Noobie VLAN/routing questions - sorry

[mpalmer999]

Hi, have worked in IT for 20 years but never really had to deal with Cisco routers before, all my work has been in small business environments, fairly simplistic really.

Now i have a problem. Just looking for some overview answers at this point, any advice would me much appreciated.

I need to set up a site for max 200 users, however for reasons i wont bore you with there will be multiple VLANS required.

If i install 4 * 48 port layer 2 cisco switches (no idea of model....) i can configure the VLANS, got that, doesnt sound too hard. There will be no need to route between the VLANS.

However i will need to provide the clients with IP via DHCP.

So presumably i set up a VTP domain and configure all the VLANS from one switch. then i configure a trunk on one of the ports of one switch (or 1 on each switch?) so that the DHCP requests get passed up to the router. Presumably i can then configure DHCP on a cisco router to provide IP addesses to some or all of the VLANS? (some VLANS may end up with their own servers so won't need DHCP)

i admit i'm fumbling around in the dark here so if someone could tell me what is wrong in simple terms with the above that would be a great start.

thanks a lot guys, i owe everyone beers

 

[VinceWhirlwind]

How are the switches connecting to the router? Does the router have a spare interface for each?

I suspect not. Perhaps one switch will uplink to the router and the others will daisy-chain from it?

So, each switch will have a trunk back to the "core switch", then that switch will have a trunk up to the router.
When you create the trunk on the router, you will have created the routed interfaces for each subnet - you then need to configure a DHCP scope for each interface.

 

[mpalmer999]

all the cat5 runs back to the computer room so i was planning on having all the switches there, daisy chained with a trunk connection to the router. presume that makes sense?

anyone got any thoughts on whether i should assign each vlan its own subnet? there is no need to router between subnets so it seems like an unnecessary complication to assign this, especially as there might but over 20 vlans.

also, if i were to use a cisco srw2048 (ie a small biz switch) instead of something more powerful will this do just as well? if the issue of getting dhcp to the client pc's is done at the router end presumably i just configure the vlans on whatever switch i like as long as its protocol compatible?

thanks a lot

oh btw, none of this needs to go live for a couple of months, am trying to get my head round it in plenty of time

 

[vipergg]

I would not daisychain them per se, make one switch the dist. switch and run all the switches to that switch then a trunk link into the router for routing those vlans . Router on a stick . Would help if you knew what model switches, a lot of them now are layer 3 switches. the only ones that are layer 2 are 2950's and 2960's at this point.

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configuration_example09186a00800949fd.shtml

 

[vipergg]

PS , if you have the router give out dhcp addresses then it is going to route bewteen those subnets, if that is a restriction of not routing between them then you get into a whole new ball of wax with setting up ACL's etc. to restrict traffic which makes it more complicated .

 

[mpalmer999]

ok thats some top info i would tell you what model switches but at this point i dont know. i'll have to recommened models shortly. thats why i asked about the small business ones because they seem a lot cheaper...

let me give you a better idea of what i'm trying to do.

basically the site is going to be for serviced offices. so some offices will just be standalone PC's, hence the dhcp, presumably some will have a server in the office, others...well, who knows at this point.

for obvious reasons i want to keep the network traffic from each office sep from other offices. i dont want people being able to go into net neighbourhood or whatever and being able to see other machines. which presumably coz they are on a vlan they wouldnt be able to do as that will restrict broadcase traffic. that was the reason for my question about different subets really, after all if broadcast traffic is restricted then pcs in one vlan cant see each other even if they are in the same subnet.

your comment about the router routing between tho throws a bit of a spanner in the works as i presume it will push the broadcase traffic out across all vlans?

aarrgh.

 

[VinceWhirlwind]

No, it will not push broadcast traffic across all VLANs, and if you want to restrict routing between the VLANs you just need to configure access lists on the router to block it from doing so.

If all your switches are in one place, then stackable switches could be a very good idea such as Cisco 3750s or Nortel 4500s/5500s with each office's connections separated by VLAN. This would reduce the total number of switches required and effectively reduce your management to simply 1 router + 1 switch.

Find our from your customer whether Gb connectivity is required - it really isn't necessary, but some people feel they have to offer it.

So, if they want Gb, you will need Cisco 2975GS-48/Nortel 4548GT.
If Gb and Layer3 - Cisco 3750G-48TS/Nortel 5510-48T.

I find the Cisco 3750 shockingly over-priced, but when the customer doesn't mind paying it's a great one to work with.
I haven't suggested Procurve because at this stage they don't offer a proper stackable switch, although that may change later this year.

 

[mpalmer999]

thanks for this, v useful Is it me or are they all really expensive? just looked at a price for a Nortel and £3.5k for one 48 port switch?? or am i going mad and thats a reasonable price?

hope everyone is having a nice new year

 

[VinceWhirlwind]

That's way more reasonable than Cisco...

 

[mpalmer999]

yeah i can see that. i seriously doubt i can justify 12k's worth of switches though. have you got any thoughts on the nortel 470 series? they can be picked up from around 2k from what i can see.

incidentally if you are london (or local) based and looking for some consultancy work....

 

[vipergg]

Isn't Nortel in bankruptcy ? I would think that over , maybe look at HP switches if price is an issue.

 

[VinceWhirlwind]

I don't really see how Nortel's financial status is relevant to whether their hardware would do the job required, providing you get a stable firmware version. I'm not a huge fan of Nortel, but for some situations/requirements they would be the first choice.

If you want HP, you could go with a 5406/5412 (depending on how many ports you need). Their 1RU-sized switches are no good because they don't stack, which would make your ongoing management more complicated.

I wish I was in London - when I was living in Oxon, I would have gladly met to discuss, however I am now far away...

 

[mpalmer999]

well looking for example at the pro curve 2810 it says

Stacking capability: single IP address management for a virtual stack of up to 16 switches

so that should do the job right?

i have no real preference between hp/nortel etc other than cost and availability. from what i've seen it doesnt appear that easy to even get hold of the nortel ones...

have a look here and see what you think Vince

http://www.procurve.com/products/switches/HP_ProCurve_Switch_2810_Series/overview.htm

shame you're not round here any more, would gladly pay to get some help with this.

 

[unclerico]

With the ProCurves you need to look closely at the services that are offered as not every model offers the same thing. For example, the 2810 series does not support ACL's. Other series don't support spanning-tree, etc. ProCurves are great switches, they are very stable and just work. Of course you have the good price also which helps a lot.

I hate all Uppercase... I don't want my groups to seem angry at me all the time! =)
- ColdFlame (vbscript forum)

 

[mpalmer999]

ok thats very useful. frankly i'm wondering if i need to use acls or not. all i care about is no easy access between vlans/subnets. there's no broadcast traffic across the vlans and 98% of users aren't going to know about pinging across subnets etc, so not sure its a big issue.

that said, lets talk routers briefly. the plan is to put 1* 100mb line in, a small percentage of that is going to be dedicated for voip. other than that the rest will be mine to play with. i will def need to do a couple of specific things basically.

1) as above split the data/voip (std stuff)
2) allocate percentages of bandwidth to different offices. ie someone may pay for more than someone else.

so the question is, do i need acls to allocate that bandwidth? if not then its the pro-curve 2810 methinks!

thoughts? i owe you guys all beers btw.

 

[VinceWhirlwind]

Mpalmer - don't be misled - the HP's do not "stack"! They call it "stacking" but it's not. All it is is "single IP address management" and nothing else. It's useless.

My experience with HP's older models over the years was excellent except with the 4100 (attractive for its high port density) which suffered port and module failures.
More recently, I'm finding the 3500 dubious in terms of reliability on . I found the 5406 was a lot cheaper than the 3500 and offered better features.

Bandwidth allocation for the internet access would probably be done on your router, as each customer would have one interface on the router (the VLAN interface) but multiple ports on the switches.

 

[mpalmer999]

ah such a confusing world. so just to be clear, the one you're recommending is

1* HP ProCurve Switch 5412zl Intelligent Edge
(J8698A)

4 * HP ProCurve Switch 5406zl-48G Intelligent Edge
(J8699A)

is that right? ie you buy a chassis and then put the switches in it?

sorry for being so specific but i need to get this right first time

 

[VinceWhirlwind]

That's the one.
A 5406 for example, lets you put in 6 modules of either
24 copper ports (including PoE)
OR
20 copper ports & 4 SFP ports
OR
24 SFP ports
(and some others if you want 10Gb ports)

And it has two power supplies. The 5412 has 3 power supplies.

 

[mpalmer999]

nice one. ok, we're settled on the switches, woohoo!

right, lets talk routers.hopefully what i said above is clear enough on requirements. i would really prefer to use cisco for this if i can, they seem to be the std in this field.

any thoughts? also Vince, i appreciate you're not local any more but if you are interested i'm sure we could come to a deal on this. as long as i can get it connected to the internet then if you were interested in some work to config it then i'd gladly make it worth you're while.

dont want to break the terms of this forum so let me know if you're interested and we could take this conversation offline.

either way though, would be very interested in hearing peoples opinions on router recommendations