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Knowledge Base

AR1820 Users' Slow Network Access Caused by Mismatching of the Operation Modes of the Equipment at Both Sides

Publication Date:  2019-07-09  |   Views:  159  |   Downloads:  0  |   Author:  SU1001732184  |   Document ID:  EKB0000358613

Contents

Issue Description

The networking diagram is as follows:
LAN users -----AR1820-----O/E converter------extranet
The fault symptom is as follows:
The LAN users attached to the AR1820 accessed the network at a low rate and the download rate was only around 400 kbit/s. When the user directly connected the PC to the O/E converter, the download rate could reach around 1 Mbit/s. 
 

Alarm Information

Null

Handling Process

1. The engineer viewed the uplink port of the AR1820, finding a large quantity of CRC check error statistics in the inbound direction that kept increasing:
Ethernet2/0 current state :UP
Line protocol current state :UP
Internet Address is x.x.x.x/x 
Media type is twisted pair, loopback not set, promiscuous mode not set
10Mb/s, Full-duplex, link type is force link
Last clearing of counters: 00:36:53 UTC Sat 01/01/2000
Last 300 seconds input rate 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Last 300 seconds output rate 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Input: 3964 packets, 5807980 bytes, 0 buffers
0 broadcasts, 9 multicasts, 0 pauses
1390 errors, 0 runts, 0 giants
652 crc, 738 align errors, 0 overruns
0 dribbles, 0 drops, 0 no buffers
Output:1891 packets, 110111 bytes, 0 buffers
0 broadcasts, 0 multicasts, 0 pauses
0 errors, 0 underruns, 0 collisions
0 deferred, 0 lost carriers
2. The engineer modified the uplink port of the AR1820 to half-duplex. Then the CRC check error packets ceased to increase.
Ethernet2/0 current state :UP
Line protocol current state :UP
Internet Address is x.x.x.x/x 
Media type is twisted pair, loopback not set, promiscuous mode not set
10Mb/s, Half-duplex, link type is force link
Last clearing of counters: 00:38:41 UTC Sat 01/01/2000
Last 300 seconds input rate 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Last 300 seconds output rate 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Input: 4422 packets, 6561747 bytes, 0 buffers
0 broadcasts, 4 multicasts, 0 pauses
0 errors, 0 runts, 0 giants
0 crc, 0 align errors, 0 overruns
0 dribbles, 0 drops, 0 no buffers
Output:2869 packets, 165435 bytes, 0 buffers
0 broadcasts, 0 multicasts, 0 pauses
0 errors, 0 underruns, 0 collisions
0 deferred, 0 lost carriers
3. After the modification, the user tested the download rate, finding that it could reach 900 kbit/s. 
 

Root Cause

The problem may be caused by the mismatching of the operation modes of the O/E converter and the uplink port of the AR1820 router. 

Suggestions

In similar circumstances, you can try modifying the DIP switch of the O/E converter. If the O/E converter cannot be changed to the half-duplex mode or does not work after such change, you can try modifying the uplink port of the AR18 router into the half-duplex mode.