Ping Plotter Question

[ColTomb]

In Ping Plotter Standard there are values to select under edit>options>packet.
What should these settings be to accurately ping AH. also, I am having trouble with
washington1.level3.net and washington4.level3.net dropping packets. No packet
loss is dispayed at the last ( 12Th ) hop to one of the AH arenas though.
Is this normal ? I am on DSL 1.5M down 512K up, with average AH ping times
93ms to 110ms. I really do not want to go back to crapcast..er I. I mean
comcast. Thanks for the help...

[Ghastly]

In order to prevent DOS attacks, ISP infrastructure routers often don't reply to the pings themselves, or do so in a very limited fashion.  "Ping" traffic will often be shunted to another device for responding, or the device itself will only respond to x number of pings per some time period. 

If you are getting no dropped packets at the destination address, but are seeing dropped packets on one or more hops to the destination, you can (generally) ignore the dropped packets on the way.  But only if you are seeing no lost packets at the destination.

And I don't recall what the options are on the screen you describe, but I doubt you want anything other than the defaults.

<S>

[Skuzzy]

Whoa there Ghastly.

Packet losses along the way are bad.  Any losses in the columns at all is bad.  All packet losses at the last hop are always going to be the return trip causing the packet loss.

Very, very few ISP routers do not respond to the ECHO type packet.  They all use it for spot checking thier own networks and there is a ton of commercial monitoring software tools which use it as well.

ISP's will and do adjust the rate of reponse so they do not get into a ping flood situation.

Level3 drops packets all the time.  It is the nature of the beast.  They have oversold thier network worse than any other ISP in the business.  They are popular because they are cheap.

[Ghastly]

Skuzzy, more and more frequently I'm seeing tools such as pingplotter report packet loss in the middle of the route on the the higher tier ISP's router's that isn't really there.   What I've been seeing over the last year or so is that if you have no packet loss to the endpoint (which presumably will respond to every packet) you need to discount the "reported" loss to the midpoint routers because they just aren't always responding to ICMP traffic.

Not because you are actually seeing loss at that point.   All of which makes troubleshooting a connection problem even more difficult than it's ever been. 

All IMHO, and YMMV - but it's sure what I've been seeing.

<S>

[Skuzzy]

That is only true if the packet loss is 100%.  Anything less than that is the router not able to respond as it is honoring ICMP ECHO packets.

[ColTomb]

The packet loss is about 20%. It drops it and then picks it up again.
with no loss at the last hop. Should I be concerned about this ?
I called my ISP. They said there was nothing they could do about it.

[Skuzzy]

Well, they are being partially honest.  They can complain to Level3 as it is their chosen Tier 1 transport provider.  Level3 has a reputation of not doing anything about these types of problems though.