RE: question : ethernet collision rule of thumb...
Title: RE: question : ethernet collision rule of thumb... Yes, you will always have some collisions on a shared medium like Ethernet (obviously I'm not included a switched environment). The general guideline is that for IP you should have no more than 500 hosts on a flat network segment; IPX allows for 300; AppleTalk for 200; NetBIOS, 200; and a mix of protocols, 200. Again, this is just a guideline, which doesn't take some things into account, such as multicasting. I have not seen a guideline that specifies the percentage of collisions above which you should definitely segment. If anyone else has, please share. - Don -Original Message- From: E Joseph [mailto:[EMAIL PROTECTED]] Sent: Wednesday, November 15, 2000 4:34 PM To: [EMAIL PROTECTED] Subject: question : ethernet collision rule of thumb... I would first like to thank everyone. I have been a member of this groups for several years now. I have never actually posted a question, generally I just absorb others questions. I realise there is no concrete answer on this, BUT how many collision on a shared media ethernet segment does it take before having a problem?? I was just invovled in a situation where we had a hub hanging off a hub connected to our 6509. The switchport error disabled and I had to track the devices down. I beleive you will always see some collisions in a shared ethernet environment??? At what collision rate should you get worried??? How much does it take to shut a switch port down??? Thanks, Ed __ Do You Yahoo!? Yahoo! Calendar - Get organized for the holidays! http://calendar.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: question : ethernet collision rule of thumb...
The network would be considered unhealthy if it is experiencing more than .1% of packets colliding (do the math). As for your question regarding what does it take to shut a port down (errDisable) take a look at this URL: http://www.cisco.com/warp/public/473/20.html -g On Wed, 15 Nov 2000, E Joseph wrote: |Date: Wed, 15 Nov 2000 16:33:37 -0800 (PST) |From: E Joseph <[EMAIL PROTECTED]> |To: [EMAIL PROTECTED] |Subject: question : ethernet collision rule of thumb... | |I would first like to thank everyone. I have been a member of this |groups for several years now. I have never actually posted a question, |generally I just absorb others questions. I realise there is no |concrete answer on this, BUT how many collision on a shared media |ethernet segment does it take before having a problem?? I was just |invovled in a situation where we had a hub hanging off a hub connected |to our 6509. The switchport error disabled and I had to track the |devices down. I beleive you will always see some collisions in a shared |ethernet environment??? At what collision rate should you get |worried??? How much does it take to shut a switch port down??? | | Thanks, | Ed _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: question : ethernet collision rule of thumb...
Title: RE: question : ethernet collision rule of thumb... Hi , How can I find out the collision rate of .1% ( comparing the collisions with Output packets or bytes) Here's the output from my ethernet interface 119069488 packets output, 3373784736 bytes, 0 underruns 31 output errors, 41597688 collisions, 0 interface resets 0 babbles, 0 late collision, 5543538 deferred Thanks Amit -Original Message- From: George Harper [SMTP:[EMAIL PROTECTED]] Sent: Thursday, November 16, 2000 9:52 AM To: E Joseph Cc: [EMAIL PROTECTED] Subject: Re: question : ethernet collision rule of thumb... The network would be considered unhealthy if it is experiencing more than .1% of packets colliding (do the math). As for your question regarding what does it take to shut a port down (errDisable) take a look at this URL: http://www.cisco.com/warp/public/473/20.html -g On Wed, 15 Nov 2000, E Joseph wrote: |Date: Wed, 15 Nov 2000 16:33:37 -0800 (PST) |From: E Joseph <[EMAIL PROTECTED]> |To: [EMAIL PROTECTED] |Subject: question : ethernet collision rule of thumb... | |I would first like to thank everyone. I have been a member of this |groups for several years now. I have never actually posted a question, |generally I just absorb others questions. I realise there is no |concrete answer on this, BUT how many collision on a shared media |ethernet segment does it take before having a problem?? I was just |invovled in a situation where we had a hub hanging off a hub connected |to our 6509. The switchport error disabled and I had to track the |devices down. I beleive you will always see some collisions in a shared |ethernet environment??? At what collision rate should you get |worried??? How much does it take to shut a switch port down??? | | Thanks, | Ed _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: question : ethernet collision rule of thumb...
Take collisions divided by packets output. You are looking for the percentage of collisions related to the number of packets that were sent out of that interface. Roman At 05:57 AM 11/16/00 +0100, you wrote: Hi , How can I find out the collision rate of .1% ( comparing the collisions with Output packets or bytes) Here's the output from my ethernet interface 119069488 packets output, 3373784736 bytes, 0 underruns 31 output errors, 41597688 collisions, 0 interface resets 0 babbles, 0 late collision, 5543538 deferred Thanks Amit -Original Message- From: George Harper [SMTP:[EMAIL PROTECTED]] Sent: Thursday, November 16, 2000 9:52 AM To: E Joseph Cc: [EMAIL PROTECTED] Subject: Re: question : ethernet collision rule of thumb... The network would be considered unhealthy if it is experiencing more than .1% of packets colliding (do the math). As for your question regarding what does it take to shut a port down (errDisable) take a look at this URL: http://www.cisco.com/warp/public/473/20.html -g On Wed, 15 Nov 2000, E Joseph wrote: |Date: Wed, 15 Nov 2000 16:33:37 -0800 (PST) |From: E Joseph <[EMAIL PROTECTED]> |To: [EMAIL PROTECTED] |Subject: question : ethernet collision rule of thumb... | |I would first like to thank everyone. I have been a member of this |groups for several years now. I have never actually posted a question, |generally I just absorb others questions. I realise there is no |concrete answer on this, BUT how many collision on a shared media |ethernet segment does it take before having a problem?? I was just |invovled in a situation where we had a hub hanging off a hub connected |to our 6509. The switchport error disabled and I had to track the |devices down. I beleive you will always see some collisions in a shared |ethernet environment??? At what collision rate should you get |worried??? How much does it take to shut a switch port down??? | | Thanks, | Ed _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: question : ethernet collision rule of thumb...
There is a book written by Scott Haugdahl called Network Analysis and Troubleshooting ISBN 0201433192 and he has a pretty good discussion on collisions, there are lots of factors that go into the number (length of the segment, number of users, etc) but I think that above 5% was where he'd start getting worried and that will have a negative effect on throughput. I personally think that 0.1% is way too low (cisco's numbers) but if you're trying to sell switches I took a quick look on google and ran into this -- a couple of guys on the free BSD mailing list that say less than 50% was ok -- obviously I think they spend too much time coding and not enough time making the network work. http://lists.openresources.com/FreeBSD/freebsd-questions/msg05297.html Joe "E Joseph" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... | I would first like to thank everyone. I have been a | member of this groups for several years now. I have | never actually posted a question, generally I just | absorb others questions. I realise there is no | concrete answer on this, BUT how many collision on a | shared media ethernet segment does it take before | having a problem?? I was just invovled in a situation | where we had a hub hanging off a hub connected to our | 6509. The switchport error disabled and I had to | track the devices down. I beleive you will always see | some collisions in a shared ethernet environment??? | At what collision rate should you get worried??? How | much does it take to shut a switch port down??? | | Thanks, | Ed | | __ | Do You Yahoo!? | Yahoo! Calendar - Get organized for the holidays! | http://calendar.yahoo.com/ | | _ | FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html | Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] | _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: question : ethernet collision rule of thumb...
It depends on what type of collisions, and whether or not your device can report the various cases (or finding out what they are called). Collisions aren't that horrible. They get requeued for transmission. Deferred transmits occur when a packet is read to be transmitted but the media is 'busy'. Excessive collisions are 8 or 16 successive collisions on the same packet (depending on who is reporting them). Deferred transmits can lead to input buffer shorage and consequently input drops. The latter case is a more true metric of media congestion. Jeff Kell <[EMAIL PROTECTED]> _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
