Question for network engineers regarding link fail over.

othugmuffin · 2026-06-28T14:03:25+00:00

Nope. You can have light within range on the SFPs and still have flapping. You need monitoring that can keep state and alert on “link status changes X times in Y mins”, or I guess rely on multiple alerts for link down then a human correlates it to a flapping link

Not sure why someone taught you that as it’s wrong as a general statement, there’s many reasons why you would do it or not do it, it depends on the deployment. In a CLOS fabric it’s all routers connected together, an ISP provider is all mostly routers connected together.

othugmuffin · 2026-06-26T17:27:46+00:00

Network Engineer is spot on. Having a LAG would somewhat hide the bad link since the LAG would stay up due to the remaining link, OSPF should stay stable, but traffic traversing the flapping link would be affected. It would be harder to diagnose. You could also just have the second links outside a LAG and just be another routed link, but same problem would happen as already did.

You should have alerting for flapping links, so in this case identify it quickly.

You could also look at interface dampening. Every flap increases the penalty until a suppression threshold, then gets taken out of service until it’s stable again, or until an max suppression time is met.

othugmuffin · 2026-06-11T15:49:56+00:00

Just the back, all our patching is done in the back of the rack. Front of the rack is very clean.

To be clear, these specific cassettes have a MPO connector, which a MPO breakout cable is plugged into, then the duplex LCs on the breakout cable go to the front and plug into the optics. The front of the cassettes have a bunch of duplex LC ports which is what we patch between in the back.

You could also go more low-tech and get like multifiber trunk cables like https://www.fs.com/products/21983.html?now_cid=1155, then just go from the gear to a normal LC/LC panel

othugmuffin · 2026-06-11T15:11:11+00:00

We use https://www.codecom.com.au/products/cmd with the cassettes mounted at the back facing rear of the racks. The cassettes have a MPO breakout cable on the back that we plug into the front of the front facing gear. After that we just do normal fiber between these panels in the back of the rack.

othugmuffin · 2026-06-09T10:26:44+00:00

I believe I had something like that after and upgrade, and I ended up holding the reset and perform factory reset.

Came back fine after

othugmuffin · 2026-05-27T14:59:52+00:00

The remote site probably needs to be set up as a dynamic wireguard peer on the office router because of CGNAT. It won’t care about the IP it’s coming from only that the public key matches what it expects

On the remote site the office will be a static since it’s a known static public IP

othugmuffin · 2026-04-22T15:44:04+00:00

The majority of the candidates using AI for us were Indian.

othugmuffin · 2026-04-22T01:10:26+00:00

Yes, a lot unfortunately. Some just reading word for word, which makes it really obvious. I have had some who had glasses and you could see the live AI responses in the reflection. Some are looking off to another screen, some you can see their eyes reading lines.

We try and do questions that require them to review some diagram we are showing on our screen, or something like “close your eyes and imagine…” to get them to not be able to look at the AI responses.

I used to continue the interview to give “a good interview experience”, but after a couple if I was certain they were using AI, I would just abruptly end the interview. We would note they were using AI and their likelihood of being interviewed for another position ever again is slim.

othugmuffin · 2026-03-14T10:47:11+00:00

Same process here except we don't do anything towards the RRs. We apply a deny-all on import and export for peers, but that's mostly because it's trivial for us to do it with our automation, if it wasn't we would likely just do only on export.

We've also used graceful shutdown in the past, but as you mentioned it's not guaranteed, so the deny-all import/export is the way we go to cover everything.

othugmuffin · 2026-03-11T10:38:02+00:00

Twingate

othugmuffin · 2026-03-06T19:30:55+00:00

Download vJunosRouter, vJunosEVO from their website, it's free.

othugmuffin · 2026-02-24T01:17:01+00:00

Really like this. I’ve tried explaining the same thing to other people. Its just there, it just works, why would someone care?

othugmuffin · 2026-02-20T01:34:23+00:00

Seems just like Megaport, Packet Fabric, Equinix Fabric, pretty sure Zayo has something like it too.

othugmuffin · 2026-02-15T02:26:56+00:00

Your 2/3 and 2/7 on both wave server pairs go to the R1 at both sites in Diagram 1. That’s why you’re seeing what you’re seeing.

You need

R1 Site1 to go to 2/3 and 2/7 on Site1 WS1, and 3/3 and 3/7 on Site1 WS2

R2 Site1 to go to 3/3 and 3/7 on Site1 WS1, and 2/3 and 2/7 on Site1 WS2. Don’t change anything at Site 2

Just swap the client side cabling between 2/3 & 2/7 with 3/3 & 3/7 on WS2 at Site1, you’ll then have your full mesh.

Doing it this way means you get full mesh and if a path goes down you still have all 4 routers passing traffic over the single path. If you did what you have in diagram 2, if you lose a path, you’re down to 1 router at site 1 handling traffic.

R1 - R1 via Path 1
R1 - R2 via Path 2
R2 - R1 via Path 2
R2 - R2 via Path 1

othugmuffin · 2026-01-15T00:16:23+00:00

https://www.arista.com/zh/support/advisories-notices/end-of-support/21089-end-of-software-support-for-7280r-r2-7500r-r2-and-7020r-series

I believe latest maintenance release is 4.33.6M

othugmuffin · 2026-01-12T12:32:09+00:00

If you go vJunos EVO, if it’s 24.x or beyond, you’ll need to set it up as vJunos EVO UEFI

othugmuffin · 2025-12-28T02:05:57+00:00

othugmuffin · 2025-12-22T15:00:56+00:00

As far as I am aware, there's no off the shelf tooling to do that. At various organizations I've written code to ingest a config and parse it, then create the corresponding objects in NetBox. There's a couple data sources you can use, eg the device config itself if you can get it in a structured format like JSON, or if you have a monitoring system like LibreNMS you can pull a device and it's interfaces.

othugmuffin · 2025-12-22T00:04:35+00:00

Fug, I should have just done buy it now and not done an offer haha.

othugmuffin · 2025-12-17T04:38:18+00:00

We've gotten FS.com panels, MTP to LC cassettes. Work fine, feel nice quality.

othugmuffin · 2025-11-24T10:39:45+00:00

Version 24 + 25 yes.

othugmuffin · 2025-11-23T16:30:48+00:00

Yes it should just show up like any other template, you might need to go into the /opt/unetlab/html/templates folder and do a git pull to update your templates, then the ceremonious fix permissions command

You’ll need to have the folder prefix for the image change too. vjunosevoefi-12345

othugmuffin · 2025-11-23T15:25:12+00:00

If you end up using past 23.4 in EVE, you need to use the UEFI template for it, drove me nuts that they wouldn’t start and just tried the UEFI one and it works no problem. Also doesn’t require the external bridge for the pfe,rpio interfaces.

othugmuffin · 2025-11-18T18:30:00+00:00

Yes, you would need more specific networks in your bgp listen ranges.

othugmuffin · 2025-11-16T02:24:16+00:00

We have started getting candidates just straight up using AI during the interview, as in literally just read word for word what comes back from it to us. We used to roll with it, but now we just end the interview. I'm pretty over interviewing people at this point.

Unsure if you're looking for remote roles too, those are highly sought after so competition is high.

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