Wired Intelligent Edge

I have two S3500-48P switches, and one S3500-24P switch to stack together. In the past I have only stacked two switches, but what would be the correct method to stack three via the 10G SFP+ cables? The diagram in the manual shows four devices being stacked (see screenshot below), but how would that be modified for three? In my setup, the top switch will be primary.

Thank you for your time.

The way we do it is:

1. Cable from stack port 1 on the first switch to stack port 2 on the second switch.

2. Cable from stack port 1 on the second switch to stack port 2 on the third switch.

3. Cable from stack port 1 on the third switch to stack port 2 on the first switch.

This should give you a ring topology and should be resilient to cable or transceiver failure.

By default port 2 and 3 on the 10G modules in S3500 switches are defined as stack ports, but this can be modified in the configuration.

Thank you very much! With stacking them this way, will that automatically set my first switch to primary? Or will I need to pre-provision the stacking members in the configuration of my first switch?

I like to have control over my stacks, so I configure a stack-profile like this in CLI:

stack-profile
member-id 0 serial-number "xxxxxxx" role primary-capable
member-id 1 serial-number "yyyyyyy" role primary-capable

member-id 2 serial-number "zzzzzzz" role line-card
!

That way I control which switch is the primary and which is secondary.

Great, thank you! Since I am not that experienced yet in CLI, especially with Aruba, could I do the same via the web GUI in Configuration --> Stacking?

I've never done it through GUI myself, but it looks like the same parameters as the CLI commands I posted.

My apologies, but I am still learning how to use these Aruba switches. Unfortunately the stacking options in the GUI do not match the suggested settings above via the CLI. According to another forum post, I initially set the following configuration:

Then I started the second switch. The stack formed perfectly, and the switches assigned themselves as primary and secondary exactly how I wanted.

I then started up the third switch. It booted, recognized the 4x10G card, then did nothing. No link lights on the stack ports.

I thought the card may be bad, so I swapped it out, same problem. I then modified the stack settings to the following:

I reset the third switch to factory defaults and restarted. This time the stack port directly connected to the primary switch started blinking slowly like it was trying to connect, but nothing happened.

Did I just really mess something up? Fortunately the primary and secondary switches are still fine, but I do need this third switch added to the stack.

Thank you for your help!

Can you run though a few CLI commands and give us the results?

show stacking members

show stacking interface member 0

show stacking interface member 1

show stacking topology

AFK, thank you for your reply. Here is the information you requested:

show stacking members

Stack status: Active, Stack Id: 001a1e1b24c057a221ba
Stack uptime: 12 days 7 hours 8 minutes 24 seconds
Id    Role       MAC Address        Priority  State     Model            Serial                 Location
--    ----       -----------        --------  -----     -----            ------                 --------
0  *  Primary    00:1a:1e:1b:24:c0  255       Active    ArubaS3500-48P   CB00034           41   Not Set
1     Secondary  00:1a:1e:1e:dc:80  255       Active    ArubaS3500-48P   CB00066           70   Not Set

show stacking interface member 0

Member-id: 0
------------
stack1/2
--------
stack1/2 is administratively Enabled, link is Up, line protocol is Up
Speed: 10 Gbps, MTU: 9224 bytes, Link flaps: 2
Last update of counters:        0d 00:00:05 ago
Last clearing of counters:      7w0d 08:09:19 ago
Link status last changed:       1w5d 07:11:44 ago
Statistics:
    Received 22649377 frames, 6701492676 octets
    15 pps, 28.918 Kbps
    2094651 broadcasts, 0 runts, 0 giants, 0 throttles
    0 error octets, 0 CRC frames
    151041 multicast, 20403685 unicast
    Transmitted 45973014 frames, 21965728959 octets
    40 pps, 57.367 Kbps
    10768952 broadcasts, 0 throttles
    7278923 multicast, 27925139 unicast
    0 errors octets, 0 deferred
    0 collisions, 0 late collisions

stack1/3
--------
stack1/3 is administratively Enabled, link is Down, line protocol is Down
Speed: N/A, MTU: 9224 bytes, Link flaps: 96
Last update of counters:        0d 00:00:00 ago
Last clearing of counters:      0d 00:00:00 ago
Link status last changed:       1w0d 06:07:16 ago
Statistics:
    Received 0 frames, 0 octets
    0 pps, 0 bps
    0 broadcasts, 0 runts, 0 giants, 0 throttles
    0 error octets, 0 CRC frames
    0 multicast, 0 unicast
    Transmitted 0 frames, 0 octets
    0 pps, 0 bps
    0 broadcasts, 0 throttles
    0 multicast, 0 unicast
    0 errors octets, 0 deferred
    0 collisions, 0 late collisions

show stacking interface member 1

Member-id: 1
------------
stack1/2
--------
stack1/2 is administratively Enabled, link is Down, line protocol is Down
Speed: N/A, MTU: 9224 bytes, Link flaps: 0
Last update of counters:        0d 00:00:00 ago
Last clearing of counters:      0d 00:00:00 ago
Link status last changed:       1w5d 07:14:06 ago
Statistics:
    Received 0 frames, 0 octets
    0 pps, 0 bps
    0 broadcasts, 0 runts, 0 giants, 0 throttles
    0 error octets, 0 CRC frames
    0 multicast, 0 unicast
    Transmitted 0 frames, 0 octets
    0 pps, 0 bps
    0 broadcasts, 0 throttles
    0 multicast, 0 unicast
    0 errors octets, 0 deferred
    0 collisions, 0 late collisions

stack1/3
--------
stack1/3 is administratively Enabled, link is Up, line protocol is Up
Speed: 10 Gbps, MTU: 9224 bytes, Link flaps: 0
Last update of counters:        0d 00:00:00 ago
Last clearing of counters:      1w5d 07:14:06 ago
Link status last changed:       1w5d 07:13:50 ago
Statistics:
    Received 45952571 frames, 21939459235 octets
    23 pps, 23.701 Kbps
    10769532 broadcasts, 0 runts, 0 giants, 0 throttles
    0 error octets, 0 CRC frames
    7279376 multicast, 27903663 unicast
    Transmitted 22650878 frames, 6701812353 octets
    6 pps, 12.128 Kbps
    2094670 broadcasts, 0 throttles
    151047 multicast, 20405161 unicast
    0 errors octets, 0 deferred
    0 collisions, 0 late collisions

show stacking topology

Member-id  Role       Mac Address          Interface  Neighbor Member-id
---------  ----       -----------          ---------  ------------------
0  *       Primary    00:1a:1e:1b:24:c0    stack1/2   1
1          Secondary  00:1a:1e:1e:dc:80    stack1/3   0

I see both stacking interfaces connected to the third switch are down. Can you connect to the CLI of that switch and confirm that stacking ports are configured? Run the 'show stacking interface' command.

If both stack1/2 and stack1/3 are configured and enabled then I would suspect hardware failure in either the switch or the cables you are using. I recommend opening a TAC case if so.

Thank you for your reply. This just does not make sense. I have reset the third switch to factory defaults twice and re-ran the quick setup. This is also the second 4x10G module that I have tried. The cables I am using are brand new, and are the same as what originally comes with these modules.

The stacking ports are also enabled on the third switch like they are supposed to. What is even more confusing is that I can't even use the first two ports on the 4x10 module to simply uplink the switch. Again, no link lights. Or, the left of the two lights will be on for about 10 seconds, then turn off.

Just a follow-up to this issue, I ended up using the third pair of my 62.5/125 fiber line to uplink this third switch directly to the datacenter. This will actually work well for me, since this third switch will be dedicated to some equipment that needs to be on it's own VLAN.

So it appears that two of the three SFP+ cables I was using to stack may be bad, which would be very surprising to me, since they are high quality cables from a repitable company. However, I will test these cables as soon as I can to find out for sure, and post a follow-up then.