Cisco Stackwise

Unanswered Question
Sep 25th, 2008

Hi All,

I am planning to upgrade my Cisco Distribution switches using Cisco 3750E switches using stackwise technology

Cost is the major consideration for us. So we are thinking of buying Dell Switches for the Access Layer, will there be a problem in integrating Dell Switches to the 3750 E L3 Distribution core (Will VLANs and STP interoperate together between two vendors, have anyone tried this)

What is the maximum length of the stack cable. My distribution closet is in two floors. Will it be possible for me to add two switches in one floor and two more in the other and maintain a single stack using a lenghty stack cable

Please let me know



I have this problem too.
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nate-miller Thu, 09/25/2008 - 08:06

You will be able to create trunks and vlans between the Cisco and the Dells, provided that the Dell's support 802.1q trunking. (ie, an unmanaged dell, you probably won't be able to create a trunk.) Spanning tree should work, but you may be restricted as to the flavor you can run. It depends upon what the Dell supports.

The maximum length of the stack cable is 3M, so you can't use the stackwise as an inter-closet connection.

csaravanan Thu, 09/25/2008 - 08:11

Hello Nate,

Thanks for the reply.

So how do I interconnect two stackes in inter-closet. Do I need to run an fiber channel between the stacks

Also how can we achieve high availablity between these two stacks



nate-miller Thu, 09/25/2008 - 08:59

Port channel between the stacks would probably be the easiest way to do it, and since you're talking about trunking, it sounds like the only way to do it.

You could introduce a set of independent routed uplinks between the closets, but it might be a big network design shift from your current state. If you're comfortable with 802.1q trunking, I would jsut create a port channel from closet 1 to closet 2.

I would make sure that members of the port channel are on the two differnet stack members.

Closet 1, 1/0/49 -> closet 2 1/0/49

Closet 1 2/0/49 -> closet 2 2/0/49

This way if you lose a single connection or a single switch, the rest of the network keeps on chugging.

As for the rest of the HA- where is the routing for the VLANs happening?

How do the distribution switches connect to the core?

GLBP or HSRP for any VLAN that is routed natively on the cores. You'll need connections from each closet to your core, and how that connection is managed (via a single trunked VLAN from distribution to core, or routed uplinks) depends upon your current design.

csaravanan Thu, 09/25/2008 - 10:23

Hi Nate,

I am not planning to have an Core Layer.

I am going to connect my Router and Firewall directly to Cisco Stack (My Distribution ) hence worried about HA between closets

I believe there are no other options availaible except for port channel between two stacks.

The routing for VLANs will happen in the stack layer switches itself

Let me know if I am missing something


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