Random loss of connection

amnixed · May 2, 2015

Hello Members,

Several workstations on our network use a "cloud" application service to which they connect with MS RDP. For the past week or so, we have had many random disconnects, and it seems that the loss of connection happened at the same time on all workstations.

The network uses a pfSense 2.1.5-RELEASE router. Checking the RRD graphs, it seems that WAN traffic wasn't unusually high when losses of connection occurred. However, the Quality graphs show spikes, although in retrospect I'm not sure if these coincided with loss of connection.

The graph shows at random times spikes in latency exceeding 1000 ms. In addition, I also ran mtr(8) which shows reports like this (apologies, not sure how to make formatting right):

Code:

Start: Sat May  2 10:38:44 2015
HOST: [myhost]                     Loss%  Snt Last  Avg    Best  Wrst  StDev
  1.|-- pfsense (192.168.0.1)       0.0%  60  0.2    0.2    0.2   0.3  0.0
  2.|-- dynamic-acs-72-23-220-1.z  10.0%  60  7.6   4470.   7.5 16117  4895.2
  3.|-- dynamic-acs-72-23-10-93.z  16.7%  60  9.7   4630.   8.5 16036  4898.5
  4.|-- 4.34.25.73                 93.3%  60  9103. 7247.  13.2 10384  4852.3
  5.|-- ae-4-90.ear2.Dallas1.Leve  93.3%  60  61.5  53.0   41.6  61.5  10.0
  6.|-- ae-4-90.ear2.Dallas1.Leve  91.7%  60  63.0  55.0   42.3  82.1  17.4
  7.|-- ARTISAN-INF.ear2.Dallas1.   5.0%  60  52.5  4196.  52.4 14670  4697.2
  8.|-- kc-fw05.net.vpdc.us (199.   6.7%  60  53.8  4477.  52.4 16582  4956.3
  9.|-- ???                        100.0  53  0.0    0.0    0.0   0.0  0.0
 10.|-- 74.123.84.131               5.7%  53  52.6  4796.  52.5 16382  5282.5

My question is: How much latency is "acceptable"? How much packet loss, if any? At what point can I say that "it's high latency/packet loss what causes RDP to lose connection"?

Please let me know what you think.

kpa · May 2, 2015

First let's get this out of the way:

https://forums.freebsd.org/threads/pc-bsd-freenas-nas4free-and-all-other-freebsd-derivatives.7290/

I would say that much latency is way too much. If you're on DSL/cable connection your average latency to a host near you should be in order of 5-15ms without any packet loss. Packet loss is what causes your connections to be aborted when either side decides after a timeout (depends on application) that the connection has terminated.

amnixed · May 2, 2015

Thanks and noted the reminder about FreeBSD derivatives. I asked the question here, because it's not specific to pfSense or the other derivatives. It's a networking related question, asking "how bad does something need to be to be called bad".

Random loss of connection

amnixed

kpa

amnixed