Switch stack vs Chassis

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May 1st, 2007

Does anyone know of a good document explaining the pros and cons of using a switch stack and a chassis?

Thanks

I have this problem too.
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sguirguis Fri, 07/22/2011 - 07:54

I would love to find that too.

A few of points IMHO

  • Budget decision, chassis usually more expensive.
  • Chassis a better option depending on your network groth needs.
  • I ve heard Chassis, less power consumption.



Sami

Joseph W. Doherty Fri, 07/22/2011 - 10:58

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I haven't seen such a document, however to build and add to Sami's comments:

Stackable switches usually cost more that "equivalent" chassis line cards.  The overall cost for a small stack, though, is often less than "equivalent" chassis due to the cost of chassis components beyond just the line cards, especially the supervisor card(s).  The overall cost for large stack can be more expensive than an "equivalent" chassis.

Chassis devices may offer much, much better performance if line cards are interconnected by a fabric.

Chassis devices, often being "premier" devices, may offer software and/or hardware features unavailable on a stack.

Stackable devices often make it easier to resize or redeploy their component devices.

Chassis often had more flexible power options, and could be a little more efficient, but later high end stackables, e.g. 3750X series, have offset this difference with their modular power supplies and stackable power.

Chassis often having longer service usage histories, might be more stable/dependable.

On-going licensing and support contracts may be less expensive than for a chassis.

Personally, I believe stackable devices are often suitable as network access edge devices.  For core and/or distribution devices, I lean toward chassis devices.

Kuldeep singh Tue, 02/05/2013 - 12:39

Hello Experts,

What is main difference between switch stack and a chassis switch?

1. both are same or different ?

2. where we can use both ?

3. Both provide redundancy or not ?

4, plz explain with good practical example.

KS

Leo Laohoo Tue, 02/05/2013 - 13:30

What is main difference between switch stack and a chassis switch?

1. both are same or different ?

4500 and 6500 (chassis)

2960S, 3750, 3850 (switch stack)

However, there's a "hybrid" called VSS.  This is when you "stack" a chassis, like a pair of 4500R+E or a pair of 4500X or a pair of 6500E, together to form a single logical switch.

1. both are same or different ?

Physically?  No they are not.  Function-wise?  A stack- or a chassis-based system are the same.

2. where we can use both ?

This will all depend entirely on your budget and your environment.

3. Both provide redundancy or not ?

If done correctly, yes.  Out from the box, you have power redundancy.  If you have two or more Etherchannels back up/downstream then you have link redundancy.  Particularly for the chassis based system (with or without VSS), if you have dual supervisor cards, then you have redundancy too.

Leo Laohoo Wed, 02/06/2013 - 13:37

Forgot the Nexus 2K FEX in the mix.  This is another "hybrid" form of  a "chassis".

Kuldeep singh Fri, 02/22/2013 - 07:27

Thanks leolaohoo for reply,

I have some confusion about Switch stacking :

1. Suppose in LAN, one PC with one NIC is connected to Switch Stacking Environment.

    If bad luck that connected port or whole switch goes down in stacking then

    How the PC will connect to remaining Switchs. How it is possible ?

    I am unable to understand here ?

2.  We know that Benefit of Stacking is “Instead of logging into each switch we can

     configure each member of the switch on one switch but I know only login process

    of single switch like as “Telnet 192.168.1.2”, I do not know about login process in

    Switch stacking plz explain with simple example.For example,I have 5 switchs

    i.e SW1, SW2, SW3, SW4, SW5 then how can I login all these through single ip ?

KS

prakadeesh Fri, 02/22/2013 - 08:08

Hi Kuldeep,

1. Say for example you have a 3 stack switch. Let us assume that switch1 is master and the rest are slaves. One of the user is connected to port number 1 of the first switch(master) does down. Now usually the second switch will become the master, but that depends on the configurations. The failed switch is out of the stack and so are the users.So your option is to migrate the physical connections from the failed switch to any other switch port in the stack or to get the failed switch back on the stack. A stack is only bundling  the switches together, if a switch has failed the users will not be automatically migrated to another, you have to move them physically.

2. when you stack the switches together all you are doing is logically bundling them togther. So the entire stack is managed by one IP. So one you have telnet/SSH to the IP you have 4 hardware switches available. A show switch will give you the details of the switches in the stack and the platfrom manger commands too. So you have fa1/0/1-48, fa2/0/1-48,fa3/0/1-48 etc. So if the master (first) switch fails the IP will just migrate to the next master (based on configs). Now you will see only fa2/0/1-48 and 3/0/1-48 etc.

HTH

Kuldeep singh Fri, 02/22/2013 - 21:20

Hello Prakadeesh & Leo,

Thanks for reply

1. You mean to say, i will need to do it manually ( unplug cable from faulty switchport

    and plug into any remaining switch working port)  then what is advantages of Stacking ?

2. Currently i have 5 cisco 3560 switch and it uses port numbers like as g0/1 - g0/48 then

    what its port will show after stacking ?  As per your suggestion, after done 3560 switchs

   stacking, Switch1 will represent ports with 1/0/1 -g1/0/24, Switch2 will represent ports

   with g2/0/1 - g2/0/24 and so on.  Am i right or wrong ?

KS

Leo Laohoo Fri, 02/22/2013 - 21:32

1. Suppose in LAN, one PC with one NIC is connected to Switch Stacking Environment.

If bad luck that connected port or whole switch goes down in stacking then

How the PC will connect to remaining Switchs. How it is possible ?

I am unable to understand here ?

You need "human intervention".  Someone needs to move the PC's connection from the faulty switch to the other switch.  But let's say you have a client with dual NICs and each NIC is connected to a stack of two switches in an etherchannel.  So when the first switch dies, then nothing happens.  The client will still be able to connect to the network via the second link.

2. Currently i have 5 cisco 3560 switch and it uses port numbers like as g0/1 - g0/48 then what its port will show after stacking ?  As per your suggestion, after done 3560 switchs stacking, Switch1 will represent ports with 1/0/1 -g1/0/24, Switch2 will represent ports with g2/0/1 - g2/0/24 and so on.  Am i right or wrong ?

3560 switches won't do stacking.  And I'm not talking about switch clustering.

If you are talking about 2960S or 3750, then the interface number of "interface A/B/C":  A means switch number, B means special module (you won't see this number change until you start using 3750X or VSS), C means interface number.

2.  We know that Benefit of Stacking is “Instead of logging into each switch we can configure each member of the switch on one switch but I know only login process of single switch like as “Telnet 192.168.1.2”, I do not know about login process in Switch stacking plz explain with simple example.For example,I have 5 switchs i.e SW1, SW2, SW3, SW4, SW5 then how can I login all these through single ip ?

Take your mind of switch clustering.  This archaic and quaint has been superseded by switch stacking.

So you have, say, a stack of 2960S or a stack of 3750.  You give the entire stack one single management address.  This is how you remote into the switch.  You treat the entire stack as a large logical switch. 

Kuldeep singh Fri, 02/22/2013 - 21:48

Hello leo,

1.  as you said that I need to put 2 NIC card into single PC and

     both NIC will connect to each individual switch in stack, But

     we can perform this without Stacking ( Suppose i have 5 3750 switchs

     in my LAN without any stacking then i can connect single PC (two NIC)

     into any two seperate switchs) then why we need to configure stacking,

     as per my understanding it's only use for centralized management

     through single ip.....

2.  This is clear to me .....Thanks

3.  Plz provide me documents or PDF for " configure Stack with cisco 3750 switchs"

KS

Leo Laohoo Fri, 02/22/2013 - 22:01
1.  as you said that I need to put 2 NIC card into single PC and both NIC will connect to each individual switch in stack, But we can perform this without Stacking ( Suppose i have 5 3750 switchs in my LAN without any stacking then i can connect single PC (two NIC) into any two seperate switchs) then why we need to configure stacking,as per my understanding it's only use for centralized management through single ip.....

Centralized management ain't the only selling point of switch stacking.  Configure, say, one port per switch into an etherchannel and connect them to a client with dual NIC and configure that client with NIC teaming.  You won't get that with an individual switch.  If that individual switch does then your client is useless.  If you have two switches in a stack and you configure one port per switch as an etherchannel.  Then one of the member of the switch stack dies, then your client is still able to move traffic.

Kuldeep singh Fri, 02/22/2013 - 22:17

Hello Leo,

I want to ask some basic things which is related to stacking

1. Suppose i have PC with two NIC card then what will be the ip address

    of both NIC,

    Same

    Nic1 = 192.168.10.5

    Nic2 = 192.168.10.5

             OR

    Different

    Nic1 = 192.168.10.5

    Nic2 = 192.168.10.8

2.  single PC with two NIC is connected to two switchs in stack but

     only one will work at a time and second will work after first failure.

     how can we configure this failover , is there any configuration required

     plz tell me config....

KS 

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