sniffer expert 的non-responsive station是什么意思？
出了这个提示，不过研究了半天也没有发现到底是说得什么。从non-responsive station的属性来看，好像是指3次没有response就会提示这个，不过这个response指的是什么？ack ?为什么有的数据包没有用户数据，仅仅是一个ack数据包，也会提示non-responsive station ？单纯的ack数据包应该不需要响应的吧？
可以看到图中220发给218的数据包仅仅是一个ack包，但是也提示了non-responsive station
[[i] 本帖最后由 iwanthome 于 2006-11-20 17:46 编辑 [/i]] The Expert generates the Non-Responsive Station alarm when the
number of consecutive retransmissions without a response on a
connection exceeds the No Response Count threshold.
查了一下sniffer的资料，和我的数据包情况对不上啊 查了下手册,解释如下:
[size=4][color=Red]Non-Responsive Station[/color][/size]
The Expert generates the Non-Responsive Station alarm when the number of
consecutive retransmissions without a response on a connection exceeds the
No Response Count threshold.
Possible causes:
Retransmissions often indicate a problem with a server. Some examples are:
1. Improperly configured software.
2. An overloaded server.
3. Faulty hardware.
[color=Red][size=4]Retransmission[/size][/color]
The Expert generates the Retransmission alarm when it sees a frame with
a TCP sequence number less than or equal to its previous value, indicating
that it contains data that has already been transmitted. The retransmission
occurred because the transmitting station did not receive an
acknowledgment (ACK) from the receiving station, and therefore
retransmitted the frame.
Possible causes:
1. The receiving station was overloaded.
2. A router was overloaded, or there was some other propagation delay.
3. The network traffic load was very high.
4. The ACK was sent but lost.
5. Either the original packet or its ACK was damaged.
6. The ACK was transmitted via a slower path.
7. An IP fragment was lost.
8. There is a network integrity problem.
[color=Red][size=4]Too Many Retransmissions[/size][/color]
The Expert generates the Too Many Retransmissions alarm when the
number of retransmissions on a connection (expressed as a percentage of
good transmissions versus retransmissions on the connection) exceeds the
Retransmission % threshold. Excessive retransmissions can result in a
noticeable reduction in response time.
Retransmissions occur when the transmitting station does not receive an
acknowledgment (ACK) from the receiving station, and therefore
retransmits the frame.
Possible causes:
1. The receiving station was overloaded. This is particularly likely if the
receiving station was a server.
2. A router was overloaded, or there was some other source of
propagation delay.
3. The network traffic load was very high.
4. The ACKs were being transmitted via a slower path.
5. There is a network integrity problem.
更多解释,请看Sniffer Pro 专家系统警报参考
[url]http://www.netexpert.cn/thread-11953-1-1.html[/url] 谢谢，我已经看到了这个解释，不过我还是理解不了。
你可以看到我的图里最后一个包从220发给218的数据包是一个ack数据包，按照sniffer的说法这个包应该已经重传了3次，可是我搜索了这个cap文件，没有发现这个ack数据包有重传的迹象，而且ack数据包按道理是不需要回应的。所以我不能理解为什么会提示这个信息。
[[i] 本帖最后由 iwanthome 于 2006-11-21 09:58 编辑 [/i]] [quote]原帖由 [i]iwanthome[/i] 于 2006-11-21 08:52 发表
谢谢，我已经看到了这个解释，不过我还是理解不了。
你可以看到我的图里最后一个包从220发给218的数据包是一个ack数据包，按照sniffer的说法这个包应该已经重传了3次，可是我搜索了这个cap文件，没有发现这个 ... [/quote]
不是啊.解释上说的是收不到接收端的ACK而重传数据的啊.并不是重传ACK啊.
可能是接收端Overloaded,或者已发出ACK但丢失了.解释上还列出了其它可能. 对，所以我理解不了。按照sniffer手册的说法是某一方连续重传3次，那么就会提示，可是对于我的这个情况，明明只是一个ack，也提示了。
我现在怀疑是sniffer的bug。
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