26
subnet is used to determine how to split an IP address to the network prefix and the
host address in bitwise basis. It is designed to utilize IP address more efficiently and
ease to manage IP network.
For a class B network, 128.1.2.3, it may have a subnet mask 255.255.0.0 in
default, in which the first two bytes is with all 1s. This means more than 60
thousands of nodes in flat IP address will be at the same network. It’s too large to
manage practically. Now if we divide it into smaller network by extending network
prefix from 16 bits to, say 24 bits, that’s using its third byte to subnet this class B
network. Now it has a subnet mask 255.255.255.0, in which each bit of the first
three bytes is 1. It’s now clear that the first two bytes is used to identify the class B
network, the third byte is used to identify the subnet within this class B network and,
of course, the last byte is the host number.
Not all IP address is available in the sub-netted network. Two special
addresses are reserved. They are the addresses with all zero’s and all one’s host
number. For example, an IP address 128.1.2.128, what IP address reserved will be
looked like? All 0s mean the network itself, and all 1s mean IP broadcast.
In this diagram, you can see the subnet mask with 25-bit long,
255.255.255.128, contains 126 members in the sub-netted network. Another is that
the length of network prefix equals the number of the bit with 1s in that subnet mask.
With this, you can easily count the number of IP addresses matched. The following
table shows the result.
Prefix Length No. of IP matched No. of Addressable IP
/32 1
-
/31 2
-
/30 4
2
10000000.00000001.00000010.1 0000000
128.1.2.128/25
25 bits
1 0000000
1 1111111
All 0s = 128.1.2.128
All 1s= 128.1.2.255
Subnet
Network
Содержание KGS-2416
Страница 2: ......
Страница 4: ......
Страница 34: ...30 Fig 2 15 Office Network Connection Fig 2 14 Peer to peer Network Connection ...
Страница 93: ...89 Fig 3 39 Fig 3 40 Fig 3 41 ...
Страница 105: ...101 Fig 3 54 Set up Typical Network Application Rules Finish Fig 3 55 Set up Typical Network Application Rules Finish ...
Страница 109: ...105 Fig 3 62 Set up VLAN Tag Priority Mapping Finish ...
Страница 116: ...112 Fig 3 67 Ingress Port Fig 3 68 ...
Страница 118: ...114 Fig 3 71 Fig 3 72 Fig 3 73 ARP ...
Страница 119: ...115 Fig 3 74 ARP Fig 3 75 ARP Fig 3 76 ARP Fig 3 77 ARP ...
Страница 120: ...116 Fig 3 78 ARP Fig 3 79 ARP Fig 3 80 ARP Fig 3 81 ARP ...
Страница 121: ...117 Fig 3 82 ARP Fig 3 83 ARP Fig 3 84 ARP Fig 3 85 ARP Fig 3 86 ARP ...
Страница 122: ...118 Fig 3 87 IPv4 Fig 3 88 IPv4 Fig 3 89 IPv4 ...
Страница 123: ...119 Fig 3 90 IPv4 Fig 3 91 IPv4 Fig 3 92 IPv4 Fig 3 93 IPv4 Fig 3 94 IPv4 ...
Страница 124: ...120 Fig 3 95 IPv4 Fig 3 96 IPv4 Fig 3 97 IPv4 Fig 3 98 IPv4 Fig 3 99 IPv4 ...
Страница 125: ...121 Fig 3 100 IPv4 Fig 3 101 IPv4 Fig 3 102 IPv4 ...
Страница 126: ...122 Fig 3 103 IPv4 Fig 3 104 IPv4 Fig 3 105 IPv4 ...
Страница 127: ...123 Fig 3 106 IPv4 Fig 3 107 IPv4 Fig 3 108 IPv4 ...
Страница 128: ...124 Fig 3 109 IPv4 Fig 3 110 IPv4 Fig 3 111 IPv4 ...
Страница 129: ...125 Fig 3 112 IPv4 Fig 3 113 IPv4 Fig 3 114 IPv4 ...
Страница 130: ...126 Fig 3 115 IPv4 Fig 3 116 IPv4 Fig 3 117 Action ...
Страница 131: ...127 Fig 3 118 Rate Limiter Fig 3 119 Port Copy ...
Страница 132: ...128 Fig 3 120 DMAC Filter Fig 3 121 VLAN ID Filter Fig 3 122 VLAN ID Filter ...
Страница 144: ...140 Fig 3 124 Wizard Fig 3 125 Set up Policy Rules Fig 3 126 Set up Policy Rules ...
Страница 145: ...141 Fig 3 127 Set up Policy Rules Fig 3 128 Set up Policy Rules Finish Fig 3 129 Set up Port Policies ...
Страница 146: ...142 Fig 3 130 Set up Port Policies Fig 3 131 Set up Port Policies ...
Страница 147: ...143 Fig 3 132 Set up Port Policies Finish Fig 3 133 Set up Typical Network Application Rules ...
Страница 148: ...144 Fig 3 134 Set up Typical Network Application Rules Fig 3 135 Set up Typical Network Application Rules ...
Страница 151: ...147 Fig 3 140 Set up Source MAC and Source IP Binding Fig 3 141 Set up Source MAC and Source IP Binding Finish ...
Страница 190: ...186 Restricted Role Same as mentioned in Port Config Restricted Tcn Same as mentioned in Port Config ...
Страница 222: ...218 Fig 4 1 Fig 4 2 ...
