Data network planning
ptp-450 (July 2014)
2-81
Example IP address and subnet mask
In
the first 16 bits of the 32-bit IP address identify the network:
Figure 25
Example of IP address in Class B subnet
Octet 1
Octet 2
Octet 3
Octet 4
IP address 169.254.1.1
10101001 11111110 00000001 00000001
Subnet mask 255.255.0.0 11111111 11111111 00000000 00000000
In this example, the network address is 169.254, and 2
16
(65,536) hosts are addressable.
Selecting non-routable IP addresses
The factory default assignments for network elements are
unique MAC address
IP address of 169.254.1.1
subnet mask of 255.255.0.0
network gateway address of 169.254.0.0
For each radio and CMMmicro and CMM4, assign an IP address that is both consistent with the IP addressing plan
for your network and cannot be accessed from the Internet. IP addresses within the following ranges are not
routable from the Internet, regardless of whether a firewall is configured:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
You can also assign a subnet mask and network gateway for each CMMmicro and CMM4.
Translation bridging
Optionally, you can configure the BHM to change the source MAC address in every packet it receives from its
BHSs to the MAC address of the BHS that bridged the packet, before forwarding the packet toward the public
network. If you do, then
not more than 10 IP devices at any time are valid to send data to the BHM from behind the BHS.
the BHM populates the Translation Table tab of its Statistics web page, displaying the MAC address and IP
address of all the valid connected devices.
each entry in the Translation Table is associated with the number of minutes that have elapsed since the last
packet transfer between the connected device and the BHS.
if 10 are connected, and another attempts to connect
o
and no Translation Table entry is older than 255 minutes, the attempt is ignored.
o
and an entry is older than 255 minutes, the oldest entry is removed and the attempt is successful.
the
Send Untranslated ARP
parameter in the General tab of the Configuration page can be
o
disabled, so that the BHM will overwrite the MAC address in Address Resolution Protocol (ARP) packets
before forwarding them.
o
enabled, so that the BHM will forward ARP packets regardless of whether it has overwritten the MAC
address.
Summary of Contents for PTP 450 series
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