Lucent Technologies DEFINITY Enterprise Communications Server Release 8.2 Administration For Network Connectivity Manual

							IP Softphones 
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1  Networking Overview
IP Softphones
This book focuses on administration for the trunk side of the DEFINITY IP Solutions offer. The administration 
of the line side (IP Softphones) is covered in DEFINITY ECS R8 Administrator’s Guide, 555-233-506. For 
completeness, a brief checklist of IP Softphone administration is presented here.
For R8, there are two main types of DEFINITY IP Softphone applications — the 
telecommuter application and the road-warrior application. The CentreVu IP Agent is 
a variation of the telecommuter application.
Te l e c o m m u t e r  
applicationThe telecommuter application uses two connections to the DEFINITY system: a 
connection to the PC over the IP network and a connection to the telephone over the 
PSTN. The user places and receives calls with the DEFINITY IP Softphone interface 
running on a PC and uses the telephone handset to speak and listen.
To administer a telecommuter application, you must complete these steps:
1  Verify that the DEFINITY system is enabled for IP Softphone use. On the System 
Parameters Customer Options screen, verify that:
~Maximum H.323 Stations is > 0
~Maximum IP Softphones is > 0
~IP Stations is y
2  Add a DCP station (or change an existing DCP station) using the Station screen:
~Type [enter the phone model you wish to use, such as 6408D]
~Port: x if virtual, or the port number of an existing phone
~Security Code: [enter the user’s password]
~IP Softphone: y
~Go to page 2; Service Link Mode: as-needed
3  Install the IP Softphone software on the user’s PC
Road-warrior 
applicationThe road-warrior application uses two separate software applications running on a PC 
that is connected to a DEFINITY system over an IP network. The single network 
connection carries two channels: one for call control signaling and one for voice. 
DEFINITY IP Softphone software handles the call signaling and an H.323 
V2-compliant audio application (such as Microsoft
â NetMeetingâ) handles the voice 
communications.
To administer a road-warrior application, you must complete these steps:
1  Verify that the DEFINITY system is enabled for IP Softphone use. On the System 
Parameters Customer Options screen, verify that:
~Maximum H.323 Stations is > 0
~Maximum IP Softphones is > 0
~IP Stations is y
2  On the DEFINITY system, add an H.323 station using the Station screen:
~Ty p e  H.322
~Port: x 
						

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3  Add a DCP station (or change an existing DCP station) using the Station screen:
~Type [enter the phone model you wish to use, such as 6408D]
~Port: x if virtual, or the port number of an existing phone
~Security Code: [enter the user’s password]
~Media Complex Ext: [enter the extension of the H.323 station from the 
previous step]
~IP Softphone: y
~Go to page 2; Service Link Mode: as-needed
4  Install the IP Softphone software on the user’s PC
5  Install an H.323 V2-compliant audio application (such as Microsoft NetMeeting) 
on the user’s PC 
						

							IP Addressing 
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1  Networking Overview
IP Addressing
This section describes IP addressing, subnetting, and routing. 
Physical Addressing
The Address Resolution Protocol (ARP) software on the C-LAN circuit pack relates 
the 32-bit logical IP address, which is configured in software, with the 48-bit physical 
address of the C-LAN circuit pack, which is burned into the board at the factory. The 
C-LAN board has an ARP table that associates the IP addresses with the hardware 
addresses, which are used to route messages across the network. Each C-LAN board 
has one physical address and up to 17 assigned IP addresses (one for each port).
Logical Addressing
An IP address is a software-defined 32-bit binary number that identifies a network 
node. The IP address has two main parts -- the first n bits specify a “network ID” and 
the remaining 32 – n bits specify a “host ID.” 
Format
Dotted Decimal 
notation
The 32-bit binary IP address is what the computer understands. For human use, the 
address is typically expressed in dotted decimal notation — the 32 bits are grouped 
into four 8-bit octets (bytes) and converted to decimal numbers separated by decimal 
points, as in the example below.
The eight binary bits in each octet can be combined to represent decimal numbers 
ranging from 0 to 255.
Class
Ty p eNetwork ID Host ID
n
32 – n
Octet 1
11000010
Octet 2
00001101
Octet 3
11011011
Octet 4
00000111
194 . 13 . 219 . 7 
						

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Conversion between 
binary and decimalConversion from binary to decimal notation is accomplished by adding the powers of 
2 corresponding to the 1’s positions in each byte:
 IP Address ClassesThe IP address space (232 or about 4.3 billion addresses) has been divided into five 
groups, Classes A–E, to accommodate the need for different network sizes. Each 
class has a different allocation of bits between the network and host IDs. The classes 
are identified by a fixed pattern of leading bits.
In Class A addresses, the first (leftmost) bit is always 0. So Class A IP addresses have 
7 bits to define network IDs; 7 bits can define a total of 128 (0-->127) Class A 
networks. The remaining 24 bits of a Class A IP address are used to define host IDs. 
So for each of the 126 networks, there are 2
24 or 16,777,216 possible hosts.
The following table shows how IP addresses are the allocated among the five classes.  
Address classes A, B, and C cover 87.5% of the address space. These addresses are 
assigned by the ISP or the Internet Assigned Number Authority (IANA) to 
organizations for their exclusive use. The remaining 12.5% of addresses, designated 
classes D and E, are reserved for special purposes. 2
7 = 
12826 = 
6425 = 
3224 = 
1623 =
822 =
421 =
220 =
1
194 =11000010
  13 =00001101
219 =11011011
7 =00000111
Class A
50%0Network ID Host ID
Class B
25%10Network ID Host ID
Class C
12.5%110Network ID Host ID
Class D
6.5%1110Reserved for Multicast addresses
Class E
6.5%1111Reserved for future use
Octet 1 Octet 2
Octet 3
Octet 4 
						

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1  Networking Overview
The IANA assigns a network address to an organization and a network administrator 
in the organization assigns the Host IDs associated with that Network ID to nodes 
within the organization’s network. 
The following table shows the ranges of network and host IDs, and the total number 
of IP addresses (# network IDs times # host IDs), for each class. 
You can tell the class of an IP address by the first octet. For example, 191.221.30.101 
is a Class B address and 192.221.30.101 is a Class C address.
Private IP AddressAddresses on the Internet need to be unique to avoid ambiguity in message routing 
over the Internet. To insure uniqueness, the Internet Assigned Number Authority 
(IANA) controls the use of IP addresses. Organizations that maintain private 
networks that never communicate with the Internet can use arbitrary IP addresses as 
long as they are unique within the private network. To help prevent the duplication of 
IP addresses on the Internet, the IANA has reserved the following ranges of IP 
addresses for private networks:
1 Class A networks: 16.6 Million addresses: 10.0.0.0 --> 10.255.255.255
16 Class B networks: 1 Million addresses: 172.16.0.0 --> 172.31.255.255
256 Class C networks: 65,000 addresses:192.168.0.0 --> 192.168.255.255
These IP addresses can be used repeatedly in separate private networks, which are not 
connected to the Internet. Routing tables prohibit the propagation of these addresses 
over the Internet. (See RFC 1918). All other IP addresses are unique and must be 
assigned by the IANA or ISP.Network ID Range Host ID Range Total IP 
Addresses
Class A 7 bits 
126 Networks:
1 to 12624 bits
16.8 Million Hosts per 
network:
0.0.1 to 255.255.2542.1 Billion
50%
Class B 14 bits,
16,382 Networks:
128.0 to 191.25516 bits
65,534 Hosts per network
0.1 to 255.2541.1 Billion
25%
Class C 21 bits,
2.1 Million Networks:
192.0.0 to 233.255.2558 bits
254 Hosts per network:
1 to 2540.5 Billion
12.5%
Classes 
D&E0.5 Billion
12.5% 
						

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Subnetting
Subnetting is the grouping of IP addresses associated with a network ID into two or 
more subnetworks. The subnets of a network ID are visible only within the 
organization that owns the network ID; Internet routers route messages based on the 
network ID and the routers within the private organization differentiate between the 
individual subnets.
Reasons for subnettingSubnetting is desirable because it enables a more efficient allocation and management 
of IP addresses.
The three-class hierarchy of IP addresses results in an inefficient allocation of 
addresses in many cases because addresses are assigned and managed in blocks by 
network ID. For example, a company that needs 10,000 IP addresses in each of two 
locations might be assigned two Class B network IDs, each of which provides 65,534 
IP addresses. Even though one Class B network ID would provide more than enough 
addresses for both locations, having a separate network ID for each location is easier 
to manage. If the company uses only 20,000 of these addresses, about 100,000 go 
unused.
In this case, subnetting would enable the company to use one Class B network ID and 
subdivide the addresses into two subnets, one for each location. Each subnet would 
have a unique “extended network ID” that would enable them to be managed as if 
they had unique network IDs. 
Typically, organizations need to manage IP addresses in separate groups based on 
several criteria in addition to location:
•different types of LANs
•different server applications
•different work projects
•security
The grouping of IP addresses provided by the three-Class structure does not allow 
nearly enough flexibility to meet the needs of most organizations. Subnetting allows 
the N IP addresses associated with a network ID to be divided into as few as 2 groups, 
each with N/2 addresses, or into as many as N/2 groups, each with 2 addresses, if 
desired.
How subnets are 
createdRFC 950 defines a standard procedure to divide a Class A, B, or C network ID into 
subnets. The subnetting adds a third level of hierarchy to the two-level hierarchy of 
the Class A, B, and C network ID number. An “extended network prefix” is formed 
by using two or more bits of the Host ID as a subnet number, and appending this 
subnet number to the network ID. 
						

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The extended network prefix is then treated as a normal network ID. The remaining 
host ID bits define the host IDs within each subnet. For example, a block of IP 
addresses could be subdivided into four subnets by using 2 host bits to “extend” the 
network ID. Now there are 4 times as many (extended) networks and 1/4 as many 
hosts per network.
Note:In adding up the number of network and host IDs, certain addresses 
cannot be counted. In general, addresses with all ones or all zeros in 
either the network portion or the host portion of the address are not 
usable. These are reserved for special uses, such as broadcasting or 
loopback.
Subnet Masks Routing protocols use a subnet mask to determine the boundary between the extended 
network ID and the host ID in an IP address. The subnet mask is a 32-bit binary 
number consisting of a string of contiguous 1’s followed by a string of contiguous 
0’s. The 1’s part corresponds to the extended network prefix and the 0’s part 
corresponds to the host ID of the address.
Each of the three classes of addresses has a default subnet mask that specifies the end 
of the 1st, 2nd, and 3rd octet as the boundary between the extended network prefix 
and the host ID. The default subnet mask in each case means “no subnetting.”
In addition to the default subnet masks, which divide the network and host IDs at the 
octet boundaries in the IP address, subnets can be formed by using 2 or more bits 
from the host octets to define the subnet ID. Two-level classful hierarchy
Three-level subnet hierarchy
Subnet mask
Class
Ty p eNetwork ID Host ID
Class
Ty p eNetwork IDSubnet ID Host ID
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
Extended Network Prefix 
Default Subnet Mask
Class A11111111.00000000.00000000.00000000
255.0.0.0
Class B11111111.11111111.00000000.00000000
255.255.0.0
Class C11111111 .11111111.11111111 .000 000 00
255.255.255.0 
						

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Class-C subnetsThe following table shows that Class-C IP addresses can have 5 subnetting schemes, 
each with a different number of subnets per network. The first and last subnet, formed 
by using 1 and 7 bits respectively, are unusable because they result in either the 
subnet ID or the host ID having all zeros or all ones.
3-bit subnets
As an example, the third row of the table shows the results of using 3 bits for the 
subnet ID. Three bits are “borrowed” from the host ID leaving 5 bits for the host IDs. 
The number of subnets that can be defined with three bits is 2
3 = 8 (000, 001, 010, 
011, 100, 101, 110, 111
). Of these, only 6 are usable (all ones and all zeros are not 
usable). The remaining 5 bits are used for the host IDs. Of these, 25 – 2 = 30 are 
usable. As shown in columns 2–4 (row 3), by using 3 bits for subnetting, a Class C 
network can be divided into 6 subnets with 30 host IDs in each subnet for a total of 
6 X 30 = 180 usable IP addresses.
Subnet mask
The subnet mask is defined as follows. The subnet bits “borrowed” from the host ID 
are the highest-order bits in the octet of the host ID. The 5th and 6th columns of the 
table show the binary and decimal subnet IDs, formed by using the subnet bits as the 
highest-order bits in an octet. For example, in the third row of the table, the binary bit 
pattern is 11100000, which is decimal 224. This is the highest number that can be 
formed with the 3 high-order bits in the octet. The subnet mask is formed by putting 
this number in the 4th octet of the default subnet mask (shown in the last column of 
the table). 
The mask, 255.255.255.224, corresponds to a bit pattern of 27 ones followed by 5 
zeros. This mask would be used to check that two IP addresses are on the same or 
different subnets by comparing the first 27 binary digits of the two addresses. If the 
first 27 binary digits are the same, the two addresses are on the same subnet.No. 
Sub-
net 
bitsNo. of 
Usable 
Subnets 
per NWNo. of 
Hosts 
per 
SubnetNo. of 
Usable IP 
AddressesBinary 
Subnet 
ID
(4th 
Octet)Decimal 
Subnet 
IDClass C 
Subnet Masks
10126010000000128255.255.255.128
2 2 62 124 11000000 192 255.255.255.192
3 6 30 180 11100000 224 255.255.255.224
4 14 14 196 11110000 240 225.225.225.240
5 30 6 180 11111000 248 255.255.255.248
6 62 2 124 11111100 252 255.255.255.252
71260011111110254255.255.255.254 
						

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Example
To continue the example using a 3-bit subnet ID, assume a Class C network ID of 
192.168.50.xxx. This network ID can provide 254 usable IP addresses, all on the 
same network — from 192.168.50.1 to 192.168.50.254. If we divide this network into 
3-bit subnets, we will have 6 usable subnets with 30 usable IP addresses in each 
subnet. Note that we have lost 74 usable IP addresses in the process because we had 
to discard the all-ones and all-zeros subnet IDs (62 addresses) and host IDs (12 
addresses). There is always a loss of usable IP addresses with subnetting.
The following table shows the subnet boundaries for the six subnets formed with 3 
bits. The boundaries are the numbers formed by using all combinations of 3 bits as the 
highest-order bits in an octet (Columns 1 and 2) and then using these numbers in the 
4th octet for the host IDs.
For example, the IP addresses 192.168.50.75 and 192.168.50.91 are on the same 
subnet but 192.168.50.100 is on a different subnet. This is illustrated in the following 
diagram where the subnet mask, 255.255.255.244 is used to compare the first 27 
binary digits or each address.Binary 
Subnet 
Boundaries 
(for 3 bits)Decimal 
Subnet 
BoundariesRange of usable IP 
Addresses in the 
Subnet
000000000not usable
00100000 32 192.168.50.33 to
192.168.50.62
01000000 64 192.168.50.65 to
192.168.50.94
01100000 96 192.168.50.97 to
192.168.50.126
10000000 128 192.168.50.129 to
192.168.50.158
10100000 160 192.168.50.161 to
192.168.50.190
11000000 192 192.168.50.193 to
192.168.50.222
11100000224not usable 
						

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The other four possible subnetting schemes for Class C addresses, using 2, 4, 5, and 6 
subnet bits, are formed in the same way. Which of the 5 subnetting schemes to use 
depends on the requirements for the number of subnets and the number of hosts per 
subnet.
Class-A and Class-B 
subnetsFor Class A and Class B IP addresses, subnets can be formed in the same way as for 
Class C addresses. The only difference is that many more subnets per network can be 
formed. For Class B networks, subnets can be formed using from 2 to 14 bits from the 
3rd and 4th octets. For Class A networks, subnets can be formed using from 2 to 22 
bits from the 2nd, 3rd and 4th octets.
The Subnet Mask field on the ppp Data Module screen (used for ppp connections) and 
on the IP Interfaces screen (used for ethernet connections) enables the specification of 
a subnet for the IP address.Subnet mask11000000 10101000 00110010 01001011
11000000 10101000 00110010 01011011
11000000 10101000 00110010 01100100
11111111 11111111 11111111 1110 000 0
192 168 50 75
192 168 50 91
192 168 50 100
255 255 255 224
27 digits