8-port Gigabit Ethernet Switch User’s Guide
22
Classless InterDomain Routing – CIDR
Under CIDR, the subnet mask notation is reduced to a simplified shorthand. Instead of specifying all of the bits of the
subnet mask, it is simply listed as the number of contiguous “1”s (bits) in the network portion of the address. Look at the
subnet mask of the above example in binary - 11111111.11100000.00000000.00000000 – and you can see that there are
11 “1”s or 11 bits used to mask the network address from the node address. Written in CIDR notation this becomes:
10.32.0.0/11
#
of
Bit
s
Subnet Mask
CID
R
Not
atio
n
# of
Subnets
# of Hosts
Total Hosts
2
255.192.0.0
/10
2
4194302
8388604
3
255.224.0.0
/11
6
2097150
12582900
4
255.240.0.0
/12
14
1048574
14680036
5
255.248.0.0
/13
30
524286
15728580
6
255.252.0.0
/14
62
262142
16252804
7
255.254.0.0
/15
126
131070
16514820
8
255.255.0.0
/16
254
65534
16645636
9
255.255.128.0
/17
510
32766
16710660
10
255.255.192.0
/18
1022
16382
16742404
11
255.255.224.0
/19
2046
8190
16756740
12
255.255.240.0
/20
4094
4094
16760836
13
255.255.248.0
/21
8190
2046
16756740
14
255.255.252.0
/22
16382
1022
16742404
15
255.255.254.0
/23
32766
510
16710660
16
255.255.255.0
/24
65534
254
16645636
17
255.255.255.128 /25
131070
126
16514820
18
255.255.255.192 /26
262142
62
16252804
19
255.255.255.224 /27
525286
30
15728580
20
255.255.255.240 /28
1048574 14
14680036
21
255.255.255.248 /29
2097150 6
12582900
22
255.255.255.252 /30
4194302 2
8388604
Table 5-2. Class A Subnet Masks
# of
Bits
Subnet Mask
CIDR
Notatio
n
# of
Subnets
# of
Hosts
Total
Hosts
2
255.255.192
/18
2
16382
32764
3
255.255.224.0
/19
6
8190
49140
4
255.255.240.0
/20
14
4094
57316
5
255.255.248.0
/21
30
2046
61380
6
255.255.252.0
/22
62
1022
63364
7
255.255.254.0
/23
126
510
64260
8
255.255.255.0
/24
254
254
64516
9
255.255.255.12
8
/25
510
126
64260
10
255.255.255.19
2
/26
1022
62
63364
11
255.255.255.22
4
/27
2046
30
61380
12
255.255.255.24
0
/28
4094
14
57316
13
255.255.255.24
8
/29
8190
6
49140
14
255.255.255.25
/30
16382
2
32764
Summary of Contents for DGS-3308 Series
Page 23: ...8 port Gigabit Ethernet Switch User s Guide 13 Figure 4 2 Switch to switch connection ...
Page 161: ...8 port Gigabit Ethernet Switch User s Guide 151 ...
Page 162: ...8 port Gigabit Ethernet Switch User s Guide 152 Layer 2 Mode ...
Page 163: ...8 port Gigabit Ethernet Switch User s Guide 153 ...
Page 164: ...8 port Gigabit Ethernet Switch User s Guide 154 ...
Page 242: ......