We are running both Ping Plotter (2.51.1) and MultiPing (1.01.2) to check the same locations for different reasons. Ping Plotter shows very good history of each hop where MultiPing gives a concise view of multiple locations. Today we noticed that MultiPing showed packet loss errors (up to 26 in 4 hours, 1/min. poll) whereas Ping Plotter running on a different PC showed only 2 lost packets in 4 hours. How come?

Both PCs are in the same network and both running Windows XP.

Don

Hi, Don.

Are both using the same packet size and packet cargo? Also, the dynamics of PingPlotter's methodology (sending out multiple packets to the same host with different TTL) and MultiPing's methodology (sending out multiple packets to multiple hosts) sometimes causes different responses by the router that's dropping packets.

The difference between 2 lost packets and 24 probably falls outside the edges of what can reasonably be called statistical variation, but it would probably make some sense to make your interval a bit shorter (ie: 5 seconds) and see if this keeps the same 1:10 ratio.

Where does PingPlotter first show packet loss?

There are numerous reasons why the packet loss might be different. Your best bet might be to use PingPlotter to try and find the problem (make the trace interval much shorter, and then try and locate the problem router), and then use the problem you find to possibly determine why MultiPing is reporting more errors than PingPlotter.

- Pete

Hi Pete,
Unfortunately (or fortunately depending on your viewpoint) the circuit is working fine today and there aren't any packet losses showing on either MP or PP. I'm using the default packet size of 56 on each and both are using the default ICMP and not UDP.

Looking at the PP graph, it appears that there were quite a few lost packets on an intermediate router hop (hop 10 of 13) but none for routers on either side of that one. I suspect that router had ICMP set for low priority and was occasionally dropping packets to it.

The main difference between MP and PP appeared at the last hop where MP showed quite a few dropped packets and PP hardly any.

Don