Re: [lwip-users] lwip reply delayed after long communication idle time

[goldsimon]

Am 4. April 2020 08:04:32 MESZ schrieb Jochen Strohbeck <address@hidden>:
>Now, in 2.1.x, the first http request after host and controller power
>up is
>served but still delayed for ca. 5s and I don't know if this is a
>"feature"
>or bug of ARP.
>Please have a look at the commented 1st trace below.

Please send packet captures as pcap file, not as text.

Regards,
Simon

>The second trace shows the normal behavior. The controller immediately
>sends
>out a ARP broadcast after receiving the first TCP msg. For me the host
>is
>expecting this broadcast but this is missing in the first trace.
>
>Who is to blame for the delay? The http server or the host? How to get
>rid
>of the delay if possible? I'm on windows 10.
>
>1880   73051.473650    de:bd:00:00:00:29       Broadcast       ARP     60      
>ARP Announcement
>for
>192.168.0.100
>-> controller power on
>
>1881   73205.861086    192.168.0.9     192.168.0.100   TCP     66      57961 → 
>80 [SYN]
>Seq=0
>Win=64240 Len=0...
>-> 1st http.get() request after power up (python requests)
>
>1882   73208.861658    192.168.0.9     192.168.0.100   TCP     66      [TCP 
>Retransmission]
>57961 → 80 [SYN] Seq=0 Win=64240...
>-> retrans after 3s
>
>1883   73210.857278    Dell_7a:2c:51   de:bd:00:00:00:29       ARP     42      
>Who has
>192.168.0.100? Tell 192.168.0.9
>-> host ARP request after 2s
>
>1884   73210.861936    192.168.0.9     192.168.0.100   TCP     66      57962 → 
>80 [SYN]
>Seq=0
>Win=64240 Len=0 MSS=1460 WS=2...
>1885   73210.862961    de:bd:00:00:00:29       Broadcast       ARP     60      
>Who has
>192.168.0.9?
>Tell 192.168.0.100
>1886   73210.862988    Dell_7a:2c:51   de:bd:00:00:00:29       ARP     42      
>192.168.0.9 is
>at
>98:e7:43:7a:2c:51
>1887   73210.863678    de:bd:00:00:00:29       Dell_7a:2c:51   ARP     64      
>192.168.0.100
>is at
>de:bd:00:00:00:29
>1888   73210.863679    192.168.0.100   192.168.0.9     TCP     60      80 → 
>57962 [SYN,
>ACK]
>Seq=0 Ack=1 Win=2920 Len=0 MSS=1460
>:
>
>1990   74227.892538    de:bd:00:00:00:29       Broadcast       ARP     60      
>ARP Announcement
>for
>192.168.0.100
>1991   74248.600750    192.168.0.9     192.168.0.100   TCP     66      58120 → 
>80 [SYN]
>Seq=0
>Win=64240 Len=0 MSS=1460...
>1992   74248.601430    de:bd:00:00:00:29       Broadcast       ARP     60      
>Who has
>192.168.0.9?
>Tell 192.168.0.100
>1993   74248.601456    Dell_7a:2c:51   de:bd:00:00:00:29       ARP     42      
>192.168.0.9 is
>at
>98:e7:43:7a:2c:51
>1994   74248.601813    192.168.0.100   192.168.0.9     TCP     60      80 → 
>58120 [SYN,
>ACK]
>Seq=0 Ack=1 Win=2920...
>
>
>
>
>--
>Sent from: http://lwip.100.n7.nabble.com/lwip-users-f3.html
>
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