Acceptable Ethernet Packet Error Rate
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Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or acceptable interface error rate posting ads with us Server Fault Questions Tags Users Badges Unanswered Ask Question _ Server Fault is packet error rate to bit error rate a question and answer site for system and network administrators. Join them; it only takes a minute: Sign up Here's how it works: Anybody can packet error rate bch ask a question Anybody can answer The best answers are voted up and rise to the top Acceptable number of ethernet errors in a medium sized environment? up vote 2 down vote favorite I'm implementing a monitoring system for an existing packet error rate wifi modest sized data center deployment. So far I've only gotten to the host / application side of the monitoring equation but I'm noticing what I consider to be an alarming number of Ethernet errors on various hosts. To me, alarming is 3 or 4 per day per host (some have none). When I look at the SNMP counters for the switches, I again see lots of errors on the counters but I'm not graphing those errors (yet). In my prior environments with
Packet Error Rate Formula
many more ports my error rate was approximately zero except for those hosts that had actual problems like duplex mismatches. None of these interfaces are saturated; they're pushing approximately 40-50 megabytes / sec over gig links. My gut feeling is that there shouldn't be any errors at all over any interface if everything is working properly but I'm worried that if I pick a fight over resolving these problems I'll just alienate everyone else who believes "it works fine; it's been working for years that way". Anyone have some good stories / studies / statistics for when to be alarmed at ethernet errors? Or something to indicate how a small volume of errors would affect, say, an iSCSI volume? Thanks! ethernet share|improve this question asked May 11 '11 at 23:30 chris 8,10132647 add a comment| 1 Answer 1 active oldest votes up vote 1 down vote TCP/IP can handle errors quite well. A single error will be retransmitted and everything will generally be hunky-dory. Consistent numbers of 3-4 errors per day is alarming because it indicates a possible problem (bad cable, port, etc), but in itself it is not an itch worth scratching. A single error could be the result of anything from electromagnetic interference to a very ill-positioned subatomic event. In both cases, the impact on your network is negligible. If it will become a political issue, just leave it be (but keep an eye on it). I'd only throw a fit if I
Team Our Approach Clients Partners Community Involvement Careers Contact Us News & Events C-MUG Events Events News 11/42011 Carole Warner Reece Understanding Interface Errors and TCP Performance application performanceerrorsMathis equationnetwork analysisnetwork performanceTCP throughput Not
Ethernet Bit Error Rate
all network engineers understand the impact of interface errors on TCP performance. ethernet bit error rate standard Interface errors can cause a BIG impact, although it may not be intuitive at first glance. We recently pointed gigabit ethernet bit error rate out some interfaces with extremely high errors to a customer. We mentioned that the links with the highest percentage loss were likely getting very little useful data through them, and that http://serverfault.com/questions/268809/acceptable-number-of-ethernet-errors-in-a-medium-sized-environment they should investigate the cause of these errors. Initially the customer did not appear to be very concerned because the percent of errors was below 3%. We personally find error rates of greater than 0.001% to be a cause for concern. Based on this experience, I thought I'd write up an article to illustrate the impact of interface errors. Best TCP/IP Performance http://www.netcraftsmen.com/understanding-interface-errors-and-tcp-performance/ Expected Perhaps the first question to consider is “What is the best TCP/IP performance you can expect on a Gigabit Ethernet link in the campus?” First let's look at the buffering required for TCP which is the bandwidth delay product (BDP). With a Gigabit Ethernet link, the buffering required in a receiving system for maximum performance is the amount of data that can be sent between ACKs. The bandwidth of a Gigabit link is 1000 Mbps. If the data exchange is inside a campus, say between a data center server and a user, the RTT should be very small, perhaps 2 milliseconds or .002 seconds. So for a Gigabit link, the receiving system needs to be able to buffer bandwidth * delay: BDP = 1000 Mb/s * .002 seconds BDP = 1000 Mb/s (1 byte/8 bits) * .002 seconds BDP = 125,000,000 bytes * .002 seconds BDP = 250,000 Bytes When the BDP is less than the TCP window size, the path BW is the limiting factor in throughput. For a Gigabit Ethernet link, the BDP of 250,000 Bytes is greater than the def
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and http://superuser.com/questions/325328/how-to-test-bit-error-rates-on-ethernet-networks policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Super User Questions Tags Users Badges Unanswered Ask Question _ Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute: Sign up Here's how it works: Anybody error rate can ask a question Anybody can answer The best answers are voted up and rise to the top How to test Bit Error Rates on Ethernet Networks? up vote 6 down vote favorite 1 I need a tool software or otherwise (preferably software) that will allow me to test Bit Error Rates on an Ethernet Network. I am using a software tool that packet error rate I did not write and do not have access to the source of to introduce Bit Errors into an Ethernet Network. I am currently trying to test to see whether this software does what it actually is supposed to do, so that it can be used in some network simulations. I know there are hardware testers like the FireBERD but it would be great if someone had some software that could do it. Although based on what I'm reading here http://www.wireshark.org/faq.html#q7.9 I don't have much hope. networking wireshark packet-loss share|improve this question edited Aug 19 '11 at 17:38 Diogo 19.7k46116193 asked Aug 19 '11 at 17:22 rhololkeolke 243312 If you have a Mac handy, it might be worth trying Wireshark on that. I've never seen Wireshark capture CRC data on any Windows machines. –sblair Aug 19 '11 at 18:21 add a comment| 5 Answers 5 active oldest votes up vote 2 down vote If you're running *NIX you can check /proc/net/dev to see stats about errors. It's vague about what errors, but according to this post on Stackoverflow it does record CRC errors.