Hi Bill, I was reading the excellent write up below by you at the mail-archive. I would like know where to set the "timeout" mentioned in your response, i.e. the "usually 3 seconds" timeout until IM counts that packet as 'lost' and retries the request.
Is it the "Server Settings" -> "Device Thresholds" -> "Response Time" -> "Warning" which is default to 3 seconds? Thanks, Leonard Siu Quantum Data Systems (H.K.) Ltd. http://www.quantum.com.hk Poley, Jason wrote: > Yeah, I get all that but what do you mean by 'lost?' What exactly is this > counting? Errors reported by the device? Lost polls? Who is loosing these > packets and what kind of packets are you referring to? I see no errors on > any interfaces anywhere. InterMapper polls devices by sending a request packet and receiving back a response packet. If InterMapper sends a request packet and does not receive a response within the specified timeout (usually 3 seconds), IM counts that packet as 'lost' and retries the request. If InterMapper's request fails to elicit a response three consecutive times, the device's status is set to down. (3 is the default) With an SNMP probe, the lost packets are SNMP packets. There are three possibilities for where the packet was 'lost': 1. The request didn't reach the target device. 2. The target device did not generate a response within 3 seconds. 3. The response did not make it back to InterMapper. The SNMP probe is slightly complicated by the fact that the final retry will be a ping packet instead of SNMP. We implemented it this way after finding that some devices do not reliably answer SNMP packets on time. For example, a busy router might leave SNMP packets unanswered, but answer pings immediately. (Responding to a SNMP query is more computationally intensive than answering an ICMP echo). A device that answers the final ping retry is marked as "No SNMP response". If pings get through fine, but an occasional SNMP packet is lost to one particular device, my sense is that nothing is wrong with the network. I would advise that you increase the threshold for packet loss for that one device to 10% and leave it at that. Let me know if this helps. Regards, Bill Fisher Dartware, LLC ____________________________________________________________________ List archives: http://www.mail-archive.com/intermapper-talk%40list.dartware.com/ To unsubscribe: send email to: [email protected]
