Auto-Negotiation or Manual Configuration [7:58904]
>From my experience in networking I made my mind that manual configuration of speed and mode is the better choice. Cisco recommends fixed configuration too. For my surprise, 802.3 specification states: "It is strongly recommended that Auto-Negotiation be used ..." "Manual configuration is not recommended" That sounds weird for me. Any thoughts? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58904&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Auto-Negotiation or Manual Configuration [7:58904]
I've discovered that if you have NICs that are relatively new (less than three years) and you have updated drivers then autonegotiation works very well. In the past it's been a rancid, evil mechanism that almost guaranteed link failure at some point. The stability of this mechanism has improved greatly over the last few years and for various reasons it may actually be better than hard-setting the speed and duplex. If you have recent NICs with the latest drivers and you have relatively new switches then give it a shot. Make sure you set BOTH sides to auto. Never configure auto on one side only. If the mechanism is to work as intended both sides must be configured for autonegotiation. People who know far more about NIC technology than I have stated that hard-setting the speed and duplex on newer switches and NICs is the absolute worst thing to do if you desire link stability. This advice does not apply if you have older NICs and switches. Do a Google Group search on this topic and you'll find some quite heated but informative debates. HTH, John >>> "[EMAIL PROTECTED]" 12/10/02 11:10:01 AM >>> >From my experience in networking I made my mind that manual configuration of speed and mode is the better choice. Cisco recommends fixed configuration too. For my surprise, 802.3 specification states: "It is strongly recommended that Auto-Negotiation be used ..." "Manual configuration is not recommended" That sounds weird for me. Any thoughts? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58909&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Auto-Negotiation or Manual Configuration [7:58904]
[EMAIL PROTECTED] wrote: > > From my experience in networking I made my mind that manual > configuration > of speed and mode is the better choice. > > Cisco recommends fixed configuration too. > > For my surprise, 802.3 specification states: > > "It is strongly recommended that Auto-Negotiation be used ..." > "Manual configuration is not recommended" > > That sounds weird for me. Any thoughts? Of course, they say that. They invented it. :-) They couldn't know that it wouldn't really work in the real world. Unlike IETF, I don't think IEEE has strict rules about there needing to be implementations that interoperate before a standard is declared finished. Actually, some of the problems come about because some vendors started implementing auto-negotation before the standard came out and did things a little differently. That always happens. There are some cases, by the way, where manual configuration won't work either! I've run into that. In general, the problems are starting to go away, however. The vendors are mostly doing things in an ineroperable manner now and auto-negotiation may be safe to use again, at least from my limited experience. ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58920&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Auto-Negotiation or Manual Configuration [7:58904]
Yes indeed there are cases where setting it manually will not work, and auto-neg needs to be in place. I've run into this with ixtreme servers connected to 2900 switches. Tis yet another reason to test before implementation. Bri On Tue, 10 Dec 2002, Priscilla Oppenheimer wrote: > [EMAIL PROTECTED] wrote: > > > > From my experience in networking I made my mind that manual > > configuration > > of speed and mode is the better choice. > > > > Cisco recommends fixed configuration too. > > > > For my surprise, 802.3 specification states: > > > > "It is strongly recommended that Auto-Negotiation be used ..." > > "Manual configuration is not recommended" > > > > That sounds weird for me. Any thoughts? > > Of course, they say that. They invented it. :-) They couldn't know that it > wouldn't really work in the real world. Unlike IETF, I don't think IEEE has > strict rules about there needing to be implementations that interoperate > before a standard is declared finished. > > Actually, some of the problems come about because some vendors started > implementing auto-negotation before the standard came out and did things a > little differently. That always happens. > > There are some cases, by the way, where manual configuration won't work > either! I've run into that. > > In general, the problems are starting to go away, however. The vendors are > mostly doing things in an ineroperable manner now and auto-negotiation may > be safe to use again, at least from my limited experience. > ___ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58921&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Auto-Negotiation or Manual Configuration [7:58904]
At Cisco we run auto/auto on our desktop network and have few problems..AS previously stated it is NIC and switch dependant. -L Priscilla Oppenheimer wrote: >[EMAIL PROTECTED] wrote: > >>From my experience in networking I made my mind that manual >>configuration >>of speed and mode is the better choice. >> >>Cisco recommends fixed configuration too. >> >>For my surprise, 802.3 specification states: >> >>"It is strongly recommended that Auto-Negotiation be used ..." >>"Manual configuration is not recommended" >> >>That sounds weird for me. Any thoughts? >> > >Of course, they say that. They invented it. :-) They couldn't know that it >wouldn't really work in the real world. Unlike IETF, I don't think IEEE has >strict rules about there needing to be implementations that interoperate >before a standard is declared finished. > >Actually, some of the problems come about because some vendors started >implementing auto-negotation before the standard came out and did things a >little differently. That always happens. > >There are some cases, by the way, where manual configuration won't work >either! I've run into that. > >In general, the problems are starting to go away, however. The vendors are >mostly doing things in an ineroperable manner now and auto-negotiation may >be safe to use again, at least from my limited experience. >___ > >Priscilla Oppenheimer >www.troubleshootingnetworks.com >www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58930&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Auto-Negotiation or Manual Configuration [7:58904]
Just got finished with a weird problem and the fix was auto negotiation on a 7200/w PA-2FE-TX. Problem was customer was seeing many CRC errors incrmenting on FE. Unfortunately another group within our organization monitors this customers network and one thing they monitor are input and output errors. For some reason which I need to figure out the CRCs were counting up but the input errors remained 0 therefore never alerting out monitoring group. I can come up with examples of many differant scenerios, as Priscilla mentions, unfortunately it's somewhat of a crapshoot!! Dave Priscilla Oppenheimer wrote: > > [EMAIL PROTECTED] wrote: > > > > From my experience in networking I made my mind that manual > > configuration > > of speed and mode is the better choice. > > > > Cisco recommends fixed configuration too. > > > > For my surprise, 802.3 specification states: > > > > "It is strongly recommended that Auto-Negotiation be used ..." > > "Manual configuration is not recommended" > > > > That sounds weird for me. Any thoughts? > > Of course, they say that. They invented it. :-) They couldn't know that it > wouldn't really work in the real world. Unlike IETF, I don't think IEEE has > strict rules about there needing to be implementations that interoperate > before a standard is declared finished. > > Actually, some of the problems come about because some vendors started > implementing auto-negotation before the standard came out and did things a > little differently. That always happens. > > There are some cases, by the way, where manual configuration won't work > either! I've run into that. > > In general, the problems are starting to go away, however. The vendors are > mostly doing things in an ineroperable manner now and auto-negotiation may > be safe to use again, at least from my limited experience. > ___ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com -- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367 "You don't make the poor richer by making the rich poorer." --Winston Churchill Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58931&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Auto-Negotiation or Manual Configuration [7:58904]
Just read this article that outlines some of the issues with auto-negotiation - http://www.nwfusion.com/columnists/2002/1209tolly.html We always use manual configuration on network devices, and typically on computers. There are always exceptions but they are pretty rare. -Kevin > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On > Behalf Of [EMAIL PROTECTED] > Sent: Tuesday, December 10, 2002 1:10 PM > To: [EMAIL PROTECTED] > Subject: Auto-Negotiation or Manual Configuration [7:58904] > > > From my experience in networking I made my mind that manual > configuration of speed and mode is the better choice. > > Cisco recommends fixed configuration too. > > For my surprise, 802.3 specification states: > > "It is strongly recommended that Auto-Negotiation be used > ..." "Manual configuration is not recommended" > > That sounds weird for me. Any thoughts? > Report misconduct > and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=59007&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Auto-Negotiation or Manual Configuration [7:58904]
The trick here is that you have to manually set both sides. You would not believe the number of times that I've seen production networks with auto-negotiation set on the PC and full duplex/speed 100 manually set on the switch. That doesn't work one bit. Frank Jimenez, CCIE #5738 [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Kevin Stone Sent: Wednesday, December 11, 2002 3:47 PM To: [EMAIL PROTECTED] Subject: RE: Auto-Negotiation or Manual Configuration [7:58904] Just read this article that outlines some of the issues with auto-negotiation - http://www.nwfusion.com/columnists/2002/1209tolly.html We always use manual configuration on network devices, and typically on computers. There are always exceptions but they are pretty rare. -Kevin > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On > Behalf Of [EMAIL PROTECTED] > Sent: Tuesday, December 10, 2002 1:10 PM > To: [EMAIL PROTECTED] > Subject: Auto-Negotiation or Manual Configuration [7:58904] > > > From my experience in networking I made my mind that manual > configuration of speed and mode is the better choice. > > Cisco recommends fixed configuration too. > > For my surprise, 802.3 specification states: > > "It is strongly recommended that Auto-Negotiation be used > ..." "Manual configuration is not recommended" > > That sounds weird for me. Any thoughts? > Report misconduct > and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=59033&t=58904 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
LONG RE: Auto-Negotiation or Manual Configuration [7:58904]
I previously mentioned that with newer hardware autonegotiation might be the way to go. Here are some snippets from a discussion of this very issue by people more NIC-savvy than me. It should be noted that NWAY refers to the autonegotiation mechanism. Along with other information, this discussion caused me to look at autonegotiation of speed and duplex settings in a new light. > but most people agree that auto-negotiation > (while being a good idea) is not the way to configure a reliable network. Oh no, they do not. Most people that really know this stuff actually agree that nway is usually the way to go, and if problems arise masking them is not the best solution. FOr instance, one of the well-known guys strongly supporting NWAY as the only real way to configure is Donald Becker, the guy writing almost all linux nic drivers. > What are (if any) the advantages or issues in choosing half or full duplex > on the server card connected to a 100mps switch and the workstation cards > connected at 100 mps as well. In my opinion you're better off setting both ends of the link to "auto" and let the NIC/switch negotiate. This is the only *correct* way to guarantee that a link will work. For a long time its been an unwritten "networking law" to always disable "auto-whatever" and force the settings, and while this may have been true for old networking gear (and is still definitely true for frame types!), its simply not the case anymore. Unless your gear is more than six years old, it should be able to negotiate the correct speed and duplex on its own. If you connect a server and switch port together with each set to auto and they *don't* negotiate a full duplex link, then you most likely have a wiring issue and forcing either or both ends to FD is only asking for trouble as it will mask the underlying problem. > Ive connected over 80 compaq servers into these switches, ranging from > single FD connections to 4 Dual port cards in a backup server. All these > were set to 100mb full duplex. The only time we had a problem was when a > server engineer left the server setting to autonegotiate. In that case you were plain lucky that it works in the combination 450T/your compaq cards, and it may fail without notice with the next update or different NIC you use. Let me explain: When two 100BaseTX devices get connected, they default to autonegotiation. First of all they try to detect if the other device does auto (NWAY) or not. By default, it would detect that, and now both devices will try to agree on the highest common speed. SO far, so good. What happens when you manually set one or both of the two devices is beyond any standard, and is completely up to the vendor. Basically, there are two possibilities, and both are equally used throughout the different vendors: a. The manually configured device still has nway enabled, but offers only the speed and duplex setting it's configured for. Some devices also offer the configured *and* lower settings. In that case, negotiation with a device that's still set for full autonegotiation could work. b. The device disables nway completely, and hardcoded simply tries to establish the LINK with it's configured setting. In that case, if the remote device is set to full autonegotiation, it *will* without a doubt fall back to half duplex, as it assumes a HUB is connected, which does not do NWAY. In case you set the fist device to FD in that case, you'll have a mismatch. THat's the worst case scenario, i.e. setting only one side manually to FD while leaving the other side set at auto. Now, if you have one side that uses a. from above, and the other device uses b., you're in trouble, *even* when both devices are set manually to FD. One of them possibly *regardless that you set it to FD*, fall back to HD as it doesn't detect a NWAY capable device on the other end. That's why I said the only guarantted working manual configuration is HD. Sure enough, FD *could* work depending on the devices in use, but it can stop working with the next driver, firmware or hardware revision. Simply put, the only guaranteed and standarized way to make full duplex work is autonegotiation. > It may not adhere to best practice or be the recommended way of doing > things, but with the 450T switches it works. Then they're broken and are not certified 100BaseTX devices. > Ive always been under the impression that autonegotiation was to be watched > carefully and not trusted in all ethernet network environments. No. Again, autonegotitaion is *the only* way to connect 100BaseTX devices according to the IEEE standard. Anything else means leaving the standard and can and does lead to unpredictable results. > So what works well with one setup, doesn't mean it will be the > same elsewhere with different equipment. This in itself is enough for us to > not rely on the technology. We have to keep the speed of the Networks at > top performance, as people's lives may depend on it (I'm not being d
