Comtech EF Data CMR-5970 Manual - Manual (Page 72)

Digicast Media Router S2 Receiver CMR-5970 (MR-S2) & CRM-5990 (MR-S2-ASI) Revision A
IP Routing Support MN/MRS2ASIDC.IOM
B.2.1 Unicast Routing
Unicast routing provides point-to-point delivery of IP datagrams. Routes for Unicast IP
packets are configured according to the following:
•
IP Addresses, which fall into three classes:
o A (0.0.0.0 to 127.255.255.255)
o B (128.0.0.0 to 191.255.255.255)
o C (192.0.0.0 to 223.255.255.255)
•
Medium Access Control (MAC) Addresses, which identifies the destination
device (next-hop) to which the packets are sent. The least-significant bit of the
first byte of the six-byte MAC address is a ‘0’. For example, 0x00 11 22 33 44 55
is a Unicast address.
Unicast is supported by the MR-S2 as it would be in any routed network. Packets
received by the MR-S2 are routed to the Ethernet if they meet the subnet criteria or the
MR-S2 is configured to route non-local packets to a default gateway.
The MR-S2 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 above, 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:
•
IP Addresses, which fall into class D (224.0.0.0 to 239.255.255.255)
•
Medium Access Control (MAC) Addresses, which identifies 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 .
Multicast IP addresses are related to multicast MAC addresses as follows:
The lower 23 bits of the IP address are mapped into the lower 23 bits of the MAC address
as shown in Figure B-1. Examples of the relationship are:
1) Received IP: 239.1.1.10 = MAC: 0x01 00 5E 01 01 0A
2) Received
IP: 224.10.10.10 = MAC: 0x01 00 5E 0A 0A 0A
3) Received IP: 228.63.10.10 = MAC: 0x01 00 5E 3F 0A 0A
B–2