Network Design Advice

[avilt]

My current network setup is shown in the attached file which is not completely redundant.
As I am replacing the current EOL switches with new one (Cisco Catalyst 4500E for L3 and Cisco WS-C2960S for L2) I would like to make it most efficient and redundant. Appreciate some advice and URL link for technical information.

[Mahesh Gohil]

Hi Avilt,

You may find many useful information from below URL of design guide

www.cisco.com/go/srnd

Regards

Mahesh

[Jon Marshall · Accepted solution]

avilt wrote:
My current network setup is shown in the attached file which is not completely redundant. 
As I am replacing the current EOL switches with new one (Cisco Catalyst 4500E for L3 and Cisco WS-C2960S for L2) I would like to make it most efficient and redundant. Appreciate some advice and URL link for technical information.

It depends on how many fibers you have from each floor to the central 4500 switches.

Most efficient and most redudant would be to uplink easch 2960S switch to both 4500 switches. If you don't have enough fibers then you should at least conect each switch stack on each floor to both 4500 switches.

Whichever way you do it from above if the 4500 switches are inteconnected with a L2 trunk then you have a L2 loop in your network. This is fine as STP (make sure to run Rapid-PVST+) will block one of the uplinks. You can "load-balance" the vlans across the uplinks from each 2960S or 2960S stack by having 4500_1 as STP root for odd vlans and 4500_2 STP root for even vlans. If you do this make sure your HSRP active gateways match the STP roots ie. 4500_1 is HSRP active for odd vlans and 4500_2 is STP active for even vlans.

An alternative solution is to run the link between the 2 4500 switches as a L3 link which means there is no L2 loop and so you can use both uplinks for forward traffic for the same vlan. Having a L3 interconnect does need extra planning though as it affects how traffic is advertised and received on the 4500 switches.

Jon

[avilt]

Thank You for the feedback. Is there any example/scenario with config details on the Cisco web site? It will be very much appreciated. I can buy enough fibre links.

[esomarriba]

What's the hardware you are going to use? Do you want the Access Layer to be fully redundant? Are you planning to run L2 or L3 on the AL?

[Leo Laohoo]

+5 Jon!

[Leo Laohoo]

Cisco Catalyst 4500E for L3 and Cisco WS-C2960S for L2

What supervisor engine for the 4500E and what particular "flavour" of the 2960S?   Another question about the 2960S is how many are there in a stack?  The 2960S will only support up to 4 2960S in a stack.

If your 2960S is the "D" sub-series it means it will have 2 SFP+ 10Gb interface (or 2 SFP 1Gb).  If this is so, then I don't recommend using the 4500E unless you use the new Sup7E.

If you have enough funds then consider a 6500E with the soon-to-be-released Sup2T (start reading from page 18).  If you are planning for the Sup2T option, then consider holding off your purchase until 3^rd quarter of 2011.

[avilt]

Hello,

L3 Switch:
WS-X45-SUP6L-E, Catalyst4500 E-Series Sup 6-E Lite 2x1 OGE(X2) w/ Twin Gig

L2 Switch:
WS-C2960S-48LPS-L

I haven't bought the devices yet but I have to place the order by December 2010 because of budgetory reasons.

I have 2 fibre lines from each floor to the L3 switch.

On each floor we will have 3 L2 switches for cascade.(Please check the attachment in my first topic)

I need a network design which is simple to manage, efficient and redundant.

[avilt]

Also can I use only one L3 switch and still provide redundancy to L2  switches by connecting 2 fibre link from each cascade to the same L3  switch?

[Jon Marshall]

avilt wrote:
Also can I use only one L3 switch and still provide redundancy to L2  switches by connecting 2 fibre link from each cascade to the same L3  switch?

You could and the uplink could be an etherchannel so you would use all the links but you are only providing redundancy if one of the links fails. You would also need to ensure from each access switch the uplinks were spread across the linecards on the 4500 in case a single linecard goes.

If you are using the 4507Eor 4510E chassis then you could have dual power supplies and dual supervisors and if you spread the uplink as suggested per access-layer switch then you have protection against -

1) failure of power supply in 4500 (providing your are running redundant mode power)

2) failure of an individual linecard in the 4500 chassis - note this means you need at least 2 physical links in the etherchannel uplink from each access switch and as i said these physical links are spread across the 4500 linecards

3) failure of a supervisor in the 4500 chassis

However it does not protect you against failure of the 4500 chassis and personally i would always have 2 layer 3 switches to connect the access-layer switches to. It is a standard and well tested design.

Jon

[avilt]

Thank You Jon.

We have decided to go for 2 L3 switches. Do you have any link/url for implementing such designs?

As far as I know we need 2 "GLC-SX-MM"  cables for each side of the L2 switch 48 ports on Floor-1, Floor-2 and Floor-3.(Total 6 cables)

How do I connect 2 L3 switches?

I am currently using Cat 4006 switch which has got both CatOS on Sup-II and IOS on L3 routing module.

What's the OS on Catalyst 4500E? Is routing also managed by supervisor engine itself? I could not find separate L3 module for 4500E series switch.

Thank You