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Contributor
Posts: 65
Registered: ‎08-22-2008
Accepted Solution

Trunking with 3 switches

Hi

I'm sure this has been asked in past but I have not found the exect question.

 

we have 3 40 8GB sna switches (FOS 7.4.2a. All 3 units have trunking licenses.

 

So I'm looking for the best way to trunk these all together .

 

Is this a viable option

 

switch 1 port35 ---> switch 2 port35

switch 2 port38 ---> switch 3 port35

switch 3 port38 ---> switch 1 port38

 

so 6 ports across 3 switches each switch having a 32GB trunk

 

Or is there a more efficient way to trunk the 3 units together ?

 

any advise gratefully received

 

 

Regular Contributor
Posts: 179
Registered: ‎04-04-2018

Re: Trunking with 3 switches

[ Edited ]

Hello,

there are more SAN designs based on type which you want to use.

In this case you will use ring/mesh topology which is not best scalable. Its depend on what you want to achive and how many hops you will have between initiator and target (in this config 2 as max)

Please check if you are using same ASIC for one trunk group (you have to use port from same port group 0-7,8-15, etc..)

You can verify it with command:

porttrunkarea --show all
Please mark this response as "Accept as Solution" if it answers your question.

Marian Bezeg
Contributor
Posts: 65
Registered: ‎08-22-2008

Re: Trunking with 3 switches

[ Edited ]

Hi Thanks for the reply

 

 

    What would be a better option to make it scalable & resiliant  ? the ports used on all switches would be ports 35 & 38  which are in the same  ASIC Trunk Group

 

 

 

Phil

 

 

External Moderator
Posts: 5,510
Registered: ‎02-23-2004

Re: Trunking with 3 switches

@AVAGO

 

--->>>we have 3 40 8GB sna switches....

 

i assume "40" is the port number ? are the switch 5100 ?

 

if yes, the 5100 is a single ASIC Switch

TechHelp24
Contributor
Posts: 65
Registered: ‎08-22-2008

Re: Trunking with 3 switches

[ Edited ]

Hi

   yes the switches are the DS5100 40port with 8GB sfp, below is some of the  output for porttrunkarea

admin> porttrunkarea --show all

Port Type   State   Master   TI DI

-------------------------------------

0   --             --     -- 0

1   --             --     -- 1

2   --             --     -- 2

3   --             --     -- 3

4   --             --     -- 4

5   --             --     -- 5

6   --             --     -- 6

7   --             --     -- 7

-------------------------------------

8   --             --     -- 8

9   --             --     -- 9

10   --             --     -- 10

11   --             --     -- 11

12   --             --     -- 12

13   --             --     -- 13

14   --             --     -- 14

15   --             --     -- 15

 

What would be the better way to trunk all 3 switches if the Ring/mesh is not efficient ? we have two fabrics each with 3 DS5100's in then the san storage is conneted to both across the switch's available also most of the servers have two or more FC connetions into the fabrics

External Moderator
Posts: 5,510
Registered: ‎02-23-2004

Re: Trunking with 3 switches

@AVAGO

 

Trunk can ONLY! be formed in the same octet 0-7 ; 8-15 and so on

 

you should not created TWO trunk group in the same octet.

TechHelp24
Contributor
Posts: 65
Registered: ‎08-22-2008

Re: Trunking with 3 switches

Hi Antonio

   Should we only use one port in each Octet

 

Switch 1 ----> port 0 to Switch 2 ---> port 0

 

Switch 2 ---> port 8 to switch 3 -----> Port 8

 

Switch 3 ---> port 16 to Switch 1---> port 16

 

The method above is Ring,using 6 ports but is this the most efficient way ?

 

Or is it better  to do it this way using 4 ports ?

 

Switch 1 --- > Port35  to switch 2 port35

Switch 2 ---> port38  to switch 3 port 35 

 

many thanks for your input

 

Phil

External Moderator
Posts: 5,510
Registered: ‎02-23-2004

Re: Trunking with 3 switches

@AVAGO

 

NO!

 

Trunk must be formed in the same Octet, example:

 

you create a trunk of TWO port in first octet, at Port 0 and port 1 - or other port as saied beetwen 0-7

 

the second trunk in another octet beetwen 8-15 and so on.

 

theoretically ( Trunk consinst at least of TWo Port ) you can create max. 4 Trunk Group in same Octet, each of TWO port, but is recommended to use different Octet.

TechHelp24
Contributor
Posts: 65
Registered: ‎08-22-2008

Re: Trunking with 3 switches

Hi Antonio

   thankyou for your quick response.

 

I thing I undersatnd what you are saying

 

Switch 1 Ports 0 & 1  to switch 2 ports 0 &1

 

so  we would have a 2 port trunk  in the same Octet , but  I have a 3rd switch is this just a case of using ports 35 & 38 on either switch 1 or 2 to trunk to switch 3

 

I'm trying to understand the best practice to trunk 3 switch's together so in the event of a switch failure the system is still efficient

 

or is it not a big issue as there are multipul connetions from the san storage split across 2 Fabrics ( with each fabric having 3 switch's )

and the servers have a minimum of 2 connections split across the 2 fabrics

 

phil

External Moderator
Posts: 5,510
Registered: ‎02-23-2004

Re: Trunking with 3 switches

@AVAGO

 

Since you have a DUAL Fabric, Core / EDGE topology is in you case the best solutions

 

One 5100 is Core, the both other 5100 will be connected as Trunk as EDGE.

 

connect the Storage to the Core, and all HOST to EDGE Switches

TechHelp24

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