Packets loss over WAN link

Unanswered Question
Feb 12th, 2008


I've got a problem (packet loss) over an Hertzian waves link (17Mb) between two routers. I think the problem is coming from the hertzian link but i just want to be sure that there is no mistake about the configuration...

You can find the configs attached. The link is between Router1 Fa0/0/0 (HWIC-4ESW) and Router2 Fa0/0. I attached also the output of ping so you can see the percent of packets lost.

Thanks for your help,


I have this problem too.
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Joseph W. Doherty Tue, 02/12/2008 - 05:45

I didn't see anything obviously wrong with your QoS configuration, where you're shaping to match 17 Mbps, but insufficient information to suggest why the ping drops. One very important factor, you didn't describe, how much traffic was being passed when you did your ping test or what your policy stats look like.

Assuming you did the test while the link was loaded, it could be as simple as router's CPU was overloaded, especially the 26xx.

I'm unfamiliar with the Hertzian waves links, but if some type of wireless, certainly possible it's corrupting packets. All media should have a designed/expected error rate, the question is whether this media is working as expected, but even if it is, it could be much worse that Ethernet.

Mohamed Sobair Tue, 02/12/2008 - 07:35

Hi Adrien,

One point about your Nested Policy, what is class POG_FH matching there??

I see ,its (match any) , do you mean to match class-default traffic , it should be as follows:

Policy-map X

class class-default (Instead Of class POG-FH)

shape average yyyy

service policy (a)

policy-map (a)

class (b)

priority (Bandwidth)

class-map match-any (b)


As for any drop packet, it could be due to a bandwidth utilization on your point-to-point links. Try doing the test when there is no utilization.

A nother cause of packet drops , could be due to any MTU mismatch on both ends.




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