Odd network behaviour -- intermittent very long ping times.

[sgbotsford]

Network topology:

Satellite modem <-> Router <-> switch <-> 2 macs

Router is wifi -))))) ipad + 2 iphones.
Additional mac wired to router.

Satellite link is by way of the new Viasat. Our ISP is Xplornet.

Starting about a week ago, we get periodic sessions of ping times running into the mid teens -- e.g. 13000 ms. Curiously packet loss is zero. E.g. ping -w 20000 -c 1000 192.168.175.250 would return stats of 12,000 with a standard deviation of about 3000. And all thousand packets would (eventually) return.

Needless to say internet browsing goes to hell.

Sessions of slow would last 10-30 minutes. Then it would be fine for a while.

Within my own network, everything is sub millesecond.

If I connect a laptop directly to the modem, I get the normal 600 ms times that are typical for satellite links.

The address used is my ISP's DNS server. Traceroute says 4 hops.

What else do I try?

 

[VinceWhirlwind]

Log onto the modem, check the CPU, logs, number of concurrent sessions.

Do the same thing on the router.

 

[sgbotsford]

If you have a secret method to log into a satellite modem, let me know. I have never been able to even find out an IP address for it. (I suspect that it operates as a bridge, with configuration only available from the NOC.)

As to logging into the router: It's a simple minded Buffalo WGR 40. I don't think I've got a way to check CPU utilization. The number of connections is not out of line.

Yesterday I was able to reproduce the problem for a while with the simpler network:

Modem <-> router <-> laptop, all connections being hardwired.