Recommendations for an 'Edge' Swith Setup?

[flyinghaggis]

Our school's recently just purchased a new building on the same site and we're trying to decide on the best plan for adding it to our exisiting network. The contractors are going to run an 8-core multimode fibre from our server room to the comms cabinet there so we can connect it.

 

Currently in the rest of edge switches are 3com 4400s running in stack setups (usually 2 or 3 48-port switches). These switches used dedicated stacking modules plugged into the backplane of the switches but most companies (3com included) seem to have ditched the dedicated hardware stacking module approach in favour of virtual stacking over existing ethernet ports. Don't know if this is better or worse? I'm guessing that if you stack over a gigabit link the throughput will probably be sufficient?

 

The new wing will have slightly over 100 network devices so I'd want a stack with a port density of at least this figure which means at least 3 (48-port) switches I'd guess to allow for expansion in future. In terms of networking I think there are probably 3 options :-

 

1) Buy 3 x 48-port switches running in a virtual stack and fit a fibre module to one to run back to the server room. The switches could then be connected (via daisy-chain) to each other using local gigabit ethernet links.

 

2) Buy 3 48-port switches but fit a fibre module to each swich and run a dedicated fibre for each switch back to the server room. This would give each switch (and the 48 ports on it) a gigabit of bandwidth direct back to the core switch.

 

3) Buy a modular switch with enough capacity for 100 ethernet ports and a fibre module (possibly with 2 connection for resiliency) for connecting it back to the server room.

 

I think option 1) is probaly the most likely route we'll go down (as I dont think we'lll need the bandwidth provided by the setup in 2 and the modular setup looks like it may be too expensive for an edge switch) but does anyone have any thought's/recommendations on the above setups?

 

TIA

Edited February 23, 2009 by flyinghaggis

[Teth]

This depends purely on Use.

 

If the machines on those switches are standard Web browsing and MS office machines then 1 GB link to your core switch an the edge switches daisy chained will be plenty. Assuming either a server to local documents and profile copy on logoff and logon or a my documents remap / mapped network drive.

 

If those machines will have heavier use ie compilers, video or sound editing you should probably think about either 10GB single fibre or put a few extra pairs into use for 1GB per switch.

 

It just comes down to how much data you really need to move back and forward over that link.

[SkreeM1980]

I would look at probably a 2gb backbone, use 2fibres to the new building into one 48port then 2x1g to each of the other 2 switches make sure the middle switch with the fibre is the hub for all three though to reduce bottle necks. you get the best of both worlds, resillient link(ish) and good performance. We have this setup over a much bigger system and no problems with the network traffic.

 

Skr

[flyinghaggis]

I would look at probably a 2gb backbone, use 2fibres to the new building into one 48port then 2x1g to each of the other 2 switches make sure the middle switch with the fibre is the hub for all three though to reduce bottle necks. you get the best of both worlds, resillient link(ish) and good performance. We have this setup over a much bigger system and no problems with the network traffic.

 

Skr

 

Cheers for the advice. As you suggest I think we'd probably want to run 2 1Gb fibre links back to our core switch and aggregate them. Do you have any whitepapers or best practice guides on how to setup stacks of switches using this method?

 

I've been checking out HP's website and I'm thinking that either on the options below might suit:-

 

1) Modular HP Procurve 4208vl (loaded with 6x24 ethernet modules and a 4 port firbre module for the uplink)

ProCurve 4208vl 96 Switch (J8775B) specifications - HP Small & Medium Business products

 

OR

 

2) 3 x HP Procurve 2610-48 in a stack (linked/stacked to each other with 1GB Ethernet modules and uplinked with a 1Gb Fibre module)

ProCurve 2610-48 Switch (J9088A) specifications - HP Small & Medium Business products

 

Is anyone on here using either of the above switches (4200vl or 2610)? Any recommondations on which setup is better (Modular vs Stackable) ?

[Geoff]

The modular solution will give you better interlink bandwidth, but practically it really doesn't matter.

[teejay]

Make sure the fibre being put in supports 10Gb as not all do. For that many PC's its not worth using 10Gb at the moment, but you may want to in the future and the cost difference is deligible.

[localzuk]

We use method 2 everywhere here. As we already have the fibre, and the cost of GBICs (£400 per fibre) isn't going to break the bank, I'd go down this route in your new building too.

[flyinghaggis]

Previously the stackable switches we've bought they've had dedicated hardware modules to stack them so they appeared and worked as a combined backplane. Most new switches now seem to utilise 'virtual stacking' so that they're connected via ethernet/fibre connections to each other. Is this different than simply 'daisy-chaining' several switches together in terms of the bandwidth it offers or does it have the same limitations? Do you have to designate one of the ports on the switch as a 'stacking' port or does it simply forward ethernet traffic?

 

I'm guessing that manufacturers wouldn't be implementing it if there were any serious performance drawbacks but on the face of it stacking over ethernet doesn't sound much better than daisy-chaining switches which we'd usually try and avoid

Edited February 26, 2009 by flyinghaggis

[plexer]

£400 for 2 gbics I presume? that's a bit expensive.

 

Ben

[localzuk]

£400 for 2 gbics I presume? that's a bit expensive.

 

Ben

 

Not really, HP J4858C Mini GBIC is around £200 (give or take £20).

[localzuk]

Previously the stackable switches we've bought they've had dedicated hardware modules to stack them so they appeared and worked as a combined backplane. Most new switches now seem to utilise 'virtual stacking' so that they're connected via ethernet/fibre connections to each other. Is this different than simply 'daisy-chaining' several switches together in terms of the bandwidth it offers or does it have the same limitations? Do you have to designate one of the ports on the switch as a 'stacking' port or does it simply forward ethernet traffic?

 

I'm guessing that manufacturers wouldn't be implementing it if there were any serious performance drawbacks but on the face of it stacking over ethernet doesn't sound much better than daisy-chaining switches which we'd usually try and avoid

 

As far as I know, a virtual stack is one used administratively. For example the HP range of 2600's use virtual stacks. This simply means you can connect to them all via one address and manage them as one.

 

The actual joining them together is up to you, either daisy chaining or going full 'star' and connecting them all back to a core.

 

But then, that is based on HP tech. I have no idea what people like 3Com do.

[flyinghaggis]

As far as I know, a virtual stack is one used administratively. For example the HP range of 2600's use virtual stacks. This simply means you can connect to them all via one address and manage them as one.

 

The actual joining them together is up to you, either daisy chaining or going full 'star' and connecting them all back to a core.

 

But then, that is based on HP tech. I have no idea what people like 3Com do.

 

Cheers for the info. Just been checking HP's site and like you say the HP 'stacking' appears to be purely there for ease of management rather than performance/resiliency.

 

On 3com's you have 2 gigabit ethernet ports on the front of each switch that you can enable as 'XRN ports'. You then daisy chain each switch together using these ports and plug the right port of the last switch in the the stack into the left port of the first switch to form a looped network. This then presents the stack as a single unit and all of the comms between switches is passed around this loop to improve the bandwidth and allow for resiliency if an individual switch in the stack fails.

[john]

On 3com's you have 2 gigabit ethernet ports on the front of each switch that you can enable as 'XRN ports'. You then daisy chain each switch together using these ports and plug the right port of the last switch in the the stack into the left port of the first switch to form a looped network. This then presents the stack as a single unit and all of the comms between switches is passed around this loop to improve the bandwidth and allow for resiliency if an individual switch in the stack fails.

Just to chip in a lot of the new Netgear Switches work this way with the stacking ports, loop them into each other on the Stack Ports (make sure you are using the stack ports and they are set up for stacking!) and then loop the last to the first and then it makes it all into a nice loop so if one switch goes down in the stack it will then go back the other way and still keep the data flowing to the rest of them

[flyinghaggis]

Seems kind of odd that HP don't have any kind of stacking methodology like 3com/netgear to improve performance and add resiliency? Appears that you want the above you're forced to run a dedicated fibre (potentially a pair for resiliency) to each individual switch or go with a modular solution?

 

Unless there's some kind of cunning way of "cross-wiring" the HP switches using link aggregation/spanning tree that I've not thought of

[SkreeM1980]

Seems kind of odd that HP don't have any kind of stacking methodology like 3com/netgear to improve performance and add resiliency? Appears that you want the above you're forced to run a dedicated fibre (potentially a pair for resiliency) to each individual switch or go with a modular solution?

 

Unless there's some kind of cunning way of "cross-wiring" the HP switches using link aggregation/spanning tree that I've not thought of

 

If you look at the 2900 series they have 2x X4 ports on the back and come with short stacking cables giving you a 10Gb backbone with 1Gb to desktop, you can also use cx4 to link to the core but i also thing there is a 10gb fibre connection available.

 

We have 2610's 2810's 2600's and 2900's all in use and all great switches we also have a 5012 core switch

 

Skr

[plexer]

Not really, HP J4858C Mini GBIC is around £200 (give or take £20).

 

These were priced at £130 by CP last week will have gone up now due to HP's price increases I expect.

 

Ben

[localzuk]

These were priced at £130 by CP last week will have gone up now due to HP's price increases I expect.

 

Ben

 

The OEM ones, yes, not the retail ones. I bought some from CP just before the holiday.

[flyinghaggis]

If you look at the 2900 series they have 2x X4 ports on the back and come with short stacking cables giving you a 10Gb backbone with 1Gb to desktop, you can also use cx4 to link to the core but i also thing there is a 10gb fibre connection available.

 

We have 2610's 2810's 2600's and 2900's all in use and all great switches we also have a 5012 core switch

 

Skr

 

10Gb would certianly provide enough bandwidth (and probably near enough backplane speeds anyway) but when HP say "stack" is it actually a resilient stack or is it just a daisy-chain networked "virtual stack" unit for management?