Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!amdcad!decwrl!mogul From: mogul@decwrl.dec.com (Jeffrey Mogul) Newsgroups: comp.dcom.lans Subject: Re: Ethernet Error Rate Message-ID: <335@bacchus.DEC.COM> Date: 18 Mar 88 01:02:11 GMT References: <66@dogie.edu> Reply-To: mogul@decwrl.UUCP (Jeffrey Mogul) Organization: DEC Western Research Lines: 59 In article <66@dogie.edu> dorl@vms.macc.wisc.edu (Michael (NMI) Dorl) writes: >What is the expected error rate for a large Ethernet? I'd like >to know what fraction of the packets could be expected to have >some error such as checksum, short packet, long packet. We have a DEC LANBridge100 separating two fairly busy halves of an Ethernet. One feature of this device (no, this is not a plug) is that it keeps statistics, which one can retrieve with the right magic. I've enclosed a statistics report taken this morning. As far as I know, our Ethernet and associated attachments are within spec and well-maintained, so I'm not surprised that the error rate is fairly low. Some interpretation: if "Bridge seconds" is really the number of seconds since the bridge was started, then this one has been running for 230 days (this is not a plug, either). It looks like about 1 out of every 42000 packets is bad on one side, and 1 out of every 5000 packets is bad on the other side; I don't know if collisions are counted as "Bad frames" or not, and it's possible that most of the bad packets were generated in brief bursts of network sickness. -Jeff ---------------------------------------------------------------- Line counters for Line 1 as of 17-MAR-1988 10:47:25 Bridge SSQ1, Address 08-00-2B-04-66-1B Bridge seconds: 19909393 Invalid protocol messages: 0 Filtered frames: 2952389947 Bad frames: 583994 Lifetime exceeded frames: 744 No forwarding entry frames: 0 Forwarding transition count: 1 Collision Presence Test errors: 0 Transmitted Received Frames: 1057044284 4035950595 Bridge frames: 19948975 11 Frames lost: 0 70118 Line counters for Line 2 as of 17-MAR-1988 10:47:26 Bridge SSQ1, Address 08-00-2B-04-66-1B Bridge seconds: 19909393 Invalid protocol messages: 0 Filtered frames: 4195296973 Bad frames: 106159 Lifetime exceeded frames: 10789 No forwarding entry frames: 0 Forwarding transition count: 1 Collision Presence Test errors: 0 Transmitted Received Frames: 1093867616 1008319522 Bridge frames: 19948987 15 Frames lost: 0 515