Hitron CGNV2 User Manual
USER’S GUIDE
VERSION 1.0
MAY 2014
DEFAULT LOGIN DETAILS
IP Address 192.168.0.1
Username cusadmin
Password password
CGNV2
ABOUT THIS USER’S GUIDE
INTENDED AUDIENCE
This manual is intended for people who want to configure the CGNV2’s features via
its Graphical User Interface (GUI).
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HOW TO USE THIS USER’S GUIDE
This manual contains information on each the CGNV2’s GUI screens, and describes
how to use its various features.
Use the Introduction (page 15) to see an overview of the topics covered in this
manual.
Use the Table of Contents (page 7), List of Figures (page 11) and List of Tables
(page
13) to quickly find information about a particular GUI screen or topic.
Use the Index (page 113) to find information on a specific keyword.
Use the rest of this User’s Guide to see in-depth descriptions of the CGNV2’s
features.
RELATED DOCUMENTATION
Quick Installation Guide: see this for information on getting your CGNV2 up
and running right away. It includes information on system requirements,
package contents, the installation procedure, and basic troubleshooting tips.
Online Help: each screen in the CGNV2’s Graphical User Interface (GUI)
contains a Help button. Click this button to see additional information about
configuring the screen.
DOCUMENT CONVENTIONS
This User’s Guide uses various typographic conventions and styles to indicate
content type:
ABOUT THIS USER’S GUIDE
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HITRON CGNV2 USER’S GUIDE
Bulleted paragraphs are used to list items, and to indicate options.
1 Numbered paragraphs indicate procedural steps.
NOTE: Notes provide additional information on a subject.
Warnings provide information about actions that could harm
you or your device.
Product labels, field labels, field choices, etc. are in bold type. For example:
Select UDP to use the User Datagram Protocol.
A mouse click in the Graphical User Interface (GUI) is denoted by a right angle
bracket ( > ). For example:
Click Settings > Advanced Settings.
means that you should click Settings in the GUI, then Advanced settings.
A key stroke is denoted by square brackets and uppercase text. For example:
Press [ENTER] to continue.
CUSTOMER SUPPORT
For technical assistance or other customer support issues, please consult your Hitron
representative.
ABOUT THIS USER’S GUIDE
HITRON CGNV2 USER’S GUIDE
Copyright 2014 Hitron Technologies. All rights reserved. All trademarks and
registered trademarks used are the properties of their respective owners.
DISCLAIMER: The information in this User’s Guide is accurate at the time of writing.
This User’s Guide is provided “as is” without express or implied warranty of any kind.
Neither Hitron Technologies nor its agents assume any liability for inaccuracies in this
User’s Guide, or losses incurred by use or misuse of the information in this User’s
Guide.
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ABOUT THIS USER’S GUIDE
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HITRON CGNV2 USER’S GUIDE
ABOUT THIS USER’S GUIDE
TABLE OF CONTENTS
About This User’s Guide .................................................................. 3
Table of Contents.............................................................................. 7
List of Figures ................................................................................. 11
7
List of Tables................................................................................... 13
Introduction ..................................................................................... 15
1.1 CGNV2 Overview ...............................................................................15
1.1.1 Key Features .............................................................................16
1.2 Hardware Connections .......................................................................16
1.3 LEDs ..................................................................................................18
1.4 IP Address Setup ...............................................................................20
1.4.1 Manual IP Address Setup ..........................................................21
1.5 Login to the CGNV2 ...........................................................................22
1.6 GUI Overview .....................................................................................22
1.7 Resetting the CGNV2 .........................................................................23
Cable ................................................................................................ 25
2.1 Cable Overview ..................................................................................25
2.1.1 DOCSIS .....................................................................................25
2.1.2 IP Addresses and Subnets ........................................................25
2.1.2.1 IP Address Format ............................................................25
2.1.2.2 IP Address Assignment .....................................................25
2.1.2.3 Subnets .............................................................................26
2.1.3 DHCP .........................................................................................27
2.1.4 DHCP Lease ..............................................................................28
2.1.5 DNS ...........................................................................................28
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2.1.6 MAC Addresses ........................................................................28
2.1.7 Routing Mode ............................................................................ 28
2.1.8 Configuration Files ....................................................................29
2.1.9 Downstream and Upstream Transmissions ..............................29
2.1.10 Cable Frequencies .................................................................. 29
2.1.11 Modulation ...............................................................................29
2.1.12 TDMA, FDMA and SCDMA ..................................................... 30
2.2 The System Info Screen .................................................................... 30
2.3 The Initialization Screen ....................................................................32
2.4 The Status Screen ............................................................................. 33
2.5 The Password Screen .......................................................................36
WAN/LAN......................................................................................... 39
3.1 WAN/LAN Overview ..........................................................................39
3.1.1 Wide Area Networks and Local Area Networks ........................39
3.1.2 WAN/LAN IP Addresses and Subnets ......................................39
3.1.3 DNS ...........................................................................................40
3.1.4 Domain Suffix ............................................................................ 40
3.1.5 MTU ........................................................................................... 40
3.1.6 Debugging (Ping and Traceroute) ............................................. 40
3.2 The LAN IP Screen ............................................................................40
3.2.1 Adding or Editing a Reserved IP ............................................... 43
3.3 The Debug Screen ............................................................................. 44
3.4 The Backup Screen ........................................................................... 45
3.5 The WAN IP Screen ..........................................................................46
Firewall ............................................................................................ 49
4.1 Firewall Overview ..............................................................................49
4.1.1 Firewall ...................................................................................... 49
4.1.2 Intrusion detection system ......................................................... 49
4.1.3 Ping ........................................................................................... 49
4.1.4 MAC Filtering ............................................................................. 49
4.1.5 IP Filtering ................................................................................. 50
4.1.6 Port Forwarding .........................................................................50
4.1.7 Port Triggering ........................................................................... 50
4.1.8 DMZ ........................................................................................... 51
4.2 The Firewall Options Screen .............................................................51
4.3 The MAC Filtering Screen .................................................................52
4.4 The IP Filtering Screen ...................................................................... 55
4.4.1 Adding or Editing an IP Filtering Rule .......................................57
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HITRON CGNV2 USER’S GUIDE
4.5 The Forwarding Screen ......................................................................59
4.5.1 Adding or Editing a Port Forwarding Rule .................................61
4.6 The Port Triggering Screen ................................................................63
4.6.1 Adding or Editing a Port Triggering Rule ...................................64
Parental Control .............................................................................. 67
5.1 Parental Control Overview .................................................................67
5.1.1 Website Blocking .......................................................................67
5.2 The Web Site Blocking Screen ..........................................................67
5.3 The Scheduling Screen ......................................................................69
5.4 The Local Logs Screen ......................................................................71
Wireless ........................................................................................... 73
6.1 Wireless Basics ..................................................................................73
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6.1.1 Wireless Standards ....................................................................74
6.1.2 Service Sets and SSIDs ............................................................74
6.1.3 Basic Wireless Security .............................................................75
6.2 Wireless Tutorials ...............................................................................75
6.2.1 Choosing a Security Method ......................................................75
6.2.2 Changing the Wireless Password ..............................................76
6.2.3 Changing the Network Name (SSID) .........................................77
6.2.4 Hiding the Network ....................................................................77
6.2.5 Improving the Wireless Network’s Performance ........................77
6.3 Advanced Wireless Networking .........................................................78
6.3.1 Advanced Wireless Security ......................................................78
6.3.2 Other Wireless Concepts ...........................................................79
6.3.2.1 WPS ..................................................................................79
6.3.2.2 WMM .................................................................................80
6.4 The Wireless Screens ........................................................................80
6.4.1 The Basic Screen ......................................................................80
6.4.2 The Security Screen ..................................................................83
6.4.3 The Access Control Screen .......................................................86
6.4.4 The WiFi Site Survey Screen .....................................................88
6.4.5 The Connection List Screen ......................................................91
eMTA ................................................................................................ 93
7.1 The Status Screen .............................................................................93
7.2 The DHCP Screen .............................................................................94
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VPN .................................................................................................. 97
8.1 VPN Overview ...................................................................................97
8.1.1 IPsec .........................................................................................97
8.1.1.1 Framework Protocols ........................................................ 97
8.1.1.2 IKE .................................................................................... 98
8.1.1.3 Encryption Algorithms ....................................................... 98
8.1.1.4 Cryptographic Hash Function ...........................................98
8.1.2 PPTP ......................................................................................... 99
8.1.3 L2TP ..........................................................................................99
8.2 The PASSTHROUGH Screen ...........................................................99
8.3 The IP Sec Screen ........................................................................... 100
8.3.1 Adding or Editing a VPN Tunnel .............................................. 102
8.4 The PPTP Screen ............................................................................105
Troubleshooting ........................................................................... 109
Index .............................................................................................. 113
TABLE OF CONTENTS
LIST OF FIGURES
FIGURE 1: Application Overview ........................................................................15
FIGURE 2: Hardware Connections .....................................................................17
FIGURE 3: LEDs .................................................................................................19
FIGURE 4: Login .................................................................................................22
FIGURE 5: GUI Overview ...................................................................................23
FIGURE 6: The Cable > System Info Screen .....................................................31
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FIGURE 7: The Cable > Initialization Screen .....................................................33
FIGURE 8: The Cable > Status Screen ..............................................................34
FIGURE 9: The Cable > Password Screen ........................................................36
FIGURE 10: The WAN/LAN > LAN IP Screen ....................................................41
FIGURE 11: The WAN/LAN > LAN IP > Add/Edit Screen .................................43
FIGURE 12: The WAN/LAN > Debug Screen .....................................................44
FIGURE 13: The WAN/LAN > Backup Screen ...................................................45
FIGURE 14: The WAN/LAN > WAN IP Screen ..................................................46
FIGURE 15: The Firewall > Firewall Options Screen .........................................51
FIGURE 16: The Firewall > MAC Filtering Screen .............................................53
FIGURE 17: The Firewall > IP Filtering Screen ..................................................56
FIGURE 18: The Firewall > IP Filtering > Add/Edit Screen ................................58
FIGURE 19: The Firewall > Forwarding Screen .................................................60
FIGURE 20: The Firewall > Forwarding > Add/Edit Screen ................................61
FIGURE 21: The Firewall > Port Triggering Screen ...........................................63
FIGURE 22: The Firewall > Port Triggering > Add/Edit Screen ..........................64
FIGURE 23: The Parent Control > Web Site Blocking Screen ...........................68
FIGURE 24: The Parent Control > Scheduling Screen .......................................70
FIGURE 25: The Parent Control > Local Logs Screen .......................................71
FIGURE 26: Example Wireless Network ............................................................74
FIGURE 27: The Wireless > Basic Screen .........................................................80
FIGURE 28: WPS PIN ........................................................................................82
FIGURE 29: The Wireless > Security Screen .....................................................83
FIGURE 30: The Wireless > Access Control Screen ..........................................87
FIGURE 31: The Wireless > WiFi Site Survey Screen .......................................89
LIST OF FIGURES
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HITRON CGNV2 USER’S GUIDE
FIGURE 32: The Wireless > Connection List Screen ......................................... 91
FIGURE 33: The eMTA > Status Screen ........................................................... 93
FIGURE 34: The eMTA > DHCP Screen ........................................................... 94
FIGURE 35: The VPN > PassThrough Screen .................................................. 99
FIGURE 36: The VPN > IPsec Screen ............................................................. 101
FIGURE 37: The VPN > IPsec > Add/Edit Screen .......................................... 103
FIGURE 38: The VPN > PPTP Screen ............................................................ 106
LIST OF FIGURES
LIST OF TABLES
TABLE 1: Hardware Connections ......................................................................17
TABLE 2: LEDs ..................................................................................................19
TABLE 3: GUI Overview ....................................................................................23
TABLE 4: Private IP Address Ranges ...............................................................26
TABLE 5: IP Address: Decimal and Binary ........................................................27
TABLE 6: Subnet Mask: Decimal and Binary ....................................................27
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TABLE 7: The Cable > System Info Screen ......................................................31
TABLE 8: The Cable > Status Screen ...............................................................34
TABLE 9: The Cable > Password Screen ..........................................................37
TABLE 10: The WAN/LAN > LAN IP Screen .....................................................41
TABLE 11: The WAN/LAN > LAN IP > Add/Edit Screen ...................................44
TABLE 12: The WAN/LAN > Debug Screen ......................................................44
TABLE 13: The WAN/LAN > Backup Screen ....................................................45
TABLE 14: The WAN/LAN > WAN IP Screen ....................................................46
TABLE 15: The Firewall > Firewall Options Screen ...........................................52
TABLE 16: The Firewall > MAC Filtering Screen ...............................................54
TABLE 17: The Firewall > IP Filtering Screen ...................................................56
TABLE 18: The Firewall > IP Filtering > Add/Edit Screen ..................................58
TABLE 19: The Firewall > Forwarding Screen ..................................................60
TABLE 20: The Firewall > Forwarding > Add/Edit Screen .................................62
TABLE 21: The Firewall > Port Triggering Screen .............................................63
TABLE 22: The Firewall > Port Triggering > Add/Edit Screen ...........................65
TABLE 23: The Parent Control > Web Site Blocking Screen ............................68
TABLE 24: The Parent Control > Scheduling Screen ........................................70
TABLE 25: The Parental Control > Local Logs Screen .....................................71
TABLE 26: The Wireless > Basic Screen ..........................................................81
TABLE 27: The Wireless > Security Screen ......................................................84
TABLE 28: The Wireless > Access Control Screen ...........................................87
TABLE 29: The Wireless > WiFi Site Survey Screen ........................................89
TABLE 30: The Wireless > Connection List Screen ..........................................92
TABLE 31: The eMTA > Status Screen .............................................................93
LIST OF TABLES
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HITRON CGNV2 USER’S GUIDE
TABLE 32: The eMTA > DHCP Screen ............................................................. 95
TABLE 33: The VPN > PassThrough Screen .................................................... 99
TABLE 34: The VPN > IPsec Screen .............................................................. 101
TABLE 35: The VPN > IPsec > Add/Edit Screen ............................................103
TABLE 36: The VPN > PPTP Screen .............................................................. 106
LIST OF TABLES
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INTRODUCTION
This chapter introduces the CGNV2 and its GUI (Graphical User Interface).
1.1 CGNV2 OVERVIEW
Your CGNV2 is a voice-enabled cable modem and wireless access point that allows
you to connect your computers, analog telephones, wireless devices, and other
network devices to one another, and to the Internet via the cable connection.
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Computers with a wired connection to the CGNV2 are on the Local Area Network
(LAN), computers with a wireless connection to the CGNV2 are on the Wireless Local
Area Network (WLAN) and the CGNV2 connects to the service provider over the
Wide Area Network (WAN).
FIGURE 1: Application Overview
INTRODUCTION
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HITRON CGNV2 USER’S GUIDE
1.1.1 KEY FEATURES
The CGNV2 provides:
Internet connection to cable modem service via CATV port (F-type RF
connector)
Voice over IP (VoIP) connection to your voice service provider.
Local Area Network connection via four 10/100/1000 Mbps (megabits per
second) Ethernet ports
Dynamic Host Configuration Protocol (DHCP) for devices on the LAN
LAN troubleshooting tools (Ping and Traceroute)
IEEE 802.11b/g/n wireless MIMO (Multiple-In, Multiple-Out) networking, allowing
speeds of up to 300Mbps
Wireless security: WEP, WPA-PSK and WPA2-PSK encryption, WiFi Protected
Setup (WPS) push-button and PIN configuration and MAC filtering
Wired security: stateful inspection firewall with intrusion detection system, IP and
MAC filtering, port forwarding and port triggering, and De-Militarized Zone
(DMZ)
Parental control: scheduled website blocking and access logs
Settings backup and restore
Secure configuration interface, accessible by Web browser
1.2 HARDWARE CONNECTIONS
This section describes the CGNV2’s physical ports and buttons.
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HITRON CGNV2 USER’S GUIDE
FIGURE 2: Hardware Connections
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TABLE 1: Hardware Connections
WPS Use this button to turn the wireless network on or off,
and to begin the WiFi Protected Setup (WPS) Push-
Button Configuration (PBC) procedure (see
page
79 for more information.)
WPS on
To turn the wireless network on or off, press the
button for between one and five seconds.
To begin the WPS PBC connection procedure, press
and hold the button for between five and ten
seconds. Press the PBC button on your wireless
clients in the coverage area within two minutes to
enable them to join the wireless network.
Reset Use this button to reboot or reset your CGNV2.
Press the button and hold it for less than five
seconds to reboot the CGNV2. The CGNV2 restarts,
using your existing settings.
Press the button and hold it for more than ten
seconds to delete all user-configured settings and
restart the CGNV2 using its factory default settings.
INTRODUCTION
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HITRON CGNV2 USER’S GUIDE
TABLE 1: Hardware Connections
LAN1 Use these ports to connect your computers and other
LAN2
LINE Use this port to connect your analog phones for VoIP
CABLE Use this to connect to the Internet via an F-type RF
POWER Use this to connect to the 12v/2A power adapter that
network devices, using Category 5 or 6 Ethernet cables
with RJ45 connectors.
services, using cables with RJ11 connector.
cable.
came with your CGNV2.
NEVER use another power adapter with
your CGNV2. Doing so could harm your
CGNV2.
1.3 LEDS
This section describes the CGNV2’s LEDs (lights).
INTRODUCTION
HITRON CGNV2 USER’S GUIDE
FIGURE 3: LEDs
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TABLE 2: LEDs
LED STATUS DESCRIPTION
WIRELESS Off No data is being transmitted or received over the
wireless network.
Blinking Data is being transmitted or received over the
wireless network.
LINE Off Your service plan does not include voice service.
Blinking A telephone is connected to the relevant Line port,
and is off-hook.
On Your service plan includes voice service.
ETH Off No device is connected to any LAN port.
Blinking A device is connected to a LAN port via a fast
Ethernet link, and is transmitting or receiving data.
On A device is connected to a LAN port via a fast
ethernet link, but is not transmitting or receiving
data.
Status Blinking The CGNV2’s cable modem is registering with the
service provider.
On The CGNV2’s cable modem has successfully
registered with the service provider.
INTRODUCTION
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HITRON CGNV2 USER’S GUIDE
TABLE 2: LEDs
US Blinking The CGNV2 is searching for an upstream frequency
on the CATV connection.
On The CGNV2 has successfully located and locked
onto an upstream frequency on the CATV
connection.
DS Blinking The CGNV2 is searching for a downstream
frequency on the CATV connection.
On The CGNV2 has successfully located and locked
onto a downstream frequency on the CATV
connection.
POWER On
Off
When you turn on the CGNV2, the LEDs light up in the following order:
The CGNV2 is receiving power.
The CGNV2 is not receiving power.
Power
US
DS
Status
The ETH 1~2 LEDs light up as soon as there is activity on the relevant port, the
LINE port light up if your service contract includes voice service, and the
WIRELESS LED lights up once the wireless network is ready.
1.4 IP ADDRESS SETUP
Before you log into the CGNV2’s GUI, your computer’s IP address must be in the
same subnet as the CGNV2. This allows your computer to communicate with the
CGNV2.
NOTE: See IP Addresses and Subnets on page 25 for background information.
The CGNV2 has a built-in DHCP server that, when active, assigns IP addresses to
computers on the LAN. When the DHCP server is active, you can get an IP address
automatically. The DHCP server is active by default.
If your computer is configured to get an IP address automatically, or if you are not
sure, try to log in to the CGNV2 (see Login to the CGNV2 on page 22).
If the login screen displays, your computer is already configured correctly.
If the login screen does not display, either the CGNV2’s DHCP server is not
active or your computer is not configured correctly. Follow the procedure in
Manual IP Address Setup on page 21 and set your computer to get an IP
address automatically. Try to log in again. If you cannot log in, follow the manual
IP address setup procedure again, and set a specific IP address as shown. Try
to log in again.
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HITRON CGNV2 USER’S GUIDE
NOTE: If you still cannot see the login screen, your CGNV2’s IP settings may have
been changed from their defaults. If you do not know the CGNV2’s new
address, you should return it to its factory defaults. See Resetting the CGNV2
on page 23. Bear in mind that ALL user-configured settings are lost.
1.4.1 MANUAL IP ADDRESS SETUP
By default, your CGNV2’s local IP address is 192.168.0.1. If your CGNV2 is using the
default IP address, you should set your computer’s IP address to be between
192.168.0.2 and 192.168.0.254.
NOTE: If your CGNV2 DHCP server is active, set your computer to get an IP address
automatically in step 5. The CGNV2 assigns an IP address to your computer.
The DHCP server is active by default.
Take the following steps to manually set up your computer’s IP address to connect to
the CGNV2:
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NOTE: This example uses Windows XP; the procedure for your operating system
may be different.
1 Click Start, then click Control Panel.
2 In the window that displays, double-click Network Connections.
3 Right-click your network connection (usually Local Area Connection) and click
Properties.
4 In the General tab’s This connection uses the following items list, scroll
down and select Internet Protocol (TCP/IP). Click Properties.
5 You can get an IP address automatically, or specify one manually:
If your CGNV2’s DHCP server is active, select Get an IP address
automatically.
If your CGNV2’s DHCP server is not active, select Use the following IP
address. In the IP address field, enter a value between 192.168.0.2 and
192.168.0.254 (default). In the Subnet mask field, enter 255.255.255.0
(default).
NOTE: If your CGNV2 is not using the default IP address, enter an IP address and
subnet mask that places your computer in the same subnet as the CGNV2.
6 Click OK. The Internet Protocol (TCP/IP) window closes. In the Local Area
Connection Properties window, click OK.
Your computer now obtains an IP address from the CGNV2, or uses the IP address
that you specified, and can communicate with the CGNV2.
INTRODUCTION
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HITRON CGNV2 USER’S GUIDE
1.5 LOGIN TO THE CGNV2
Take the following steps to login to the CGNV2’s GUI.
NOTE: You can login to the CGNV2’s GUI via the wireless interface. However, it is
strongly recommended that you configure the CGNV2 via a wired connection
on the LAN.
1 Open a browser window.
2 Enter the CGNV2’s IP address (default 192.168.0.1) in the URL bar. The Login
screen displays.
FIGURE 4: Login
3 Enter the Username and Password. The default login username is cusadmin,
and the default password is password.
NOTE: The Username and Password are case-sensitive; “cusadmin” is not the same
as “Cusadmin”.
4 Click Login. The System Info screen displays (see The System Info Screen on
page
30).
1.6 GUI OVERVIEW
This section describes the CGNV2’s GUI.
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HITRON CGNV2 USER’S GUIDE
FIGURE 5: GUI Overview
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TABLE 3: GUI Overview
Primary
Navigation Bar
Secondary
Navigation Bar
Main Window Use this section to read information about your CGNV2’s
Use this section to move from one part of the GUI to another.
Use this section to move from one related screen to another.
configuration, and make configuration changes.
1.7 RESETTING THE CGNV2
When you reset the CGNV2 to its factory defaults, all user-configured settings are
lost, and the CGNV2 is returned to its initial configuration state.
There are two ways to reset the CGNV2:
Press the RESET button on the CGNV2, and hold it in for ten seconds or longer.
Click WAN/LAN > Backup. In the screen that displays, click the Factory Reset
button.
INTRODUCTION
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HITRON CGNV2 USER’S GUIDE
The CGNV2 turns off and on again, using its factory default settings.
NOTE: Depending on your CGNV2’s previous configuration, you may need to re-
configure your computer’s IP settings; see IP Address Setup on page 20.
INTRODUCTION
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CABLE
This chapter describes the screens that display when you click Cable in the toolbar.
2.1 CABLE OVERVIEW
This section describes some of the concepts related to the Cable screens.
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2.1.1 DOCSIS
The Data Over Cable Service Interface Specification (DOCSIS) is a
telecommunications standard that defines the provision of data services) Internet
access) over a traditional cable TV (CATV) network.
Your CGNV2 supports DOCSIS version 3.0.
2.1.2 IP ADDRESSES AND SUBNETS
Every computer on the Internet must have a unique Internet Protocol (IP) address.
The IP address works much like a street address, in that it identifies a specific
location to which information is transmitted. No two computers on a network can have
the same IP address.
2.1.2.1 IP ADDRESS FORMAT
IP addresses consist of four octets (8-bit numerical values) and are usually
represented in decimal notation, for example 192.168.1.1. In decimal notation, this
means that each octet has a minimum value of 0 and a maximum value of 255.
An IP address carries two basic pieces of information: the “network number” (the
address of the network as a whole, analogous to a street name) and the “host ID”
(analogous to a house number) which identifies the specific computer (or other
network device).
2.1.2.2 IP ADDRESS ASSIGNMENT
IP addresses can come from three places:
The Internet Assigned Numbers Agency (IANA)
CABLE
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HITRON CGNV2 USER’S GUIDE
Your Internet Service Provider
You (or your network devices)
IANA is responsible for IP address allocation on a global scale, and your ISP assigns
IP addresses to its customers. You should never attempt to define your own IP
addresses on a public network, but you are free to do so on a private network.
In the case of the CGNV2:
The public network (Wide Area Network or WAN) is the link between the cable
(CATV) connector and your Internet Service Provider. Your CGNV2’s IP
address on this network is assigned by your service provider.
The private network (in routing mode - see Routing Mode on page 28) is your
Local Area Network (LAN) and Wireless Local Area Network (WLAN), if
enabled. You are free to assign IP addresses to computers on the LAN and
WLAN manually, or to allow the CGNV2 to assign them automatically via DHCP
(Dynamic Host Configuration Protocol). IANA has reserved the following blocks
of IP addresses to be used for private networks only:
TABLE 4: Private IP Address Ranges
FROM... ...TO
10.0.0.0 10.255.255.255
172.16.0.0 172.31.255.255
192.168.0.0 192.168.255.255
If you assign addresses manually, they must be within the CGNV2’s LAN
subnet.
2.1.2.3 SUBNETS
A subnet (short for sub-network) is, as the name suggests, a separate section of a
network, distinct from the main network of which it is a part. A subnet may contain all
of the computers at one corporate local office, for example, while the main network
includes several offices.
In order to define the extent of a subnet, and to differentiate it from the main network,
a subnet mask is used. This “masks” the part of the IP address that refers to the main
network, leaving the part of the IP address that refers to the sub-network.
Each subnet mask has 32 bits (binary digits), as does each IP address:
A binary value of 1 in the subnet mask indicates that the corresponding bit in the
IP address is part of the main network.
A binary value of 0 in the subnet mask indicates that the corresponding bit in the
IP address is part of the sub-network.
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For example, the following table shows the IP address of a computer (192.168.1.1)
expressed in decimal and binary (each cell in the table indicates one octet):
TABLE 5: IP Address: Decimal and Binary
192 168 0 1
11000000 10101000 00000000 00000001
The following table shows a subnet mask that “masks” the first twenty-four bits of the
IP address, in both its decimal and binary notation.
TABLE 6: Subnet Mask: Decimal and Binary
255 255 255 0
11111111 11111111 11111111 00000000
This shows that in this subnet, the first three octets (192.168.1, in the example IP
address) define the main network, and the final octet (1, in the example IP address)
defines the computer’s address on the subnet.
The decimal and binary notations give us the two common ways to write a subnet
mask:
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Decimal: the subnet mask is written in the same fashion as the IP address:
255.255.255.0, for example.
Binary: the subnet mask is indicated after the IP address (preceded by a forward
slash), specifying the number of binary digits that it masks. The subnet mask
255.255.255.0 masks the first twenty-four bits of the IP address, so it would be
written as follows: 192.168.1.1/24.
2.1.3 DHCP
The Dynamic Host Configuration Protocol, or DHCP, defines the process by which IP
addresses can be assigned to computers and other networking devices
automatically, from another device on the network. This device is known as a DHCP
server, and provides addresses to all the DHCP client devices.
In order to receive an IP address via DHCP, a computer must first request one from
the DHCP server (this is a broadcast request, meaning that it is sent out to the whole
network, rather than just one IP address). The DHCP server hears the requests, and
responds by assigning an IP address to the computer that requested it.
If a computer is not configured to request an IP address via DHCP, you must
configure an IP address manually if you want to access other computers and devices
on the network. See
IP Address Setup on page 20 for more information.
By default, the CGNV2 is a DHCP client on the WAN (the CATV connection). It
broadcasts an IP address over the cable network, and receives one from the service
provider. By default, the CGNV2 is a DHCP server on the LAN; it provides IP
addresses to computers on the LAN which request them.
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2.1.4 DHCP LEASE
“DHCP lease” refers to the length of time for which a DHCP server allows a DHCP
client to use an IP address. Usually, a DHCP client will request a DHCP lease
renewal before the lease time is up, and can continue to use the IP address for an
additional period. However, if the client does not request a renewal, the DHCP server
stops allowing the client to use the IP address.
This is done to prevent IP addresses from being used up by computers that no longer
require them, since the pool of available IP addresses is finite.
2.1.5 DNS
2.1.6 MAC ADDRESSES
Every network device possesses a Media Access Control (MAC) address. This is a
unique alphanumeric code, given to the device at the factory, which in most cases
cannot be changed (although some devices are capable of “MAC spoofing”, where
they impersonate another device’s MAC address).
MAC addresses are the most reliable way of identifying network devices, since IP
addresses tend to change over time (whether manually altered, or updated via
DHCP).
Each MAC address displays as six groups of two hexadecimal digits separated by
colons (or, occasionally, dashes) for example 00:AA:FF:1A:B5:74.
NOTE: Each group of two hexadecimal digits is known as an “octet”, since it
represents eight bits.
Bear in mind that a MAC address does not precisely represent a computer on your
network (or elsewhere), it represents a network device, which may be part of a
computer (or other device). For example, if a single computer has an Ethernet card
(to connect to your CGNV2 via one of the LAN ports) and also has a wireless card (to
connect to your CGNV2 over the wireless interface) the MAC addresses of the two
cards will be different. In the case of the CGNV2, each internal module (cable modem
module, Ethernet module, wireless module, etc.) possesses its own MAC address.
2.1.7 ROUTING MODE
When your CGNV2 is in routing mode, it acts as a gateway for computers on the LAN
to access the Internet. The service provider assigns an IP address to the CGNV2 on
the WAN, and all traffic for LAN computers is sent to that IP address. The CGNV2
assigns private IP addresses to LAN computers (when DHCP is active), and
transmits the relevant traffic to each private IP address.
NOTE: When DHCP is not active on the CGNV2 in routing mode, each computer on
the LAN must be assigned an IP address in the CGNV2’s subnet manually.
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When the CGNV2 is not in routing mode, the service provider assigns an IP address
to each computer connected to the CGNV2 directly. The CGNV2 does not perform
any routing operations, and traffic flows between the computers and the service
provider.
Routing mode is not user-configurable; it is specified by the service provider in the
CGNV2’s configuration file.
2.1.8 CONFIGURATION FILES
The CGNV2’s configuration (or config) file is a document that the CGNV2 obtains
automatically over the Internet from the service provider’s server, which specifies the
settings that the CGNV2 should use. It contains a variety of settings that are not
present in the user-configurable Graphical User Interface (GUI) and can be specified
only by the service provider.
2.1.9 DOWNSTREAM AND UPSTREAM TRANSMISSIONS
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The terms “downstream” and “upstream” refer to data traffic flows, and indicate the
direction in which the traffic is traveling. “Downstream” refers to traffic from the
service provider to the CGNV2, and “upstream” refers to traffic from the CGNV2 to
the service provider.
2.1.10 CABLE FREQUENCIES
Just like radio transmissions, data transmissions over the cable network must exist
on different frequencies in order to avoid interference between signals.
The data traffic band is separate from the TV band, and each data channel is
separate from other data channels.
2.1.11 MODULATION
Transmissions over the cable network are based on a strong, high frequency periodic
waveform known as the “carrier wave.” This carrier wave is so called because it
“carries” the data signal. The data signal itself is defined by variations in the carrier
wave. The process of varying the carrier wave (in order to carry data signal
information) is known as “modulation.” The data signal is thus known as the
“modulating signal.”
Cable transmissions use a variety of methods to perform modulation (and the
“decoding” of the received signal, or “demodulation”). The modulation methods
defined in DOCSIS 3 are as follows:
QPSK: Quadrature Phase-Shift Keying
QAM: Quadrature Amplitude Modulation
QAM TCM: Trellis modulated Quadrature Amplitude Modulation
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In many cases, a number precedes the modulation type (for example 16 QAM). This
number refers to the complexity of modulation. The higher the number, the more data
can be encoded in each symbol.
NOTE: In modulated signals, each distinct modulated character (for example, each
audible tone produced by a modem for transmission over telephone lines) is
known as a symbol.
Since more information can be represented by a single character, a higher number
indicates a higher data transfer rate.
2.1.12 TDMA, FDMA AND SCDMA
Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA)
and Synchronous Code Division Multiple Access (SCDMA) are channel access
methods that allow multiple users to share the same frequency channel.
TDMA allows multiple users to share the same frequency channel by splitting
transmissions by time. Each user is allocated a number of time slots, and
transmits during those time slots.
FDMA allows multiple users to share the same frequency channel by assigning a
frequency band within the existing channel to each user.
SCDMA allows multiple users to share the same frequency channel by assigning
a unique orthogonal code to each user.
2.2 THE SYSTEM INFO SCREEN
Use this screen to see general information about your CGNV2’s hardware, its
software, and its connection to the Internet.
NOTE: Most of the information that displays in this screen is for troubleshooting
purposes only. However, you may need to use the MAC Address information
when setting up your network.
Click Cable > System Info. The following screen displays.
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