Core Switch Failover

[us2001irvine]

This is a reposting from an old thread because the problem statement has been re-defined and I would like to start a new thread for advice.

I need to re-define the problem statement as I get more info for the project: I have a network spreading on two floors in a building. Each floor has a Cisco Catalyst 3508 8-port fiber core switch connecting each sub-switch. The problem or risk for this design is that if the core switch is down then that floor network will be down and if the core switch in the server room which is connecting the other floor is down, then both the two floors network will be down. So, I would like to provide link redudancy at core switch level.

Right now I run Cisco 3508 8-port fiber switch as core switch. I would like to have 3550 10-port fiber switch or higher for the failover. Can anyone give some comments on this in terms of hardware requirements and setup configurations. (I need to use fiber to connect the core switch in the server room to the other floor for both main and failover core switches. There is one thing that I am not sure is that how to connect the two core switches on the same floor. Do we use crossover cable to hook it up like what I do for Cisco PIX 525?)



Fiber connect
Floor_1 (server room) ----> Floor_2 (Core SW)
Floor_1 (server room) ----> Floor_2 (Failover SW)

SW1(failover)--SW1(main) ------> SW2(main)--SW2(failover)
| Cross connect? | | Cross connect? |
| | | |
| | | |
sub_sw sub_sw sub_sw sub-sw



Thanks a lot

 

[lui3]

if your core switches are configured for layer 3 failover via hrsp then yes you can use a cross connect. other wise if they are layer 2 switches then you will want to leave the cross connect out or set the cross connect port cost on both sides to something really high like 500 so that it never becomes a root port. i would just not use the cross connect with a layer 2 core. check out the CCDP/CCDA material for more information on core network design. the cisco internetwork design document is a great source for core designs as well.

 

[lui3]

here is the link to the design guide. happy reading

http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/index.htm

 

[us2001irvine]

Thank you Lui3.

1. I intend to use 3750 instead of 3550, because 3750 is designed for the next 5 year technology while 3550 is almost out of stock now.

2. When using 3750, how to connect 2 core fiber switch to make it failover. Do we use 2 fiber ports to connect or do we use stackwise interconnect?

3. How to connect two floors' core fiber switch as failover. I have connect two floors with fiber. Do I need to have another pair of fiber line to connect the failover switch between the two floors?

4. Where to get best quote for the equipment and service? And how much will four 3750 cost?

Thanks so much.

 

[congogrey]

I guess I am a little lost. Are you dual homing all of your hosts? If not what is the point of having two switches on each floor since the hosts can only be on one switch at a time?

Also, is this the access layer switches (in the Cisco Layered model) or are you just trying to connect three switches together?

"For every complex problem, there is a solution that is simple, neat and wrong" -- H.L. Mencken

 

[us2001irvine]

Thank you Congogrey.

My network spreads across two floors in a building. The line comes into the server room in upper floor and the network core switch in upper floor connects to fiber core switch in lower floor.

So, there are two points of failover: one is the core switches itself for each floor and the other one is fiber connection between the two floors. I am not quite sure how to make this failover work at core switch level and between the two floors in this senario.

Thanks.