Solved

cisco switch stacking

Posted on 2016-11-11
6
65 Views
Last Modified: 2016-11-14
How does redundancy/failover work in stacked switches? If I have a router with an uplink to master that has 4 more switches, if that master fails , how do the other 4  switches know how to get to the router since I dont have a link going to the router directly  from all the switches but only master? Or, do I need ethernet links from all switches to the router?
0
Comment
Question by:Shark Attack
  • 4
  • 2
6 Comments
 
LVL 28

Expert Comment

by:Predrag Jovic
ID: 41884423
You need at least two uplinks from 2 different switches in a stack to neighboring (upstream/downstream) device(s). Available uplink connection will be used (in the case that device with previously active uplink is not available). Also, it is recommended to use LACP for interconnection to the same neighboring device (if multiple links to the that devices are available).

Cisco Catalyst 3850 Series Switches StackWise-480 Architecture White Paper

According to configuration upstream devices are configured as VSS or vPC.
In the case that you have 2 uplinks to one device configuration is basically the same, except that less ports should be configured.
With 2 uplinks to two devices there would be no LACP configuration.
With 4 uplinks to 2 switches that are not configured as VSS or vPC there should be 2 channel groups (one channel-group to each upstream device).
0
 
LVL 3

Author Comment

by:Shark Attack
ID: 41886421
would the attached set up be OK? ESW1-5 is 1 stack and then ESW6-8 is second stack. Both stacks are on different floors. There are ether-channel links uplinks.

Untitled.png
0
 
LVL 28

Accepted Solution

by:
Predrag Jovic earned 500 total points
ID: 41886486
You can do it that way, but you can also do it this way.
stackLet's say that on stack on the left all interfaces connected to core are 1/0/49, 2/0/49, 4/0/49, 5/0/49
interface po1
 switchport mode trunk
!
interface range Gi1/0/49, Gi2/0/49, Gi4/0/49, Gi5/0/49
 switchport mode trunk
 channel-group 1 mode passive

Open in new window

Core configuration for left stack
interface po1
 switchport mode trunk
!
interface range Gi1/0/1 - 4
 switchport mode trunk
 channel-group 1 mode active

Open in new window


The same goes for stack on the right side (except that you have one port 50 there) :)
interface po2
 switchport mode trunk
!
interface range Gi1/0/49, Gi2/0/49, Gi3/0/49 - 50
 switchport mode trunk
 channel-group 2 mode passive

Open in new window

Core
interface po2
 switchport mode trunk
!
interface range Gi1/0/20 - 23
 switchport mode trunk
 channel-group 2 mode active

Open in new window

0
How our DevOps Teams Maximize Uptime

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us. Read the use case whitepaper.

 
LVL 28

Expert Comment

by:Predrag Jovic
ID: 41886523
This way the only difference is the number of uplinks that will be available if some device(s) quit. :)
0
 
LVL 3

Author Closing Comment

by:Shark Attack
ID: 41886535
Thanks!
0
 
LVL 28

Expert Comment

by:Predrag Jovic
ID: 41886538
You are welcome.
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Exchange server is not supported in any cloud-hosted platform (other than Azure with Azure Premium Storage).
Many of the companies I’ve worked with have embraced cloud solutions due to their desire to “get out of the datacenter business.” The ability to achieve better security and availability, and the speed with which they are able to deploy, is far grea…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

679 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question