how to generate and print barcode in c# windows application Lesson 1 in C#

Create Denso QR Bar Code in C# Lesson 1

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network into two smaller subnets, you could do this by assigning the subnet mask 255.255.255.128 to all of the workstations and placing a router between the two seg ments. See Figure 8-2.

Multiple Broadcast Domain Subnet 1 192.168.1.0/25

IP: 192.168.1.129 Subnet 2 192.168.1.128/25 Windows Server 2003 IP: 192.168.1.5 Subnet Mask: 255.255.255.128 Default Gateway: 192.168.1.1 IP: 192.168.1.140 Subnet Mask: 255.255.255.128 Default Gateway: 192.168.1.129

Figure 8-2

All of the nodes in Subnet 1 would be assigned IP addresses in the range of 1 through 126. Workstations in Subnet 2 would be assigned IP addresses in the range of 129 through 254. Each of the segments represents its own broadcast domain. Note also that the ports on the router need to be assigned IP addresses that correspond to the default gateway IP address that each node needs configured if that node connects to resources outside its subnet. In Lesson 3 you ll see how DHCP can be configured to assign these parameters to your workstations.

Table 8-4

Borrowed Bits 1 2 3 4 5 6 7 8 9 Resulting Subnet Mask (CIDR Notation) 255.128.0.0/9 255.192.0.0/10 255.224.0.0/11 255.240.0.0/12 255.248.0.0/13 255.252.0.0/14 255.254.0.0/15 255.255.0.0/16 255.255.128.0/17 Number of Hosts per Subnet 8,388,606 4,194,302 2,097,150 1,048,574 524,286 262,142 131,070 65,534 32,766

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Table 8-4

(continued)

Number of Subnets 513 1,024 1,025 2,048 2,049 4,096 4,097 8,192 8,193 16,384 16,385 32,768 32,769 65,536 65,537 131,072 131,073 262,144 262,145 524,288 524,289 1,048,576 1,048,577 2,097,152 2,097,153 4,194,304

Table 8-5

Resulting Subnet Mask (CIDR Notation) 255.255.192.0/18 255.255.224.0/19 255.255.240.0/20 255.255.248.0/21 255.255.252.0/22 255.255.254.0/23 255.255.255.0/24 255.255.255.0/25 255.255.255.192/26 255.255.255.224/27 255.255.255.240/28 255.255.255.248/29 255.255.255.252/30

Number of Hosts per Subnet 16,382 8,190 4,094 2,046 1,022 510 254 126 62 30 14 6 2

Borrowed Bits 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Resulting Subnet Mask (CIDR Notation) 255.255.128.0/17 255.255.192.0/18 255.255.224.0/19 255.255.240.0/20 255.255.248.0/21 255.255.252.0/22 255.255.254.0/23 255.255.255.0/24 255.255.255.128/25 255.255.255.192/26 255.255.255.224./27 255.255.255.240/28 255.255.255.248/29 255.255.255.252/30 Number of Hosts per Subnet 32,766 16,382 8,190 4,094 2,046 1,022 510 254 126 62 30 14 6 2

Number of Subnets 1 2 3 4 5 8 9 16 17 32 33 64 65 128 129 256 257 512 513 1,024 1,025 2,048 2,049 4,096 4,097 8,192 8,193 16,384

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Resulting Subnet Mask (CIDR Notation) 255.255.255.128/25 255.255.255.192/26 255.255.255.224/27 255.255.255.240/28 255.255.255.248/29 255.255.255.252/30

In companies that have workstations manually configured with IP address infor mation, there is a good chance that an error will occur while filling out the fields. One of the most common errors is inadvertently entering an incorrect subnet mask for a workstation. For example, if a workstation is configured with a Class C address of 192.16.9.131, it is easy to assume that the default subnet mask of 255.255.255.0 is being used for all workstations. Let s suppose the other workstations on the subnet are using a 255.255.255.192 mask. Recall that this mask will create four subnets: 192.168.9.0, 192.168.9.64, 192.168.9.128, and 192.168.9.192. If a router separated these networks, and the workstation you configured with an incorrect subnet mask tried to ping a workstation on the 192.168.9.64 network segment, the workstation would receive four Request Timeout messages. This would occur because the workstation you configured would not go to the default gateway, if one were configured, because it would see that its address of 192.168.9.131 was on the same segment as 192.168.9.66. In other words, it would calculate that both addresses were on the 192.168.9.0 subnet and therefore that the address it was trying to reach was a local address and did not require the use of a router. This, of course, is not true. When manually configuring a workstation with IP information, always verify that subnetting is not being used. A simple way to do this is to look at the configura tion of several other workstations in the area and any network topology diagrams available to you.