使用调制解调器的高RX数据包错误计数-如何分析？

Question

我正在Debian嵌入式Linux系统上测试CDMA调制解调器。我正在做一些大文件的预告，并不时地看到连接下降。查看PPP接口的ifconfig输出，我看到错误的计数似乎相当高(353个错误)。有什么简单的方法来确定这些错误到底是什么吗？

ppp0      Link encap:Point-to-Point Protocol
          inet addr:166.248.251.38  P-t-P:66.174.217.80  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:6490 errors:353 dropped:0 overruns:0 frame:0
          TX packets:5901 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:7712851 (7.3 MiB)  TX bytes:568635 (555.3 KiB)

Answer 1

我相信您可以使用Wireshark来确定这些数据包为什么要重新传输。摘自Wireshark论坛的这篇文章，标题是：Wireshark-用户: Re：[Wireshark-users] tcp错误检测。

节选1

在太阳，2010年4月18日下午4点17分，Victor lyamtsev写道:嗨，在wireshark捕获中如何定位TCP序列的重传错误？我应该寻找具有重复序列号的ACK吗？例如：确认 Seq =1355ack= 13409 . 确认 Seq =1355ack= 13500如何从捕获中检测校验和错误？谢谢，-vvv

节选2

Also just go to the menu item Analyze>Expert Info.  Click on a, for
example, Retransmission row inside the Expert Infos box and it will
take you to the exact location within the pcap.

On 4/18/10, Abhik Sarkar <sarkar.abhik@xxxxxxxxx> wrote:
> Hi Victor,
>
> Have a look at this page: http://www.wireshark.org/docs/dfref/t/tcp.html
>
> You can use display filter on the following fields:
> tcp.analysis.retransmission
> tcp.analysis.fast_retransmission
> tcp.checksum_bad
>
> For TCP checksums, please also refer to this page:
> http://wiki.wireshark.org/TCP_Checksum_Verification
> For retransmissions, also refer to this page:
> http://wiki.wireshark.org/PacketLoss
>
> HTH
> Abhik.
>
> On Sun, Apr 18, 2010 at 4:17 PM, Victor lyamtsev <vlyamtsev@xxxxxxxxx>wrote:
>
>> Hi,
>>
>>  how can i locate retransmission error for TCP sequence in wireshark
>> capture ?
>> Should I look for ACK with repeated sequence number ?
>> For example:
>>
>> [ACK] Seq = 1355 Ack = 13409 ...
>> [ACK] Seq = 1355 Ack = 13500
>>
>> How can i detect checksum errors from the capture ?
>>
>> Thanks,
>> -vvv

该线程的关键资源：

• TCP校验和
• 重传

你会想要在“专家信息”下面的分析下拉，从那里，如果你捕获的数据包，你应该看到几个重传输，当这将与您的错误相关。