# Ping bandwidth cost and ways to keep a GSM connection alive

## Logicien

Hi,

I use a GSM modem to connect to Internet. I can get disconnected if the idle time is to long. In that case I often need to unplug the modem to reconnect. During my connection time, there is often a delay to access a site if I wait to long between two requests.

I just come to try the ping command to keep my connection, my link alive between my Gentoo machine and my ISP server. From the moment a ping echo succeed, all subsequents one succeed too. Than, I do not suffer any delay, and probably any disconnection, anymore.

```
ping -f -I ppp0 -i 1 96.23.2.145
```

I ping the first public address that traceroute give to me. It is modemcable145.2-23-96.mc.videotron.ca, my ISP:

```
traceroute google.ca

traceroute to google.ca (173.194.73.94), 30 hops max, 60 byte packets

 1  10.208.9.197 (10.208.9.197)  39.704 ms  39.603 ms  49.265 ms

 2  10.208.11.101 (10.208.11.101)  49.326 ms  49.297 ms  69.057 ms

 3  modemcable145.2-23-96.mc.videotron.ca (96.23.2.145)  69.230 ms  69.190 ms  69.161 ms

 4  10.170.176.65 (10.170.176.65)  79.005 ms  78.979 ms  78.960 ms

 5  216.113.122.129 (216.113.122.129)  99.541 ms  49.126 ms  69.148 ms

 6  216.113.123.190 (216.113.123.190)  89.110 ms  89.073 ms  89.041 ms

 7  72.14.214.126 (72.14.214.126)  59.745 ms  80.258 ms  80.229 ms

 8  72.14.232.102 (72.14.232.102)  80.199 ms 72.14.232.118 (72.14.232.118)  80.168 ms 209.85.252.80 (209.85.252.80)  129.383 ms

 9  209.85.241.222 (209.85.241.222)  100.089 ms  109.748 ms  100.033 ms

10  64.233.174.87 (64.233.174.87)  119.531 ms 216.239.48.103 (216.239.48.103)  119.373 ms 64.233.174.87 (64.233.174.87)  89.281 ms

11  * * *

12  vb-in-f94.1e100.net (173.194.73.94)  99.108 ms  69.991 ms  79.945 ms
```

The questions I ask to myself are

- Does an infinitive ping to a machine correct?

- Is an infinitive ping consummate a lot of bandwidth and can be critical to a limited data transfer contract?

- Would it be better to ping a local, a private address like 10.208.9.197?

- Is there something better than the ping command to keep an Internet (GSM) connection alive?

----------

## eccerr0r

You're doing what your provider does not want you to do, which is stay connected the whole time.

Ping packets are fairly small at least.  You have to ping out of the network to your ISP's machine that keeps track of activity, so you'll have to test.  Probably that first hop is OK.

Ping sends some packets out, and get a couple back in, it's probably on the order of 0.1KB/sec if you ping a standard packet every second.

I've found that dropouts due to interference of radio signal (out of range, shielded, etc.) can also cause a disconnect...

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## Logicien

Your probably right eccerr0r. If my ISP want to count the ping as data transfer, it must be from local network to Internet and then back to local network. I am not complely sure if a local ping cannot be count as a transfer data. It can be log at least.

I can reduce the amount of data send to zero by using the -s switch of the ping command. According to the ping output, each echo request per second send 28 bytes. So 28 x 60 x 60 x 24 = 2419200 bytes per day, divided by 1024 give 2,362 megabytes per day of data transfer in upload. I do not know how much it is in download. Probably it is configurable by the machine who is being ping. For me, it is enough economic because it keep my connection continuously alive and I can stop it anytime.

My command is

```
urxvt -bg black -fg yellow -geometry 80x24+261+174 -hold +sb -T 'Urxvt ping modemcable145.2-23-96.mc.videotron.ca' -tr +vb -e ping -I ppp0 -i 1 -s 0 10.208.9.197
```

Thank's.

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