01-dslam troubleshooting training issue1.0
DESCRIPTION
DSLAM troubleshootingTRANSCRIPT
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DSLAM Troubleshooting
TrainingISSUE 1.0
Fixed Network Broadband Technical
Support Department
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Introduction
Do you know about DSLAM equipments of
Huawei?
Do you know about the architecture of HuaweiDSLAM products?
Do you know about the general flow of Huawei
DSLAM troubleshooting?
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Objectives
Know the general situations of DSLAM
equipment Master the troubleshooting flow of
MA5100
Master the troubleshooting flow of
MA5300
Master the troubleshooting flow of
MA5600
After this course, you should be able to:
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Reference
MA5100V200R005 Troubleshooting Manual
MA5300V100R005 Troubleshooting Manual
You can get these materials at the website
http://support.huawei.com.
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Contents
Chapter 1 DSLAM Troubleshooting Flow
Chapter 2MA5100Troubleshooting Flow
Chapter 3MA5300Troubleshooting Flow
Chapter 4MA5600Troubleshooting Flow
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DSLAM Troubleshooting Flow
1 Architecture of Broadband Network
2 DSLAM Troubleshooting Flow
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DWDM /METRO
Quidway NE80
Access layer
iManagerTM N2000
L3
Spread users/Old
residential communityDense commercial subscribers
New residential community
LAN
L2
L2 S3026V
MA5600
MA5100MA5300
FE
GE
ADSLFE/GE L2
GE
FE
L2
VDSL
iTELLINTM
BAS
FE/GEFE/GE
LAN
BAS
MA5105
MD5500
PSTN
Networking of Broadband Network
FE/GE
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DSLAM Troubleshooting Flow
In case of faults, judge whether they occur to DSLAM or to
upper layer equipment first according to the phenomenon. A
correct judgment leads you to the preliminary success. The
troubleshooting flow of DSLAM equipment is detailed below.
For DSLAM equipment faults, the troubleshooting flow is
described at two aspects:
Internet access failure
Slow Internet access
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DSLAM Fault Internet Access Failure
Check whether allsubscribers on DSLAMfail to access Internet
Y
Upper layer equipmentruns normally
Check whether opticalchannel/transmission is
normal
Check whether maincontrol board/upstream
board runs normally
Restore opticalchannel/transmission
Y
N
Y
Y
Solveproblem
Change slot
position/board
YN
N
N
Check whetherMODEM isactivated
ChangeMODEM/externalline
Test upstream boardwith PC
View port states.If abnormal, reset the
ferrule
Y
N
N
Y
Solveproblem
Y
N
Y
Check/Modify DSLAM dataconfiguration
N
Modify upperlayer data
Y
N
N
Collectinformation
Submit CRMS/Broadband-support Collect
information
Submit CRMS/Broadband-support
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DSLAM Fault Slow Internet
Whether all subscribers onDSLAM access Internet at
a low speed
Y
Check optical power/workingmode of optical
channel/transmission
Check data/flowinformation of flow
control/CAR and broadcastpacket
Y
N
N
Solveproblem
Y
N
N
Compare accessible rate
with port restricted rate
Punch wires at the near end totest Internet accessing rate
Check subscriber
terminal
Check flow control/CAR
information
Y
N
N
Problem issolved
Y
N
Y
Reset
ferrule/board
N
Y
Capture packet
on upstream
board
Modify CAR/flow
control data
Y
N
Y
N
Modify CAR/flow
control
N
Y
Capture packet on
upstream board
Y
Upper layer equipment
runs normally
Collect
information
Submit CRMS/
Broadband-support
Restore opticalchannel/transmission
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Fault Information Collection
In collection of fault information, please refer to XXX Product
Fault Information Collection Guide at the website
support.huawei.com, collect the information by service types
and fault phenomenon, and feed back to CRMS or mail to
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected] -
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Problems
Which layers are the broadband network divided
into? And which layer is the DSLAM located in?
How to solve the problem that all users cannot
access the Internet/access the Internet at a low
speed when the DSLAM is faulty?
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Course Content
Chapter 1 DSLAM Troubleshooting Flow
Chapter 2 MA5100 Troubleshooting Flow
Chapter 3MA5300Troubleshooting Flow
Chapter 4MA5600Troubleshooting Flow
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MA5100 Troubleshooting Flow
1 LAN upstream Failure Internet
Access Failure
2 LAN upstream Failure
Slow
Internet Access
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Categories of Internet Access Failures of
LAN upstream Users
Whether data
configurations are correct
Whether the system,
LAN board and ports are
normal
Whether the opposite
equipment works normally
Whether subscriber
side settings are correct
Analyze Internet
access failure causes
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Working Modes of LAN Board
Application of LAN Board The LAN board converts ATM cells and Ethernet frames when the
MA5100 uses LAN board upstream.
Being used in IP upstream, the LAN board supports three
working modes:
GENERAL mode: The LAN board can process VLANs, and control
transparent transmission of VLAN information, but supports relatively
less VLANs.
IP-DSLAM mode: The LAN board only transmits VLANs transparently,
supports 2K/4K VLANs and isolates users effectively.
IPCASCADE mode: The LAN can process VLANs, control transparent
transmission of VLAN information, support relatively less VLANs, and
supports neighborhood VLANs (only the LAND).
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Checking Running of Upper Layer Equipment
Check the upper layer equipment
A faulty upper layer equipment usually affects the users greatly,
that is, users on one or multiple MA5100 cannot access the
Internet. In this case, check the upper layer equipment at the
following aspects:
Working states and port states of the upper layer equipment that is
connected with MA5100
Transmission between the MA5100 and upper layer equipment
States of the upper layer BAS, router and switch. You can test the
address of the upper layer equipment by PING or TRACERT, so as
to locate the problems.
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Checking Running of Upper Layer
Equipment Test Method
Test Method
Categorize the upper port and another port into the same VLAN, and
set the DEFAULT VLAN ID and VLAN ID of the test port identical.
Connect the PC on the test port, and begin the test.
If the PC can be connected to the Internet, it indicates that no faults
occur to the upper layer equipment and LAN board. You should focus on
checking MA5100.
Set the PC address and user address to the same segment, and
execute the PING commands. If the command is executed successfully,
it indicates that no faults occur to MA5100. You should focus on
checking the settings of the upper layer equipment.
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Checking Running of System and LAN Board
Whether the working states of the system, LAN board and ports arenormal
A faulty MA5100 or a faulty LAN board affects all users on the MA5100.
In this case, check the working state, board states and alarm information
of MA5100. Check the connection LED on the LAN board port. When the green LED is
always on, it indicates that the connection is normal. When the yellow LED
flashes, it indicates that data is being forwarded. At the same time, you can
query whether the port state of the LAN board is ONLINE or ACTIVE through
the console.
View the alarm information of MA5100, so as to make clear whether faults
occur to the MA5100 or its boards.
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Checking Running of System and LAN
Board Test Method
For the System
To find whether there are problems in data forwarding through the system,
connect the PC to the ASDL port with a PVC, set the PC address and NMS
address to the same network segment, add the PC address to the system
IP-ACCESS list, and ping the NMS address on the PC.
For the LAN Board
Set the two ports of the LAN board to the same VLAN, set their modes to
UNTAGGED, and make the VLAN ID and DEFAULT VLAN ID of the ports
identical. Connect both ports to the PC, set addresses of the ports to the
same network segment, and ping packets mutually, so as to find whether
there are problems in data forwarding through the LAN board.
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Checking Data Configuration
Check whether data configuration is correct
Incorrect data configuration usually happens in new deployment or addition of
new users. When problems occur to an online equipment, focus on checking
these two items at the following aspects:
Check whether the working modes (TAGGED/UNTAGGED), VLAN ID and
DEFAULT VLAN ID of the ports are correct. When the upper layer equipment does
not support VLAN, it is necessary to make the VLAN ID and DEFAULT VLAN ID of
the ports identical and make the VLAN self terminate on MA5100. To transmit
VLANs transparently through the ports, it is necessary to set the ports to TAGGED
mode and make the VLAN ID and DEFAULT VLAN ID different.
Check whether the information of the upper layer equipment of MA5100 is correct,
such as the accounts, VLANs and route.
Check whether the PVC of the ADSL subscriber port and the RTU on the
subscriber side are set correctly.
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Checking Subscriber Side Settings
Check whether the settings of subscriber side are correct
When only some subscribers have difficulties in Internet access, focus on
checking the configurations and states of these subscriber sides.
Check the settings of the equipments on the subscriber side such as the
router and switch. Check whether the network adapters of the subscribers work normally and
connections are normal.
For a dialup subscriber, check the installation and settings of the dialup
software. The Enternet 300 or Enternet 500 software is recommended.
Check the settings of the subscriber address, gateway, DNS and route table
entry.
Check whether the PC is infected by viruses.
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Internet Access Failure of LAN upstream
Subscriber Case 1
Case: An O/E converter only supports 10-network cables, making LAN board
upstream blocked.
[Phenomenon] For MA5100 IP-DSLAM networking, the LAN board has the FE optical
port connected through the O/E converter. The fiber is placed in the transmission
equipment room. There are about 60M from the data equipment room to the
transmission equipment room. Lack of a tail fiber long enough, place the O/E
converter to the transmission equipment room, and connect to the data equipment
room with a network cable. After installation, you can find that the LINK LEDs on the
O/E converter and LAN board are off.
[Handling]
Remake the connectors at both ends of the network cable, check the sequence, and
measure with the cable tester to prove that the network cable is normal. However, Internet
access still fails.
Adjust the DIP switch on the network port of the O/E converter. There is no response.
Connect a laptop with the LAN board. The connection is normal, indicating that the LAN
board is normal.
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Internet Access Failure of LAN upstream
Subscriber Case 1
Connect the PC with the O/E converter on the MA5100, the LINK LED is off. However,
connect the PC with the O/E converter with the attached short network cable in the
transmission equipment room, the connection is normal.
Read the instruction of the O/E converter, and you can find that the network ports of the
O/E converter only supports the network cables that are 10M long at most.
[Analysis]
Connecting equipments through network cables is usually the easiest mode so long as the
equipment works normally, network ports are kept undamaged, and network cables are not
longer than 100M, being wired correctly on two sides and without any broken cable in the
middle.
In principle, there should be no problems so long as connectors are in good contact.
However, this fault was resulted from the length of the category 5 UTP (the O/E converter
can only support up to 10M category 5 UTP).
Be sure to find the indexes of the equipment before use, for example, to use the O/E
converter, query the supported distance, wavelength, transmitting optical power and
receiving sensitivity of its optical ports, as well as the types and supported network cable
length of its network ports.
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Internet Access Failure of LAN upstream
Subscriber Case 2
Case: VLAN IDs are restricted in transmission, resulting in service failure.
[Phenomenon] For one office, networks are networked in IP upstream mode, go
through the 2.5G transmission equipment of vendor Z, and finally are accessed to
MA5200. Two VLANs were previously set on MA5100 LAN board, namely service
VLAN22 and NMS VLAN65, and services and NMS are normal. In recent capacity
expansion, the office is intended to assign other ports of the LAN board to cybercaf subscribers, but subscribers cannot access the Internet after VLANs are
reassigned to the ports.
[Handling]
Check the data configurations of MA5200 and MA5100. The configurations are
correct.
Define a new subscriber on the LAN board, and assign the VLAN ID 10. This
subscriber cannot access the Internet. Define a subscriber on other LAN board,
and assign the VLAN ID 10. This subscriber still cannot access the Internet.
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Internet Access Failure of LAN upstream
Subscriber Case 2
Define new subscribers on this LAN board and other LAN board, and assign the
VLAN ID 22. The subscribers can access the Internet.
Analyze the packets from MA5100 through sniffer, and you can find that packets
are in a standard format, and carry correct VLAN IDs, proving that the LAN board
works normally.
Define a subscriber with the VLAN ID 65 on the LAN board to check whether the
intermediary transmission equipment sets restrictions. The subscriber can access
the Internet normally.
Consult the engineer from the vendor of the intermediary, and you will learn that
the transmission equipment processes VLANs while processing packets, and you
must preset the VLANs.
Coordinate with the engineer to define the corresponding VLANs. Then, the
subscribers on the LAN board can dial up to the Internet normally.
[Analysis]
Most transmission equipments transmit data transparently, but the transmission
equipments of this office only process the VLAN IDs of packets. Therefore, you
should throw away the traditional ideas for troubleshooting.
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Fault Categories of Slow Internet Access of
LAN Board upstream Subscriber
Whether upper layer
equipments are congested
Whether equipments
control subscriber flows
Whether ports are
corrected to upper layer
equipments normally
Whether LAN board
ports are congested
Analyze slow
Internet access causes
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Check Congestion among Upper Layer Equipments
Unstable connections or congestions among upper layer
equipments
Unstable connections or congestions among upper layer equipments may
result in slow Internet access, for example, Internet accessing slows downon MA5100 after some time or with more and more subscribers.
Test method: Know networking conditions, ping the address of the
interfaces of upper layer equipments orderly, observe the packet loss ratio
and delay, and compare with the values in normal cases to find whether
faults occur to the upper layer equipments.
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Checking Flow Control Settings
Check whether upper layer equipments and MA5100 control
the flows of subscribers.
Under flow control, the downloading ratios of subscribers vary unnoticeably and
usually the same. There are some common flow control modes:
Limit port rates for ADSL subscribers
Control flows by upper layer BAS according to accounts, ports and VLANs
Note: With IP upstream, MA5100 does not support PVC flow control. It is
recommended to limit port rates on MA5100 for ADSL subscribers.
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Checking Operation of System and LAN Board
Check the system, LAN board ports and upper layer equipments areconnected normally.
Query whether the ports on LAN board work in 100M full duplex. If not, set
100M full duplex forcibly. Otherwise, Internet accessing may slow down in
case of great traffic. And traffics are considerable when LAN board upstream
is used, so it inevitably results in slow Internet access if ports does not work
in 100M duplex.
Be sure to make the network cables between LAN board ports and subscriber
equipments strictly according to requirements. Otherwise, network cables
may fail to satisfy high rate requirements, and packets may loss in case of
great traffics, thereby resulting in slow Internet access.
Query the system alarm messages to find whether there are related alarms.
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Checking Congestions on LAN Board Ports
Check whether the ports on LAN board are congested.
Due to the limited subscriber line rate, subscriber lines must be
congested when a great amount of broadcast packets, multicast
packets or unknown unicast packets are sent to the subscriber, thereby
resulting in slow Internet access. In this case, monitor the traffic over
lines on the subscriber side through Netxrav or Sniffer, and capture the
data to find the congestion causes.
For ADSL subscribers using LAN board upstream, increase the
subscriber bandwidths and observe the faults to find whether
subscriber lines are congested.
When congestion occurs when many subscribers go through upstream
over multiple ports of one LAN board, you can trunk the multiple ports
on the LAN board to share loads and increase effective bandwidth.
Slow Internet Access of LAN upstream
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Case: The upstream ports are not separated from VLAN, making slow
Internet access of ADSL subscribers.
[Phenomenon] Subscriber networking: FE port on MA5100 LAN board - LAN Switch
O/E converter - O/E converter - LAN Switch - O/E converter router. During some period
in the evening (19:30 21:00), ADSL subscribers access the Internet at a low speed, with
many ping packets lost and many bandwidth occupied by irrelative broadcast packets or
multicast packets.
MA5100 SwitchO/E
converterO/E
converter
O/E
c
onverte
r
Router
Switch
INTERNET
Slow Internet Access of LAN upstream
Subscriber Case 1
Sl I t t A f LAN t
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[Handling]
To find out whether IP address conflicts result in low Internet, the problem still exists
without any IP address conflict.
Check the working modes of the LAN board and O/E converter of MA5100. All work in
100M full duplex.
To find out whether problems occur because VLANs are not allocated by LanSwitch
(LanSwitch is a lower level D-Link, and cannot allocate VLANs, just equivalent to a HUB
over the network), capture packets on the ADSL subscriber port. Many irrelative
broadcast packets and multicast packets are captured, which occupy many bandwidth
and result in slow Internet access.
Separate VLANs of Lan Switch on the upstream ports, and this problem can be nearly
solved.
[Analysis]
When the IP-DSLAM networking upstream is connected with LAN Switch, the VLANs
must be allocated to separate broadcast packets, instead of simply connected. This is
because many irrelevant packets may occupy effective bandwidth of subscribers and
thereby result in slow Internet access when there are many subscribers.
Slow Internet Access of LAN upstream
Subscriber Case 1
Sl I t t A f LAN t
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A faulty O/E converter results in slow Internet access.[Phenomenon] MA5100 uses IP-DSLAM and ATM upstream modes at the same time. One
hundred and forty-four subscribers are uplinked to IP network nodes through LAN, and other
subscribers are uplinked to the ATM network through the MMX board. Not long after using
these two modes, the Internet accessing speed of LAN board upstream subscribers greatly
decreases, falling from 30Kbit/s to 10Kbit/s or so.
[Handling]
As the ATM upstream subscribers can access the Internet normally, so you can sure that
the problem occurs to the LAN board. Through NMS, log in to this MA5100, and you can
find that the port 7 on the LAN board is connected with a new equipment and alarms are
frequently reported. In onsite check, find that the board is connected with an optical
MODEM for downstream VPN subscribers. Because this equipment is not a auto-
negotiation equipment, it reports a lot of alarms and affects normal use of the LAN board.
Slow Internet Access of LAN upstream
Subscriber Case 2
Slow Internet Access of LAN upstream
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[Handling] Change the port mode to a fixed mode that corresponds to the optical
MODEM. The alarms on this port disappear.
Test the subscriber line from the office end measurement room, and find that
the downloading rate has been increased to about 36kbit/s. The problem is
solved.
[Analysis]
The optical MODEM makes a lot of LAN board alarms. In addition, the
upstream cell VLAN includes all the eight ports and cannot separate broadcast
packets. In this case, repeated auto-negotiation of a port may slow down
Internet accessing rate of other subscribers.
For use of the LAN board, try to only set VLANs to the required ports to
prevent unnecessary broadcast problems.
Slow Internet Access of LAN upstream
Subscriber Case 2
Slow Internet Access of LAN upstream
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Case: The broadcast packets on the subscriber side make ports
congested, resulting in slow Internet access.
[Phenomenon] The MA5100 of one office is uplinked through the LAN board and
directly connected to layer 3 switch. In this case, subscribers are connected to
the Internet by a fixed IP, and each subscriber is allocated with a public network
address. When ADSL subscribers access the Internet, some packets (2%-7%)are lost, resulting in slow Internet access.
[Handling]
There are three possibility for this problem:
The MA5100 and third party equipment have hardware failures.
Faults occur to communication lines.
Network performances are deteriorated, such as the network storm
(resulting in bandwidth congestion) and malicious attack.
Slow Internet Access of LAN upstream
Subscriber Case 3
Slow Internet Access of LAN upstream
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Cause 1: Connect a laptop to one port of the LAN board, and allocate this port to
the same cell VLAN as the upstream port.
Ping the subscriber IP address, and no packets are lost, indicating that the LAN board
works normally.
Ping the gateway (interface address of the third party equipment), and some packets are
lost, indicating that communication lines and third party equipment result in slow Internet
access.
Directly connect the laptop to the third party equipment, directly ping the gateway, and no
packets are lost, indicating that the third party equipment is not faulty.
Set the ports of the equipments on both sides to 100M duplex, and the problem still exists.
From this test, you can find that our third party equipment runs normally.
Cause: After a test, there is no error occurring to the communication line (network
cable) from our equipment to third party equipment. The second possibility is
impossible.
Slow Internet Access of LAN upstream
Subscriber Case 3
Slow Internet Access of LAN upstream
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Cause 1: Use Netxry to capture packets. Connect the laptop to one port on the LAN board that is in the same cell VLAN as the
upstream port. Capture packets with Netxray, and many packets with the network
segments of private networks, broadcast packets and multicast packets are captured,
80% to 95% of which came from 192.168.0.0/24 network segment and nearly all are
from 4/9, 5/1, 12/14, 10/15 subscribers of MA5100. Check the networking mode on the
port of the subscriber, and you can find that the subscriber is directly connected with the
LAN through ADSL MODEM, and separate private network from public network through
a MODEM that fails to shield the private network address and results in many private
network packets over the network (about 90%).
Test the backbone equipment and MA5100 again: add an Ethernet switch C between
them, connect a laptop to the Ethernet switch C, and then ping the gateway through the
laptop.
Slow Internet Access of LAN upstream
Subscriber Case 3
Slow Internet Access of LAN upstream
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In this case, packet loss ratio reaches 3% to 5%, and that for ping subscriber
address is 0%. Disconnect MA5100, and ping the gateway from PC. In this case,
the packet loss ratio is 0%. This indicates that MA5100 and upper layer equipment
work normally. In addition, MA5100, a layer 2 access equipment, only transmits
subscriber packets to the upper layer equipment without any prior processing.
Therefore, it is mostly possible that the backbone equipment, the layer 3 switch,
has a limited processing capability against packets, resulting in packet loss.
Because the router has a powerful processing capability against packets, the
problem of packet loss can be solved by commissioning the MA5100 to one router
over the backbone network.
[Analysis] Subscribers send a lot of broadcast packets and private network packets that
occupy many network resources and affect the overall network performances,
thereby resulting in packet loss and slow Internet access.
Slow Internet Access of LAN upstream
Subscriber Case 3
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Questions
What are the major causes resulting in Internet
access failure when LAN upstream is used?
What are the major causes resulting in slow
Internet access when LAN upstream is used?
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Course Contents
Chapter 1 DSLAM Troubleshooting Flow
Chapter 2 MA5100 Troubleshooting Flow
Chapter 3 MA5300 Troubleshooting Flow
Chapter 4MA5600Troubleshooting Flow
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MA5300 Troubleshooting Flow
1 Internet Access Failure
2 Slow Internet Access
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Categories of Internet Access Failures
Whether data
configurations are correct
Whether the system,
ESM and ports are normal
Whether theopposite equipment
works normally
Whether subscriber
side settings are correct
Analyze Internet
access failure causes
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Checking Running of Upper Layer Equipment
Check the upper layer equipment
A faulty upper layer equipment usually affects the users greatly,
that is, users on one or multiple MA5300 cannot access the
Internet. In this case, check the upper layer equipment at the
following aspects:
Working states and port states of the upper layer equipment that is
connected with MA5300
Transmission between the MA5300 and upper layer equipment
States of the upper layer BAS, router and switch. You can test the
address of the upper layer equipment by PING or TRACERT, so as to
locate the problems.
Checking Running of Upper Layer
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Checking Running of Upper Layer
Equipment Test Method
Test method
If there is an idle port on the main control board, allocate the
upstream and idle port (hereinafter referred to as testport) to
the same VLAN. Then, connect the PC to the test port, and begin
the test. If the PC can be connected to the Internet, it indicates that no faults
occur to the upper layer equipment and ESM. You should focus on
checking MA5300.
Set the PC address and subscriber address to the same segment, andexecute the PING commands. If the command is executed successfully,
it indicates that no faults occur to MA5300. In this case, you should
focus on checking the settings of the upper layer equipment.
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Checking Running of System and ESM
Check the working states of the system, ESM and ports
A faulty MA5300 or a faulty ESM affects all subscribers on the
MA5300. In this case, check the version configuration, main
control board states and network cable length of MA5300.
Check whether ESM work normally, and versions of the service board,
main control board and ISU are matched.
Check whether the LINK LED is normal on the ESM, and check whether
entries in the MAC table are set correctly.
Check whether the concatenation and upstream network cables of MA5300
are not longer than five meters, but too short network cables may result in
many CRC errors or even blocked service on the interface.
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Checking Data Configuration
Check data configurations
Incorrect data configuration usually happens in new deployment or
addition of new users. When problems occur to an online
equipment, focus on checking these two items.
Check whether the information of the upper layer equipment of MA5300
is set correctly, such as the accounts, VLANs and routes.
Check whether the PVC of the ADSL subscriber port and the RTU on the
subscriber side are set correctly.
Check whether the encapsulation type of ADSL ports are correct, forexample, if the ADSL port is Auto type by default, and coordinates with
the MODEM of the Auto type, subscribers may fail to access the Internet.
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Checking Subscriber Side Settings
Check subscriber side settings
When only some subscribers have difficulties in Internet access,
focus on checking the configurations and states of these subscriber
sides.
Check the settings of the equipments on the subscriber side such as therouter and switch.
Check the network adapters and connections.
For a dialup subscriber, check the installation and settings of the dialup
software. The Enternet 300 or Enternet 500 software is recommended.
Check the settings of the subscriber address, gateway, DNS and route
table entry.
Check whether the PC is infected by viruses.
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The subscriber name and password for PPPOE dialup are correct, but
fail to be authenticated by the server.
[Phenomenon] ADSL subscribers are authenticated with PPOE for Internet accessing.
The correct subscriber name and password are input, but the dialup program returns
the authentication failure alarm. Dial up again after one hour, and the authentication is
successful. The used PPPOE dialup software is ENTERNET300.[Alarm] The dialup software returns the alarm authenticationfail.
[Analysis]
Because the Radius Server restricts the number of the concurrent subscribers with the
same account, and sets the time for checking the accounts that are disconnected and
exit abnormally. In this case, the Radius Server restricts the number of the concurrent
users of this account, and sets a longer time for check and update, so the server still
keeps the access information of this account after the subscriber side was abnormally
terminated due to the computer breakdown or other reasons.
Internet Access Failure Case 1
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When the subscriber dials up again, the server considers an illegal access (user
number>1) , rejects the access request, and returns an alarm as it already has the
account use information. After the preset update time, the server terminates the
access process of this account when it does not receive any access information, so
the later dialup request is accepted and authenticated.
[Handling Process]
Terminate the access process of the account manually on the Radius Server.
Increase the number of concurrent account users in the account settings on
the Radius Server.
Shorten the user information update time on the Radius Server, for example,
changing it to 5 minutes.
Internet Access Failure Case 1
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An abnormal DNS server results in Internet access failure of ADSL
subscribers.
[Phenomenon] The ADSL subscriber complained about Internet access
failure through his computer or even through another computer.
[Analysis] This problem is caused by the office DNS server, but the
DNS server cannot be pinged only by disconnecting it. In this case,
compare its settings with other computers to find the real cause. If the
domain name cannot be directly input, input the IP address (not through
the DNS).
Internet Access Failure Case 2
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[Handling Process] Observe whether the RTU is deactivated, and you can find that the MODEM
works normally.
Ping the gateway and DNS server. Both operations are successful.
Change a computer, but the problem still exists.
Directly input the IP address, and you can find that accessing the Internet is
successful.
Then, you can sure that the DNS server is faulty.
The Internet is accessed successfully from other IP addresses successfully.
Then, compare the DNS data, and find that there are backup data on other
DNS servers. The Internet is accessed successfully even by changing to
another DNS server. Then, the problem is solved.
Internet Access Failure Case 2
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Categories of Slow Internet Access
Whether the upperlayer equipments are
congested
Whether equipments
control subscriber flows
Whether ports are
connected to upper layer
equipments normally
Whether ESM
ports are congested
Analyze slow
Internet access causes
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Check Congestion among Upper Layer Equipments
Unstable connections or congestions among upper layer
equipments
Unstable connections or congestions among upper layer
equipments may result in slow Internet access, for example,
Internet accessing slows down on MA5300 after some time orwith more and more subscribers.
Test method: Know networking conditions, ping the address of
the interfaces of upper layer equipments orderly, observe the
packet loss ratio and delay, and compare with the values in
normal cases to find whether faults occur to the upper layer
equipments.
Ch ki Fl C l S i
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Checking Flow Control Settings
Check whether upper layer equipments and MA5300 control
the flows of subscribers.
Under flow control, the downloading ratios of subscribers vary
unnoticeably and usually the same. There are some common flowcontrol modes:
Limit port rates for ADSL subscribers
Control flows by upper layer BAS according to accounts, ports and
VLANs
Ch ki O ti f S t d ESM
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Checking Operation of System and ESM
Check connections among the system, ESM and upper layerequipment.
If ESM uses FE upstream, query whether the ports on ESM board
work in 100M full duplex. If not, set 100M full duplex forcibly.
Otherwise, Internet accessing may slow down in case of great traffic.
Check whether the concatenation and upstream network cables of
MA5300 are not longer than five meters, but too short network cables
may result in many CRC errors or even blocked service on the
interface.
Query the system alarm messages to find whether there are related
alarms.
Ch ki C ti ESM P t
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Checking Congestions on ESM Ports
Check whether the ports on ESM are congested.
The MUX VLAN or Smart VLAN is recommended. Otherwise, subscriber lines must
be congested when a great amount of broadcast packets, multicast packets or
unknown unicast packets are sent to the subscriber, thereby resulting in slow Internet
access. In this case, monitor the traffic over lines on the subscriber side through
Sniffer to find out the congestion causes.
If there is an idle port on the main control board, allocate the upstream port and idle
port to the same VLAN. Then, connect the PC to the test port to test the Internet
accessing rate, and compare it with that of the XDSL subscriber.
For the ADSL subscriber using the ESM upstream, add the subscriber bandwidth,
and check whether the faults are gradually removed to judge whether the subscriber
line is congested.
When the ports are congested when many subscribers go through multiple FE
upstream of ESM, convergent multiple ports on the ESM to share loads and add valid
bandwidth.
Sl I t t A C 1
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Too many broadcast packets result in a high CPU usage of MA5300 main controlboard, unstable Internet access and a high packet loss ratio.
[Phenomenon] ISN8850-MA5300_A-MA5300_BThe CPU usage on the main
control board of MA5300_A is rather high, and its concatenated MA5300_B also
undergoes a high CPU usage reaching 70%. The subscribers for MA5300_B
cannot access the Internet, gain an unstable access or gain a high packet loss
ratio. Networking: ISN8850-MA5300_A-MA5300_B
[Handling]
Check whether there are multiple layer 3 interfaces. Check the data configurations of
two MA5300, and find that only one layer 3 interface is configured.
Check the upstream interface and concatenated interface on MA5300_A, and find
that broadcast packets undergo a great growth rapidly. It is necessary to find out the
equipment that send the broadcast packets.
Slow Internet Access Case 1
Sl I t t A C 1
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MA5300_A concatenated interface:
MA5300(config)#show interface ethernet 7/2/0
...........................................
74564 packets output, 1274 packets/sec, 98396 bytes/sec
5730844 bytes, 1 multicasts, 15 broadcasts, 0 pauses
76685 packets input, 1309 packets/sec, 134346 bytes/sec
7795122 bytes, 37 multicasts, 69292 broadcasts, 0 pauses
MA5300(config)#show interface ethernet 7/2/0
..................................
154032 packets output, 1260 packets/sec, 99635 bytes/sec
11958885 bytes, 2 multicasts, 25 broadcasts, 0 pauses
158497 packets input, 1296 packets/sec, 129185 bytes/sec
16100054 bytes, 98 multicasts, 143182 broadcasts, 0 pauses
Slow Internet Access Case 1
Sl I t t A C 1
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MA5300_A upstream interface:
MA5300(config)#show interface ethernet 7/1/0
...................................................
30510 packets output, 867 packets/sec, 124524 bytes/sec
4390774 bytes, 7 multicasts, 12477 broadcasts, 0 pauses
26313 packets input, 740 packets/sec, 633726 bytes/sec
22561390 bytes, 7 multicasts, 7 broadcasts, 0 pauses
Check the input/output the receiving & transmitting broadcast packets, and findthat:
The output broadcast packets grow rapidly on the upstream interface 7/1/0:
30510 packets output, 867 packets/sec, 124524 bytes/sec
4390774 bytes, 7 multicasts, 12477 broadcasts, 0 pauses
The input broadcast packets grow rapidly on the upstream interface 7/2/0:
158497 packets input, 1296 packets/sec, 129185 bytes/sec
16100054 bytes, 98 multicasts, 143182 broadcasts, 0 pauses
This indicates that broadcast packets are sent from the interface 7/2/0,
estimating that some subscriber under the frame sends a great amount of
broadcast.
Slow Internet Access Case 1
Sl I t t A C 1
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Set the interface of the MA5300_B that is connected to the slave frame to
shutdown first and then no shutdown. Then, you can find that the CPU
usage of MA5300_A recovers to normal.
Capture the broadcast packets with the capture software to find out the MAC
that sends the packets. Then, find the corresponding subscriber ports, removeviruses on the subscriber machine, and the problem is solved.
[Analysis]
This problem is resulted from too many broadcast packets. Because
broadcast packets should be submitted to CPU for processing, it causes a
high CPU usage and failure in processing normal service packets.
Slow Internet Access Case 1
Q ti
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Questions
What are methods adopted for testing the
upper layer equipment in case of Internet
access failure or slow Internet access from
MA5300?
Why is MUX VLAN or Smart VLAN rather
than alternate VLAN required for deployment
and maintenance?
Course Contents
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Course Contents
Chapter 1 DSLAM Troubleshooting Flow
Chapter 2MA5100Troubleshooting Flow
Chapter 3MA5300Troubleshooting Flow
Chapter 4 MA5600 Troubleshooting Flow
MA5600 Troubleshooting Flow
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MA5600 Troubleshooting Flow
1 Internet Access Failure
2 Slow Internet Access
Categories of Internet Access Failures
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Categories of Internet Access Failures
Whether data
configurations are correct
Whether the
system, SCU and
ports are normal
Whether theopposite equipment
works normally
Whether subscriber
side settings are correct
Analyze Internet
access failure causes
Categories of Slow Internet Access
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Categories of Slow Internet Access
Whether upperlayer equipments
are congested
Whether equipments
control subscriber flows
Whether ports are
connected to upper layer
equipments normally
Whether SCU
ports are congested
Analyze slowInternet access
causes
MA5600 Troubleshooting Flow Description
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MA5600 Troubleshooting Flow Description
The troubleshooting flow of MA5600 is similar to that of
MA5300. For details, please refer to MA5300 Troubleshooting
Flow.
MUX VLAN Configuration
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MUX VLAN Configuration
Add Multiple Ports to Different MUX VLAN
Add all ADSL and SHDSL ports to MUX VLANs, with the first
port corresponding to VLAN 2.
MA5600(config)#multi-service-port from-vlan 2 board 0-15 vpi0 vci 35 rx-cttr 2 tx-cttr 2