3Com Router WL-602 User Manual

							Wireless Networking129
unsure try relocating both the wireless computers and the Router to 
establish whether this problem exists.
■Most wireless computer adapters will scan the channels for the 
wireless Router. If a wireless computer has not located the Router then 
try initiating a search manually if the client software supports this 
feature or manually set the channel on your wireless computer to 
correspond to the Router channel number. Please refer to your 
wireless computer adapter documentation and vendor to do this.
■Speed of connection: The 802.11b and 802.11g standards will 
automatically choose the best speed depending on the quality of your 
connection. As the signal quality weakens then the speed falls back to 
a lower speed. The speeds supported by 802.11g are 54 Mbps, 
48 Mbps, 36 Mbps, 24 Mbps, 18 Mbps, 12 Mbps and 6 Mbps. The 
speeds supported by 802.11b are 11 Mbps, 5.5 Mbps, 2 Mbps and 
1 Mbps. In general the closer you are to the Router the better the 
speed. If you are not achieving the speed you had anticipated then try 
moving the antenna on the Router or moving the wireless computer 
closer to the Router. In an ideal network the Router should be located 
in the centre of the network with wireless computers distributed 
around it. Applications are generally available with the computer 
wireless card to carry out a site survey. Use this application to find the 
optimal siting for your wireless computer. Consult your Computer 
Card documentation and vendor for more details. 
						

							130CHAPTER 6: TROUBLESHOOTING
Recovering from 
Corrupted SoftwareIf the system software has become corrupted, the Router will enter a 
“recovery” state; DHCP is enabled, and the LAN IP address is set to 
192.168.1.1. Follow the instructions below to upload a new copy of the 
system software to a Router unit in this state.
Ensure that one of your computers has a copy of the new software image 
file stored on its hard disk or available on CD-ROM.
Check on www.3com.com for the latest version firmware.
1Remove power from the Router and disconnect from DSL or Cable 
modem and all your computers, except for the one computer with the 
software image.
2You will need to reconfigure this computer to obtain an IP address 
automatically (see Obtaining an IP Address Automatically
 on page 23).
3Restart the computer, and re-apply power to the Router.
4Using the Web browser on the computer, enter the following URL in the 
location bar: 
http://192.168.1.1. 
This will connect you to the Recovery utility in the Router.
5Follow the on-screen instructions. Enter the path and filename of the 
software image file.
6When the upload has completed, the Router will restart, run the self-test 
and, if successful, resume normal operation.
7Refer to the Installation Guide to reconnect your Router to the telephone 
line and the computers in your network. Do not forget to reconfigure the 
computer you used for the software upload.
If the Router does not resume normal operation following the upload, it 
may be faulty. Contact your supplier for advice.
Power AdapterPower Status Logo not lit. 
This is probably because the switch does not have power. Check the 
following: 
■Make sure the power lead from the power adapter is properly 
connected and the cord is not damaged. 
						

							Power Adapter131
■Ensure the power adapter is correctly fitted into the power outlet 
socket and that the socket switch is turned on if applicable.
■Ensure you are using only the 3Com power adapter supplied with the 
Router.
If there is still no power, contact 3Com Technical Support and ask for 
assistance
Caution: Only use the power adapter supplied with the Router or a 
replacement 3Com power adapter. Do not use any other power adapter.
For reference, the part number for the power adapter supplied for your 
region is: 
3Com Number Region 
3C12VUS US and Canada
3C12VUK or 3C15VUK UK
3C12VME or 3C15VME Europe and Middle East
3C12VAAAustralasia (except Japan and Korea)
3C12VSA South Africa
3C12VKR Korea
3C12VRA Argentina 
						

							132CHAPTER 6: TROUBLESHOOTING
Frequently Asked 
QuestionsHow do I reset the Router to Factory Defaults?
See Forgotten Password and Reset to Factory Defaults on 
page 127.
How many computers on the LAN does the Router support?
Up to a maximum number of 253 total users on the LAN are 
supported. Please note that the maximum number of users 
supported will be vary depending on the amount of traffic that 
each user generates.
How many wireless clients does the Router support?
Up to 32 wireless clients are supported. Please note that the total 
practical number of wireless users depends on the network 
environment and the amount of bandwidth consumed by each 
user. 
There are only 4 LAN ports on the Router. How are additional 
computers connected?
You can expand the number of connections available on your LAN 
by using hubs, switches and wireless access points connected to 
the Router. 3Com wireless access points and hubs and switches 
provide a simple, reliable means of expanding your network; 
contact your supplier for more information, or visit:
http://www.3com.com/
Does the Router support virtual private networks (VPNs)?
The Router supports both VPN passthrough and VPN 
initiation/termination. VPN initiation/termination is useful when 
you need to establisha secure site-to-site communication or make 
your network accessible to remote teleworkers. 
VPN passthrough is used when you are connected to 3Com Router 
and access the corporate network from your laptop with VPN 
client. 
						

							A
IP ADDRESSING
The Internet 
Protocol SuiteThe Internet Protocol suite consists of a well-defined set of 
communications protocols and several standard application protocols. 
Transmission Control Protocol/Internet Protocol (TCP/IP) is probably the 
most widely known and is a combination of two of the protocols (IP and 
TCP) working together. TCP/IP is an internationally adopted and 
supported networking standard that provides connectivity between 
equipment from many vendors over a wide variety of networking 
technologies.
Managing the 
Router over the 
NetworkTo manage a device over the network, the Router must be correctly 
configured with the following IP information:
■An IP address
■A Subnet Mask
IP Addresses and
Subnet MasksEach device on your network must have a unique IP address to operate 
correctly. An IP address identifies the address of the device to which data 
is being sent and the address of the destination network. IP addresses 
have the format n.n.n.x where n is a decimal number between 0 and 255 
and x is a number between 1 and 254 inclusive.
However, an IP address alone is not enough to make your device operate. 
In addition to the IP address, you need to set a subnet mask. All networks 
are divided into smaller sub-networks and a subnet mask is a number 
that enables a device to identify the sub-network to which it is 
connected. 
						

							134APPENDIX A: IP ADDRESSING
For your network to work correctly, all devices on the network must have:
■The same sub-network address.
■The same subnet mask.
The only value that will be different is the specific host device number. 
This value must always be unique.
An example IP address is ‘192.168.100.8’. However, the size of the 
network determines the structure of this IP address. In using the Router, 
you will probably only encounter two types of IP address and subnet 
mask structures.
Ty p e  O n e
In a small network, the IP address of ‘192.168.100.8’ is split into two 
parts:
■Part one (‘192.168.100’) identifies the network on which the device 
resides.
■Part two (‘.8’) identifies the device within the network.
This type of IP address operates on a subnet mask of ‘255.255.255.0’.
See Ta b l e 3 for an example about how a network with three computers 
and a Router might be configured.
Ta b l e 3    IP Addressing and Subnet Masking
Ty p e  Tw o
In larger networks, where there are more devices, the IP address of 
‘192.168.100.8’ is, again, split into two parts but is structured differently:
■Part one (‘192.168’) identifies the network on which the device 
resides.
■Part two (‘.100.8’) identifies the device within the network.
DeviceIP AddressSubnet Mask
PC 1192.168.100.8255.255.255.0
PC 2192.168.100.33255.255.255.0
PC 3192.168.100.188255.255.255.0
Router192.168.100.72255.255.255.0 
						

							How does a Device Obtain an IP Address and Subnet Mask?135
This type of IP Address operates on a subnet mask of ‘255.255.0.0’.
See Ta b l e 4 for an example about how a network (only four computers 
represented) and a Router might be configured.
Ta b l e 4    IP Addressing and Subnet Masking
How does a Device 
Obtain an IP 
Address and Subnet 
Mask?There are three different ways to obtain an IP address and the subnet 
mask. These are:
■Dynamic Host Configuration Protocol (DHCP) Addressing
■Static Addressing
■Automatic Addressing (Auto-IP Addressing)
DHCP AddressingThe Router contains a DHCP server, which allows computers on your 
network to obtain an IP address and subnet mask automatically. DHCP 
assigns a temporary IP address and subnet mask which gets reallocated 
once you disconnect from the network.
DHCP will work on any client Operating System such as Windows 98, 
Windows NT 4.0, Windows 2000, Windows XP, and Windows Vista. 
Also, using DHCP means that the same IP address and subnet mask will 
never be duplicated for devices on the network. DHCP is particularly 
useful for networks with large numbers of users on them.
Static AddressingYou must enter an IP Address and the subnet mask manually on every 
device. Using a static IP and subnet mask means the address is 
permanently fixed.
Auto-IP AddressingNetwork devices use automatic IP addressing if they are configured to 
acquire an address using DHCP but are unable to contact a DHCP server. 
Automatic IP addressing is a scheme where devices allocate themselves 
DeviceIP AddressSubnet Mask
PC 1192.168.100.8255.255.0.0
PC 2192.168.201.30255.255.0.0
PC 3192.168.113.155255.255.0.0
PC 4192.168.002.230255.255.0.0
Router192.168.002.72255.255.0.0 
						

							136APPENDIX A: IP ADDRESSING
an IP address at random from the industry standard subnet of 
169.254.x.x (with a subnet mask of 255.255.0.0). If two devices allocate 
themselves the same address, the conflict is detected and one of the 
devices allocates itself a new address. 
Automatic IP addressing support was introduced by Microsoft in the 
Windows 98 operating system and is also supported in Windows 2000 
and Windows XP. 
						

							B
TECHNICAL SPECIFICATIONS
This section lists the technical specifications for the 3Com Wireless 11n 
Cable/DSL Firewall Router.
3Com Wireless 11n 
Cable/DSL Firewall 
RouterInterfaces
WAN connection — one 10 Mbps/100Mbs dual speed Ethernet port 
(10BASE-T/100BASE-TX)
LAN connection — four 10 Mbps/100 Mbps dual speed Ethernet ports 
(10BASE-T/100BASE-TX)
Antenna 
Two external Dipole antennas for TX/RX function and the gain value 
is 2 dBi. 
One internal PIFA antenna for RX function only and the gain value 
is 2 dBi.
WLAN Interfaces
IEEE draft 802.11n, Orthogonal Frequency Division Multiplexing (OFDM)
Transmission rate: 802.11n 40MHz: 300 Mbps, automatic fallback to 
243, 216, 162, 135, 121,5, 108, 81, 54, 40.5, 27, 13.5Mbps
802.11n 20MHz: 130Mbps, automatic fallback to 117, 104, 78, 65, 58.5, 
52, 39, 26, 19.5, 13, 6.5Mbps
Maximum channels: 13
Range up to 304.8m (1000ft)
Sensitivity: 11 Mbps: -82 dBm; 54 Mbps: -68 dBm;
MCS15 (20MHz): -65 dBm ; MCS15 (40MHz): -62 dBm 
Modulation: CCK, BPSK, QPSK, OFDM
Encryption: 40/64 bit WEP, 128 bit WEP, WPA/WPA2
Maximum clients: 128
O/P Power: 14dBm 
						

							138APPENDIX B: TECHNICAL SPECIFICATIONS
Standard IEEE 802.11g, Direct Sequence Spread Spectrum (DSSS)
Transmission rate: 54 Mbps, automatic fallback to 48, 36, 24, 18, 12, or 
6Mbps
Maximum channels: 13
Range up to 304.8m (1000ft)
Sensitivity:  6, 12, 18, 24, 36, 48 Mbps: -85 dBm;
54 Mbps -66 dBm typical
Modulation: CCK, BPSK, QPSK, OFDM
Encryption: 40/64 bit WEP, 128 bit WEP, WPA/WPA2
Maximum clients: 128
O/P Power: 14dBm
Standard IEEE 802.11b, Direct Sequence Spread Spectrum (DSSS)
Transmission rate: 11Mbps, automatic fallback to 5.5, 2, or 1 Mbps
Maximum channels: 13
Range up to 304.8m (1000ft)
Sensitivity: 1, 2, 5.5 Mbps: -85 dBm; 11 Mbps -82 dBm typical
Modulation: CCK, BPSK, QPSK
Encryption: 40/64 bit WEP, 128 bit WEP, WPA/WPA2
Maximum clients: 128
O/P Power 18dBm
Operating Temperature
0 °C to 40 °C (32 °F to 105 °F)
Power 
15V0.8A/15V1A
Humidity
0% to 90% (non-condensing) humidity
Dimensions
■Width = 178 mm (7.0 in.)
■Depth = 160 mm (6.1 in.)
■Height = 39 mm (1.5 in.)
Weight
Approximately 285 g