Lucent Technologies 6000 User Manual
9-2
MAX 6000/3000 Network Configuration Guide
Configuring IP Routing
Introduction to IP routing on the MAX
Introduction to IP routing on the MAX
For example, a class C address, such as 198.5.248.40, has 24 network bits, leaving eight bits
for the host portion of the address. If no subnet mask is specified for a class C address, the
MAX assumes the default mask of 24 bits, as shown in Figure 9-1.
for the host portion of the address. If no subnet mask is specified for a class C address, the
MAX assumes the default mask of 24 bits, as shown in Figure 9-1.
Figure 9-1. Default mask for class C IP address
Subnet mask format
To specify a subnet mask, you append a modifier that specifies the number of network bits in
the address. For example:
the address. For example:
198.5.248.40/29
In this example, the /29 indicates that 29 bits of the address are used to specify the network.
This is referred to as a 29-bit subnet. The three remaining bits specify unique hosts, as shown
in Figure 9-2.
This is referred to as a 29-bit subnet. The three remaining bits specify unique hosts, as shown
in Figure 9-2.
Figure 9-2. A 29-bit subnet mask and the number of supported hosts
In Figure 9-2, three available bits present eight possible bit combinations. Of the eight possible
host addresses, two are reserved, as follows:
host addresses, two are reserved, as follows:
000 — Reserved for the network (base address)
001
010
011
100
101
110
111—Reserved for the broadcast address of the subnet
001
010
011
100
101
110
111—Reserved for the broadcast address of the subnet
Class B
128.0.0.0—191.255.255.255
16
Class C
192.0.0.0—223.255.255.255
24
Table 9-1. IP address classes and number of network bits (continued)
Class
Address range
Network bits
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0
Default 24 bits
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0
Default 24 bits
5-bit subnet
Total network bits=29
255
128
64
32
16
8
4
2
Number of host addresses
(2 of which are reserved)
(2 of which are reserved)