使用調製解調器的高 RX 數據包錯誤計數 - 如何分析？

我正在我的 Debian 嵌入式 Linux 系統上測試 CDMA 調製解調器。我正在處理一些大文件的 wgets 並且不時看到連接斷開。查看ifconfigPPP 介面的輸出，我發現錯誤計數似乎很高（353 個錯誤）。有沒有簡單的方法來確定這些錯誤實際上是什麼？

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)

我相信您可以使用 Wireshark 來確定這些數據包被重傳的原因。摘自 Wireshark 論壇中的這個文章，標題為：Wireshark-users: Re:$$ Wireshark-users $$tcp 錯誤檢測。

摘錄#1

在 2010 年 4 月 18 日星期日下午 4:17，Victor lyamtsev 寫道：

> > 你好， > > > 如何在wireshark擷取中定位TCP序列的重傳錯誤？我應該尋找具有重複序列號的 ACK 嗎？例如： > > > $$ ACK $$序列 = 1355 確認 = 13409 … > $$ ACK $$序列 = 1355 確認 = 13500 > 如何從擷取中檢測校驗和錯誤？ > > > 謝謝，-vvv > > >

摘錄#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

該執行緒的關鍵資源：

• TCP 校驗和
• 重傳

您需要進入“分析”下拉菜單下的“專家資訊”下，如果您正在擷取數據包，則應該從那裡看到與您的錯誤相關的多次重新傳輸。

引用自：https://unix.stackexchange.com/questions/116931