IP Infusion OcNOS 6.0: Tag Operations

IP Infusion MikroTik Uncategorized

IP Infusion OcNOS 6.0: Tag Operations

One of the biggest misconceptions I had before moving into the service provider space was that all layer 2 operations had been replaced with layer 3. I quickly found out that even if you are routing everything there are still a lot of layer 2 overlays in place, carrier ethernet, or even spanning-tree (STP). Running these technologies, hopefully not STP, is especially important rural broadband, electric co-ops, and telcos to enable things such as IP conservation and subscriber management on a broadband network gateway.

The side effect of layer 2 transport technologies being so heavily used in last mile internet service providers is having to understand vlan tagging operations. The are occasions where one side of the circuit will be double tagged and the other side will be single tagged or everything will be double tagged/single tagged/untagged. Let’s take a quickly look at some simple tag operations on IP Infusions OcNOS SP 6.0.

IGP and MPLS setup

We setup a simple topology of isis and ldp to create VPWS circuits. We are going to build two circuits in this example.

ipi-1.lab.jan1.us.ipa.net#show run mpls
<<output snipped>>
mpls l2-circuit TAG-TEST 123
mpls l2-circuit TEST-TAG-4 1234
<<output snipped>>
router ldp
 targeted-peer ipv4

VPWS and Attachment Circuit Topology

We are going to attach the circuits to the same physical ports and utilize tags to place the traffic into the correct VPWS circuit. Mikrotik-1 is double tagged and Mikrotik-2 is single tagged.

If you’ve built pseudowires on OcNOS before you might be familiar with the service-template model. However, when building VPWS circuits and utilizing the same interface this isn’t an option. You have to make a subinterface that is a switchport. This also changes the method for tag operations.

ipi-1.lab.jan1.us.ipa.net#show run interface

<<output snipped>>

interface xe2
interface xe2.3 switchport
 encapsulation dot1q 3 inner-dot1q 400-499
 rewrite pop
  mpls-l2-circuit TAG-TEST primary
interface xe2.4 switchport
 encapsulation dot1q 4 inner-dot1q 400-499
 rewrite pop
  mpls-l2-circuit TEST-TAG-4 primary

The switchport subinterfaces are then assigned as an access interface matching specific tags. In this case outer tag 3 and inner tag 400-499. On IPI-2 we are expecting single tagged frames instead of double tagged. This is where the rewrite pop comes in. This will remove the outer tag on ingress to the PW and push it back on on egress towards Mikrotik-1.

ipi-2.lab.jan1.us.ipa.net#show run interface

<<output snipped>>

interface xe11
 speed 1g
interface xe11.4 switchport
 encapsulation dot1q 401
  mpls-l2-circuit TEST-TAG-4 primary
interface xe11.400 switchport
 encapsulation dot1q 400
  mpls-l2-circuit TEST-TAG primary

Since the AC towards Mikrotik-2 is only expecting single tagged packets we just do a simple match on encapsulation.

Let’s do some verification. First we’ll verify that the circuits are up.

ipi-2.lab.jan1.us.ipa.net#show ldp targeted-peers
IP Address          Interface         xe48

ipi-2.lab.jan1.us.ipa.net#show ldp mpls-l2-circuit
Transport     Client     VC     VC            Local       Remote      Destination
VC ID         Binding    State  Type          VC Label    VC Label    Address
123           xe11.400   UP     Ethernet VLAN 25602       26240
1234          xe11.4     UP     Ethernet VLAN 25603       26241

ipi-2.lab.jan1.us.ipa.net#show ldp mpls-l2-circuit detail
PW ID: 123, VC state is up
Access IF: xe11.400,up,AC state is up
Session IF: xe48, state is up
Destination:, Peer LDP Ident:
Local vctype: vlan, remote vctype :vlan
Local groupid: 0, remote groupid: 0
Local label: 25602, remote label: 26240
Local MTU: 1500, Remote MTU: 1500
Local Control Word: disabled  Remote Control Word: Not-Applicable  Current use: disabled
Local Flow Label Direction: Disabled, Static: Disabled
Remote Flow Label Direction: Both , Static: Disabled
Local PW Status Capability : disabled
Remote PW Status Capability : disabled
Current PW Status TLV : disabled

PW ID: 1234, VC state is up
Access IF: xe11.4,up,AC state is up
Session IF: xe48, state is up
Destination:, Peer LDP Ident:
Local vctype: vlan, remote vctype :vlan
Local groupid: 0, remote groupid: 0
Local label: 25603, remote label: 26241
Local MTU: 1500, Remote MTU: 1500
Local Control Word: disabled  Remote Control Word: Not-Applicable  Current use: disabled
Local Flow Label Direction: Disabled, Static: Disabled
Remote Flow Label Direction: Disabled, Static: Disabled
Local PW Status Capability : disabled
Remote PW Status Capability : disabled
Current PW Status TLV : disabled 

Then let’s verify that we can pass traffic.

Mikrotik-1 Interfaces
Mikrotik-1 ping results
Mikrotik-2 Interfaces

We have successfully manipulated the tags and passed traffic end to end. We started with a double tagged packet, pop off the outer tag, placed it into a PW, spit out a single tagged packet, and had end to end reachability.


There are various methods and configurations to manipulate traffic. This is one of the more common examples of tag manipulation that occurs in broadband aggregation. I will explore tag manipulation with service-templates and VPLS in a later post.

MikroTik RouterOSv7

WEBINAR: MikroTik RouterOS v7: Layer 3 Deep Dive

Recently, we recorded a webinar to explain a design concept frequently used by iparchitechs.com to build and migrate WISP, FISP and Telco networks – separation of network functions. It centers around simplification of roles within an ISP network. It also explores the use of lower-cost commodity network equipment to maximize the service area for a given ISP footprint while meeting key requirements like scale, redundancy and capacity.

Video: https://iparchitechs.com/presentations/2022-RouterOS7-Layer-3-Deep-Dive/RouterOS-7-Layer-3-Deep-Dive.mp4

Slides: https://iparchitechs.com/presentations/2022-RouterOS7-Layer-3-Deep-Dive/RouterOS-7-Layer-3-Deep-Dive.pdf

Topics that were covered include:

  • ROSv7 basics, lab setup and /routing/route/
  • BGP and OSPF for IPv4 and IPv6
  • L3 hardware offload for IPv4/IPv6 unicast and nat hardware offload for IPv4

Overview of the lab network used to test MikroTik ROS v7

MikroTik RouterOSv7

MikroTik RouterOS v7.5 stable released

The pace of development for MikroTik RouterOS version 7 has definitely sped up in 2022 and we are seeing the results in improved stability and features added.

As of August 31st, 2022, MikroTik moved ROS v7.5rc2 into v7.5 stable

MikroTik Routers and Wireless – Software

Noteworthy additions

dhcpv6-relay – not being able to relay a PD request from a delegating router for IPv6 has been a limitation of MikroTik routers for a while so getting this fixed has a big impact on scaling MikroTik IPv6 deployments

RTSP helper – The addition of a Real Time Streaming Protocol helper is a great addition to ROSv7 to make NAT traversal for realtime applications (IPTV, SIP and IP cameras) easier.

A good overview of the discussion leading up to the addition of RTSP is here: RTSP Helper – MikroTik

l3hw – fixed hw offloaded NAT – This feature still has some issues as IP ArchiTechs recently filed a bug (SUP-91389) where src-nat traffic that carries an H flag in the connection table will die after 1 hour with a 10G load on the router. Once this feature receives further bug fixes and testing, it’s going to be very useful for high capacity but low cost NAT44 gateways.

lte – this category got a significant amount of development work as there are numerous fixes with many relating to the Chateau devices.

wifiwave2 – There was also a significant amount of development in wifi wave 2 which included notable additions like 802.11k for roaming.

 vrrp – added “sync-connection-tracking” compatibility with preemption-mode – this is a long awaited feature that showed up early in ROSv7 but did not have pre-emption mode capabilities. The addition of connection synching between routers positions MikroTik routers much closer to traditional enterprise firewall vendors so that failover between devices can include connections.

MikroTik RouterOSv7

MikroTik: Upgrading from ROSv6 to ROSv7

One of the common questions asked by MikroTik users is how to go about upgrading from ROSv6 to ROSv7.

Before upgrading, always make sure:

– The config is backed up using ‘export’ and ‘backup’ and the files have been moved off the router
– Console access is working (if applicable)
– A method to netinstall is available in case the upgrade fails for any reason

Understanding config migration

MikroTik added a helpful chart to the support docs that shows what config is automatically upgraded and what needs to be manually adjusted.

Upgrading to v7 – RouterOS – MikroTik Documentation

Exceptions and notes

BGP config migration has gotten better in the last few versions of v7. For the most part, it works without intervention but occasionally config will need to be removed and readded or edited.

Note the changes below to the structure of BGP menus and peerings as it has changed.

OSPF has come a long way in RouterOS v7 and is stable as well as interoperable with RouterOSv6. Interface templates have replaced network statements to advertise prefixes and form neighbor adjacencies, so be sure to look in that menu after upgrade to work with network statements in v7. Upgrading to v7 for OSPF normally works without issue or intervention.

MPLS is still a work in progress. Like the other protocols it has gotten better but still may need adjustments since it now includes the AFIs for IPv4 and IPv6 with LDP. Be sure to review the syntax pre and post upgrade as well as the operation state and be prepared to delete and re-add the configuration as needed if MPLS is not functional post upgrade. In general, MPLS and VPLS works between ROSv6 and ROSv7

Routing filters are also a work in progress. Most of the functionality and config upgrade works now when moving to v7 but the context sensitive help and tab complete is still being developed and filled in.

For more details, take a look at this article: MikroTik – RouterOSv7 first look – feedback on routing filters – StubArea51.net

User manager has no direct upgrade path available and must be migrated manually.

MikroTik Network Engineering

Understanding the MikroTik Support process

Understanding how the MikroTik support process works and how to ask for help can save a lot of time and frustration when you need assistance with features, configurations, hardware or potential bugs.

MikroTik Support…where do I start?

There are a number of ways to get assistance with MikroTik devices and software including: Jira ticket support, documentation, forums, Reddit, Facebook, distributors and professional consulting. One thing to keep in mind for all correspondence with MikroTik is they are based in Riga, Latvia which is GMT+3 in the spring/summer and GMT +2 in the fall/winter.

Current time in Riga, Latvia

MikroTik Documentation

As RouterOS Version 7 was released in Beta, MikroTik began moving to Confluence for documentation instead of the Wiki.

RouterOS – RouterOS – MikroTik Documentation

The information in the new documentation is better organized and the visuals are all being updated to give the docs a consistent feel.

Here is an example from the OSPF section under routing protocols:

MikroTik Forums

MikroTik – Forum index

This is probably the best place to start if you need assistance figuring out an issue or what support avenue to use.

The MikroTik forums are a great resource as long as you do a little homework.

The key to getting answers out of the forums is to provide:

  • – Information that describes the issue and how to repeat it (if possible)
  • – Configurations (edited for sensitive information)
  • – Drawings to help clarify your issue.
  • – Software versions
  • – Hardware being used and interop with other vendors (if relevant)

Forum members and official MikroTik support members are more likely to provide support when they can read a post and quickly offer a recommendation without having to ask lots of follow up questions.

Tips for getting the most out of the forums


Use the search feature in the forums to see if your issue has been discussed before

Use google to help with this by adding site:forum.mikrotik.com in your search.


If possible, try all of the latest code versions from the Long Term, Current, Release Candidate and Beta versions to see if it resolves the issue.

Writing your posts

Read MikroTik’s suggestions for writing a forum post which includes text formatting suggestions:

Getting the most out of the MT forum

ASCII drawings’ and network drawings using paint or other drawing programs make it more difficult to understand the topology.

Use a program like Visio or lucidchart.com to illustrate your network topology.

Describing the network topology (even a simple one) makes it much harder for people to help you.

If you want answers, draw it out.

Forum Etiquette

Be polite – don’t ‘demand’ answers if nobody has answered your question in a few hours. Sometimes it takes a while to get the right answers.

The more you contribute to the forum, the more likely you’ll be to get answers when you need them.

Users who only ask questions and never provide feedback or help other users don’t tend to get as much help after a while.

For the reason above, the forum should not be considered a resource to address critical and time-sensitive issues – the forums are best for issues that don’t need to be resolved immediately.

Official MikroTik support – Jira

Service Management (mikrotik.com)

Prior to 2020, MikroTik support used e-mail ticketing to work issues which made complex issues a little harder to work on as the chain of discussion was sometimes difficult to follow.

Move to Jira

MikroTik migrated to Jira in 2020 which improved the support experience.

The key to understanding how to interact with MikroTik support is much like the advice for the forums. The more complete and well documented your ticket is, the better chance you have of getting a resolution.

The most important part of opening a ticket is to test the issue you’re experiencing on all versions of RouterOS 6 or 7 (Long Term, Stable, Release Candidate, Beta) and obtain a supout.rif for each of them.

This is very important as it will minimize a follow up e-mail from MikroTik support asking you to upgrade and then test again.

Tips for opening and managing a ticket

Provide detailed information.

  1. – Description of the issue and the steps to repeat it.
  2. – Network drawings.
  3. – Configurations of other devices (if relevant)
  4. – Packet captures (can be very helpful to identify
    and correct bugs

Be aware of the time difference between where you are and MikroTik (Riga, Latvia) – If you send and respond to support tickets during hours that MikroTik is awake and working, you’ll sometimes see faster responses but there is no guaranteed response time.

Waiting for bug fixes

Understand the limitations of fixing issues in RouterOS – If something can be fixed quickly, MikroTik is pretty good about getting it fixed and released.

Some issues can be patched easily and MikroTik will put them in the list for a future RouterOS release.

Some issues take longer to patch due to complexity and may be a while before they can be tested and

Certain issues cannot be fixed due to limitations in the Linux kernel and MikroTik will usually tell you if this is the case although with RouterOS 7 now released, this may happen less often than it did with RouterOS 6.

MikroTik Distributors

MikroTik Distributors can be a great source of support for assistance with setup and configuration as well as issues with hardware.

If you suspect that you have a hardware issue that might require an RMA, try a netinstall first to see if that
corrects the issue and if it doesn’t, work with your distributor to replace the device.

Netinstall – RouterOS – MikroTik Documentation

MikroTik Experts (Unofficial) Facebook group

Mikrotik Experts | Facebook

The MikroTik Experts group is a fantastic source of information and news about MikroTik.

Many of the same rules as the forums apply in the Facebook group.

Be sure to search the group to see if your question has already been asked, be polite and be as detailed as possible when asking questions to get better answers.

This is actually one of the fastest ways to get answers as the group is rather large and many MikroTik consultants participate in the group and are willing to help newcomers.

Professional MikroTik Consulting

If all of the other resources don’t seem to get you the answer you’re looking for or you don’t have time to
wait, consider hiring a professional MikroTik consultant.

MikroTik consultants must hold at least one engineering level certification to be listed on the consulting list.

Participation in the MikroTik forums, Attendance at MikroTik User Meetings and presentation at MikroTik
User Meetings all influence the ranking of a MikroTik consultant.


IP ArchiTechs is the largest MikroTik consulting company in the world and has certified MikroTik consultants on multiple continents.