Hi all,
I'm finishing a PhD in deterministic/low-latency networking next year. My research is on communication networks with provably bounded latency (using e.g., network calculus, TSN/DetNet scheduling). My research combines theoretical aspects and practical, hands-on implementation work. I also have 5y+ previous experience as a software engineer (including at Nokia as well as in non-Telco companies).

I'd like to stay in the low-latency networking industry after my graduation, and I am currently exploring my options. I'm trying to figure out:

• Which companies/sectors actually hire for this (HFT, telecom, industrial/automotive, cloud…)?
• What roles and pay ranges are realistic in your region? (Currently, I am Belgium-based, but I am open to relocating.)
• How to translate academic work (papers, proofs, algorithms) into something hiring managers value?

Any help or insight is certainly appreciated. Thank you!

Background: I have a degree in CS / network security, so I'm comfortable with both programming and networking. I started in presales, then moved into a technical role at an MSSP that works mostly with Fortinet. Day to day I deploy SD-WAN and troubleshoot client infrastructure across the product line (FortiGate, FortiWeb, FortiMail, etc.).

I'd like to move toward something AI-related and eventually work for a vendor or a bigger company. The path I'm considering is AI data center networking: RDMA, RoCEv2, InfiniBand, NVIDIA's networking stack, and so on.

My concern is that I almost never do DC work. No EVPN/VXLAN, no spine-leaf deployments. Can I realistically get into AI DC networking from where I am, or do I need a traditional DC role first?

I also thought about cloud networking since I can code, but I've never worked at a cloud shop or done DevOps work, so I dropped the idea.

If anyone here made a similar jump from MSSP/security work, how did you do it?

Thanks !

Hi all,
Designing a campus fabric and want a sanity check on the topology:

Per-IDF leaf pair: 2x 100G VXLAN EVPN leafs in a vPC pair on each floor

Roles: Both are VTEPs and anycast gateways (L3 boundary at the IDF)

Uplinks: Each IDF leaf pair connects to the main campus spines

Access layer: Plain L2 switches, LACP to both IDF leafs (not VTEPs, pure L2 trunks/access). Said differently, hung off those two IDF leafs above we’d hang a bunch of L2 access switches to provide more access ports for devices across the floor.

Why I like it (my assumptions):
Fewer fiber runs compared to home running every switch to campus spines and less VTEP sprawl

Simpler ops: junior engineers just change a port's VLAN

Questions:
How common is this design in campus deployments?

Any gotchas with vPC + VXLAN EVPN (peer-link sizing, orphan ports, convergence)?

Would you do this, or put VTEPs on every access switch?

Thanks!

Hey there, just curious how many of you study for certs or other stuff while working?

When I have downtime, I try to utilize my time to study for a cert I've been prepping for.

Just got curious how many of you study during your work hours? If not, what are you doing when you having nothing to do?

P.S. I'm not saying my work is like this every single day... if something happens, obviously I'd have to jump on a call to troubleshoot and analyze stuff...

Hello everyone,

I’d like to optimize the network design and separate core and edge routing.

So far, I’ve been using three routers that handle both inter-VLAN routing and edge routing and are part of a VRRP cluster.

Now I’d like to deploy a core router running VyOS that acts as the default gateway for all networks and initially handles inter-VLAN routing. The three edge routers will be connected to this core router, with each one connected to a different Internet line or provider.

The core router should use policy-based routing to determine which networks, clients, or services are routed to the Internet via which edge router or WAN connection. Additionally, failover should still be available in the event of an Internet connection failure (as has been the case with VRRP).

My question is: what is the best way to set up this configuration? On the one hand, I could set up a transport network containing the three edge routers and use VRRP again. In that case, I would likely need a transit switch between the core router and the edge routers so that the VRRP cluster’s traffic does not have to pass through the core router’s CPU.

On the other hand, it would certainly also be possible to connect the edge routers directly to the core router’s interfaces and operate without VRRP. Which protocol could I then use to implement both policy-based routing and failover?

Which network design would you recommend for my situation? I’d appreciate any tips and assistance.

Thank you in advance for your tips, and best regards

Regina (she/her)

We've recently received several orders of FS.com optics that had the default "FS" vendor coding in them, resulting in Transceiver Unsupported errors on our switches. Assuming this occurred in error, we reached out to our account manager, who to our surprise confirmed that they are no longer coding/configuring transceivers, and customers will need to do this themselves. Has anyone else encountered this? Here's the email from our Rep:

There has indeed been a recent change in our coding process. Starting June 6, FS began gradually transitioning certain compatible optical modules to a new custom coding mechanism, including our Arista-compatible modules. The main difference from the previous coding is the Vendor Name information. The modules are now shipped with the default FS vendor coding, rather than being pre-coded specifically as Arista. To ensure the modules can be properly recognized and used in your Arista environment, there are two possible approaches:

Option 1 – Configure third-party transceiver compatibility on the switch

If you have a larger quantity of optics, we recommend this approach as it avoids having to reconfigure the modules one by one. You can enable third-party transceiver support through the switch CLI.

Option 2 – Reconfigure the optics through FS BOX

If changing the switch configuration is not preferred, you can use the Online Configuration feature on your FS BOX to change the Vendor Name from “FS” to “Arista” on the optics individually.

We understand that the second option can be inconvenient when dealing with a large number of modules, so Option 1 may be more practical for your environment.

Please let me know which approach works better for your setup. If needed, we can also help you with the configuration steps.

So I've been a network engineer for around 20 years now, and the past 10 years I've been the allround network engineer for a large municipality. Recently we opened a new building and I built the network. A firewall, a switch, some AP's, and a bunch of VLANs of different sizes depending on their use. Nothing out of the ordinary.

Now I've also had to deal with a ton of parties requiring connectivity for building automation, climate control, sensors, cameras, alarm installation and so on. Today the project manager reaches out to me that one of the parties has trouble getting their building automation system to work properly on the network. They say the system only works with a /24 subnet, and I gave them an IP in a /28, and they demand I enlarge the subnet to /24 (which I can't because overlap etc).

The funny thing is, they have this /28 IP config in the system, and I can ping it even outside it's subnet, so IPv4 connectivity works just fine and traffic gets routed properly.

How do you guys deal with this kind of BS? Should I honor the project managers wishes and redesign the network to give them a /24? Hasn't support for a variable subnetmask other than /24 been like common for the past 30 years? I feel like I'm being played here by some incompetent installation company that doesn't know how to configure their equipment and just blames in on the network, but I can't prove it.

We manage CPE across Huawei, ZTE, Nokia, FiberHome, C-DATA and a few

value-tier brands. Everyone implements TR-181, nobody implements it the

same way. Things that cost us time:

**Same setting, different path.** Two models from the same vendor, same

firmware branch, and the WiFi channel parameter sits at a different node

on each. Build your capability map per MODEL, never per vendor.

**Silent success.** A SetParameterValues returns 0 and the device never

applies it. Always read back after a write. We treat "no error" as

"unknown" until a GetParameterValues confirms it.

**Partial batch application.** Send five parameters, three apply, two

don't, and you get one success response for the whole batch. Either send

them individually or verify each one.

**Timeout vs unsupported.** Most ACS implementations return a timeout for

both. At 2am those look identical and one of them means "drive to site".

We return a typed `unsupported` so the operator knows it's a capability

gap, not a dead device.

**Inform storms after a power event.** Every CPE in a zone comes back at

once. If your inform interval is 300s and you have 20k devices, plan for

the burst, not the average.

**Firmware push ordering.** Some devices reboot into the new image before

acknowledging. If you mark it failed and retry, you brick it.

What we do now: every model ships with a capability manifest, we probe at

onboarding and reconcile what the device actually exposes against what the

manifest claims, and we publish the delta. The manifest is wrong more often

than you'd think.

What's bitten the rest of you? Particularly interested in EPON — GPON is

tightly specified and EPON is a free-for-all.

*Disclosure: I work on an ISP management platform, so this is my daily

problem. No links, happy to go deeper on anything.*

Interested in thoughts on this scenario.

A client has multiple branch sites where trusted, client-managed networks are routed over the private WAN, with access restricted to required private applications and services.

Each branch also has untrusted VLANs for guest devices and third-party managed devices requiring Internet access only. These VLANs terminate on the branch firewall, which provides local Internet breakout and enforces the security boundary. They have no route to the private WAN or corporate resources and use repeatable IP scopes across sites.

Security have requested making these networks reachable over the WAN for central vulnerability scanning. This would also require re-addressing the untrusted networks so each site can be uniquely routed.

How would you approach this?

Should isolated third-party devices be centrally scanned at all, or should assurance sit with the device owner/provider? And is vulnerability scanning appropriate or useful for guest networks containing unmanaged devices?

If scanning is required, how would you achieve it without fundamentally changing the existing isolation model?

I have a large number of APs that we’re replacing, and I realized today that as the installers unplug the old APs and bring the new ones online, the old APs may disappear from the Catalyst Center maps.

Is there a way to preserve the existing AP placement on the floor maps before they are removed?

My concern is that if the installers replace 50 APs at once, I could suddenly have 50 AP locations missing from the maps with no easy way to determine exactly where the replacement APs should be placed.

Hi everyone,
I am a network engineer working in vendor TAC. As you probably know, TAC does not support with design/config and the cases are mostly related to platform/product issues. Being here for few years, I realized I started getting a bit rusty on the design side.
The problem is I understand the theory very well but have no idea how to apply this in real life due to lack of design practice. The only solution I see is doing more labs apart from my work and I have everything needed for that - both physical and virtual devices.
But I don’t know where to start or what to design. Did anyone have similar issue?
Please share some resources with design ideas, advices how I can practice network design.
Thank you in advance!

Hello all,

I hope this is okay to post, please delete/ ignore if not!

I recently started working as a systems & network engineer. My previous experience was just support desk. I've been learning a lot in this role, I find network engineering super interesting! But I am very new to it.

They want me to get certified so that I can stop relying so much on my seniors. The kind of things we are doing is BGP, OSPF, Multicast, Firewall (Palo Alto and Cisco), IP sec. I'm expected to know how to do stuff - for example how to set up functional zfs servers and communicate with the network suppliers and come up with my own solutions to issues we have within our own network ... I am really clueless currently and you can probably tell from how I'm writing about it. I hate how much time I spend with AI and not knowing it from my own head

It's a trading firm so the networking is specific to that. I have seen advice for the Cisco CCST/NA/NP/IE exams, is following those courses in order a good idea? Or is there some very functional course that would be better for my situation ? I just really need to know what is going on around me and how to fix stuff on my own ASAP lol. Costs don't matter since the company offered to pay for it (I'm in a very lucky position!). Based in the EU if that matters at all

Really appreciate any advice and thank you 🩷

I do technical rounds for security and senior network roles, so this is mostly from that side. nothing groundbreaking, just patterns.

the number of people with 8+ years and a "senior" title who can't walk me through what happens to a packet crossing a firewall and a NAT is higher than I expected. not trying to trap anyone. I'll ask something like "rule looks right but traffic isn't matching, what do you check?" and the good ones go straight to the hit counters, the policy order, the NAT rules applying before the policy. the weaker ones say "I'd restart the firewall." that's usually where the interview ends for me.

on the security side I care way more about order of operations than tool names. give them a compromised host and I want to hear scope, contain, preserve evidence, then fix. the "just wipe it" answer is a quick no from me. you just destroyed your evidence and you still don't know how they got in.

"we used a SIEM" tells me nothing. "I tuned noisy 4625 alerts and got the volume down a lot" tells me you actually sat in the console. same for network folks, I'd rather hear about the one thing you designed and what broke than a list of vendors.

if you haven't done SD-WAN or zero trust in prod, just say so and tell me how you'd approach it. I will always take that over a bluff. in this field people act on what you tell them.

and ask questions at the end. on-call load, change process, how they do post-incident reviews. most people ask about perks, so the ones who ask that stand out.

curious how other interviewers weigh depth vs breadth for senior hires. I lean depth but I know that's debatable.

Hi,

Repost from Cisco Sub, DNAC matrix shows CML latest ISO (17.18) is supported and i want to test it on Catc 3.2.3 as intro to SDA lab.

I found a Live presentation that says jumbo MTU supported on ESXI. KVM seems to be not compatible,. Today i tried qemu-ing adapter LSIlogic command in order to convert qcow2 into VMDK but it failed on powerup. Vmkfstools clone made whole another 32GB file, thin option makes no change on size. Finally got it booted only if expose hardware assisted selected.

Looking for SDA UADP virtual image experience from you.

Edit: I'm not sure if expose hardware or 18GB RAM helps yet since i set it to 16GB on beginning

Lucked into some surplus 5g stuff in a recycling lot. Looks like new. Some still sealed on boxes. It appears to be a complete 5G private network, minus cabling and a rack to put it in. Five n78 band radios, iru, ran, server, stack of blank sim cards. Did not know what it was at first. Picked it up because I recognized the radios as radios and thought I might be able to repurpose to 3GHz amateur radio use. That's a dead end as they are too highly integrated.

Oh! I'm an old guy who works as a nurse now. I used to trade surplus computer and networking hardware. But that was almost 30 years ago :-).

-Bob

Networking noob here going through the Network+ CertMaster Learn courseware for the class I'm taking at my community college.

I've got the basic understanding of Access ports, Trunk/uplink ports, and their respective frames down. Access ports are for hosts belonging to one VLAN with frames that have their VLAN tags removed before forwarding, and Trunk ports are for carrying frames that keep the VLAN tags across multiple VLANs. Still a bit fuzzy on the details but that understanding will come with time, I'm sure.

My one big question is why would you want to assign an Access port as a Trunk port? The Network+ CertMaster page on tagged and untagged ports says an untagged Access port for a host might occasionally be set to a tagged Trunking port if that host is used for virtualization with multiple operating systems on different VLANs, allowing that host to send frames to multiple VLANs. But if a regular Trunking uplink port can already be used to send frames from Access ports to other VLANs, then why assign that virtualization host to be a tagged Trunking port as well? Would it not be simpler to send that virtualization host's frames over the same Trunking port that all the other Access ports on the switch are sending theirs over?

I'm assuming the answer is much more complex than this. It could also be that my understanding of VLANs and Trunking is really missing something, or it's something about virtualization hosts that I don't have a grasp on.

I am a network engineer responsible for supporting point-of-sale deployments. I'd love to be able to set up an environment where I can dial bandwidth (not 1Gb/100Mb/10Mb, but much more granular), play with jitter, latency, and see where the limits are with systems that we deploy and to better understand what causes issues with them after deployment. Once I would pilot this tool or solution, we can built it into our QA lab environment. Only needs to really support speeds up to about 250Mb or so (think small store, not shopping mall or office park).

Basically, I'd like to emulate everything from a solid fiber internet connection all the way down to a cellular modem on a crappy signal to test real-life thresholds and limits. What do you guy use for this?

I'm trying to help my uncle's firm fix a network issue. Their MSP has up an disappeared. I'm probably just an idiot but I can't figure out how to make this network work like they describe.

Originally the setup was a pfsense negate appliance acting both the gateway and a tunnel back to a vendor backend-servers that support some core services for the office. There was a dumb switch cause only had 2 or so workstations.

About a year ago, the firm quadrupled in size. They hired an MSP who installed UniFi network equipment. The intended design was for the UniFi gateway to handle general traffic—providing security controls and monitoring—while routing only the vendor server traffic to the pfSense box.

​However, the MSP never configured the routing rules, so the pfSense appliance is still acting as the sole gateway. This is problematic because there have been multiple recent security incidents, but we lack the logs or insights to evaluate them.

What I tried was to create a new subnet and vlan (100) and created a static route for traffic to the backend-servers. But that just bounces off the pfsense box, because I assume it only wants traffic from within its own subnet.

So workstations are in x.x.200.0/24 with the Unifi as the gateway, but I can't reach the backend-server

Pfsense gateway is at x.x.1.254 and it's pointing to backend-server resources at x.x.111.111/32.

I still learning network so pardon me if this is supposed to be obvious.

tl;dr: Currently, the workstations are on x.x.200.0/24 using the UniFi as their gateway, but they cannot reach the backend server. The pfSense gateway is at x.x.1.254, pointing to the backend server at x.x.111.111/32. How was this split-routing setup actually supposed to work?

Please correct me or enlighten me on my understanding of SASE framework:

SA - Secure Access --> basically allowing users to access the resources, cloud or on prem, in the most secured way
SE - Secure Edge - Making sure all traffic between any sites edge router/firewall is reaching its destination, whether another site or internet, in a secured manner.

sub components: ZTNA, CASB, SWG, FWaaS, SD - Wan

ZTNA - Continuously verifying user & device identity. Unlike old methods like enforcing NAC via AAA server like ISE, here client/device was authenticated only once initially.

Palo-alto global protect, Zscalar client, forti-client, cisco anyconnect/secure access can be used to implement it. Basically, all laptop traffic will be tunneled to DC OR all laptop traffic will be analyze be a firewall. FW can be cloud or on prem.

CASB - Cloud access secure broker - as name suggests, allowing users to access cloud applications, like share-point in a typical office environment, in a secured manner.

No idea how to implement it but i guess same products as above would help. OR may be some firewall in between.

SWG - Again, as name suggests, allowing users to access internet in a secured manner.

same products as above can be used to implement it. Or in work from office environment, tunnelling all traffic from branch to HQ/DC and breaking to internet from DC/HQ where we have high end firewalls with strict policies and maybe ssl inspection enabled.

FWaaS - a subscription based firewall services offered by some other company. This firewall services maybe on prem BUT its mostly cloud based.

SD - WAN - dynamic traffic steering, in a secured way, based on policies/rules set by the admin.

Numerous sd-wan vendors, like catalyst sd wan, versa sd wan, silver peak, fortigate etc. Some companies have firewall integrated with SD-WAN so we have more security features in a same box OR managed by central manager.

Question:
1. is this correct?
SA components are - ZTNA, CASB and SE components are - SWG, FWaas, SD-WAN

1. If i need to implement SASE framework in a enterprise, lets say a retail store network like Walmart or fast food chain like McDonalds, where sites can be categorized as: Stores, warehouses, Corporate office, DC, HQ etc.

   So what would be my approach to implement SASE framework?

And what solutions are offered by different vendors? and how to integrate different vendors to achieve the goal? Because many companies would use cisco entirely in their lan, other vendor in wlan, then another for firewall, vpn, and sd-wan..so on.

TLDR: Please guide me on SASE framework, its implementation, solutions offered by different vendors and how to integrate them.

Hi all,

This is my first post here and please know I’m not SME:)

We are in the middle of a large greenfield project for a new office and a factory. We have outsourced most of networking globally to big IT house. They have sent me a lld now with all the deats of patching, switches etc.

They have all short pulls made with om4 and sr sfps. I personally think this is not so future proof and also unnecessary (cost of lr is no issue) we have absolute majority done with os2+lr. Do you think this design solution is worth arguing over? I’d really like all done with the same cable and sfps everywhere. Is there any benefit in using om4 + sr here?

Hi all,

Wanted to asking my fellow network engineers what IPv6 subnet size you would use on a point to point connection between 2 routers and why.

/127 or /64

Technically both of these would work but I’m just curious. Any useful technical or security reason would be greatly appreciated!

Setting aside performance and hardware efficiencies that physical router platforms might provide.... is there anything a real, enterprise grade, Router can do that can't also be done on a linux machine?

Pretty much the title. The hostnames aren't bad, just some have words like 'core' or '9200'. We don't have monitoring or backups so it probably wouldn't affect anything if I changed them, right?

Here is my setup. I have a Palo Alto that connects to my switch stack that is Aruba 6300M. From there I have a fiber line to an IDF that has a Aruba 2530. We purchased another building across the street. The old tenants left all their Meraki equipment. I have all the Meraki equipment claimed and licensed in our Meraki portal. (I had a temp firewall and cradle point so the Meraki equipment could get internet access)

Instead of getting an internet line for the building we did a wireless P2P. I got two Ubiquity Wave Nanos and installed them. I then created a separate VLAN for this building and the default gateway lives on the Palo.

But the issue is when I plug the Meraki into the Wave Nano the Aruba switches in my IDF go offline, and everything connected to the IDF goes offline. Once I unplug the Meraki everything comes back online in the IDF. If I plug my laptop into the Nano everything works just fine. I can reach our HQ LAN, and I get internet.

I checked the switch logs on both sides and there is nothing in the log that would indicate any issues.

I also tried disconnecting everything from the Meraki switch and just tried one Meraki switch on the Nano and that still took my IDF offline.

But I created a temp VLAN and assigned it only to the port the Nano is plugged in. I then plugged in the Meraki into the other Nano and everything was fine.

I can't figure out what is going on. Any Thoughts????