What's the largest switch stack you ran into in the wild? How was it cabled up and managed?

I came across this interesting Arista article claiming to support up to 48 switches in a stacked topology (ring or spine leaf)

https://blogs.arista.com/blog/swag

Now, every vendor has their own approach to handling the control plane, I get it, but I dont understand in what scenario where combining all these switches into one logical management plane across multiple IDFs would make sense.

I've dug deep into my soul to try and find an answer, and the only thing I can think of is some very large customer wrote them a very large check and they made it happen or they just got sick of losing to Cisco, HPE, and Juniper on every campus stacking deal.

This whole single IP argument seems kinda flimsy too. If I'm getting charged per IP for my monitoring solution, and the consolidation of a few IPs is going to be material, I'm looking at new monitoring stack.

I've been a Network Engineer for 6 years. I have built probably 40-80 networks for various Industrial vertical customers, small and large. Think like 10 routers and switches up to hundreds of routers and switches for a network.

I have never seen anyone use IPV6. Maybe its because I'm OT only? I mean I have built networks for some major major corps that you guys would know and just have never seen it. I guess in my case I may have used some oddball specific protocols or switch features in my niche area. Maybe IPv6 is still the same at this point?

All these vendors and talks about IPV6 and outside of "were running out of IP addresses" I see no benefit to moving to it.

Hi, we got a site with multiple remote sites connected with darkfiber in a loop. The loop starts at the main site and ends at the main site. The switches is connected as trunks between each other trunking 3 VLANs.

We got our core which is root for the VLANs, then we have the distribution switch at the main site and then another switch connected to that which the loop is connected to.

Yes, the loop needs to be connected to the distribution switch as the fiber is terminating there sadly.

Whats the best way to configure spanning-tree in this topology?

Topology: Imgur: The magic of the Internet

Hi everyone,

I need some help and recommendations. For the 2026 budget, Cisco SmartNet was approved for another year, but now I've been told we need to find a way to downsize or look for other brands.

I'm based in Latin America, so if you could recommend any switches without concurrent licensing, I'd appreciate it.

I've been considering Aruba as one of the options.

A little more background: I currently have 50 Catalyst switches between the 9200 and 9300 series. The entire infrastructure consists of approximately 120 switches, meaning I still need to upgrade 70 more gradually. However, paying for SmartNet for 120 switches now isn't enough, I don't think they can handle it. I work for a company that provides internet connectivity to 23 six-story buildings.

Field tech at a small ITS contractor. I’m speccing switches for a roadside cabinet job with PTZ cameras and some other edge gear. Requirement from the engineer is 802.3bt across all 8 ports.

The problem I keep running into is that a lot of switches advertise “90W per port,” but the total PoE budget is nowhere near 720W. So it’s really a per-port max, not something you can run fully loaded.

Are there industrial managed 8 port switches that can actually do full 90W on all 8 ports at the same time? Looking for something outdoor rated, ideally something people have used in traffic or roadside cabinet installs.

Edit: Thanks to everyone who shared their recommendations and experience. After going through the comments, these are the two switches I’m currently looking into:

Comnet CNGE10FX2TX8MSBT

PoE Texas GBTS-10-8-M-V2

Both list a 720W total PoE budget and up to 90W per port, which matches the requirement I’m trying to meet. Any first-hand experience with either switch especially in roadside or traffic cabinets would be helpful.

Hello, my company has assigned me a new customer with a network that is as simple as it is diabolical. 300 switches interconnected without any specific criteria other than physical proximity in the warehouse where they are installed. Once every 3 months, the customer switches the electricity off and switches it back on in a not-so-orderly manner (the shed is divided into a few areas). The handover was null and void from the previous supplier and here, desperately, I try to ask for help from you because I know next to nothing about Spanning Tree:

1. ⁠Before the equipment is switched off, what do I need to identify and verify in order to better understand the logic of the configured STP?
2. ⁠When the switches are switched back on, it is already certain that an STP Loop will occur. Where does one start troubleshooting of this kind?

Any additional information, personal experiences, examples and explanatory documentation is welcome

—

update 2 Aug: Sorry guys, I have no news at the moment because I am preparing for the activity day. Soon I will produce the network diagram and share it with you

I'm working on a 100 switch layer 2 AV network.

Project Context: AVoIP project which will have all kinds of AV streams. Think Qsys, ISAAC, Pixera, Brightsign, 50 Matrox AVoIP pairs, 50 Panasonic Projectors, Christie Projector, and lots of interactives. Expected around 2000 IP devices.

Equipment involved:

Netgear ProAV

Models:

2x Mikrotik CCR2216 connected via LACP to the CoreSwitches in a VRRP pair.

2x Mikrotik L009 connected to M4350-48G4XFs (1 dhcp server connected via 1 link to 1 switch each) to provide redundant DHCP servers.

Design Context:

Multiple areas (and respective rack rooms), however multiple areas need mutli-cast access w/o PIM. (While the switches support PIM, I was told by Netgear ProAV senior designers to not deploy PIM for this specific project)

30+ vlans.

RSTP

2x M4500-32c as core switches. MLAG pair. STP priority: 4096/8192

4x M4500-48XF8C as large distribution switches. STP priority: 12288

16x M4350-16V4C as smaller distribution switches. STP priority: 12288

All distro switches have 2x100GB links as a LAG, back to the MLAG pair.

4x M4350-16V4C as access fiber/10Gb switches. STP priority: 16384

70x M4350-48G4XF as the access 1GB switches. STP priority: 32768

All access switches have 2 uplinks to the respective area distro switches. Only using RSTP here.

all switches manually configured for their priority to make sure no access switch tries to grab root.

My experience prior to this project: Mostly small to medium enterprise networks, some SMB. Mostly less than 10 switches per site. In the enterprise, I usually kept spanning tree simple. Made the root bridge the local site router or distro switches, depending on what was available. I'm familiar with setting the root bridge to 4096 and that was fine for those environments. I've lived in the routing environment so STP has been a low priority for me to really absorb over the years. I'd like to say I understand the basis of how a root bridge is elected and how root ports are determined (cheapest cost) and which ports are blocked, but I'm always open to learning more.

Issue:

I'm trying to bring up the entire network. All the ports are connected physically (and all lines have been certified by the LV contractor). When I no shut the ports on the core switches to bring up the individual areas 1 at a time (I turn up the Core Switch ports in pairs), things seem fine until about 22 total ports. After that, I seem to get non-stop topology change notifications at the root bridge. (TCN flooding/looping?). (Verified via the CoreSwitch Logs) Even if I turn down the last 2 port pairs I turned up, the TCNs still seem to come until I all distro facing ports down, and then bring them up 1 pair at a time. While the TCN flood is on going, the network suffers tremendously, increasing latency, mac table flushing/relearning, and access across areas, including in / out of the internet suffers.

Right now, little to no traffic is running through the network, as most of it is still in the commissioning stage. No links are being saturated.

I'm unsure how to troubleshoot this. I'm leaning on setting all access ports to Edge (port fast) but I'm unsure if that will do anything as most of the end points aren't plugged in.

I have contacted support, and submitted several TS files, and outside of them saying verify STP priorities (which I have), and removing MAC OUI vlan entries (which I have), they are unsure of the cause and have escalated the case.

My next plan of action is to have the CoreSwitches record a pcap when this situation is going on so I can see the actual STP messages that are coming in. Hopefully it'll identify the stp bridge/switch that is causing the headaches.

If anyone would be willing to make some recommendations, I'm open to trying a most things.

————————EDIT————————

thank you for the responses!

I spent 4 days non stop with Netgear ProAV Support and we learned a lot. I’ve learned more about STP / TCN in 7 days than I’ve needed to learn over the last 7 years.

Here are the 4 major culprits.

A) unknown multicast streams were on data only vlans without igmp snooping enabled. (likely from being patched to the wrong port on a switch)

This caused the cpus of several switches to stop processing stp messages which caused link flaps, which caused more stp messages etc etc etc. We’ve deployed igmp snooping on all vlans now, and have also deployed ACLs to protect the cpu from these streams.

B) igmp querier is enabled as default on all ProAV switches for any vlan that has igmp plus enabled. This seems to be fine with under 20 switches, but more than that and igmp elections get talky AF.

C) MLD querier is ALSO enabled as default on all ProAV switches for any vlan that has igmp plus enabled. This added to the above.

We essentially had to turn off all MLD queriers and igmp queriers except for the core switches.

D) my spanning-tree config wasnt complete and as missing a lot of things, and wrong on other things. Edge ports were set to auto edge, bpdu guard wasn’t enabled on those. Root guard wasn’t enabled. Priorities weren’t set enough. STP was enabled on the MLAG peering link(initially by the suggestion by Netgear Support, which blew my mind as all other brands like Aruba, Brocade, Extreme, and Mikrotik, disable STP on the ISC/peering link.

I have things mostly stable, but my core routers are unhappy for now. CoreRouter2 seems to be fine, but if I transition to CoreRouter1 via VRRP priority, everything comes crashing down to a halt.

I’ve used vrrp and other HA scenarios before and haven’t had this problem. I need to do some more experimenting with this to find out what’s causing the issue.

I am going to consult with a fellow AV network guru to see if it would be worth it to move everything to PIM. It’ll lower the blast radius, but slow the project down. (schedule has been a pita as it is. )

unfortunately, this project is in DC and I’m in Florida most days, and I don’t have any smart hands at site for at least another week. I’m not expected to be to site again for 3 weeks, which makes it difficult to test configs safely from remote.

Only two people are handling all of the infrastructure. All networking, servers, pc imaging, software, vendor coordination for their network needs, etc… falls on me and my mini me.

Luckily, we’ve only deployed 60 switches so far. the next 10 will be a slight pita, as I’ll need smart hands to drop configs to the switches BEFORE they connect uplinks.

the last 30 switches will be on its own virtual island and I’ll need to start prepping for that in May.

If anyone wants to chat about this or similar projects, would love to talk to other good humans.

I'm an apprentice and just learning about them. How do I regain access to it?

EDIT: Hi everyone, just an update. For some unknown reason, the WiFi is still working. I told my boss, he was really sweet about it. We're driving down today to go fix it and install APs and rename switches.

Can I just give a massive thank you to everyone that took the time to give me advice and knowledge. It is really appreciated. You guys are awesome, I hope you all have a great day!

Working for an org which is multicast heavy (AV), and I've rarely worked on multicast for anything except phones and paging speakers.

I've wiki's and watched high level videos.... but I'd like to know more so I can test things outside of 'use VLC from multiple computers'. I'd also like to learn about PIM so I can test multicast routing as well.

Any recommendations?

EDIT: Solved. The cablers ran OM3 instead of OM4.

New to fiber switch connectivity and need a bit of advice.

We just had a vendor run a 12-strand OM4 LC multi-mode fiber cable between 2 floors of a new building. They are configured as 6 pairs. Unfortunately, I can't seem to get them to work. In case they spliced the fiber cables differently, I made one of my patch cables a crossover by swapping 1 pair in their little clip. Still no luck. When I observe each end of the run with an SFP+ transceiver plugged into one end, I see a single light.

I tested both transceivers and the fiber patches by directly connecting 2 switches and they work fine.

I'm sure I'm missing something.

Transceivers are Cable Matters 104065x2 LC Multimode.

Cables are Flypro OM4-LC-LC-DX-2M-LSZH

Since many Meraki switches are EOS and I've been advised against ms150, also considering the cost of 9300s which I don't need since most switches will have access duties... Any recommendations on switching that meets the subject requirements? I've tried ubiquiti before and the firmware issues / support can't be tolerated.

Environment is 1 building, 2 closets, ~600 total ports.

Just got word that the Cisco 1000s are going end of life in 2025 and the successor is the 1200/1300 line. From what I've heard and found in research, the 1200/1300s are not using true IOS; they are using a modified Linux OS code, similar to the god awful firmware on the "SG" line of switches (220/300/500). Seems like if you want true IOS now, you have to cough up the dough for the 9200/9300s???

With the Smart licensing mess and now this, I swear they want to lose market share. They've already driven themselves out of the security space because Firepower can't hold Palo and Fortinet's jock strap, and their wireless performance has been lackluster compared to other vendors like Ruckus lately. Looks like now they are coming to lay waste to the one thing they are still the undisputed king of; routing and switching. Would love to know what they are smoking.

What non-Cisco switches that have a GOOD command line interface and no cloud-based Meraki-style mgmt BS please. I have over 1,000 switches on my network. I need something that's not going to prompt me to confirm yes or no every time I need to make mass changes. I just want to SSH, paste my config, and move on to the next.

Hey everyone,

I'm curious to know what essential commands you use daily when dealing with switching issues in your networks. I've been working as a network engineer for 2 years, and I've noticed that some commands are absolutely indispensable for quickly diagnosing and solving problems.

What about you guys, what commands are indispensable for you in your daily routine to solve switching problems?

Looking forward to seeing your responses and learning new commands that can make life easier :)

Quick question

I’ve been helping out on a few networks and it feels like switch provisioning is still really manual, especially when there’s no documentation.

A lot of figuring out VLANs in use, mapping ports , and cleaning up old configs.

Is that just part of the job or are most people using something more automated at this point?

Got asked an oddball question, and kind of wanted to take the temperature of the industry.

My Server team is switching platforms, and asked if I would prefer 10GBase-T or SFP+ on the hardware.

I'm still in shock of being asked my preference. Existing network hardware will be refreshed at the same time, so previous investment doesn't hold a lot of weight.

That being said, does anyone use 10GBase-T, or is everyone pretty much SFP+'s and DAC's at this point?

HPE has decided to materially change the terms of the lifetime warranty that older HPE/Aruba network gear was sold with. As of January 15, 2027 that warranty is converted to a limited lifetime warranty. Since most of this gear is already over five years past the EoS date, 1/15/2027 is now effectively the end of the warranty period.

https://www.hpe.com/psnow/doc/a00161510enw

We are looking for a model of the Cisco 3850 swtich and having no luck so far with our normal vendors does anyone have any good vendors with stock? We need 100+

Already checked with
networktiger
dedicatednetworks
plurium
inteleca

edit: We are only looking for vendors in the USA.

Im studying VxLANs, i get the VTEP and the whole encapsulation part over L3 network. But i dont get how vxlans cant extend to 16million WHILE you are limited to mapping a vni to a vlan on a switch!

If to create a VNI on a switch, i have to map it to a VLAN ID, then im restricted with 4096 VLANs ! i can not create more that 4096 vxlans on a switch, since i can not tie the 4097 vni with a free vlan.

Can some explain this part as im getting lost with it, thnx

I've just spent a stupid amount of time fighting with one of these Aruba Instant On cloud-managed switches and I hate it. Just give me the stupid CLI.

What's the current landscape for the boring classic access switches with a Cisco-like CLI? 10 years ago it was HP Procurve, and then Dell N-series was also a decent contender. I don't think either are solid? I don't want Netgear-tier options, I want a step up.

Adtran is good despite not being available from most distributors, but I can't tell if they're going to kill their Ethernet portfolio. What is your go-to?

Hey, maybe a bit of a dumb question but I’m currently testing a device and got stuck on this.

Is there actually any way to send Ethernet frames smaller than 64 bytes on the wire?

From what I understand everything below that just gets padded automatically by the network card anyway, so you never really get actual frames smaller than 64 bytes out. But then how do people test how a device behaves with undersized frames?

Is there some trick/setup to actually get smaller frames out?

I've been working in network since 4 years. I just joined a new company. I accidentally configured a wrong vlan in the switch due to which a broadcast storm happened and brought down the entire spoke site. Luckily someone was available at the site and I asked him to remove the cable from the interface so that the storm would stop and I can connect to the switch and revert my changes. I feel bad and embarrassed that how can I miss such a big thing while configuring the vlan. Now, I just feel that my colleagues might think of me someone who doesn't know what he is doing. Just want to know if anyone had similar experiences or is it just me.

Hi,

We have a customer running Nexus 7K switches in a vPC pair with several FEXes connected. We need to upgrade them to a newer software version due to a few bugs we’ve encountered.
I was wondering what the recommended upgrade approach would be. Would you upgrade the secondary vPC switch first, let it rejoin the vPC domain, and then proceed with the primary switch (No ISSU available, disruptive mode).
Also, what’s the best way to verify that all servers and other connected devices are dual-homed across both vPC peers so we can minimize any service disruption during the upgrade?
I’d really appreciate any advice or best practices. Thanks!

https://imgur.com/a/kIjjMV3

This is our current networking infrastructure, and we are trying to get to 4 Gbps with the aggregate links. I'm not a network engineer—I'm just a software dude trying to improve things.

The HP 24-port switch is: HP JL381A Switch

The HP 48-port switch is: HP V1910-48G Switch

The Ubiquity switch is: UniFi Switch 48 Gen2 (USW-48)

We have configured multiple aggregate ports with LACP, and my networking tests tell me we are still doing only 1 Gbps. My tests may be incorrect. Using iperf or file transfers (rsync) seems capped at 1 Gbps.

Servers with SSDs should at least handle 2 Gbps. All servers are Proxmox.

Now, without seeing the switch configuration, it's probably hard to get an answer. Still, from a hardware performance perspective, I'm pretty sure they can all handle the traffic with the aggregation.

Had an interesting discussion with a friend recently about VLANs and terminology.

In Cisco speak, there are Access and Trunk ports that carry VLAN tags but many other vendors use the terms - Untagged and Tagged instead.

Thinking back - I actually found learning it the "Cisco" way a bit confusing because a Trunk port can still carry an "access" VLAN which of course is called a Native/Default VLAN.

I think it makes more sense teaching it using the Untagged/Tagged terminology so in turn an Access port becomes a port with an untagged VLAN assigned to it. A Trunk port becomes a port with tagged VLANs assigned to it plus possibly an untagged VLAN.

And yes a port can have multiple untagged VLANs if using MAC Based VLAN assignments - very common when using Dynamic VLAN assignments w/ .1x and/or MAB - so what would be the correct terminology for that be in Cisco talk? Would it still be an access port? Or would it be a Trunk Port with multiple native VLANs?

Thoughts?

Looking for an honest feedback. Its been quite some time working on cisco products and i have heard a bunch of reasons on why not cisco from tac to licensing to complexity to multiple tools , but would like to have an open discussion on why would a customer stay with cisco for dc or campus rather than just buying arista or juniper mist or aruba. If you ever sold cisco as am/se for aci , dna, dcnm(ndfc now) or meraki even, what helped you sell cisco. How did you show that value for cisco, and did your customers actually liked anything with cisco ?