ZyXEL Communications MSC1000G Series, User Manual

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Chapter 4 Access Control List Screens
Management Switch Card User’s Guide
145
An IP address with host IDs of all zeros is the IP address of the network (192.168.1.0 with a 24-bit
subnet mask, for example). An IP address with host IDs of all ones is the broadcast address for that
network (192.168.1.255 with a 24-bit subnet mask, for example).
As these two IP addresses cannot be used for individual hosts, calculate the maximum number of
possible hosts in a network as follows:
Notation
Since the mask is always a continuous number of ones beginning from the left, followed by a
continuous number of zeros for the remainder of the 32 bit mask, you can simply specify the
number of ones instead of writing the value of each octet. This is usually specified by writing a “/”
followed by the number of bits in the mask after the address.
For example, 192.1.1.0 /25 is equivalent to saying 192.1.1.0 with subnet mask 255.255.255.128.
The following table shows some possible subnet masks using both notations.
4.31 MACFF ARP Proxy Screen
Click ACL > MACFF ARP Proxy to open the screen. Use this screen to view Address Resolution
Protocol (ARP) entries of Access Routers (ARs) and Application Servers (ASes) for which the MSC
acts as a proxy to respond to ARP queries from subscribers.
Table 52
Maximum Host Numbers
SUBNET MASK HOST ID SIZE MAXIMUM NUMBER OF HOSTS
8 bits 255.0.0.0 24 bits 2
24
– 2 16777214
16 bits 255.255.0.0 16 bits 2
16
– 2 65534
24 bits 255.255.255.0 8 bits 2
8
– 2 254
29 bits 255.255.255.248 3 bits 2
3
– 2 6
Table 53
Alternative Subnet Mask Notation
SUBNET MASK
ALTERNATIVE
NOTATION LAST OCTET
(BINARY) LAST OCTET
(DECIMAL)
255.255.255.0 /24 0000 0000 0
255.255.255.128 /25 1000 0000 128
255.255.255.192 /26 1100 0000 192
255.255.255.224 /27 1110 0000 224
255.255.255.240 /28 1111 0000 240
255.255.255.248 /29 1111 1000 248
255.255.255.252 /30 1111 1100 252