Need Help from Admin

Hello Chris,
TOday i gotta question for you as usual. The question goes like this....
Let's say i have to network 300 nodes with 2 DCs in them.
-2DCs with windows 2000 Adv Server
-298 nodes with windows 2000 professional
which will be located in 3 flats in a building. Using a DHCP server.
If u have to network this, i would like to know how would u approach for best network performance. I m asking this because in future i may have to do it. Plzzzzz Admin give me clear idea on this question. HOpe to receive your reply soon. See ya

Sussan,

Just a friendly reminder not to please post questions directly to me. This is because other people might be able to help and choose not to simply cause the question is directed to an individual. Also, what I consider as a great solution might not be seen the same way from another professional - people's opinion vary, and we need to also keep that in mind [img]images/smiles/icon_smile.gif[/img]

Coming to your question, well I thought about how I would implement such a network. There are though some key factors which one would need to know in order to be sure that the solution we/she would propose, will be able to completely satisfy the company's needs and future growth.

Without having all the information I would like, this is what I would suggest:

We have a network with 300 users and two servers spread amongst 3 floors.

I would place the servers in the floor that would use them most (e.g if we had a team that would constantly read/write to the server disk, I'd place them on the same floor). This is also subject to the available space and security.

I would have three manageable switches e.g Cisco, one on each floor, connected between each other with 2 fibre optic links OR ethernet Gigabit, of which one would be redundant. The switches between them would run STP (spanning tree protocol) to make sure you dont get broadcast loops created and I would also implement VLANS on each floor.

The Vlans would be designed depending on the various departments on each floor and if required, I would use VPN trunking on the switches in order to allow pc's from one floor to be in the same VLAN with PC's from the other floors. A simple example would be having a technical support group on each floor, I would want them to be part of the same VLAN.

If I decided that the server was to be put on the 2nd floor, then I would run two fibre or gigabit links from that switch to the servers - increasing the available bandwidth.

At the same time, the servers would run on scsi drives, minimising the chance of having the hard drive subsystem becoming the bottleneck of the network.

Lastly, you would need to have a few more switches running off the main switch of each floor. These 'smaller' switches would need to also support STP and VLANS.

Quick summary:

Floor3

---

switch/switches----pc's
Switch
|
|2x gig
|link
|
|Floor2

---

switch/switches--- pc's
switch=============== Servers
| 2x 1Gig link
|2xGig
|link
|
Floor 1
Switch

---

switch/switches---pc's


Thats that I recon will do the job fine [img]images/smiles/icon_smile.gif[/img]

Let me know what you think.

Cheers,

Chris,
Thank you for your kind co-operation and hope to recieve in near future also. Regarding ur answer to my question , i found it confusing, specially about STP & VPN Trunking ( NO idea what it does). Could u be more clear about these topics admin. Thank you for u r kind response to my question.

Sussane,

I've been told that I do have the talent of confusing people.... you must forgive me for it [img]images/smiles/icon_smile.gif[/img]

Let me give you some details on STP and VPN trunking.

STP - Spanning Tree Protocol
is mostly used between switches that have redundant links.
For example,

PC1----Switch1=======Switch2----PC2

In this diagram, each pc is connected to a switch, but the two switches are connected between each other using 2 links (. These two links are to provide redundancy, so if one link fails (e.g. the cable gets accidently cut) the other link will continue to pass the packets between the two switches.

The problem that now arises is that loops are created when using redundant links. Let's say PC1 sends a broadcast to switch1. Switch1 will then send this broadcast to all ports, including the two links it has to Switch2: (ignore the dots, they exist to maintain the formatting)

.............(link1)
PC1---Switch1---->---Switch2
......Switch1---->---Switch2
.............(link2)

Now Switch2 received 2 broadcasts... one from the top link and one from the bottom one. Switch2 now must send these broadcasts out all ports. So the broadcast that came from the top link, named link1, goes out through link2 - on its way back the switch1 and the broadcast that came from link2, now goes out from link1 - on its way to switch1.

So what is happening here is that a broadcast will be send from one switch to another, constantly, chewing up the bandwidth and creating problems. This is where the STP protocol comes in.
This 'smart' protocol understands that there are two links between the switches and automatically blocks a port from receiving data:

switch1--<->---switch2
switch1

---

Xswitch2

As you can see, the bottom link has been disabled on switch2. This will now prevent the loop that we just described!

That was crash course 101 on STP [img]images/smiles/icon_smile.gif[/img]

Now for VLAN Trunking.
Let's first explain what a VLAN is.
VLAN is a way to create isolated networks without using a router.

Lets say you need two networks which are isolated an no traffic is sent from one to another, then you would use a router in most cases:

Network1

---

router----Network2

Only packets you want/define at the router will be allowed to transit from one network to another.

A VLAN has sort of the same effect. You basically tell the switch which ports of the switch will be part of the same VLAN. Each VLAN is treated like an isolated network:

|

---

|
| p1 p2 p3 p4 p5 p6 p7 p8 |
| v1 v1 v1 v1 v2 v2 v2 v2 |
|

---

|

In the ***y switch above (gosh I'm good at diagrams [img]images/smiles/icon_smile.gif[/img] ) I've drawn 8 ports , that is, p1 to p8. I've told the switch that p1 to p4 will be part of VLAN1 while port 5 to port 8 will be part of VLAN2.

This means that the switch has now two isolated networks. Computers on VLAN1 cannot talk to computers in VLAN2. Of course, you would also have different network addresses for each VLAN. You should also know that and broadcasts created in one VLAN are NOT sent to the other VLAN, even if they are on the same switch, they are TOTALY isolated, which means you need some type of router to allow communications between the two VLANS.

Now, to get to VLAN Trunking....

As the years passed, the networks grew and it was time to add more pc's to the VLANs we created, so we decided we needed to double the capacity by buying another switch.

In order for this to work, we need to connect the two switched between each other:

switch1

---

switch2

We assigned a few ports from switch2 to VLAN1 and a few to VLAN2, allowing more workstations to become part of the existing networks.

Because now the VLANS are spread over two switches, these switches need to communicate between each other so they can send the packets to the correct VLANs, and this is where the work 'Trunking' comes in.

The two switches will run a special protocol which is called VTP - Virtual Trunking Protocol. This protocol adds extra information on the packets, allowing the switches to identify which VLAN the packets show be sent to. This 'extra' information is stripped off the packets before it exits the destination port.

That pretty much completes the crash course 101 on VLANS [img]images/smiles/icon_smile.gif[/img]

These two topics are on the wish list and should be covered sometime this year.

I hope that helps!

Cheers,

[ 01 July 2003: Message edited by: Admin ]