Network Dictionary — Mythinformation
July 15, 2008 by Greg Ferro · 6 Comments
Mythinformation is the term used to describe some form of knowledge that is based on apocryphal, false or old knowledge. A play on the the word misinformation.
A classic piece of mythinformation is the belief the Ethernet auto-sensing does not work. The stories of a misconfigured Ethernet ports causing major problems are either mythical or based in the past when there were no accepted standards for auto-negotiation.
The only instance for locking duplex/speed is when using obselete equipment, or when you do not know the configuration of the remote side. In fact, forcing speed and duplex reduces Ethernet functionality. For Gigabit Ethernet particularly, disabling auto-negotiation will almost definitely cause poor performance and outages when the Gigabit Ethernet line gets heavily congested.
Please rate this post:
Why Rate Posts?
(No Ratings Yet)
Loading ...Probably Related Posts on the Same Topic
- young and inexperienced
- insecure and lacking in sufficient knowledge / training
- inflated sense of worth
- working on really old software and hardware that needs constant upgrades.
- company has not invested in KVM equipment — even though it costs
Network Dictionary — Marketing Math
Marketing is a world of it’s own, where the rules of honesty, math, logic, and humanity do not apply. The ultimate example of this is marketing math when calculating bandwidth. …
Read the full articleNetwork Dictionary — Fancy Ethernet
Fancy Ethernet — generalised term used to describe Converged Enhanced Ethernet (CEE). Also used for Cisco’s trademarked and proprietary superset known as Data Centre Ethernet (DCE).
…
Read the full articleNetwork Dictionary — Server Hugger
Server Hugger — a sysadmin who like to able to touch their servers, typically to the point of obsession. Thus they must have data centers in their building or very nearby (which is becoming increasingly difficult).
As read on GigaOM
Trailer Park 2.0: Where your data lives.
Server huggers like being near their servers -– they feel that the emotional well-being and efficient operation of their servers requires them to be physically close at all times.
In my experience these people fit one of the following categories:
…
Read the full articleNetwork Dictionary — RITA — Reliable Internetworking Troubleshooting Agent
Reliable Internetworking Troubleshooting Agent RFC 2321
Key Facts
Firstly you should consult the RFC for background.
You don’t hit something with RITA, you ‘wang’ it.
Wanging your computer or router may not necssarily fix it, but you will feel better
Wanging management or co-workers is not generally a good idea ™
…
Read the full article
I think you could have picked a better example. Autoneg *does* fail on a lot of equipment which is arguably either obsolete or cheap or both, but still quite common even in serious data centers. I’ve seen it with my own eyes, it’s no myth, and don’t go all No True Scotsman on me by saying anything that fails autoneg is obsolete by definition. If you want a real myth, how about the one about the “vast majority” of servers not being able to generate 1GE worth of HBA traffic? That’s apocryphal, false, or old for you.
I have a different experience. The only autoneg problems I have seen in the last 3 years where when someone else wasn’t using it, or when the cabling was faulty. Hard setting bypassed the faulty cabling, by in the long term it did cause errors and was replaced.
And yes, I and others, still believe that. However, it gonna be pretty subjective, your experience may be with high quality servers with good HBA / TOE / setup parameters and that will make the difference, but most people don’t have that setup or that experience so I still stand by my statement.
I also know that it will not true in the future, but, hey, its a moving target.
There’s a pattern here: you haven’t *personally* seen something so you dismiss it as a myth. Well, I’ve seen the things you claim are mythical. I have several dozen I/O nodes in my lab at work, each of which is a real-life counterexample to your “1GE worth of HBA traffic” claim. The kicker is that, on an individual basis, each of those nodes is not very expensive or powerful. This laptop could beat one on most tasks. Clearly it’s the *non*existence of such things that’s a myth. The target has *already* moved.
Yes, you have a different experience. You can stand by your statements all you like, but that doesn’t make them true. My experiences aren’t mythical; I prefer to think of them as legendary.
“My experiences aren’t mythical; I prefer to think of them as legendary”
Great line, just brilliant.
Just two notes:
1) Never dealt with OOOOOLD cabling, which still uses 2-pairs patches on PC110 connectors. Well, we had to manually force our gigabit switch to run 100 FD.
2) On the other hand, talking about Cisco equipment, I found old FastEthernet switches were really a mess w/ autosensing; it worked no more than 50% of cases.
BUT, autonegotiation on gigabit-class ones (not only against gigabit hosts, but also down to FastEthernet) was indeed really working.