User Manual

Aolynk DR811/DR814 ADSL2+Broadband Router

6 IP Addresses, Network Masks, and Subnets

58

Table 6-1

IP Address structure

Class

Field1

Field2

Field3

Field4

Class A

Network ID

Host ID

Class B

Network ID

Host ID

Class C

Network ID

Host ID

Here are some examples of valid IP addresses:

Class A: 10.30.6.125 (network = 10, host = 30.6.125)

Class B: 129.88.16.49 (network = 129.88, host = 16.49)

Class C: 192.60.201.11 (network = 192.60.201, host = 11)

6.1.2 Network Classes

The three commonly used network classes are A, B, and C. (There is also a class D but

it has a special use beyond the scope of this discussion.) These classes have different

uses and characteristics.

Class A networks are the Internet's largest networks, each with room for over 16 million

hosts. Up to 126 of these huge networks can exist, for a total of over 2 billion hosts.

Because of their huge size, these networks are used for WANs and by organizations at

the infrastructure level of the Internet, such as your ISP.

Class B networks are smaller but still quite large, each able to hold over 65,000 hosts.

There can be up to 16,384 class B networks in existence. A class B network might be

appropriate for a large organization such as a business or government agency.

Class C networks are the smallest, only able to hold 254 hosts at most, but the total

possible number of class C networks exceeds 2 million (2,097,152 to be exact). LANs

connected to the Internet are usually class C networks.

Here are some important notes regarding IP addresses:

●

The class can be determined easily from field1:

field1 = 1-126:

Class A

field1 = 128-191:

Class B

field1 = 192-223:

Class C

(field1 values not shown are reserved for special uses)

●

A host ID can have any value except all fields set to 0 or all fields set to 255, as

those values are reserved for special uses.

6.2 Subnet Masks

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Aolynk DR811/DR814 ADSL2+Broadband Router

6 IP Addresses, Network Masks, and Subnets

59

&

Note:

A mask looks like a regular IP address, but contains a pattern of bits that tells what

parts of an IP address are the network ID and what parts are the host ID: a bit set to 1

means "this bit is part of the network ID" and a bit set to 0 means "this bit is part of the

host ID."

Subnet masks

are used to define

subnets

(what you get after dividing a network into

smaller pieces). A subnet's network ID is created by "borrowing" one or more bits from

the host ID portion of the address. The subnet mask identifies these host ID bits.

For example, consider a class C network 192.168.1. To split this into two subnets, you

would use the subnet mask:

255.255.255.128

It's easier to see what's happening if we write this in binary:

11111111.11111111.11111111.10000000

As with any class C address, all of the bits in field1 through field 3 are part of the

network ID, but note how the mask specifies that the first bit in field 4 is also included.

Since this extra bit has only two values (0 and 1), this means there are two subnets.

Each subnet uses the remaining 7 bits in field4 for its host IDs, which range from 1 to

126 hosts (instead of the usual 0 to 255 for a class C address).

Similarly, to split a class C network into four subnets, the mask is:

255.255.255.192 or 11111111.11111111.11111111.11000000

The two extra bits in field4 can have four values (00, 01, 10, and 11), so there are four

subnets. Each subnet uses the remaining six bits in field4 for its host IDs, ranging from

1 to 62.

&

Note:

Sometimes a subnet mask does not specify any additional network ID bits, and thus no

subnets. Such a mask is called a default subnet mask. These masks are:

●

Class A:

255.0.0.0

●

Class B:

255.255.0.0

●

Class C:

255.255.255.0

These are called default because they are used when a network is initially configured,

at which time it has no subnets.

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Aolynk DR811/DR814 ADSL2+Broadband Router

7

Service Configuration

60

7

Service Configuration

7.1 Configuration Overview

ATM is a connection oriented packet switching technology using fixed size packets,

called cells. These cells consist of a header and a payload and are switched through a

public or private ATM network depending on the contents of the header. End-to-end

connections are formed by cross-connecting individual ATM segments in ATM

switches.

Each ATM cell carries two labels called Virtual Path Identifier (VPI) and Virtual Channel

Identifier (VCI) as part of its header. An ATM channel, commonly referred to as virtual

channel, is fully identified by these two labels. Therefore, multiple ATM channels can

reside on your DSL line. All ATM connections are static, i.e. of type permanent virtual

channel (PVC).

Following are 5 modes of ATM setting:

●

PureBridge

●

DHCP/StaticIP

●

PPPoA

●

IPoA

●

PPPoE

Click

WAN Setting

in the Main menu and choose the

WAN

tab in the Main Frame to

open the WAN connection configuration page.

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Service Configuration

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Figure 7-1

WAN connections

To add a new WAN service, click the

label to open the web page

WAN Connection: create service

.

Figure 7-2

Create a new connection

7.2 PureBridge

To create a PureBridge WAN connection, click the radio button

labeled

PureBridge

,

then

click

the

button

to

open

the

web

page

WAN

Connection:PureBridge.

Enter the proper values of connection options, and then click the

button.

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Service Configuration

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Figure 7-3

Pure bridge

7.3 DHCP/StaticIP

To create a DHCP/StaticIP WAN connection, click the radio button

labeled

DHCP/StaticIP

, then click the

button to open the web page

WAN

Connection:DHCP/StaticIP.

Figure 7-4

DHCP/StaticIP

Enter the proper values of connection options, and then click the

button.

7.4 IPoA

To create an IPoA WAN connection, click the radio button

labeled

IPoA

, then click

the

button to open the web page

WAN Connection:IPoA.