 01 is a multicast address.
Broadcast frames are identified by the MAC Address, 0x FF FF FF FF FF FF.
The lower 23 bits of the IP address are mapped into the lower 23 bits of the MAC
address.

Figure B-1. Multicast Mapping (IP to MAC)

Received IP: 239.1.1.10 = MAC: 0x01 00 5E 01 01 0A
Received IP: 224.10.10.10 = MAC: 0x01 00 5E 0A 0A 0A
Received IP: 228.63.10.10 = MAC: 0x01 00 5E 3F 0A 0A
B-2
Revision A
MN/MRASIRCDC.IOM