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Cisco 3750 installation and VLAN

We have a lan with 185 nodes on it. The netork diagram is attached.
We had standard switches but recently the network has been very slow. we have just acquired a lot of 4 cisco switches.
1 x 48 Port 3750G
3 x 24 Port 3759G
- I will like to install the switches to provide connectivity to the nodes on my lan. Further I will like to split my LAN into three VLANS so that I can reduce latency on the LAN.
I want to 3 Vlans for ( DIrectors , Finance and Rest of Staff )
I want to give priority to Directors and Finance on the LAN
I need everyone to still get IP address from the DHCP Server

I will like to use the following 172.15.234.0 / 255.255.252.0
How can I further split the subnets to get all of this working and get some stability on my dying lan ?
Can I configure VTP Server on one of the switches ? If Yes, how do I interconnect the switches on the various floors. Each switch has 4 gigabit ports in addition to the ethernet ports.
Kindly assist me with a complete configuration.


LAN.jpeg
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kediboy
Asked:
kediboy
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1 Solution
 
atlas_shudderedSr. Network EngineerCommented:
If I am understanding what you are asking correctly, the answer is yes to all.

1.  For VTP - determine your core device (consider configuring this device as both your VTP server, inter-vlan router/gateway and STP root-bridge).

2.  Utilizing the SFP ports on your switches - interconnect with fiber then configure the ports as trunks in an etherchannel config to increase through put up and down the switch stack.

This is the short answer, if interested in pursuing, I can post up more detail.
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kediboyAuthor Commented:
Hi Atlas,

This I am interested in pursuing. However note a few issues here :

1 - I don't have access to Fiber - How else can I interconnect the switches ?
2 - Yes the core device will be the 48 Port switch on the first floor.

3 - Can I use the 48 Port Switch as the Inter-VLAN router/Gateway and yet all nodes on my network getting IP's from the DHCP Server as illustrated on the diagram ?

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atlas_shudderedSr. Network EngineerCommented:
DHCP - When you set up your 48 port as your inter-vlan router, you will need to set up a DHCP helper address for your access vlans.

Fiber - you can use copper just as easily as fiber, same concepts different media.

Questions - how many floors to your facility? 3 or 4?
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kediboyAuthor Commented:
Actually 3 floors plus the basement.
There will be 4 switches as denoted on the network diagram.
By copper how do you mean ? Standard CAT6 ?
- there will be users of each VLAN on each of the floors, e.g there are 3 Directors on each floor.

Can you kindly offer me a step by step procedure from interconnecting the switches to cofiguring the VTP server on the 48 Port and configuring the other switches ?

With the distance involved, they cannot be stacked how do I configure the backbone ?
thanks
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atlas_shudderedSr. Network EngineerCommented:

kedi -
Okay With the 3750, you can use what you like 5/5e/6. I would use the highest speed cable you can afford.

To configure VTP

On server/core switch
conf t
vtp mode server
vtp domain XXXXXXXXX
vtp password XXXXXXX


On client switches
conf t
vtp mode client
vtp domain XXXXXXXXX
vtp password XXXXXXXX


Configuring routed switch port on core switch
conf t
int gig 0/x
no switchport
ip address ip address  netmask
ip route 0.0.0.0 0.0.0.0 next hop ip

Configuring vlans on core switch
conf t
vlan X1
description Directors
vlan X2
description Finance
vlan X3
description Staff
exit
interface vlan X1
ip address ip address  netmask
dhcp helper-address DHCP server ip
interface vlan X2
ip address ip address  netmask
dhcp helper-address DHCP server ip
interface vlan X3
ip address ip address  netmask
dhcp helper-address DHCP server ip
exit


Configuring VLANs and DHCP helper on access switches
conf t
interface vlan X1
ip address ip address  netmask
dhcp helper-address DHCP server ip
interface vlan X2
ip address ip address  netmask
dhcp helper-address DHCP server ip
interface vlan X3
ip address ip address  netmask
dhcp helper-address DHCP server ip
exit
default-gateway this should be the ip address of interface vlan 1/default vlan on core switch

Configure trunk ports
conf t
int range gig 0/x-xx
switchport trunk encap dot1q
sw mode trunk

Configure access ports
conf t
int range gig 0/x-xx
sw mode access
sw access vlan (appropriate vlan)
spanning-tree bpdu-guard enable
spanning-tree bpdu-filter enable
spanning-tree portfast


This is the information for the switch initial config
How many users per vlan do you have?  That will define how to spread your ip netspace.
Also - you can reference Cisco's 3750 config manual here:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_sec/configuration/guide/3750scg.html
 
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kediboyAuthor Commented:
ok,

I did before a config very similar to this and the vtp server has worked fine.
I want to assign the following IP's to the varios VLANS

Vlan 2 ip 172.15.10.2 255.255.255.192   ----->director vlan
vlan 3 ip 172.15.11.2 255.255.255.192   -----> finance vlan
vlan 4 ip 172.15.12.2 255.255.255.128   -----> staff vlan

the DHCP Server will have ip 172.15.10.1 255.255.0.0  and should serve all vlans.

I also wanto to provide interVlan routing.
thanks
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atlas_shudderedSr. Network EngineerCommented:
Think about this:

Use the IP scheme:

Vlan 2 ip 172.15.2.2 255.255.255.192   ----->director vlan
vlan 3 ip 172.15.3.2 255.255.255.192   -----> finance vlan
vlan 4 ip 172.15.4.2 255.255.255.128   -----> staff vlan

Matching your subnets to the expected vlan will make identification a little easier.

The DHCP server address needs to be placed in the field noted in the config at the command:

dhcp helper-address DHCP server ip

in the section:

Configuring VLANs and DHCP helper on access switches

For inter-vlan routing, setup the routed interface as noted above in the sections:

Configuring routed switch port on core switch
Configuring vlans on core switch
Configuring VLANs and DHCP helper on access switches

After the routed interface is set up and trunking established - the default-gateway command on the access switches will enable your inter-vlan routing.
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atlas_shudderedSr. Network EngineerCommented:
For serving DHCP to multiple scopes/vlans reference:
http://tcpmag.com/qanda/article.asp?editorialsid=336
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kediboyAuthor Commented:
Yes it was has worked for me.
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