ZyXEL Communications P-660HN-T1A Manual

P-660HN Series Support Notes
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All contents copyright © 2010 ZyXEL Communications Corporation.
P-660HN-T1A
802.11n 1x1 Wireless ADSL2+ 4-port Gateway
Support Notes
Version3.40
Apr. 2010

P-660HN Series Support Notes
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All contents copyright © 2010 ZyXEL Communications Corporation.
FAQ..................................................................................................................... 6
System FAQ...................................................................................................6
1. What’s Multilingual Embedded Web Configurator? .........................6
2. How do I access the P-660HN-T1A Command Line Interface (CLI)?
.....................................................................................................................6
3. How do I update the firmware and configuration file?.....................6
4. How do I upgrade/backup the firmware by using TFTP client
program via LAN? .....................................................................................6
5. How do I restore P-660HN-T1A configurations by using TFTP client
program via LAN? .....................................................................................7
6. What should I do if I forget the system password?..........................7
7. How to use the Reset button?.............................................................7
8. What is SUA? When should I use SUA?............................................7
9. What is the difference between SUA and Full Feature NAT?..........8
10. Is it possible to access a server running behind SUA from the
outside Internet? How can I do it?..........................................................8
11. When do I need select Full Feature NAT? .......................................8
12. What IP/Port mapping does Multi-NAT support? ...........................9
13. How many network users can the SUA/NAT support?................10
14. What are Device filters and Protocol filters? ................................10
15. How can I protect against IP spoofing attacks? ...........................10
Product FAQ ................................................................................................12
1. How can I manage P-660HN-T1A?.................................................... 12
2. What is the default password for Web Configurator? ................... 12
3. What’s the difference between ‘Common User Account’ and
‘Administrator Account’? .......................................................................12
4. How do I know the P-660HN-T1A's WAN IP address assigned by
the ISP?.....................................................................................................12
5. What is the micro filter or splitter used for? ...................................13
6. The P-660HN-T1A supports Bridge and Router mode, what's the
difference between them?......................................................................13
7. How do I know I am using PPPoE?...................................................13
8. Why does my provider use PPPoE?................................................. 13
9. What is DDNS? .................................................................................... 13
10. When do I need DDNS service? ...................................................... 14
11. What is DDNS wildcard? Does the P-660HN-T1A support DDNS
wildcard?..................................................................................................14
12. What is Traffic Shaping?..................................................................14
13. Why do we perform traffic shaping in the P-660HN-T1A?...........15
14. What do the parameters (PCR, SCR, MBS) mean?....................... 15
15. What do the ATM QoS Types (CBR, UBR, VBR-nRT, VBR-RT)
mean? .......................................................................................................15
16. What is content filter? ......................................................................16
ADSL FAQ .................................................................................................... 17

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1. How does ADSL compare to Cable modems?................................17
2. What is the expected throughput? ...................................................17
3. What is the microfilter used for? ......................................................17
4. How do I know the ADSL line is up? ................................................17
5. How does the P-660HN-T1A work on a noisy ADSL? ....................17
6. Does the VC-based multiplexing perform better than the
LLC-based multiplexing? .......................................................................18
7. How do I know the details of my ADSL line statistics? .................18
8. What are the signaling pins of the ADSL connector?....................18
9. What is triple play? ............................................................................. 18
Firewall FAQ ................................................................................................ 20
General......................................................................................................20
1. What is a network firewall? ....................................................20
2. What makes P-660HN-T1A secure? .....................................20
3. What are the basic types of firewalls?...................................20
4. What kind of firewall in the P-660HN-T1A?...........................21
5. Why do you need a firewall when your router has packet
filtering and NAT built-in?...........................................................21
6. What is Denials of Service (DoS) attack?..............................21
7. What is Ping of Death attack?................................................22
8. What is Teardrop attack?.......................................................22
9. What is SYN Flood attack? ....................................................22
10. What is LAND attack?..........................................................22
11 What is Brute-force attack?...................................................23
12. What is IP Spoofing attack?.................................................23
13. What are the default ACL firewall rules in P-660HN-T1A?.23
Configuration........................................................................................... 23
1. How do I configure the firewall?.............................................23
2. How do I prevent others from configuring my firewall?.........23
3. Why can't I configure my P-660HN-T1A using Web
Configurator/Telnet over WAN?.................................................24
4. Whycan't I upload the firmware and configuration file using
FTP over WAN?..........................................................................25
Log and Alert ...........................................................................................26
1. When does the P-660HN-T1A generate the firewall log?.....26
2. What does the log show to us?..............................................26
3. How do I view the firewall log?...............................................26
4. When does the P-660HN-T1A generate the firewall alert?...27
5. What is the difference between the log and alert?................27
Wireless FAQ...............................................................................................28
General FAQ............................................................................................. 28
1. What is a Wireless LAN?.....................................................28
2. What are the advantages of Wireless LAN?.....................28
3. What is the disadvantage of Wireless LAN? ....................28

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4. Where can you find 802.11 wireless networks?...............29
5. What is an Access Point? ...................................................29
6. Is it possible to use wireless products from a variety of
vendors?....................................................................................29
7. What is Wi-Fi?.......................................................................29
8. What types of devices use the 2.4GHz Band? .................29
9. Does the 802.11 interfere with Bluetooth device?...........30
10. Can radio signals pass through wall?.............................30
11. What are potential factors that may causes interference
among WLAN products? .........................................................30
12. What's the difference between a WLAN and a WWAN? 31
13. Can I manually swap the wireless module without
damage any hardware? ...........................................................31
14. What wireless security mode does P-660HN-T1A support?
.....................................................................................................31
15. What Wireless standard does P-660HN-T1A support? .31
16. Does P-660HN-T1A support MAC filtering?....................31
17. Does P-660HN-T1A support auto rate adaption?...........31
Advanced FAQ.........................................................................................32
1. What is Ad Hoc mode? ........................................................32
2. What is Infrastructure mode?.............................................32
3. How many Access Points are required in a given area? 32
4. What is Direct-Sequence Spread Spectrum Technology –
(DSSS)?......................................................................................32
5. What is Frequency-hopping Spread Spectrum Technology
–(FHSS)?...................................................................................32
Security FAQ............................................................................................33
1. How do I secure the data across the P-660HN-T1A Access
Point's radio link?.....................................................................33
2. What is WEP?........................................................................33
3. What is WPA-PSK? ..............................................................34
4. What is the difference between 40-bit and 64-bit WEP?.34
5. What is a WEP key? .............................................................34
6. Will 128-bit WEP communicate with 64-bit WEP? ...........34
7. Can the SSID be encrypted?...............................................34
8. By turning off the broadcast of SSID, can someone still
sniff the SSID? ..........................................................................35
9. What are Insertion Attacks? ...............................................35
10. What is Wireless Sniffer?..................................................35
Application Notes........................................................................................ 36
General Application Notes.....................................................................36
1. Internet Access Using P-660HN-T1A under Bridge mode....36
2. Internet Access Using P-660HN-T1A under Routing mode..39
3. Setup the P-660HN-T1A as a DHCP Relay..........................42

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4. SUA Notes ..............................................................................43
5. Using Full Feature NAT..........................................................52
6. Using the Dynamic DNS (DDNS)...........................................64
7. QoS(802.1Q) ..........................................................................66
8. Network Management Using SNMP......................................67
9. Using syslog ...........................................................................69
10. Using IP Alias .......................................................................70
11. Using IP Policy Routing........................................................72
12. Using Call Scheduling..........................................................75
13. Using IP Multicast.................................................................78
14. Using Zero-Configuration.....................................................79
15. How to configure packet filter on P-660HN-T1A?...............81
16. Change WAN MTU via WEB-GUI........................................84
Wireless Application Notes....................................................................86
1. Configure a Wireless Client to Ad hoc mode.........................86
2. MAC Filter...............................................................................92
3. Setup WEP (Wired Equivalent Privacy).................................94
4. Site Survey..............................................................................98
5. Configure 802.1x and WPA..................................................102
6. The WPS/WLAN Button.......................................................106
Support Tool..............................................................................................107
1. LAN/WAN Packet Trace....................................................................107
Online Trace ........................................................................107
Offline Trace ........................................................................109
Capture the detailed logs by Hyper Terminal ................110
2. Firmware/Configurations Uploading and Downloading using TFTP
.................................................................................................................112
Using TFTP client software..............................................112
Using TFTP command on Windows NT..........................114
Using TFTP command on UNIX .......................................114
3. Using FTP to Upload the Firmware and Configuration Files ......115
CI Command Reference ...........................................................................118
Command Syntax and General User Interface......................................118

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FAQ
System FAQ
1. What’sMultilingual Embedded Web Configurator?
Multilinggual Embedded Web Configurator means that it can display with 3
kinds of languanges: English, French, and German, Italian. By factory default it
displays with English, and you can change it in Web GUI.
2. How do I access the P-660HN-T1A Command Line Interface (CLI)?
The Command Line Interface is for the Administrator use only, and it could be
accessed via telnet session.
Note: It is protected by super password, ‘1234’by factory default.
3. How do I update the firmware and configuration file?
You can do this if you access the P-660HN-T1A as Administrator. You can
upload the firmware and configuration file to Prestige from Web Condigurator,
or using FTP or TFTP client software. You CAN NOT upload the firmware and
configuration file via Telnet because the Telnet connection will be dropped
during uploading the firmware. Please do not power off the router right after the
FTP or TFTP uploading is finished, the router will upload the firmware to its
flash at this moment.
Note: There may be firmware that could not be upgraded from Web
Configurator. In this case, ZyXEL will prepare special Upload Software
for you. Please read the firmware release note carefully when you want to
upload a new firmware.
4. How do I upgrade/backup the firmware by using TFTP client program
via LAN?
The P-660HN-T1A allows you to transfer the firmware to P-660HN-T1A using
TFTP program via LAN. The procedure for uploading firmware via TFTP is as
follows.
a. Use the TELNET client program in your PC to login to your
P-660HN-T1A.
b. Enter CI command 'sys stdio 0' to disable Stdio idle timeout
c. To upgrade firmware, use TFTP client program to put firmware in file
'ras' in the Prestige. After data transfer is finished, the P-660HN-T1A
will program the upgraded firmware into FLASH ROM and reboot itself.
d. To backup your firmware, use the TFTP client program to get file 'ras'
from the Prestige.

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5. How do I restore P-660HN-T1A configurations by using TFTP client
program via LAN?
a. Use the TELNET client program in your PC to login to your
P-660HN-T1A.
b. Enter CI command 'sys stdio 0' disable Stdio idle timeout
c. To backup the P-660HN-T1A configurations, use TFTP client program
to get file 'rom-0' from the P-660HN-T1A.
d. To restore the P-660HN-T1A configurations, use the TFTP client
program to put your configuration in file rom-0 in the P-660HN-T1A.
6. What should I do if I forget the system password?
In case you forget the system password, you can erase the current
configuration and restore factory defaults this way:
Use the RESET button on the rear panel of P-660HN-T1A to reset the router.
After the router is reset, the LAN IP address will be reset to '192.168.1.1', the
common user password will be reset to 'user', the Administrator password will
be reset to „1234’.
7. How to use the Reset button?
a. Turn your P-660HN-T1A on. Make sure the POWER led is on (not
blinking)
b. Press the RESET button for longer than one second and shorter than
five seconds and release it.
c. Press the RESET button for six seconds and then release it. If the
POWER LED begins to blink, the default configuration has been
restored and the P-660HN-T1A restarts.
8. What is SUA? When should I use SUA?
SUA (Single User Account) is a unique feature supported by Prestige router
which allows multiple people to access Internet concurrently for the cost of a
single user account.
When Prestige acting as SUA receives a packet from a local client destined for
the outside Internet, it replaces the source address in the IP packet header
with its own address and the source port in the TCP or UDP header with
another value chosen out of a local pool. It then recomputes the appropriate
header checksums and forwards the packet to the Internet as if it is originated
from Prestige using the IP address assigned by ISP. When reply packets from
the external Internet are received by Prestige, the original IP source address
and TCP/UDP source port numbers are written into the destination fields of the

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packet (since it is now moving in the opposite direction), the checksums are
recomputed, and the packet is delivered to its true destination. This is because
SUA keeps a table of the IP addresses and port numbers of the local systems
currently using it.
9. What is the difference between SUA and Full Feature NAT?
There will be three options for you:
None
SUA Only
Full Feature
SUA (Single User Account) is a NAT set with 2 rules: Many-to-One and
Server. With SUA, 'visible' servers had to be mapped to different ports, since
the servers share only one global IP.
The P-660HN-T1A now has Full Feature NAT which supports five types of
IP/Port mapping: One to One, Many to One, Many to Many Overload, Many to
Many No Overload and Server. You can make special application when you
select Full Feature NAT. For example: With multiple global IP addresses,
multiple severs using the same port (e.g., FTP servers using port 21/20) are
allowed on the LAN for outside access.
The P-660HN-T1A supports NAT sets on a remote node basis. They are
reusable, but only one set is allowed for each remote node. The P-660HN-T1A
supports 8 sets since there are 8 remote nodes.
By fatory default, the NAT is select as SUA in Web Configurator, Advanced
Setup, Network -> NAT -> General -> NAT Setup.
10. Is it possible to access a server running behind SUA from the outside
Internet? How can I do it?
Yes, it is possible because P-660HN-T1A delivers the packet to the local
server by looking up to a SUA server table. Therefore, to make a local server
accessible to the outside users, the port number and the inside IP address of
the server must be configured. (You can configure it in Web Configurator,
Advanced Setup, Network -> NAT -> Port Forwarding).
11. When do I need select Full Feature NAT?
Make multiple local servers on the LAN accessible from outside with
multiple global IP addresses

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With SUA, 'visible' servers had to be mapped to different ports, since the
servers share only one global IP. But when you select Full Feature, you can
make multiple local servers (mapping the same port or not) on the LAN
accessible from outside with multiple global IP addresses.
Support Non-NAT Friendly Applications
Some servers providing Internet applications such as some MIRC servers do
not allow users to login using the same IP address. Thus, users on the same
network can not login to the same server simultaneously. In this case it is
better to use Many-to-Many No Overload or One-to-One NAT mapping types,
thus each user login to the server using a unique global IP address.
12. What IP/Port mapping does Multi-NAT support?
Multi-NAT supports five types of IP/port mapping: One to One, Many to One,
Many to Many Overload, Many to Many No Overload and Server. The details
of the mapping between ILA and IGA are described as below. Here we define
the local IP addresses as the Internal Local Addresses (ILA) and the global IP
addresses as the Inside Global Address (IGA),
One to One: In One-to-One mode, the P-660HN-T1A maps one ILA to
one IGA.
Many to One: In Many-to-One mode, the P-660HN-T1A maps multiple
ILA to one IGA. This is equivalent to SUA (i.e., PAT, port address
translation), ZyXEL's Single User Account feature (the SUA is optional
in today's Prestige routers).
Many to Many Overload: In Many-to-Many Overload mode, the
P-660HN-T1A maps the multiple ILA to shared IGA.
Many One-to-One: In Many One-to-One mode, the P-660HN-T1A
maps each ILA to unique IGA.
Server: In Server mode, the P-660HN-T1A maps multiple inside
servers to one global IP address. This allows us to specify multiple
servers of different types behind the NAT for outside access. Note, if
you want to map each server to one unique IGA please use the
One-to-One mode.
The following table summarizes the five types.
NAT Type
IP Mapping
One-to-One
ILA1<--->IGA1
Many-to-One
(SUA/PAT)
ILA1<--->IGA1
ILA2<--->IGA1
...

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Many-to-Many
Overload
ILA1<--->IGA1
ILA2<--->IGA2
ILA3<--->IGA1
ILA4<--->IGA2
...
Many
One-to-One
ILA1<--->IGA1
ILA2<--->IGA2
ILA3<--->IGA3
ILA4<--->IGA4
...
Server
Server 1 IP<--->IGA1
Server 2 IP<--->IGA1
13. How many network users can the SUA/NAT support?
The Prestige does not limit the number of the users but the number of the
sessions. The P-660HN-T1A supports 4k sessions that you can use the 'ip nat
session' command in CLI to see. You can also use „ip nat hashTable wanif0‟
to view the current active NAT sessions.
14. What are Device filters and Protocol filters?
The filters have been separated into two groups. One group is called 'device
filter group', and the other is called 'protocol filter group'. Generic filters
belong to the 'device filter group', TCP/IP and IPX filters belong to the 'protocol
filter group'. You can configure the filter rule in CLI.
15. How can I protect against IP spoofing attacks?
The P-660HN-T1A's filter sets provide a means to protect against IP spoofing
attacks. The basic scheme is as follows:
For the input data filter:
Deny packets from the outside that claim to be from the inside
Allow everything that is not spoofing us
Filter rule setup:
Filter type =TCP/IP Filter Rule
Active =Yes
Source IP Addr =a.b.c.d
Source IP Mask =w.x.y.z
Action Matched =Drop

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Action Not Matched =Forward
Where a.b.c.d is an IP address on your local network and w.x.y.z is your
netmask:
For the output data filters:
Deny bounce back packet
Allow packets that originate from us
Filter rule setup:
Filter Type =TCP/IP Filter Rule
Active =Yes
Destination IP Addr =a.b.c.d
Destination IP Mask =w.x.y.z
Action Matched =Drop
Action No Matched =Forward
Where a.b.c.d is an IP address on your local network and w.x.y.z is your
netmask.

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Product FAQ
1. How can I manage P-660HN-T1A?
Multilingual Embedded Web GUI for Local and Remote management
CLI (Command-line interface)
Telnet support (Administrator Password Protected ) for remote
configuration change and status monitoring
FTP/ TFTP sever, firmware upgrade and configuration backup and
restore are supported(Administrator Password Protected)
2. What is the default password for Web Configurator?
There are two different accounts for P-660HN-T1A Web Configurator:
Common User Account and Administrator Account.
By factory default the password for the two accounts are:
Common User Account: user
Administrator Account: 1234.
You can change the password after you logging in the Web Configurator.
Please record your new password whenever you change it. The system
will lock you out if you have forgotten your password.
3. What’s the difference between ‘Common User Account’and
‘Administrator Account’?
For Common User Account, it can only access the status monitor of
P-660HN-T1A and check the current system status.
For Administrator Account, besides accessing the status monitor of
P-660HN-T1A, it can also access Wizard setup/ Advanced setup of
P-660HN-T1A:
Moreover, only with Administrator Password, you could manage the
P-660HN-T1A via FTP/TFTP or Telnet.
4. How do I know the P-660HN-T1A's WAN IP address assigned by the
ISP?
You can view "My WAN IP <from ISP> : x.x.x.x" shown in Web Configurator
„Status->Device Information ->WAN Information‟to check this IP address.

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5. What is the micro filter or splitter used for?
Generally, the voice band uses the lower frequency ranging from 0 to 4KHz,
while ADSL data transmission uses the higher frequency. The micro filter acts
as a low-pass filter for your telephone set to ensure that ADSL transmissions
do not interfere with your voice transmissions. For the details about how to
connect the micro filter please refer to the user's manual.
6. The P-660HN-T1A supports Bridge and Router mode, what's the
difference between them?
When the ISP limits some specific computers to access Internet, that means
only the traffic to/from these computers will be forwarded and the other will be
filtered. In this case, we use bridge mode which works as an ADSL modem to
connect to the ISP. The ISP will generally give one Internet account and limit
only one computer to access the Internet.
For most Internet users having multiple computers want to share an Internet
account for Internet access, they have to add another Internet sharing device,
like a router. In this case, we use the router mode which works as a general
Router plus an ADSL Modem.
7. How do I know I am using PPPoE?
PPPoE requires a user account to login to the provider's server. If you need to
configure a user name and password on your computer to connect to the ISP
you are probably using PPPoE. If you are simply connected to the Internet
when you turn on your computer, you probably are not. You can also check
your ISP or the information sheet given by the ISP. Please choose PPPoE as
the encapsulation type in the P-660HN-T1A if the ISP uses PPPoE.
8. Why does my provider use PPPoE?
PPPoE emulates a familiar Dial-Up connection. It allows your ISP to provide
services using their existing network configuration over the broadband
connections. Besides, PPPoE supports a broad range of existing applications
and service including authentication, accounting, secure access and
configuration management.
9. What is DDNS?
The Dynamic DNS service allows you to alias a dynamic IP address to a static
hostname, allowing your computer to be more easily accessed from various

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locations on the Internet. To use the service, you must first apply an account
from several free Web servers such as http://www.dyndns.org/.
Without DDNS, we always tell the users to use the WAN IP of the
P-660HN-T1A to reach our internal server. It is inconvenient for the users if this
IP is dynamic. With DDNS supported by the P-660HN-T1A, you apply a DNS
name (e.g., www.zyxel.com.tw) for your server (e.g., Web server) from a
DDNS server. The outside users can always access the web server using the
www.zyxel.com.tw regardless of the WAN IP of the P-660HN-T1A.
When the ISP assigns the P-660HN-T1A a new IP, the P-660HN-T1A updates
this IP to DDNS server so that the server can update its IP-to-DNS entry. Once
the IP-to-DNS table in the DDNS server is updated, the DNS name for your
web server (i.e., www.zyxel.com.tw) is still usable.
10. When do I need DDNS service?
When you want your internal server to be accessed by using DNS name rather
than using the dynamic IP address we can use the DDNS service. The DDNS
server allows to alias a dynamic IP address to a static hostname. Whenever
the ISP assigns you a new IP, the P-660HN-T1A sends this IP to the DDNS
server for its updates.
11. What is DDNS wildcard? Does the P-660HN-T1A support DDNS
wildcard?
Some DDNS servers support the wildcard feature which allows the hostname,
*.yourhost.dyndns.org, to be aliased to the same IP address as
yourhost.dyndns.org. This feature is useful when there are multiple servers
inside and you want users to be able to use things such as
www.yourhost.dyndns.org and still reach your hostname.
Yes, the P-660HN-T1A supports DDNS wildcard that http://www.dyndns.org/
supports. When using wildcard, you simply enter yourhost.dyndns.org in the
Host field in Menu 1.1 Configure Dynamic DNS.
12. What is Traffic Shaping?
Traffic Shaping allocates the bandwidth to WAN dynamically and aims at
boosting the efficiency of the bandwidth. If there are serveral VCs in the
P-660HN-T1A but only one VC activated at one time, the P-660HN-T1A
allocates all the Bandwidth to the VC and the VC gets full bandwidth. If another
VCs are activated later, the bandwidth is yield to other VCs after ward.

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13. Why do we perform traffic shaping in the P-660HN-T1A?
The P-660HN-T1A must manage traffic fairly and provide bandwidth allocation
for different sorts of applications, such as voice, video, and data. All
applications have their own natural bit rate. Large data transactions have a
fluctuating natural bit rate. The P-660HN-T1A is able to support variable traffic
among different virtual connections. Certain traffic may be discarded if the
virtual connection experiences congestion. Traffic shaping defines a set of
actions taken by the P-660HN-T1A to avoid congestion; traffic shaping takes
measures to adapt to unpredictable fluctuations in traffic flows and other
problems among virtual connections.
14. What do the parameters (PCR, SCR, MBS) mean?
Traffic shaping parameters (PCR, SCR, MBS) can be set in Web Configurator,
Advanced Setup, Network -> Remote Node -> Edit -> ATM Setup:
Peak Cell Rate(PCR): The maximum bandwidth allocated to this connection.
The VC connection throughput is limited by PCR.
Sustainable Cell Rate(SCR): The least guaranteed bandwidth of a VC.
When there are multi-VCs on the same line, the VC throughput is guaranteed
by SCR.
Maximum Burst Size(MBS): The amount of cells transmitted through this
VC at the Peak Cell Rate before yielding to other VCs. Total bandwidth of the
line is dedicated to single VC if there is only one VC on the line. However, as
the other VC asking the bandwidth, the MBS defines the maximum number of
cells transmitted via this VC with Peak Cell rate before yielding to other VCs.
The P-660HN-T1A holds the parameters for shaping the traffic among its
virtual channels. If you do not need traffic shaping, please set SCR = 0, MBS =
0 and PCR as the maximum value according to the line rate (for example, 2.3
Mbps line rate will result PCR as 5424 cell/sec.)
15. What do the ATM QoS Types (CBR, UBR, VBR-nRT, VBR-RT) mean?
Constant bit rate(CBR): An ATM bandwidth-allocation service that requires
the user to determine a fixed bandwidth requirement at the time the connection
is set up so that the data can be sent in a steady stream. CBR service is often
used when transmitting fixed-rate uncompressed video.
Unspecified bit rate(UBR): An ATM bandwidth-allocation service that does
not guarantee any throughput levels and uses only available bandwidth. UBR
is often used when transmitting data that can tolerate delays, such as e-mail.

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Variable bit rate(VBR): An ATM bandwidth-allocation service that allows
users to specify a throughput capacity (i.e., a peak rate) and a sustained rate
but data is not sent evenly. You can select VBR for bursty traffic and
bandwidth sharing with other applications. It contains two subclasses:
Variable bit rate nonreal time (VBR-nRT):
Variable bit rate real time (VBR-RT):
16. What is content filter?
Internet Content filter allows you to create and enforce Internet access policies
tailored to your needs. Content filter gives you the ability to block web sites that
contain key words (that you specify) in the URL. You can set a schedule for
when the P-660HN-T1A performs content filtering. You can also specify
trusted IP Addresses on LAN for which the P-660HN-T1A will not perform
content filtering. You can configure the details about it in Web Configurator,
Advanced setup, Security -> Filter.

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ADSL FAQ
1. How does ADSL compare to Cable modems?
ADSL provides a dedicated service over a single telephone line; cable
modems offer a dedicated service over a shared media. While cable modems
have greater downstream bandwidth capabilities (up to 24 Mbps), that
bandwidth is shared among all users on a line, and will therefore vary, perhaps
dramatically, as more users in a neighborhood get online at the same time.
Cable modem upstream traffic will in many cases be slower than ADSL, either
because the particular cable modem is inherently slower, or because of rate
reductions caused by contention for upstream bandwidth slots. The big
difference between ADSL and cable modems, however, is the number of lines
available to each. There are no more than 12 million homes passed today that
can support two-way cable modem transmissions, and while the figure also
grows steadily, it will not catch up with telephone lines for many years.
Additionally, many of the older cable networks are not capable of offering a
return channel; consequently, such networks will need significant upgrading
before they can offer high bandwidth services.
2. What is the expected throughput?
In our test, we can get about 1.6Mbps data rate on 15Kft using the 26AWG
loop. The shorter the loop, the better the throughput is.
3. What is the microfilter used for?
Generally, the voice band uses the lower frequency ranging from 0 to 4KHz,
while ADSL data transmission uses the higher frequency. The micro filter acts
as a low-pass filter for your telephone set to ensure that ADSL transmissions
do not interfere with your voice transmissions. For the details about how to
connect the micro filter please refer to the user's manual.
4. How do I know the ADSL line is up?
You can see the DSL LED Green on the P-660HN-T1A's front panel is on
when the ADSL physical layer is up.
5. How does the P-660HN-T1A work on a noisy ADSL?
Depending on the line quality, the P-660HN-T1A uses "Fall Back" and "Fall
Forward" to automatically adjust the date rate.

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6. Does the VC-based multiplexing perform better than the LLC-based
multiplexing?
Though the LLC-based multiplexing can carry multiple protocols over a single
VC, it requires extra header information to identify the protocol being carried
on the virtual circuit (VC). The VC-based multiplexing needs a separate VC for
carrying each protocol but it does not need the extra headers. Therefore, the
VC-based multiplexing is more efficient.
7. How do I know the details of my ADSL line statistics?
You can use the following CI commands to check the ADSL line
statistics.
CI> wan adsl perfdata
CI> wan adsl status
CI> wan adsl linedata far
CI> wan adsl linedata near
You can also do it in Web Configurator, Advanced Setup,
Maintenance -> Diagnostic -> DSL Line -> DSL Status:
8. What are the signaling pins of the ADSL connector?
The signaling pins on the P-660HN-T1A's ADSL connector are pin 3 and pin 4.
The middle two pins for a RJ11 cable.
9. What is triple play?
More and more Telco/ISPs are providing three kinds of services (VoIP, Video
and Internet) over one existing ADSL connection.

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The different services (such as video, VoIP and Internet access) require
different Qulity of Service.
The high priority is Voice (VoIP) data.
The Medium priority is Video (IPTV) data.
The low priority is internet access such as ftp etc …
Triple Play is a port-based policy to forward packets from different LAN port to
different PVCs, thus you can configure each PVC separately to assign different
QoS to different application.

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Firewall FAQ
General
1. What is a network firewall?
A firewall is a system or group of systems that enforces an access-control
policy between two networks. It may also be defined as a mechanism used to
protect a trusted network from an untrusted network. The firewall can be
thought of two mechanisms: One to block the traffic, and the other to permit
traffic.
2. What makes P-660HN-T1A secure?
The P-660HN-T1A is pre-configured to automatically detect and thwart Denial
of Service (DoS) attacks such as Ping of Death, SYN Flood, LAND attack, IP
Spoofing, etc. It also uses stateful packet inspection to determine if an inbound
connection is allowed through the firewall to the private LAN. The
P-660HN-T1A supports Network Address Translation (NAT), which translates
the private local addresses to one or multiple public addresses. This adds a
level of security since the clients on the private LAN are invisible to the
Internet.
3. What are the basic types of firewalls?
Conceptually, there are three types of firewalls:
1. Packet Filtering Firewall
2. Application-level Firewall
3. Stateful Inspection Firewall
Packet Filtering Firewalls generally make their decisions based on the header
information in individual packets. These headers information include the
source, destination addresses and ports of the packets.
Application-level Firewalls generally are hosts running proxy servers, which
permit no traffic directly between networks, and which perform logging and
auditing of traffic passing through them. A proxy server is an application
gateway or circuit-level gateway that runs on top of general operating system
such as UNIX or Windows NT. It hides valuable data by requiring users to
communicate with secure systems by mean of a proxy. A key drawback of this
device is performance.