Wired Networks Thread, New network planning questions in Technical; Afternoon chaps and chappettes.
After a fair big of ear twisting it looks like SLT are ready to look at ...
23rd April 2012, 04:10 PM #1
New network planning questions
Afternoon chaps and chappettes.
After a fair big of ear twisting it looks like SLT are ready to look at an infrastructure upgrade in the near future, possibly starting as soon as the end of this year.
I've been in the job 4 years with no previous experience so I'm looking for some advice and hopefully if there is anything stupid you can point me in the right direction, but I think I've got this... My CCNA1 came in handy
Right, we have around 350 workstations including laptops which are wireless (The wireless system is a whole different issue though...). We have two virtual hosts supporting 7 or 8 virtual servers, the most intensive of those network wise will probably be the SQL stuff which ultimately provides data for Sharepoint and the SIMS server and finally a microsoft RDS server providing remote desktops outside school for staff use. We also have two physical AD servers in a failover cluster handling DHCP/DNS/AD and file sharing. We have a massive subnet at the moment (255.255.0.0) so DHCP and related services do take up a chunk....
That's the background info anyway.
So, firstly why should we use fibre? I fully intend on using it but if someone asked me why I wouldnt know an answer... Properly terminated and placed in theory cat5e and 1gb fibre have the same bandwidth but I have a feeling this is more to do with latency, signal quality and signal speed meaning fibre gives a more reliable and speedier signal from one end to the other. The higher signal quality reduces lost packets at the receiver and gives an illusion of faster speed...? Google hasnt helped so far with that one......
Secondly is toology. Without writing a life story I am leaning towards an extended star topology with a 10gb fibre backbone connecting servers and the "primary" switches, then 1gb fibre starring out from the primaries to "secondary" switches which just spew out cat5 to the desktop.
The theory behind it being that if the secondaries are connected by 1gb fibre and we have say, 7 of those, then primary switch is only dealing with 7gb worth of data and putting that on a 10gb line to the server, hence bottlenecks will be very few and far between. We are not going to get anywhere near to the 10gb limit any time soon but as it stands media are trialling some Mac desktops and if they get the go ahead they could end up with 20-30 macs all streaming HD video footage at the same time as everyone else trying to logon, use SIMS etc... at the start of a lesson.
Anyhoo, that's enough for now! Would really like an answer as to why to use fibre instead of copper (aside from distance limitations).
24th April 2012, 08:42 AM #2
Nice, simple answer regarding Fibre vs Copper. Distance - nothing else. It's no faster, the quality is no better (unless the copper cables are in dire straits) and as a result streaming won't be any better. Fibre's big selling point is the ability to shift data over longer distances, which is very useful when you bear in mind the 100M limits of copper; and I'd suggest putting fibre in place of any 100m runs too. The speed will only come into it for much faster connections but even now 10GBps over copper is hardly rare.
An extended star is the sort of thing you'd want to go for anyway - you'll want to avoid too many switch to switch connections as it'll make life a fair bit more difficult when some simple yet problematic things happens (like loopbacks). Core switches -> edge switches > desktop.
The 10GBps thing has been done to death here, the upshot is another simple one, currently you can stream all you want and if you touch 100MBps of it day to day, then you'll probably want to find out who's munching your bandwidth Of course though you never plan for now, and if you've got the thumbs up from SLT to upgrade your infrastructre, grab it with both hands. Try and plan your servers around it, get link aggregation working where it's needed especially for any SANS or file system servers which are going to get hammered; both reliability and performance, this will almost certainly help if you get a lot of users streaming media at the same time.
One consistent is going to be slowdowns during logon/logoff times as profiles synchronise (Depending on your setup there of course) which is usually down to storage on your user system rather than infrastructure bottlenecks. There's nothing worse than heeding someones complaint about speed problems during start/end of lessons and sitting watching your servers do absolutely nothing, memory, processor or network.
Thanks to synaesthesia from:
shadowx (24th April 2012)
24th April 2012, 10:07 AM #3
Thanks for the reply, what I am hoping to do with the extended star is to give us loads of expansion, currently if media wanted 15 macs we dont have the capacity to wire them in so we would have to either daisy chain a new switch from the existing one in that area of the school using cat5e or run a whole new fibre link down a pretty tough corridor, and whack a new switch on that. If we do what I want to do then we would have our fibre termination point in that corner of the school anyway so we can easily patch in a new switch directly on to that fibre and be done with it.
It makes sense to me anyway...
To be honest we arent sure what causes the occasional slow down on our network, the server side of things is all brand new and running over multiple 1gbe lines so I reckon it's purely the dodgy state of some of the cabling (bad trunking, kinked cables, interference) and the huge subnet we have.
You answered my questions anyway so thanks!
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