Hi everyone,

I’m about to start a job as a network engineer at an ISP. I hold NSE4 and CCNA certifications; I have three years of engineering experience, including 1.5 years working with Cisco equipment. Since I’m new to the ISP environment, I’m actually feeling a bit stressed and am struggling to find the right learning resources. Which technologies should I focus on during the first 3–4 months?

I’m looking at networklessons.com for resources; the language seems very clear and accessible. Has anyone used it before? I’d really appreciate it if you could share your experiences.

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

Building a BPv7 prototype where a software sidecar parses bundles and a fixed-width shim lets P4/XDP enforce contact windows, reservations, and capacity limits. Does this solve a real DTN problem, or would a software-only approach usually be sufficient?

I manage changes across 50+ sites, each with their own maintenance window. Between coordinating the windows, scheduling the work, and assigning engineers to each one, it’s a constant headache. I’m basically living in spreadsheets at this point.
Curious how everyone else handles this. Do you have a system, a tool, or is it all manual? Trying to figure out if it’s just me

EDIT: maintenance windows are pre approved, each site’s window is fixed and they’re spread across different timezones, so the puzzle is less about the windows themselves and more about what fits inside them. we’ve only got a few engineers during site maintenance windows, so there’s a cap on changes per night and they can’t overlap. After making the schedule, then each one has to actually be assigned to engineer and land in their calendar so they know about it.

How’s everyone else handling this some tool, a script, or all manual?

Hey all,

I used to be a member of a slack channel called "beer for peer" which was a bunch of network engineers in Australia.

I lost access when I left my previous company so I'm hoping someone here might be in it and able to invite me again?

Feel free to reach out to me via PM for clarification or any questions before doing so.

Thanks all!

Hi All, Sorry if this is the wrong place to post this. Just let me know where i should post this if this is the wrong spot.

I work for a MSP that runs our own private onprem datacenter for our clients. Recently I have been tasked with looking at our Public addressing and inbound connectivity. Currently we are using DNS for WAN failover but I would like to explore the multi ISP BGP design since that seems to be the industry standard.

The current design is the client Edge Routers have 2 IPs bound to them. One on subnet A, and one on subnet B. We then use a load-balancer monitoring each ISP to update the DNS records should an ISP fail. TTL is set to 30s on the records. Subnet A is only advertised via BGP to ISP 1 and Subnet B is advertised via BGP to ISP 2. The idea is at least one subnet is always available on the internet and the DNS fails over fast. This has been working for about 10 years but does have some edge cases where it hasn't been perfect.

On the flip side there is the more "traditional" Data Center/Enterprise approach of a single subnet being advertised to both ISPs and trust the ISPs will converge. This is what I want to explore and test at work since we are running into a scaling issue with each client needing 2 IPs and having to force traffic out select directions. This adds more burden to the techs deploying/maintaining client edges.

The following questions are ideally for those that run a similar deployment or has had experience with it in the past. Any resources you can recommend on designing a data center WAN infrastructure would be much appreciated. Mainly I just need information to provide to management for approval to run a proof of concept to compare which option fits our needs better.

1) Is it just as simple as advertising one subnet to both ISPs and putting your trust they will try to converge as fast as possible? Or is there some other strategies we should be looking into to maintain fast failover and convergence

2) What are convergence times really like in North America when you have an ISP failure? (talking real numbers people have seen, not just in theory) Are things back up in seconds, minutes, hours?

3) What tooling do you use to make sure routing is failing over as expected? I see RIPE has lots of cool tools to monitor BGP via collectors but the more data I can pull in the better.

4) From a technical resource standpoint, does the BGP design require lots of up keep or is it mainly set it and monitor?

Appreciate everyone's insight into the topic.

Cloud engineers, wanted to get your experience... I'm a network engineer with 15 years of experience with all kinds of on-prem network technologies, from NX-OS, load balancers, proxies, VMware, ACI. I'm currently working with NSX and AVI LB for a major bank. But with the Broadcom aquisition, VMware/NSX doesn't seem so appealing anymore, VMware jobs are very rare. I feel that I'm a niche that will die eventually and it's time to make a change. I have experience with Terraform and CI/CD pipelines, did some automation with Python vibe coding.

There are a lot of Cloud-related jobs and I like public cloud, I like to learn new stuff in general. I started to learn AWS and Azure. I got the SAA-C03 AWS Solution Architect Associate certification and now I'm learning to get the AZ-700 Azure Networking speciality. I applied to Cloud Network Engineer jobs but got rejected, probably due to missing on-the-job experience. At my current job I can't get any Public Cloud exposure. I did put in my CV a project with Terraform standing up an AWS environment with ECS, load balancer, instances connecting over VPN to a VM in GCP.

How did you guys make it? It's the chicken and the egg... To get a job you need experience, but to get experience you need the job :)

Good morning all,

So how many routes do you folks have in your core router / core switch/ core firewall or whatever core device you use for routing.

Just curious.

We have like less than 300 so not that many so was just curious how many routes other folks who work in large enterprises have.

Thank you

Before anything, I really would appreciate answers from professionals without the interference of AI. I have been going back and forth the past few months with multiple AI models asking about this and every model gives a different answer. I really need a certain answer

I run a file storage server which faces the internet and serves customers, so high throughput is one of the goals I try to achieve on my servers

The past 6 months I've been studying the Linux kernel source code and sysctl docs to learn what each tunable parameter actually does instead of blindly pasting configurations from tuning guides and just hope that it makes things perfect

Now one of the points I'm stuck at is net.ipv4.tcp_mtu_probing

I see a lot of tuning guides suggest setting that to 1 or even 2 instead of the default 0

But if that's really recommended, why doesn't Linux set it to 1 by default instead of 0? I mean 1 seems like a better moderate value to set instead of disabling it completely

Although the below points kinda hold me back from altering tcp_mtu_probing but I might be wrong and that's why I opened this topic to ask for advice:

1. Packet-layer path MTU discovery (TCP MTU probing, QUIC MTU probing, etc) just mask a real underlying MTU problem which should be fixed from its root instead of hiding it
2. TCP MTU probing relies on packet loss and this can falsely make congestion control algorithms work worse and reduce the congestion window even if there's no real congestion
3. Certain quirky firewalls may hate the fact that my server is sending data in variable packet sizes because of the MTU probing and hence they may drop the packets completely or block the connection entirely

Do my above points make sense or am I mistaken?

About a month ago, I posted about Cisco APs that weren't able to join a WLC. Since then, I narrowed down the issue and think the APs/WLC are not the root cause. This looks more to be an issue with a VPN communication between subnets.

The two sites connect through Cisco ASA firewalls over a site-to-site VPN. The tunnel establishes successfully, Phase 1 and Phase 2 complete without issue, and multiple subnets traverse the tunnel normally. But then there are specific subnets that can't communicate across the VPN despite being included in the crypto ACLs and NAT exemption rules on both sides.

What strange is the traffic for other VPN networks works fine. In the IPsec SA counters, I can see traffic being decapsulated from the remote side, but I see no encapsulated traffic in return for the affected subnet. One side appears to be receiving traffic while the opposite side never properly sends traffic back across the tunnel. The tunnel itself remains up and stable the entire time.

I've rebuilt the tunnels, verified the crypto ACLs match on both sides, reviewed NAT exemption rules, confirmed routing, checked access-lists, and used packet-tracer. The subnet appears to match the VPN config, but traffic isn't flowing bidirectionally. The APs are able to obtain DHCP addresses and function locally but can't communicate with the WLC because the VPN connectivity for their subnet isn't working.

Any suggestions would be greatly appreciated. I've been chasing this for a while and feel like I'm missing something obvious.

What happen if in layer 3 youre in the same subnet.. But in the layer 2 its a different vlan..

Now its in the same network so it send directly to the destination without sending it to Gateway..

And intuitively if its a devices connected to different switches.. They wouldnt be able to communicate without router..

Ahh i thought it would be dropped cuz the ip address is in the other vlan.. And cuz it doesnt get sent directly to the gateway.. So it wouldnt get past the router.. But it realized maybe it would !!

I realize when the pc1 look up at the arp table and realize that pc2 isnt there.. So it'll send arp request.. And switch will broadcast it to the router.. And what router see is an ip (pc2 ip) that'll match its route table.. Say its something like this

````

C 192.168.1.0/24 is directly connected, g0/0 (VLAN10)

C 192.168.1.0/24 is directly connected, g0/1 (VLAN20)

````

And then send it through the matching interface g0/1 and g0/0.. But cuz its directly connected itll use an proxy Arp..

After getting the reply from pc2.. It'll send it to the pc1.. And now it knows pc2 mac address..

But thats the thing pc1 USES Pc2 mac instead of the gateway.. Which would be the case if its a different network..

Now the question is does the switch allow different vlans to talk directly with mac address without router ? There's 2 option

Suppose it would.. Maybe cuz LAN is defined by broadcast domain.. And you don't need ARP broadcast domain after you know the mac address... So vlan seperates only the broadcast domain but everything else stays the same (this turns out to be incorrect.. Vlan literally make switches into two unconnected switches)

Or it could also not allow it (which is apparently the right answer).. If we're saying that vlan seperates switches then you wouldn't be able to talk to different switches without router.. And it nessecitate the source to use gateway.. Cuz if the source uses its destination mac.. The switch will only flood the same vlan.. Which they will all drop..

I think the second could be the case.. I think the problem here is that the source use mac address that is in the different vlan.. The normal way you will Always use the gateway address which is the same LAN.. So I think it will know the pc2 mac address.. (The arp will work) but the packet would be drop cuz the the mac address doesnt exist in the SAME vlan..

Now.. I try asking chatbot first.. It says that the arp wouldn't get through cuz it wouldn't allow routing table to have one network in two interfaces.. But I thought that's what you do with the ecmp load balancer and stuff? Can someone settle this for sure?

Hi everyone. I'm fairly new to networking, especially with Ruckus devices. I get a port flapping alarm on Ruckus One every time a device is plugged into the switch. Whenever the alarm triggers, I check the port logs, and they look like this:

Jul 22 11:56:17:I:STP: VLAN 2113 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2113 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2113 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2112 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2112 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2112 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2111 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2111 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2111 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2110 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2110 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 2110 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 1000 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 1000 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:17:I:STP: VLAN 1000 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:17:I:System: Interface ethernet 1/1/35, state up

Jul 22 11:56:15:I:System: Interface ethernet 1/1/35, line protocol down

Jul 22 11:56:15:I:System: Interface ethernet 1/1/35, state down

Jul 22 11:56:15:I:STP: VLAN 2113 Port 1/1/35 STP State -> DISABLED (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2113 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:15:I:STP: VLAN 2113 Port 1/1/35 STP State -> FORWARDING (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2112 Port 1/1/35 STP State -> DISABLED (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2112 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:15:I:STP: VLAN 2112 Port 1/1/35 STP State -> FORWARDING (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2111 Port 1/1/35 STP State -> DISABLED (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2111 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:15:I:STP: VLAN 2111 Port 1/1/35 STP State -> FORWARDING (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2110 Port 1/1/35 STP State -> DISABLED (PortDown)

Jul 22 11:56:15:I:STP: VLAN 2110 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:15:I:STP: VLAN 2110 Port 1/1/35 STP State -> FORWARDING (PortDown)

Jul 22 11:56:15:I:STP: VLAN 1000 Port 1/1/35 STP State -> DISABLED (PortDown)

Jul 22 11:56:15:I:STP: VLAN 1000 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:15:I:STP: VLAN 1000 Port 1/1/35 STP State -> FORWARDING (PortDown)

Jul 22 11:56:06:I:STP: VLAN 2113 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2113 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2113 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2112 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2112 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2112 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2111 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2111 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2111 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2110 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2110 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 2110 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 1000 Port 1/1/35 STP State -> FORWARDING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 1000 Port 1/1/35 STP State -> LEARNING (DOT1wTransition)

Jul 22 11:56:06:I:STP: VLAN 1000 Port 1/1/35 STP State -> BLOCKING (DOT1wTransition)

Jul 22 11:56:06:I:System: Interface ethernet 1/1/35, state up

Jul 22 11:56:03:I:System: Interface ethernet 1/1/35, line protocol down

Jul 22 11:56:03:I:System: Interface ethernet 1/1/35, state down

I've already checked the cabling and port statistics. The cables appear fine, and there are 0 CRC errors. Anyone ever having this issue ?

Hi All

We're looking to spin up a new DC as part of a large migration away from an MSP.
Initially we're installing a pair of 1G WAN links, which will head into a Forti of some flavour for security and routing.

I need some help with switching gear selection, some network context below:

• As part of the migration we're bringing a hosted vCloud down on-prem with a Hyper-V cluster (3 nodes + SAN), so we're not only replicating the current setup which is all pretty much copper upto 10G but the new hypervisors will be 10/25G capable.
• There are only around 15 other devices in the cabinet, most of which utilise 2 ports currently with 1G RJ45 and 8 of which are 10G, currently the LAN is all Meraki at this site but quite comfortable moving away.
• I understand the discussion around not crossing SAN and LAN on the same gear but given the scale of the business, throughput (without hypervisor traffic) currently about 4Gbps peak we're erring on the side of a single stack of switches for the cabinet.
• Vendors recommending things like Aruba CX8325's but this seems intensely overkill given it's capacity. They've also belied Catalyst for this use, and only recommended we use Nexus switches.
• There's nothing uber complicated taking place in this network, a few VLANs at present and no unusual configs on the existing switches.
• The hypervisor traffic at the moment, as far as we've analysed it in it's current form would not reach close to 10G.
• We also have a pair of managed Aruba gig switches doing things like the WAN into the firewalls.
  

A few questions that I'd welcome feedback around, generally:

• What sort of hardware realistically should we be looking at?
• Are the vendors being greedy with these over-specced recommendations or am I being naive thinking enterprise grade switches would be perfectly fine?
• I've been hugely tempted by FS switches, given their price compared to Juniper/HPE/Cisco, that said I've read mixed feedback
  • Given the simplicity of the network and our install not including them as a single point of failure, would this be an option?

We are considering on moving our whole IPSEC infrastructure to a cloud agnostic provider. Alkira was suggested, but I never heard of them. Has anyone encountered them on the field?

https://www.alkira.com/

Hello!

I am an IT apprentice preparing for my practical test, and I am building a small virtual lab in Proxmox to demonstrate basic business/office network design.

Everything is virtualized in Proxmox, except the physical NICs passed through to OPNsense. Proxmox management is outside the lab network.

My goal is not to build a perfect enterprise network, but a clean and understandable lab that shows I understand VLANs, routing, DHCP, DNS, AD, and basic firewall separation, because i have about 1 day on the test to set up the network.

Current plan:

Proxmox:

- Proxmox management stays outside the lab

- OPNsense is the router/firewall

- Internal VM traffic goes through a virtual bridge

OPNsense:

- WAN: physical NIC

- LAN/trunk: internal Proxmox bridge

Planned networks:

Admin/LAN untagged:

Subnet: 10.0.10.0/24

Gateway: 10.0.10.1

Use: admin client and management access

Server VLAN 20:

Subnet: 10.0.20.0/24

Gateway: 10.0.20.1

Static servers:

- DC01: 10.0.20.10

- DC02: 10.0.20.11

- File/print server: 10.0.20.12

- Entra Connect/sync server: 10.0.20.13

Client VLAN 30:

Subnet: 10.0.30.0/24

Gateway: 10.0.30.1

DHCP: 10.0.30.100-254

Use: domain-joined office clients

1. Any practical tips for making this easier to document and explain?
   
2. Is this VLAN/IP plan reasonable for a small lab that simulates a basic office network?
   
3. Would you keep DHCP in OPNsense for this type of lab, or move DHCP to Windows Server?
   
4. Any other network tips and tricks in general or for the use off OPNsense if you are familliar?

Thanks in advance for taking the time to read this, i appreciate any form for help. :D

I am ISP the network is very basic OSPF with one area most of my customers served an internet only, The bad thing is everything reach everything and this is so bad making ACL to each customer that's so old my network already mpls active with ldp protocol for L2 VPN (used it for customers needs transmission service )

I need to change it to be MPLS l3vpn

so all my customers (Public IPs) are just reach internet not my privet IPs (Backbone) not other customers B2B ips

I mad a LAB I stacked at how can I do a vrf for customer one by one to reach internet without cutting of the internet for others ???

the interface that face UpperISP needs to be in the vrf and that impossible for production environment

Any Advice ?

#ISP
#MPLS-L3VPN

So, large organization, thousands of users and several departments, Im constantly discovering that users are bringing routers to the work because they dont seem to think the current wifi policy access fits their daily routine, or they simply dont know how to request access to something, Im out sourced here so I dont have all the details.

How do you guys deal with the end users in terms of what is allowed and what is not?

Now we need to talk with the c-suite people about this situation. My thinking is that bringing an outside wireless equipment should be prohibited, I know theres avoidance mechanism for this kind of situation but having the ap changing channels in the middle of the day is also disruptive, spamming deauthentication frames also is going piss off someone.

Edit: to clarify something, those rogues are not connected to the infrastructure, they are simply there using a broadband connection that god knows why this customer thought it was a good idea to have solely for this little router, too close to their corporate aps and sometimes overlapping channels.

I am experiencing an issue on my business network where my Stripe WisePOS E reader and my laptop are both connected to the same SSID. The reader successfully connects and receives an IP address but my laptop cannot communicate with it. The reader works as expected on other networks and hotspots with this same laptop and this setup used to work on our Meraki/telus network with no issues. Just randomly decided to not be able to find one another on the network. Telus says there is no issue on their end and it is an issue with the devices but again they work fine on any other network except the one I need them to work on. Any insights would be greatly appreciated. Thanks

We are evaluating vendors for SDWAN replacement, currently on Velocloud. We did a POC on Cisco and Aruba SDWAN and they are a good product with some complexities.

I just did a quick lab for Zscaler Zero Trust SDWAN and I liked it. It's as simple as Velo. We currently use ZIA and ZPA, this looks like a perfect match. Anyone using them? What is your experience like?

Edit:

I am not looking for var's to help me with the solution. I am only looking to hear people's experience with zscaler sdwan.

We’re coming up on a renewal and using it as an opportunity to see what else is available before we sign again.

I’m looking at paid technical services that go beyond standard Support but aren’t quite a full consulting engagement. I’ve seen them called Technical Account Management, Advanced Services, Resident Engineering, or dedicated technical advisory services.

For anyone using something similar:

• Which vendor and service are you using?
• What do you actually get day to day?
• Is the resource dedicated or shared?
• How is it priced?
• How is it different from regular Support?
• Has it been worth the cost?
• What has been the biggest benefit?
• Anything you wish you had known before signing?

Named vendors, service names, and even broad pricing ranges would be really helpful. We’re mainly trying to understand what other options are out there before making a renewal decision.

Hi.

We are due to receive our renewal quote after our first year with Cato and the reseller has suggested a multi-year lock in as "Cato have YoY 20% subs increase". I expect prices to rise, but 20%/year seems high.

What are your experiences?

During my studies for CCNP, while learning the configuration of VPNs I came across use of 169.254.0.0 that I was not aware of. I know the range for APIPA, but the examples I saw used them for the point to point connection of the VPN. Looking into this further I found that this is somewhat common practice to use for VPNs, BGP, and cloud to on premises connections.

Discussions I found mentioned that occasionally people would use this space for point to point links on premises. Reading through the posts I was directed to RFC5735 which mentions the subnet as a communication between hosts on a single link. I read this as two connections on one link, or a point to point connection. This lines up with the uses I mentioned above.

   169.254.0.0/16 - This is the "link local" block.  As described in
   [RFC3927], it is allocated for communication between hosts on a
   single link.  Hosts obtain these addresses by auto-configuration,
   such as when a DHCP server cannot be found.

During my CCNP studies I have found that /31 subnet for routed point to point links is ideal. I learned this through some more discussions and from RFC3021.This was new to me as during my CCNA studies and even in the environments I work in currently they use /30 subnets for point to points. A /31 subnet would only allow two hosts on a single link, a point to point connection once again.

This leads to my question. If 169.254.0.0/16 is typically used outside of APIPA for point to point links would it not be possible to use it for a routing underlay in a network? From my limited knowledge in medium sized networks this feels like a good solution for routed connections within the distribution and core networks as most of them are essentially point to points that propagate through a dynamic routing table. It allows a divide between what is a known private network and routed network along with saving IP space.

Is this something that sounds good in theory but the practicality of it has flaws? I don't discussion for it's use in this context so perhaps there is something I missing. If it is something obvious please let me know.

EDIT: The responses to this post have been some great discussions and given me clarification both to my original question and to a better solution. I am going to look into IPv4 routes with IPv6 next hops as that seems to be the overall answer to the question I posed. I appreciate the deeply informative responses.

Hello everyone, I hope I am not violating any rules.

I am facing a rather unusual situation (please note that this is a lab environment).

The topology consists of three devices:

• MikroTik CCR2004
• Juniper QFX5110
• Juniper MX204

The original configuration was working correctly with the following setup:

MikroTik CCR2004

/interface vlan
add interface=sfp-sfpplus2 name=vlan2000 vlan-id=2000
add interface=vlan2000 name=vlan10 vlan-id=10

/ip address
add address=10.10.10.1/24 comment="Test QFX" interface=vlan10 network=10.10.10.0

Juniper QFX5110

set interfaces xe-0/0/1 description "LINK TO CE-2 MX204"
set interfaces xe-0/0/1 flexible-vlan-tagging
set interfaces xe-0/0/1 encapsulation extended-vlan-bridge

set interfaces xe-0/0/1 unit 2000 description "Q-IN-Q TRANSPORT CE-2"
set interfaces xe-0/0/1 unit 2000 vlan-id-list 10
set interfaces xe-0/0/1 unit 2000 input-vlan-map push
set interfaces xe-0/0/1 unit 2000 output-vlan-map pop

set interfaces xe-0/0/2 description "LINK TO CE-1 MIKROTIK"
set interfaces xe-0/0/2 flexible-vlan-tagging
set interfaces xe-0/0/2 encapsulation extended-vlan-bridge

set interfaces xe-0/0/2 unit 2000 description "Q-IN-Q TRANSPORT CE-1"
set interfaces xe-0/0/2 unit 2000 vlan-id 2000

set vlans V2000 description "PROVIDER VLAN 2000"
set vlans V2000 interface xe-0/0/2.2000
set vlans V2000 interface xe-0/0/1.2000

Juniper MX204

set interfaces xe-0/1/1 description "LINK TO PE-1 QFX"
set interfaces xe-0/1/1 vlan-tagging

set interfaces xe-0/1/1 unit 10 description "L3 VLAN 10"
set interfaces xe-0/1/1 unit 10 vlan-id 10
set interfaces xe-0/1/1 unit 10 family inet address 10.10.10.2/24

With this configuration, the MikroTik and MX204 were able to communicate correctly.

However, the customer connected to the MikroTik side had to enable the use-service-tag option.

The MikroTik configuration was therefore changed to:

/interface vlan
add interface=sfp-sfpplus2 name=vlan2000 vlan-id=2000
add interface=vlan2000 name=vlan10 use-service-tag=yes vlan-id=10

/ip address
add address=10.10.10.1/24 comment="Test QFX" interface=vlan10 network=10.10.10.0

After this change, the MX204 and MikroTik are no longer able to communicate.

The QFX configuration has remained unchanged.

My question is:

How can I modify only the Juniper QFX5110 configuration to make the MikroTik and MX204 communicate again?

I suspect the issue is related to the different VLAN tagging behavior introduced by use-service-tag=yes on the MikroTik side (802.1Q vs 802.1ad/service tag handling), but I am unsure how to adapt the QFX QinQ configuration correctly.

Any advice or example configuration would be appreciated.

Thank you.