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User Manual
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Tahoe 4681 User Manual

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User Manual
Tahoe 4681
(4-port G.shdsl.bis/FastEthernet modem card)
User Manual
Tah o e 4681
(4-port G.shdsl.bis/FastEthernet modem card)
II
Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card) User Manual Firmware version 1.3.0 Published July 2006 ©2005-2006 Tahoe. All rights reserved. Trademarks of other companies are used only for explanation and to the owner’s benefit, without intent to infringe.
THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS, INFORMATION, AND RECOMMENDA­TIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE, BUT ARE PRESENTED WITHOUT WAR­RANTY OF ANY KIND, EXPRESS OR IMPLIED AND TAHOE MAKES NO COMMITMENT TO UPDATE THE INFORMATION CONTAINTED HERE.
NOTWITHSTANDING ANY OTHER WARRANTY HEREIN, ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED “AS IS”. TAHOE DISCLAIM ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF MERCHANTABILITY, FITNESS FOR A PAR­TICULAR PURPOSE AND NONINFRINGEMENT OR ARISING FROM A COURSE OF DEALING, USAGE, OR TRADE PRACTICE.
IN NO EVENT SHALL TAHOE BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCI­DENTAL DAMAGES, INCLUDING, WITHOUT LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Contents
Introduction ..............................................................................................................................................1
Front Panel ..............................................................................................................................................1
Leased Line ..............................................................................................................................................1
LAN ..........................................................................................................................................................2
Status LEDs .............................................................................................................................................2
Installation .................................................................................................................................................3
Advanced Configuration and Management ......................................................................................5
Telnet Connection ..................................................................................................................................5
Internal Backplane Connection ...........................................................................................................5
Commands Summary ...........................................................................................................................6
DHCP Server Configuration ..............................................................................................................25
Appendix A, Troubleshooting ............................................................................................................. 31
Appendix B, Technical Specification ................................................................................................. 32
Appendix C, Safety Information ........................................................................................................33
Appendix D, Declaration of Conformity ..........................................................................................35
IV
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Preface
About this Manual
is manual contains following chapters:
Chapter 1, Introduction An overview of the modem, description of its interfaces
and features
Chapter 2, Installation How to install the card in a DSL Access Multiplexer
Chapter 3, Advanced Configuration and Management
List of commands used to configure the modem using serial console or telnet connection
Appendix A, Troubleshooting Description of typical problems that may occur during
use of the modem
Appendix B, Technical Specification Parameters of the modem
Appendix C, Safety Information Important information about hazards involved with us-
age of electrical devices
Appendix D, Declaration of Con­formity
Information about compliance to European standards
VI
Document Conventions
is manual uses following conventions:
boldface font Commands and keywords
< > Arguments for which you have to supply values
[ ] Optional arguments
{ a | b | c } Alternative arguments
[ a | b | c ] Alternative optional arguments
typewriter font
Information displayed during a serial or telnet connection
boldface typewriter font
Information that must be entered during a serial or telnet connection
LCD font
Information displayed on the LCD
Note
Notes contain helpful suggestions that may be worth remembering
Caution
is symbol means a situation that requires you to be careful. Otherwise equipment damage or loss of data may occur.
Warning
is warning symbol means danger. You are in a situation that could cause bodily injury. Before you work on any equipment, be aware of the hazards involved with electrical circuitry and be familiar with standard practices for preventing accidents.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Introduction
ank you for purchasing the Tahoe 4681 modem card. We did our best to ensure highest stand­ard of reliability and performance of our products. Devoting many years of research and devel­opment we are proud to provide a superior quality device unfolding new possibilities for the use of the copper lines.
Tahoe 4681 modem card contains four G.shdsl.bis modems which allow data transmission with speeds up to 5696 kbps on a 2-wire line, 11392 kbps on a 4-wire line and 22784 kbps on an 8-wire line. anks to powerful TCPAM-32 modulation throughputs are much higher than using HDSL technology and reach is nearly twice that of VDSL.
Front Panel
Leased Line
Four 6-pin RJ-11 connectors are used to connect the leased lines. e polarization of a line is not important.
Pin Signal
1-
2-
3 line
4 line
5-
6-
2
LAN
e Fast Ethernet interface is used to connect the modem to the Local Area Network (LAN). It may work at speeds of 10 Mbps (10Base-T) or 100 Mbps (100Base-Tx), in full-duplex or half­duplex mode. e mode of transmission is selected automatically, although a specific setting can be forced.
Modem should be connected to an Ethernet switch or a hub using a straight patch-cord or to a PC, a router or an uplink port in a switch using a crossed-over. Aer connecting the cable a LED named “LAN Link” should light up.
Status LEDs
Besides LEDs on the LAN connector there are four LEDs representing state of the G.shdsl link. ree behaviours of these LEDs are possible:
off – line is not connected, no signal is detected blinking – line is in progress of synchronization on – line is synchronized, the data stream may flow through the modem
LAN Link LAN Activity
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Installation
Before installing the card make sure that your working site is properly grounded. Hold the card by the front panel handler and do not touch other components to prevent damage caused by electro­static discharge.
To install the card in a DSL Access Multiplexer follow these steps:
Find an empty slot and remove a blank panel if the slot is covered:
Insert the card into the slot. Make sure that the card enters two red rails on the top and the
bottom:
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Tighten the card to the DSLAM using two screws:
e card can be inserted and removed without switching the power off. e DSLAM management card will automatically detect new device and display its status on the LCD.
e card can be configured through a telnet connection or using the DSLAM management card. Configuration using telnet is described in next chapter, while the management card configura­tion is described in Tahoe Network Management Card User Manual.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Advanced Configuration and Management
Telnet Connection
To connect to the modem the network interface on PC has to be in the same IP subnet as the mo­dem. By default the modem’s Ethernet interface is set to 10.0.0.1 address and 255.0.0.0 netmask, so the PC may have IP address set to 10.0.0.2 and the same netmask.
If the modem was already configured and the routing table is correctly set, a telnet connection to its IP address is possible from anywhere in the network.
Aer connecting a password prompt will appear:
User Access Verification
Password:
e default password is “Tahoe” (case sensitive). If the password entered is correct, a command prompt will appear:
Tahoe>
Internal Backplane Connection
If the telnet connection is not possible (e.g. there’s no telnet client available or the modem’s IP address is unknown), you can connect to the modem through the main DSLAM management card and the internal backplane. Aer connecting to the management card (using telnet or serial console) type:
Tahoe> console connect <slot number>
You will get the same connection as if you were connected to the modem using telnet, i.e. the regular command prompt appears:
Tahoe>
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Commands Summary
Complete command set
? displays command list
arp ARP table configuration
bridge bridge mode settings
bundle groups DSL lines into bundles
config displays current configuration
console console access settings
dhcp DHCP configuration
dsl G.shdsl line configuration
eepromdump dumps EEPROM (configuration memory) contents
eraseconfig erases EEPROM configuration
exit closes connection with modem
help displays command list
http web server configuration
ifconfig interface configuration
ipchains NAT/PAT/firewall settings
keypad LCD keyboard locking
lang language selection
lcd LCD text modification
masq NAT status
mem memory usage
mii MII (Ethernet) transceiver settings
more enables or disables ’more’ prompt
netstat TCP/IP connections list
ping checks network device availability
prompt changes command prompt
ps displays process list
quit closes connection with modem
reboot reboots modem
route routing table settings
snmp SNMP settings
strictarp forcing IP-MAC binding
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
syslog sending logs to remote syslogd
tech system information for tech support
telnet telnet server settings
tcpdump shows interface traffic
tp TFTP server settings
timeout login and session timeout settings
uptime shows router uptime
user user management
ver shows firmware version
vlan VLAN bridging configuration
wshows router uptime
wake powers on a LAN station using Wake-On-LAN feature
watchdog watchdog settings
write writes settings to EEPROM
?
Shows a list of available commands.
arp
e arp command is used to configure the ARP table. e arp alone shows the list of bindings between IP and hardware (MAC) addresses:
Tahoe> arp IP address Hardware address Type Expires
10.0.0.2 00:50:04:0D :70:31 dy n a m ic 215s Tahoe>
e “Type” can be “dynamic” (learnt from the network traffic), “static” (added manually) or “proxy” (a proxy ARP entry). e value in the “Expires” column denotes the time le until the ARP table entry removal. e ARP entries are removed when they are not used for 5 minutes.
ARP table entries can be deleted using arp del command:
Tahoe> a r p d el 10.0.0.2
(insert the IP address to be deleted instead of “10.0.0.2”).
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A static ARP entry can be added using arp add:
Tahoe> a r p a d d 10.0.0.3 0 0: 5 0:13: E9 : 5C : 01
A proxy ARP entry can also be added using arp add:
Tahoe> a r p a d d 10.0.0.4 p r o x y
When a proxy ARP entry is added, the modem will respond with its own MAC address to the ARP requests asking of the specified IP address. anks to such a behaviour you may select an IP address from the network connected to the Ethernet interface and assign it to the device on the other end of WAN link. e modem will pretend to have that IP address, answer to ARP requests and then forward received packets over the WAN link aer an appropriate routing entry is added.
e dynamic hardware address resolution may be disabled using the ifconfig command. When disabled, only those stations whose IP and MAC addresses are entered staticaly into the ARP table using the arp add command are allowed to connect to the modem.
bridge
e bridge command enables or disables the bridge mode, in which two interconnected LANs create united one in the hardware layer. e stations in both LANs behave like if they were con­nected to one Ethernet switch, e.g. PCs working under Microso® Windows™ operating system will see each other in the network neighbourhood.
Following settings are available:
off – regular TCP/IP (Layer 3) routing
on – the bridge mode is enabled, but the modem is still available under its IP address and
thus may be managed remotely
transparent – completely transparent bridge, modem does not respond to its IP address
dumb – the bridge mode is enabled, but no MAC address checking is performed. In the
regular bridge mode the modem checks on which interface (G.shdsl or LAN) the packet’s destination MAC address was heard and decides whether to forward that packet or not. e dumb mode does not do any MAC checking, thus is more efficient. It will work properly in most cases, because the external Ethernet switch does the MAC checking on its own.
dumbtrans – a combination of two above modes, no MAC address check is performed and
the modem isn’t available under its IP address
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Entering bridge list displays a list of MAC addresses with the name of the interface on which certain address was heard.
If you select transparent or dumbtrans mode while being connected to the modem via telnet you will loose the possibility of remote management (the modem will stop responding to its IP address). us you’ll be unable to change that setting back to on or off remotely – you’ll have to change it lo­cally by the serial console or built-in keyboard and LCD display.
To enable bridging the Cisco® HDLC link protocol should also be selected using the bundle or dsl command (selected as factory default)
bundle
e bundle command allows grouping of several DSL lines into bundles and configures them. ere are four WAN interfaces – wan0, wan1, wan2 and wan3.
bundle <interface> add <line number> – adds a line to a bundle:
Tahoe> bundle wan0 add 1
bundle <interface> del <line number> – removes a line from a bundle:
Tahoe> bundle wan0 del 1
bundle <interface> link { hdlc | raw | fr | ppp } – selects the link protocol
– Cisco® HDLC, raw HDLC, Frame Relay or synchronous PPP. e Cisco® HDLC proto­col („hdlc” option) should be used in most cases, the others are provided for compatibility only
bundle <interface> speed <value> – sets total throughput of a bundle. e speed
range depends on number of lines belonging to the bundle, i.e. 64 - 5696 kbps in case of one line, 128 - 11392 kbps in case of two lines, etc. New speed is set aer renegotiating the DSL connection.
bundle <interface> type { master | slave } – selects modem type of all lines in
the bundle. New type is set aer renegotiating the DSL connection. One modem should be set as a Master, while the other one as a Slave
bundle <interface> mod { auto | tcpam32 | tcpa m16 | tcpam8 | tcpam4
| pam16 | pam8 | pam4 | pam2 }
– selects line coding (modulation type) of all lines
in the bundle. e TCPAM32 modulation is recommended, as it is the most efficient – the
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rest is available to provide compatibility with devices from other manufacturers. Moreover TCPAM32 allows throughputs from 256 kbps to 5696 kbps per line, while TCPAM16 – from 128 kbps to 2304 kbps and TCPAM4 – 64 kbps. e “auto” setting forces use of TCPAM32 for speeds greater than or equal to 256 kbps per line and TCPAM16 or TCPAM4 for lower rates.
bundle <interface> txgain <value> – sets transmitter gain of all lines in the bundle.
e gain may be selected from 0.0 – 1.6 range. e modem reach may be slightly higher if the gain is increased. New mode is set aer renegotiating the DSL connection.
bundle <interface> reset – renegotiates connection on all lines in the bundle
bundle show – shows current settings
config
e config command displays current configuration. e command output can be entered on another modem to make an exact copy of the configuration.
console
is command is used to enable or disable password protection of the serial console. By default the console is unprotected and user has full access to the modem. By entering:
Tahoe> console passwd on
the password requirement is enabled and modem will ask for it in the same manner as during the telnet connection. To disable password protection type:
Tahoe> console passwd off
dhcp
e dhcp command is used to configure the DHCP server or DHCP relay. Refer to the DHCP Server Configuration section for detailed information about that command.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
dsl
is command is used to configure specific DSL line. Following options are available:
dsl <line> speed <value> – sets the throughput of a single line. e speed ranges from
from 64 to 5696 kbps. New speed is set aer renegotiating the DSL connection.
dsl <line> type { master | slave } – selects modem type. New type is set aer
renegotiating the DSL connection. One modem is always set as a master, while the other one as a slave
dsl <line> mod { auto | tcpam32 | tcpam16 | tcpam8 | tcpam4 | pam16 |
pam8 | pam4 | pam2 }
– selects line coding (modulation). e TCPAM32 modulation is recommended, as it is the most efficient – the rest is available to provide compatibility with devices from other manufacturers. e TCPAM32 allows throughputs from 256 kbps to 5696 kbps per line, while TCPAM16 – from 128 kbps to 2304 kbps and TCPAM4 – 64 kbps. e auto setting forces use of TCPAM32 for speeds greater than or equal to 256 kbps per line and TCPAM16 or TCPAM4 for lower rates.
dsl <line> txgain <value> – sets transmitter gain. e gain can range from 0.0 to
1.6. e modem reach may be slightly higher if the gain is increased. New mode is set aer renegotiating the DSL connection.
dsl <line> reset – renegotiates connection
dsl show – shows current settings
eepromdump
is command displays the complete contents of the EEPROM (non-volatile) memory in hexa­decimal form. It is used for debugging only.
eraseconfig
e eraseconfig command erases whole configuration from the EEPROM. Aer rebooting the modem it will return to its factory defaults. Until the reboot it will continue to run with its cur­rent settings, which can be saved again using write command.
exit
is command closes the configuration session and disconnects user from the modem.
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help
Shows a list of available commands.
http
e http command configures the built-in web server. It is used to provide an access to modem statistics. Server can be enabled or disabled by entering, respectively:
http on
or
http off
e access to the server can be limited by entering:
Tahoe> http host <IP address>
en the server is only reachable from the given IP address. To remove the limitation enter
0.0.0.0 as the IP address.
ifconfig
at command allows configuring the network interfaces. Following interface names are avail­able:
eth0 – Ethernet interface
eth0.1, eth0.2, etc. – VLAN networks (LAN networks separated from each other, al-
though using the same cabling)
wan0, wan1, etc. – G.shdsl bundle, the WAN interface
is command has similar syntax as the Linux ifconfig:
Tahoe> ifconfig < interface name> [<IP address>] [netmask <network mask>] [bcast <broadcast address>] [ static | dynamic ] [bridge { on | off }]
e ifconfig alone displays information about all active interfaces. Entering ifconfig <interface name> shows information about a specific interface. An information about the interface’s IP ad-
dress, number of packets and bytes sent and received, number of transmission errors and other important data is displayed.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
You can assign an IP address to an interface, together with subnet mask and broadcast address. You can also enable or disable dynamic Address Resolution Protocol (ARP, enabled by default).
ipchains
is command is used to control the firewall and the network address translation (NAT, called also “masquerade” – gives network an access to the Internet using only one public IP address). To configure the firewall you should make a list of rules that define actions that should be taken when a matching packet is received.
ipchains add – adds an entry at the end of the list
ipchains insert – adds an entry at the beginning of the list
ipchains del – removes an entry
ipchains list – displays current settings
ipchains flush – removes all entries from the list
Aer the add, insert or del option, following parameters can be added:
Tahoe> ipchains { add | insert | del } [-s <source subnet>/<netmask>
[<port range>]] [- d <destination subnet>/<netmask> [<port range>]] [- p { tcp | udp | icmp }] [-y] [-m <IP address>] { accept | deny | masq | pat <IP ad d ress>[:<port>]}
-s <source subnet>/<netmask> [<port range>]
Defines the source addresses that this entry concerns. If this parameter is omitted, then the
entry applies to all source addresses. e port range can be specified only if the TCP or UDP protocol is selected using -p option.
-d <destination subnet>/<netmask> [<port range>]
Defines the destination addresses that this entry concerns. If this parameter is omitted, then
the entry applies to all destination addresses. e port range can be specified only if the TCP or UDP protocol is selected using -p option.
-p { tcp | udp | icmp }
Optionally the application of this rule can be limited to a specified protocol
-y
e rule can be applied to the TCP SYN packets only (i.e. the packets that initiate the TCP
connection). It allows inhibiting the incoming connections while the returning packets for the outgoing connections will pass.
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-m <IP add ress>
During the masquerade process the outgoing interface’s IP address is used by default. e
option above allows force use of other address.
accept
A packet that matches the rule will be accepted, i.e. will be forwarded for further processing.
No other firewall rule will be apply.
deny
A packet that matches the rule will be dropped. No other firewall rule will be applied.
masq
A packet will be masqueraded, i.e. its IP address will be changed to the IP address of an
outgoing interface of the modem to allow access to the Internet to stations without public IP addresses.
pat <IP address[:port]>
Do Port Address Translation, i.e. change the destination IP address (and port) and forward
the packet to another station in the network. Allows certain ports on the modem to be redi­rected to stations without public IP addresses that are hidden from the outside network.
e modem always chooses the first matching rule from the list. So if the more general rule comes first, and the more specific is later, then the former will be applied and the latter ignored. us the specific rule has to be inserted before the general one, as in following example:
Tahoe> ipchains add -s 215.16.11.0/24 deny
Tahoe> ipchains insert -s 215.16.11.5 accept
Commands above inhibit the access for the whole 215.16.11.0/24 subnet except the 215.16.11.5 ad­dress.
e specific accept rule (concerning one IP address) has to be inserted before the general rule (con­cerning the whole subnet), by using the insert command as in the example above or by adding the specific rule first and then the general rule aer.
Otherwise the router will always apply the first deny rule and will never reach the second one, as the packet coming from 215.16.11.5 fits both of them and if the general one is first, then it will be applied.
More examples:
Tahoe> ip c h a i n s a d d d 0.0.0.0/ 0 8 0 -8 0 p t c p d e n y
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Inhibits access to the port 80 on all external servers.
Tahoe> ipchains add s 192.168.0.0/16 masq
Enables masquerade for the 192.168.0.0/16 subnet (packets coming from other addresses remain unchanged).
lang
Selects the language used to display messages during the telnet or console connection and on the LCD.
masq
e masq command displays a list of masqueraded connections. e list consists of the source and destination addresses, the port assigned by the modem, the time remaining to the removal of an entry in case of connection inactivity and the amount of remaining free table entries that can be used for new connections.
mem
Mem shows the memory usage statistics. e free entry shows how much free memory is le and the free bufs informs about the amount of free memory destined for network packet.
mii
e mii command allows access to the Ethernet transceiver. Following options are available:
status – displays Ethernet port status (link state, negotiated speed, etc.)
reset – resets the transceiver to the default settings
auto – enables Ethernet auto-negotiation (default)
adv { mode [, mode,…] } – sets a list of modes used during the auto-negotiation. e
modes may be selected from following values: 100BaseTx-FD, 100BaseTx-HD, 10BaseT-FD, 10BaseT-HD
force { mode } – forces a specific mode and disables auto-negotiation
16
power { on | off } – enables or disables the Ethernet port
read [ address ] – read all or selected MII registers
write { address } { value } – writes to a MII register
Configuring the Ethernet transceiver may cause loss of the LAN connection, which in turn may make it impossible to manage the modem remotely.
more
e more command enables (default) or disables the “-- more --” prompt. is prompt is dis­played aer each screen of command output when the results of this command do not fit one screen. e syntax is:
more { on | off }
netstat
Shows a list of TCP connections.
ping
Checks the availability of a device with selected IP address. For example ping 10.0.0.2 displays the time necessary to send packet to the 10.0.0.2 station and back or reports its unavailability:
Tahoe> ping 10.0.0.2
PING 10.0.0.2: 64 bytes 64 bytes from 10.0.0.2: seq = 0 ttl=64 time = 0.623 ms 64 bytes from 10.0.0.2: seq =1 ttl=64 time=0.471 ms 64 bytes from 10.0.0.2: seq =2 ttl=64 time = 0.471 ms
--- 10.0.0.2 ping statistics --­ 3 packets transmitted, 3 packets received, 0% packet loss r o u n d -t ri p m i n /a v g / m a x = 0.471/0.522/0.623 m s Tahoe>
To stop pinging press Ctrl+C.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
prompt
By using the prompt command you may change the default Tahoe> prompt to any other text that will help you identifying the device.
ps
Shows the processes list
quit
is command closes the configuration session and disconnects from the modem.
reboot
Reboots the modem.
All unsaved changes to the configuration will be lost.
route
e route command is similar to analogous Linux command. It is used to configure the IP routing. e route alone shows the current routing table. It may be modified using following options:
route add <address> <interface> – adds the route to a specific host directly through
the interface (the station with this address has to be in the network directly connected to that interface)
route add <address> gw <gateway> – adds the route to a specific host through a gate-
way
route add -net <address> netmask <network mask> <interface> – adds the
route to a subnet with given address and network mask directly on the specified interface
route add -net <address> netmask <network mask> gw <gateway> – adds the
route to a subnet with given address and network mask through the specified gateway
route add default gw <address> – adds the default route through the specified gate-
way
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route del <address> – removes route to the specified IP address
route del -net <address> netmask <network mask> – removes route to the speci-
fied subnet
route del default – removes the default route
snmp
e snmp command is used to configure the SNMP (Simple Network Management Protocol) support. It has following syntax:
snmp – shows current settings:
Tahoe> snmp SNMP on Read community: public Write com munity: private SNMP host1: <any> SNMP host2: <disabled> SNMP host3: <disabled> Tahoe>
snmp on – enables SNMP support
snmp off – disables SNMP support
snmp rdcomm <community> – sets the read community – the password used to read the
SNMP parameters
snmp wrcomm <community> – sets the write community – the password used to write the
SNMP parameters
snmp host1 <address> snmp host2 <address> snmp host3 <address> – allows setting of up to 3 addresses, from which the SNMP ac-
cess will be permited. Entering 0.0.0.0 allows access from any address, while 255.255.255.255 disables an entry (entering 255.255.255.255 in all three positions is equal to disabling the SNMP service)
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
strictarp
e strictarp command helps protecting the LAN against the unauthorized access. Aer ena­bling the “strictarp” mode (by typing strictarp on) and entering the static IP-MAC assignments (using arp add) the modem would listen to incoming ARP requests asking for the addresses it has in its static table. If the request comes from another MAC address than in the modem’s ARP table, it will send an answer with the correct MAC address.
Such request is sent by the PCs working under the Microso® Windows™ operating system dur­ing the boot-up. Aer the ARP reply from the modem is received, the PC will show an error message saying that the IP address is occupied and an illegal use of that IP address would be impossible. e “strictarp” mode may be disabled using strictarp off.
syslog
e modem may send the messages about its status and important events to a syslog server. To configure syslog logging following commands may be used:
syslog on – enables logging
syslog off – disables logging
syslog host <IP add ress> – sets the IP address to which the messages will be sent
tech
e tech command displays a detailed report about modem’s internal state. at output may be used by the technical support for debugging purposes.
telnet
e command allows limiting the telnet access to the modem. e access may be enabled or disabled by entering:
telnet on
or
telnet off
20
respectively. Moreover the access may be limited to a certain IP address:
Tahoe> telnet host <IP address>
If the IP address is set as 0.0.0.0, then the access is possible from anywhere in the network.
If you disable telnet access while connected through telnet connection you will loose possibility to manage the modem remotely and you won’t be able to enable telnet access again without a reboot or local management through serial console.
tcpdump
e tcpdump command is used to monitor the network traffic on a specified interface. When no interface is specified eth0 is used by default:
Tahoe> tcpdump wan0 05:51:27.453 > cisco hdlc (56) IP 192.168.20.101 -> 192.168.14.67 ICMP echo request seq 2 05:51:27.541 < cisco hdlc (62) IP 192.168.14.67 -> 192.168.20.101 ICMP echo reply seq 2
To stop monitoring traffic press Ctrl+C.
tftp
e command allows limiting the TFTP access used for the firmware upgrade. e access may be enabled or disabled by entering:
tftp on
or
tftp off
respectively. Moreover the access may be limited to a certain IP address:
Tahoe> tftp host <IP address>
If the IP address is set as 0.0.0.0, then the access is possible from anywhere in the network.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
timeout
e command sets the inactivity time (in seconds), aer which the telnet connection is closed:
Tahoe> timeout <during the session> [<during logging in>]
e first parameter is used aer logging in, while the second one (optional) during the login process. Entering 0 disables the timer.
ese settings are also applied to the serial console if its access is password protected (i.e. console
passwd on command was used).
Timeout without any arguments displays current settings.
uptime
Shows the time elapsed since the modem booting and the current processor temperature.
user
e user command is used to manage users having access to the modem. e modem may work in two different modes:
single user – only the password is necessary to access the modem. e user that logs in has
the full access to the device (default mode)
multiple users – allows creating many users with different names, passwords and access lev-
els
e user command has following syntax:
user list – shows the user list
user add <name> – adds a new user
user del <name> – removes an user
user passwd < name> <password> – changes the user’s password
user level <name> <access level> – changes the user’s access level. e <access
level> argument may be one of:
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admin – full access to the device read-only – permits only reading of the configuration and the statistics
user mode { single | multi } – selects the working mode – to either single or multi-
user
ver
Displays current firmware version and compilation date.
vlan
e vlan command is used to manage VLAN configuration. e modem may work in one of following modes:
transparent – the VLAN-tagged packets are passed transparently. e modem is transparent
to the traffic and it’s up to user to manage VLANs on external devices (default)
non-transparent – the modem may be set up to analyse the traffic and some packets may be
directed to specified interfaces, while others may be filtered. Also VLAN headers may be removed or added while forwarding a packet, thus encapsulating a data stream from a speci­fied interface into a VLAN.
e command has following syntax:
vlan show – shows current settings
vlan transparent { on | off } – enables or disables the transparent mode
vla n cre ate <vid> – inserts a new VLAN ID into the list of supported VLANs
vla n re move <vid> – removes a VLAN ID from that list
vla n <vid> add <interface> – adds an interface to a VLAN
vla n <vid> del <interface> – removes an interface from a VLAN
vla n <vid> name <name> – sets a VLAN name to ease identification
vla n <vid> { tag | untag } <interface> – sets an interface as tagged or untagged.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
To manage VLAN traffic first you have to follow these steps:
1. Disable transparent mode using vlan transparent off command.
2. Add VLANs you want to forward using vlan create <vid>.
3. Add interfaces to that VLAN using vlan <vid> add <interface>.
4. Decide whether interfaces should be tagged or untagged using vlan <vid> { tag | untag } <interface> command. A tagged interface means that all traffic belonging to specified VLAN will be transmitted through that interface without modification (with a VLAN header). Such traffic can be further separated using an external VLAN-aware switch.
In case of an untagged interface the VLAN headers will be stripped from the packets be-
fore they are transmitted over that interface. In the opposite direction the VLAN headers will be added to all untagged (i.e. regular) packets received on that interface. is way only regular Ethernet packets would appear on that interface (so you can connect regular Eth­ernet devices) while the modem will see VLAN traffic only. Such VLAN traffic can be sent further to other devices without being mixed with packets coming from other sources.
e non-VLAN traffic is directed to a default VLAN with ID 1. at VLAN is used for internal processing only. All interfaces are added to that VLAN by default and are marked as untagged.
w
Shows the time elapsed since the modem booting and the current processor temperature.
wake
e wake command is used to power-on LAN devices that have Wake-On-LAN feature enabled. To send a wake-up packet to a specified MAC address type:
Tahoe> wake < MAC address>
An -b option may be added before MAC address to generate a broadcast packet. is may be necessary in some cases, when the regular packet isn’t forwarded through the Ethernet switch or another device.
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watchdog
e watchdog command gives additional control over the modem’s unpredicted behavior (i.e. a misconfiguration disabling further communication with the modem). e modem sends ICMP ping packetd to check the availability of certain IP addresses and reboots, if it doesn’t receive ping reply from one of them.
e command has following syntax:
watchdog on – enables the watchdog
watchdog off – disables the watchdog
watchdog <interval> <amount> <wait> <IP address> [<additional IP address>]
– configures the watchdog. Aer <interval> seconds the modem sends <amount> of pings to the <IP address> (and the <additional IP address> if set) waiting <wait> seconds aer each of them. If there is no answer for any of the pings sent to the first address or for any of the pings sent to the second address, then the modem is rebooted.
write
Saves the current configuration to the EEPROM (non-volatile memory) so the modem keeps it aer reboot or power off. e command also displays an information about the EEPROM us­age. If the configuration is too large to be stored some settings should be deleted, like static ARP entries, DHCP options, etc.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
DHCP Server Configuration
e dhcp command is used to configure DHCP/BOOTP server and relay agent. e server is used to assign IP addresses, network masks, gateway and DNS addresses and other parameters to the network stations. It is easy to reconfigure a network that uses a DHCP server – it is enough to change server settings and every station will automatically retrieve new configuration.
e BOOTP protocol is an earlier and simpler version of DHCP. Its common use is booting of diskless workstations. A workstation uses BOOTP to get its IP address and other network param­eters together with TFTP server address, from which the operating system may be downloaded.
e DHCP protocol may deliver more working parameters including domain name, DNS address, print server, syslog server, XWindow fontserver, MTU and TTL settings, and many others.
DHCP/BOOTP Relay Agent transfers DHCP and BOOTP requests and replies between separate networks. e DHCP and BOOTP protocols work only within one physical subnet. e station using such protocols doesn’t know its IP address yet, so its packets cannot be routed to other networks. Relay Agent listens for such requests and forwards them to a DHCP server, which may be placed anywhere in the network.
Review of the settings
Entering dhcp alone displays current server settings. Here is an example:
Tahoe> dhcp DHCP/BOOTP server default-lease-time 43200 max-lease-time 86400 network “lan” (eth0): default-lease-time 43200 max-lease-time 86400 domain-name tahoe.pl s u b n e t “l o c a l”: 10.0.0.0/255.255.255.0 default-lease-time 43200 max-lease-time 86400 filename vmlinuz.2.6.15 next-server 192.168.0.5 routers 10.0.0.1 domain-na me-ser vers 192.168.0.4 domain-name tahoe.pl ad d r e ss ra n g e s: 10.0.0.3 -10.0.0.15
relay server 192.168.0.5 67
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e meaning of subsequent entries is described later in this chapter.
Basic DHCP server configuration rules
Before starting using DHCP server please read following guidelines:
the configuration is organized in a hierarchical manner – the most general group of set-
tings is a network – the physical interface of a modem. Any number of IP subnets may exist within a network. Inside an IP subnet an IP address range may be selected – IP addresses from that range will be dynamically assigned to the network stations. A static connection between an IP address and a hardware address may also be set.
Each group (network, subnet) has its own options (name server addresses, domain names,
etc.). Creating a new group (e.g. a subnet within a network) causes copying of the options from the parent group (e.g. if the lan network has a domain-name option, aer adding a subnet named local within the lan the option will be automatically copied – it may be modi­fied or deleted later)
on the beginning a network for each interface should be created
in each of the networks an IP subnet should be created according to IP subnets connected
to that interface (modem may not have the routing set up to each of them – it’s enough that they are in the same physical network)
now IP ranges and static IP entries may be added
dhcp { on | off | relay }
DHCP/BOOTP server may work in one of three modes:
on – the server in enabled and answers to the requests
off – the server is disabled
relay – the server is disabled, but the relay agent is enabled and listens for the requests to be
forwarded to other DHCP server
dhcp add
e dhcp add commands add a network, subnet, IP range, etc. Following variants are sup- ported:
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
dhcp add network <name>
Adds a new physical network connected to the modem’s interface. ere should be the same
number of networks and interfaces. e interface name will be assigned automatically aer adding the IP subnets.
Tahoe> dhcp add network lan
dhcp add subnet <name> <network> <address> <netmask>
Adds a IP subnet to a given network. For each IP subnet connected to the LAN or WAN in-
terface an DHCP subnet should be added (with the same IP addresses, as configured on each of the interfaces). Moreover additional IP subnets may be added – those which are not set up on any of the interfaces, but do exist in the same physical network or behind a DHCP relay:
Tahoe> dhcp add subnet local lan 10.0.0.0 255.0.0.0
dhcp add host <name> < MAC address> <IP ad d ress>
Adds a static connection between hardware (MAC) and IP addresses. e IP address must
belong to one of the configured subnets. Only this IP address will be assigned to the given MAC address:
Tahoe> dhcp add host server 00:50:13:2e:15:ca 10.0.0.5
dhcp add range <start address> <end address>
Adds an IP address range, from which addresses will be assigned to the network stations. e
address range must be contained inside one of the subnets:
Tahoe> dhcp add range 10.0.0.5 10.0.0.37
e DHCP server wil automatically decide to which subnet that IP address range belongs.
dhcp add option <option> <value>
Adds a global DHCP option sent to the requesting station. Available options are:
routers – network gateways (usually the gateways should be separate for each subnet, so
they shouldn’t be defined globally)
domain-name – domain name
domain-name-servers – DNS addresses
filename – name of the file containing the operating system
next-server – server from which the mentioned above file will be downloaded using TFTP
protocol
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Example:
Tahoe> dhcp add option domain-name tahoe-group.com
dhcp add relay <address> [<port>]
Adds a DHCP server address to which the DHCP requests are forwarded, when the Relay
Agent mode is enabled. e <port> parameter is optional – its default value is 67:
Tahoe> dhcp add relay 192.168.0.3
dhcp del
e command deletes a network, subnet, address range, etc.
dhcp del network <name> dhcp del subnet < name> dhcp del host <name>
e commands above delete, respectively, a network, an IP subnet or a host (a static IP-MAC
connection) with given name.
dhcp del relay <address>
Deletes a DHCP server address used in the Relay Agent mode.
dhcp del range <start address> <end address>
Deletes an IP address range assigned to the network stations.
dhcp del option <name> <value>
Deletes a global option. Besides the option name, its value should also be given, because
some options may have more than one value (e.g. domain name servers, routers, etc.).
dhcp rename
e command changes the name of a network, subnet or host:
dhcp rena me network <old name> <new name> dhcp rename subnet <old na me> <new name> dhcp rename host <old name> <new name>
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
dhcp { network | subnet | host }
e command adds or deletes an option within a specified group – network, subnet or host. To add an option to a network type:
dhcp network <name> add <option name> <value>
To remove an option:
dhcp network <name> del <option name> <value>
Similarily subnet and host options may be added or deleted by replacing the network keyword by subnet or host. Example:
Tahoe> dhcp subnet local add domain-name tahoe-group.com
Options are valid only for a given network, subnet or host. e option list is available in the dhcp add command description above.
Besides these standard options two other parameters can be set:
dhcp network default-lease-time <value>
Sets the time (in second), for which the IP address is assigned to the station. Aer that time
the station must inform the DHCP server that it still uses that address. Otherwise the ad­dress will be considered as unused. is time-out prevents blocking an IP address when a station is switched off without releasing that address.
dhcp network max-lease-time <value>
A station may request a lease time other than the default value – the negotiated time may not
be higher than this setting.
dhcp default-lease-time <value> dhcp max-lease-time <value>
ese commands are similar to those described in the previous paragraph, but their meaning is global.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Appendix A, Troubleshooting
Problem Possible solutions
e modems cannot synchronize with each other
check the cables and connector pinouts check if the speed setting is the same on both modems check if one modem is set as Master and the other one as
Slave
the line may be too long for selected speed – lower the
speed setting on both modems
e modems are synchronized, but no data flows
if transparent bridge is required – check if it is enabled· check if the Noise Margin (Signal/Noise Ratio) is greater
or equal to 6 dB – decrease the line throughput if it the NMR is too low
check the LAN cables issue mii reset command to reset the Ethernet interface
e data isn’t transferred at full speed or the throughputs are asymmetrical (higher in one direction and lower in the other direction)
check if the Noise Margin (Signal/Noise Ratio) is greater
or equal to 6 dB – decrease the line throughput if it the NMR is too low
ensure that the modem and the LAN device on the other
end of the cable has the same Ethernet interface setting – either autonegotiation, or forced mode
e modems loose synchronization from time to time
check if the Noise Margin (Signal/Noise Ratio) is greater
or equal to 6 dB – decrease the line throughput if it the NMR is too low
try to change the leased line or at least some sections of it
– there may be loose connectors, damaged insulation or other transient problems with the line
telecom line consists of two twisted wires – ensure that
both wires of a twisted pair are connected to pins of the same line
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Appendix B, Technical Specification
processor:
Motorola PowerPC, 100MHz
memory:
4MB SDRAM
network protocols:
IP, TCP, UDP, ICMP, TFTP, SNMP, DHCP, BOOTP, RFC-1490, PPP, Frame Relay, Cisco® HDLC, IEEE 802.1q
G.shdsl interface:
connector: 4 x RJ-11 standards: ITU G.991.2 (G.shdsl), ITU G.994.1 (G.hs) modu lat ions : TCPA M-32 , TCPAM-16 , TC PAM- 8, TCPA M- 4, PAM-16 , PA M-8 , PA M- 4, PAM-2
throughput:
64-5696 kbps per line, 256-22784 kbps aggregate
Ethernet interface:
10/100Base-T, RJ-45 connector
dimensions:
30 mm (width) x 128 mm (height) x 185 mm (depth)
power consumption:
10W
environmental conditions:
storage: temperature -20°C to 65°C, humidity 5 to 95% operation: temperature 0°C to 50°C, humidity 0 to 85%
34
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Appendix C, Safety Information
Read the following safety notices before installing or using the Tahoe modem:
is warning symbol means danger. You are in a situation that could cause bodily injury. Before you work on any equipment, be aware of the hazards involved with electrical circuitry and be familiar with standard practices for preventing accidents.
Read the installation instructions before you connect the device to its power source.
Do not work on the system or connect or disconnect cables during periods of lightning activity.
Do not connect the low voltage circuits (LAN port) to leased line circuits (G.shdsl port). Some LAN and WAN ports use RJ-45 connectors. Use caution when connecting cables.
is product relies on the building’s installation for short-circuit (overcurrent) protection. Ensure that a fuse no larger than 240 VAC, 16A is used.
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
Appendix D, Declaration of Conformity
TAHOE Piotr Kaczmarzyk ul. Uniwersytecka 1 50-951 Wroclaw, Poland
We declare that the product Tahoe 4681 complies with the regulations of the following European Directives:
73/23/EEC low voltage safety requirements  89/336/EEC EMC requirements  99/5/EEC radio & telecommunication terminal equipment requirements
e compliance of Tahoe 4681 with the requirements of the above mentioned directives is en­sured by complete application of the following harmonized European Standards:
EN 60950:2000EN 55022:1998EN 61000-6-1:2002EN 61000-6-3:2002
e product also complies with the Directive 2002/95/EC on the restriction of the use of cer­tain hazardous substances in electrical and electronic equipment („RoHS Directive”) with the exemptions applicable for network infrastructure equipment for switching, signalling, transmis­sion and network management (according to the clause 7 of the Annex to the Directive).
Signed: Piotr Kaczmarzyk Position: Director
Signature:
Date: 30 June 2006 Place: Wroclaw, Poland
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
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Tahoe 4681 (4-port G.shdsl.bis/FastEthernet modem card)
42
Uniwersytecka 1 50951 Wrocław, Poland phone: +48 71 344 26 37, fax: +48 71 344 26 42 www.tahoe-group.com
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