Chapter 11 Voice and Video Over IP
IP telephony (VoIP) gives you the ability to communicate via voice and/or video using an internet connection. This is a fairly new/old technology. In reality it started with the inventors of the telephone giving us the ability to transmit voice over copper wire. In the mid 1990s companies started testing with it however due to slower internet connection and less sophisticated data compression technologies the quality of these transmissions was sub-quality. Voices were garbled and transmissions were unreliable. With current technologies the VoIP arena has taken off like a rocket and in the next few years with the current state of the world economy we will see this become more and more widely used.
My current experiences using the VoIP technologies have saved our organization time and money. Examples of this are: We have been using the Vontage service for the last 4 to 5 years to communicate with our sales people in Europe, Asia and the UK. We are currently using Webex for conference calling, web presentations along with technical support. Then for the last year we have made it a standard for managers, sales and frontline information workers to use Skype as a softphone to communicate via voice and web cam. They are using it’s instant messenger feature to ping an online colleague to see if they are available to take a Skype call. In a cost comparison we are currently moving from WebEx to MicroSoft’s Live Meeting to further cut costs and give us better capabilities with our new Polycom CX5000 video conferencing equipment. http://www.polycom.com/products/voice/conferencing_solutions/microsoft_optimized_conferencing/cx5000.html Our next project research and move our outdated Nortel phone system to a hosted solution such as Microsoft Unified communications. http://www.microsoft.com/uc/en/us/default.aspx.
Wednesday, November 11, 2009
Thursday, November 5, 2009
Chapter 10 In-Depth TCP/IP Networking
Chapter 10 In-Depth TCP/IP Networking
Designing TCP/IP-Based Networks
Most Modern networks rely on the TCP/IP suite for transmitting data over private connections along with internet/public connectivity.
Subnetting is used to separate networks that logically defined segments (subnets) geographically, departmentally, technologically. This enhances security, improves performance along with simplifying troubleshooting. The following will address the techniques to set up a TCP/IP based network.
Classful Addressing in IPv4 addresses are made up of four 8-bit octets binary or dotted decimal. It is the simplest, and adheres to network class distinctions (Class A, B, and C). The address consists of network and host information. The follow is an example of an address from each class how it is broken down into the bit level (1 = on, 0 =off) and then broken down in to the network and host information.
Class A 114.150.129.67 = 01110010. 10100000.1000001.010000011
Class B 150.129. 151.131 = 10100000.100000001. 10100001.100000011
Class C 192.128.65.115 = 11000000.1000000.010000001.0111oo11
•Network information (network ID)
–First 8 bits in Class A address 01110010 = 114
–First 16 bits in Class B address 10100000.100000001 =150.129
–First 24 bits in a Class C address 11000000.1000000.010000001 = 192.128.65
•Host information
–Last 24 bits in Class A address 10100000.1000001.010000011 = 150.129.67
–Last 16 bits in Class B address 10100001.100000011 =151.131
–Last 8 bits in Class C address 01110011 = 115
I finally have a pretty good idea of how the binary numbers work to make up the octets of IP addressing and the following helped me understand how it works. Maybe it will help you.
1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1
00000001 = 1
00000011 = 3
00000111 = 7
00001111 = 15
00011111 = 31
00111111 = 63
01111111 = 127
11111111= 255
11111110 = 254
111111100 = 252
111111000 = 248
11110000 = 240
11100000 = 224
11000000 = 192
10000000 = 128
IPv4 Subnet Masks identifies how network subdivided and indicates where network information located. Each network class (A, B, C) is associated with a default subnet mask of 255 or in binary 11111111. As noted early the network information in each class is represented in the first 8 bits for class A… therefore following represents the subnet masks for each class
Class A 255.0.0.0 = 11111111. 00000000.00000000.00000000
Class B 255.255.0.0 = 11111111. 1111111.00000000.00000000
Class C 255.255.255.0 = 11111111.11111111.11111111.00000000
To come up with the network ID we then need to combine the bits.
•Bit value of 1 plus another bit value of 1 results in 1
•Bit value of 0 plus any other bit results in 0
As an example let’s use the Class C IP address from above and combine it with the subnet mask to get it Network ID
Class C Address 192.128.65.115 = 11000000.1000000.010000001.0111oo11
Class C Subnet Mask 255.255.255.0 = 11111111.11111111.11111111.00000000
Network ID: =192.128.65.0 = 11000000.10000000.010000001.00000000
Reserved Addresses cannot be assigned to node network interface or be used as subnet masks. Network ID bits available for host information set to 0 therefore a host address cannot be set to zero 192.128.65.0 and also can’t be set to the broadcast address of 11111111 or 255. 0-255 equals 256 combinations however we need to subtract 2 address (0 & 255) equaling 254 addresses available for that Class C network. (Class C 2 to the 8 = 256-2 =254)
IPv4 Subnetting Techniques breaking the classful IPv4 addressing rules. IP address bits representing host information change to represent network information. As you increase the number of subnets you reduce usable host addresses per subnet.
Calculating IPv4 Subnets
Formula: 2n−2=Y (n) is number of subnet mask bits needed to switched from 0 to 1 and y represents the number subnets. We need to – 2 because of the reserved addresses noted above.
Example of a Class C with the Network ID: 199.34.89.0 divided into six subnets: 6=2 (power of) N- 2 or 8 = 2(power of) 3 there for the bits borrowed are 3 so the subnet mask is made up of the first 27 bits.
11111111.11111111.1111111.11000000 or 255.255.255.224
Using 27 of the 32 bits available you are left with the five last bits (00011111) adding them up you get 31 = (16 + 8 + 4 + 2 +1). However, you still have the two reserved for Network ID and Broadcast so you only end up with 30 hosts each of the 6 subnets.
Extended network Prefix Broadcast Address Usable hosts
199.34.89.32 199.34.89.63 199.34.89.33-62
199.34.89.64 199.34.89.95 199.34.89.65-94
199.34.89.96 199.34.89.127 199.34.89.97-126
199.34.89.128 199.34.89.159 199.34.89.129-159
199.34.89.160 199.34.89.191 199.34.89.33.161-190
199.34.89.192 199.34.89.223 199.34.89.193-222
CIDR (Classless Interdomain Routing) AKA SUPER Networking were as in Subnet you remove the bits to the right to create more subnets into CIDR you move them to the left to create more useable IP addresses on your net work.
Example of a class C with the Network ID: 199.34.89.0/22 is use the CIDR notation (or slash notation) Network ID followed by forward slash ( / ), followed by number of bits used for extended network prefix. This changes your subnet mask to 255.255.252.000 from 255.255.255.000increasing your host addresses from 254 to 1022.
Internet Gateway facilitates communication between different networks and subnets. A default gateway first interprets its outbound requests to other subnets, and then interprets its inbound requests from other subnets.
NAT (Network Address Translation) allows you to hide internal/private IP addresses from the outside internet. The gateway provides valid internet addresses when sending transmissions to the internet.
SNAT (Static Network Address Translation) establishes a one to one correlation between each IP address and internet IP address.
DNAT (Dynamic Network Address Translation) AKA IP masquerading allows one or more IP addressed to be shared with multiple clients.
TCP/IP Mail Services are the most frequently used internet service to deliver, store, and communicate with other mail servers.
SMTP (Simple Mail Transfer Protocol) is responsible for moving messages from one mail server to another over TCP/IP-based networks operating at Application layer and replies on TCP at Transport layer over port 25.
MIME (Multipurpose Internet Mail Extensions) delivers the SMPT drawback of 1000 ASCII character limit. It also encodes, interprets binary files, images, video, non-ASCII character sets within e-mail message. It does not replace SMTP and works in conjunction with it.
POP (Post Office Protocol) the user retrieves messages from mail server. It is like the postal worker it brings the mail to your house and leaves it there. With this is mind you should only retrieve form one computer one mailbox.
IMAP (Internet Message Access Protocol) IMAP4 is the current version where E-mail stays on server after retrieval. Users can retrieve all or portion of mail message create delete when offline and update with the server when an internet connection is established.
TCP/IP Tools/Utilities to help track down most TCP/IP related problems discovering information about node, network
Ipconfig (Windows) and Ifconfig (UNIX)
Command-line utility to identify and change network adapter information (IP address, subnet mask, default gateway)
Netstat Displays TCP/IP statistics, component details, host connections and active TCP/IP connections on node
Nbtstat utility provides information about NetBIOS statistics along with resolving NetBIOS names to IP addresses. It is useful on Windows-based operating systems and NetBIOS
Hostname is a utility provides client’s host name.
Host utility to learn the IP address from host name.
Nslookup is used to query DNS database from any network computer and can find the device host name by specifying its IP address.
Dig (Domain information groper) similar to nslookup where it queries a DNS database and to find a specific IP address host name. Useful for diagnosing DNS problems and provides more detailed information than nslookup
Whois Query DNS registration database to obtain domain information
Troubleshoot network problems. Syntax: whois xxx.yy
Traceroute give you the ability to trace the path from one networked node to another identifying all intermediate hops between the two nodes using either IP address or host name.
Windows-based systems: tracert
Linux systems: tracepath
Designing TCP/IP-Based Networks
Most Modern networks rely on the TCP/IP suite for transmitting data over private connections along with internet/public connectivity.
Subnetting is used to separate networks that logically defined segments (subnets) geographically, departmentally, technologically. This enhances security, improves performance along with simplifying troubleshooting. The following will address the techniques to set up a TCP/IP based network.
Classful Addressing in IPv4 addresses are made up of four 8-bit octets binary or dotted decimal. It is the simplest, and adheres to network class distinctions (Class A, B, and C). The address consists of network and host information. The follow is an example of an address from each class how it is broken down into the bit level (1 = on, 0 =off) and then broken down in to the network and host information.
Class A 114.150.129.67 = 01110010. 10100000.1000001.010000011
Class B 150.129. 151.131 = 10100000.100000001. 10100001.100000011
Class C 192.128.65.115 = 11000000.1000000.010000001.0111oo11
•Network information (network ID)
–First 8 bits in Class A address 01110010 = 114
–First 16 bits in Class B address 10100000.100000001 =150.129
–First 24 bits in a Class C address 11000000.1000000.010000001 = 192.128.65
•Host information
–Last 24 bits in Class A address 10100000.1000001.010000011 = 150.129.67
–Last 16 bits in Class B address 10100001.100000011 =151.131
–Last 8 bits in Class C address 01110011 = 115
I finally have a pretty good idea of how the binary numbers work to make up the octets of IP addressing and the following helped me understand how it works. Maybe it will help you.
1 1 1 1 1 1 1 1
128 64 32 16 8 4 2 1
00000001 = 1
00000011 = 3
00000111 = 7
00001111 = 15
00011111 = 31
00111111 = 63
01111111 = 127
11111111= 255
11111110 = 254
111111100 = 252
111111000 = 248
11110000 = 240
11100000 = 224
11000000 = 192
10000000 = 128
IPv4 Subnet Masks identifies how network subdivided and indicates where network information located. Each network class (A, B, C) is associated with a default subnet mask of 255 or in binary 11111111. As noted early the network information in each class is represented in the first 8 bits for class A… therefore following represents the subnet masks for each class
Class A 255.0.0.0 = 11111111. 00000000.00000000.00000000
Class B 255.255.0.0 = 11111111. 1111111.00000000.00000000
Class C 255.255.255.0 = 11111111.11111111.11111111.00000000
To come up with the network ID we then need to combine the bits.
•Bit value of 1 plus another bit value of 1 results in 1
•Bit value of 0 plus any other bit results in 0
As an example let’s use the Class C IP address from above and combine it with the subnet mask to get it Network ID
Class C Address 192.128.65.115 = 11000000.1000000.010000001.0111oo11
Class C Subnet Mask 255.255.255.0 = 11111111.11111111.11111111.00000000
Network ID: =192.128.65.0 = 11000000.10000000.010000001.00000000
Reserved Addresses cannot be assigned to node network interface or be used as subnet masks. Network ID bits available for host information set to 0 therefore a host address cannot be set to zero 192.128.65.0 and also can’t be set to the broadcast address of 11111111 or 255. 0-255 equals 256 combinations however we need to subtract 2 address (0 & 255) equaling 254 addresses available for that Class C network. (Class C 2 to the 8 = 256-2 =254)
IPv4 Subnetting Techniques breaking the classful IPv4 addressing rules. IP address bits representing host information change to represent network information. As you increase the number of subnets you reduce usable host addresses per subnet.
Calculating IPv4 Subnets
Formula: 2n−2=Y (n) is number of subnet mask bits needed to switched from 0 to 1 and y represents the number subnets. We need to – 2 because of the reserved addresses noted above.
Example of a Class C with the Network ID: 199.34.89.0 divided into six subnets: 6=2 (power of) N- 2 or 8 = 2(power of) 3 there for the bits borrowed are 3 so the subnet mask is made up of the first 27 bits.
11111111.11111111.1111111.11000000 or 255.255.255.224
Using 27 of the 32 bits available you are left with the five last bits (00011111) adding them up you get 31 = (16 + 8 + 4 + 2 +1). However, you still have the two reserved for Network ID and Broadcast so you only end up with 30 hosts each of the 6 subnets.
Extended network Prefix Broadcast Address Usable hosts
199.34.89.32 199.34.89.63 199.34.89.33-62
199.34.89.64 199.34.89.95 199.34.89.65-94
199.34.89.96 199.34.89.127 199.34.89.97-126
199.34.89.128 199.34.89.159 199.34.89.129-159
199.34.89.160 199.34.89.191 199.34.89.33.161-190
199.34.89.192 199.34.89.223 199.34.89.193-222
CIDR (Classless Interdomain Routing) AKA SUPER Networking were as in Subnet you remove the bits to the right to create more subnets into CIDR you move them to the left to create more useable IP addresses on your net work.
Example of a class C with the Network ID: 199.34.89.0/22 is use the CIDR notation (or slash notation) Network ID followed by forward slash ( / ), followed by number of bits used for extended network prefix. This changes your subnet mask to 255.255.252.000 from 255.255.255.000increasing your host addresses from 254 to 1022.
Internet Gateway facilitates communication between different networks and subnets. A default gateway first interprets its outbound requests to other subnets, and then interprets its inbound requests from other subnets.
NAT (Network Address Translation) allows you to hide internal/private IP addresses from the outside internet. The gateway provides valid internet addresses when sending transmissions to the internet.
SNAT (Static Network Address Translation) establishes a one to one correlation between each IP address and internet IP address.
DNAT (Dynamic Network Address Translation) AKA IP masquerading allows one or more IP addressed to be shared with multiple clients.
TCP/IP Mail Services are the most frequently used internet service to deliver, store, and communicate with other mail servers.
SMTP (Simple Mail Transfer Protocol) is responsible for moving messages from one mail server to another over TCP/IP-based networks operating at Application layer and replies on TCP at Transport layer over port 25.
MIME (Multipurpose Internet Mail Extensions) delivers the SMPT drawback of 1000 ASCII character limit. It also encodes, interprets binary files, images, video, non-ASCII character sets within e-mail message. It does not replace SMTP and works in conjunction with it.
POP (Post Office Protocol) the user retrieves messages from mail server. It is like the postal worker it brings the mail to your house and leaves it there. With this is mind you should only retrieve form one computer one mailbox.
IMAP (Internet Message Access Protocol) IMAP4 is the current version where E-mail stays on server after retrieval. Users can retrieve all or portion of mail message create delete when offline and update with the server when an internet connection is established.
TCP/IP Tools/Utilities to help track down most TCP/IP related problems discovering information about node, network
Ipconfig (Windows) and Ifconfig (UNIX)
Command-line utility to identify and change network adapter information (IP address, subnet mask, default gateway)
Netstat Displays TCP/IP statistics, component details, host connections and active TCP/IP connections on node
Nbtstat utility provides information about NetBIOS statistics along with resolving NetBIOS names to IP addresses. It is useful on Windows-based operating systems and NetBIOS
Hostname is a utility provides client’s host name.
Host utility to learn the IP address from host name.
Nslookup is used to query DNS database from any network computer and can find the device host name by specifying its IP address.
Dig (Domain information groper) similar to nslookup where it queries a DNS database and to find a specific IP address host name. Useful for diagnosing DNS problems and provides more detailed information than nslookup
Whois Query DNS registration database to obtain domain information
Troubleshoot network problems. Syntax: whois xxx.yy
Traceroute give you the ability to trace the path from one networked node to another identifying all intermediate hops between the two nodes using either IP address or host name.
Windows-based systems: tracert
Linux systems: tracepath
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