Packet loss from Switch and Router

[chartervoss1]

I was told that packet loss from a newer model switch and/or router is expected when doing ping tests. This is because of built-in rate limiting.

Can anyone confirm this?

I've been told the following:

Ping from 7600 to Server = packet loss (rate-limiting)

Ping from Server to 7600 = packet loss (rate-limiting)

Ping from Server to Server over 7600 = no packet loss

Whenever we ping from a 7600 to a GSR or any other device on the network, we have packet loss. Is this expected?

[glen.grant]

This is false as far as I know , have never seen this on any model even the newer Super 720's or 4500's . Any kind of rate limiting has to be specifically configured and is not usually on by default . You have something else going on if you are losing packets , start by looking at any l1 or l2 type problems , speed/duplex issues etc .....

[chartervoss1]

Thanks. Cisco TAC states that the packet loss is exptected on the 7600 and GSR's. I asked for documentation to back up their assertion and they can provide none but they still will not back down from this. We drop one in 15 packets when pinging from and to our 7609. Again, they state they will not troubleshoot because it is expected behavior.

Each side is configured full/1000.

[glen.grant]

Have never heard of that or even seen anything like that and we use a wide variety of their boxes not specifically the 7600 but 7200's , 6500's with sup 720's etc... . What kind of box is that if it randomly drops packets? How can that be considered normal ???? It certainly shouldn't be dropping packets on a simple ping test , that is no load at all .

[dave.keith]

The phenomena of a box not generating an ICMP Echo-Reply in response to an ICMP Echo-Request is quite common in my experience. It's not a case of random dropping of packets, rather a Real-Time OS having something ("anything" is really the case) better to do. If the mechanism was more reliable then the ping generation on various OS's would only send out 1, rather than the 4, 5, or 10 that is the default in most cases.

Dave

[b.orth]

I agree with Dave..... "Something better to do"

If you ping a router directly, he knows it is a ping, and will drop it if he has somethimg better to do. If you ping across the router as in one of your senarios, he only knows it is a data packet and he must forward it. Thus your No drops across the router.

[glen.grant]

I agree with what you are saying it's just that I have never seen this unless a router is really busy like running 80-95% cpu for some reason .