Alexei Cherubin
@acherubin.bsky.social
#DalhousieU Alum / Former Design Engineer / Former Physics Teacher / Content Creator (https://youtube.com/@AlexeiCherubin) / #NeverGiveUp
Just testing out a new screen recorder. May need to lower the resolution a bit. Works well though. Have a look:
👇👇👇
youtu.be/g5RI9vnYwWk
#cisco #ciscomodelinglabs #cml
👇👇👇
youtu.be/g5RI9vnYwWk
#cisco #ciscomodelinglabs #cml
Cisco Modeling Labs - Basic OSPF Lab
YouTube video by Alexei Cherubin
youtu.be
January 4, 2026 at 5:11 PM
Just testing out a new screen recorder. May need to lower the resolution a bit. Works well though. Have a look:
👇👇👇
youtu.be/g5RI9vnYwWk
#cisco #ciscomodelinglabs #cml
👇👇👇
youtu.be/g5RI9vnYwWk
#cisco #ciscomodelinglabs #cml
I have been busy tinkering with a VLAN Trunking lab. It is not something I practiced every day when I was working. All VLANs are encapsulated using 802.1q. alpine-0 can ping alpine-3 after passing through the trunk.
#cisco #ciscomodelinglabs #cml #VLAN #TRUNK
#cisco #ciscomodelinglabs #cml #VLAN #TRUNK
December 15, 2025 at 5:21 AM
I have been busy tinkering with a VLAN Trunking lab. It is not something I practiced every day when I was working. All VLANs are encapsulated using 802.1q. alpine-0 can ping alpine-3 after passing through the trunk.
#cisco #ciscomodelinglabs #cml #VLAN #TRUNK
#cisco #ciscomodelinglabs #cml #VLAN #TRUNK
As a Data Engineering Assistant providing support for the core network at C&W, I would deal with routing problems daily. I did not get much experience with switching issues. I'm now taking the time to catch up on switching problems I was exposed to in the CCNA back then.
#VLAN
#VLAN
December 7, 2025 at 8:23 AM
As a Data Engineering Assistant providing support for the core network at C&W, I would deal with routing problems daily. I did not get much experience with switching issues. I'm now taking the time to catch up on switching problems I was exposed to in the CCNA back then.
#VLAN
#VLAN
I just uploaded a new video on OSPFv3 routing. It was designed for routing IPv6 packets but it also caters to IPv4.
Have a look.
👇👇👇
youtu.be/zHHtduvkfhU
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
Have a look.
👇👇👇
youtu.be/zHHtduvkfhU
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
Cisco Modeling Labs - OSPFv3 Routing
YouTube video by Alexei Cherubin
youtu.be
November 19, 2025 at 9:24 PM
I just uploaded a new video on OSPFv3 routing. It was designed for routing IPv6 packets but it also caters to IPv4.
Have a look.
👇👇👇
youtu.be/zHHtduvkfhU
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
Have a look.
👇👇👇
youtu.be/zHHtduvkfhU
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
I added some alpine nodes to my OSPFv3 lab to show how the routing works. From alpine-0, a packet takes the path with the least cost to get to alpine-1. This is through R3. The attached diagram clearly illustrates this.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
November 19, 2025 at 7:23 AM
I added some alpine nodes to my OSPFv3 lab to show how the routing works. From alpine-0, a packet takes the path with the least cost to get to alpine-1. This is through R3. The attached diagram clearly illustrates this.
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
#cisco #ciscomodelinglabs #cml #IPv6 #OSPFv3
OSPFv3 uses IPv4 loopback addresses as router IDs. Don't get confused. I did when I first learnt this stuff. Link-local addresses in the routing table are used where possible. Other than that OSPFv3 functions mostly like a standard OSPF routing protocol.
#cisco #ciscomodelinglabs #cml #OSPFv3
#cisco #ciscomodelinglabs #cml #OSPFv3
November 14, 2025 at 11:52 AM
OSPFv3 uses IPv4 loopback addresses as router IDs. Don't get confused. I did when I first learnt this stuff. Link-local addresses in the routing table are used where possible. Other than that OSPFv3 functions mostly like a standard OSPF routing protocol.
#cisco #ciscomodelinglabs #cml #OSPFv3
#cisco #ciscomodelinglabs #cml #OSPFv3
Here's a NAT lab I cooked up tonight. It involves NAT, OSPF, Containers and DNS. I did something like this before but they were no docker containers in CML then. I love labs like this.
#cisco #ciscomodelinglabs #cml #NAT #OSPF #Docker #Containers
#cisco #ciscomodelinglabs #cml #NAT #OSPF #Docker #Containers
November 6, 2025 at 3:15 AM
Here's a NAT lab I cooked up tonight. It involves NAT, OSPF, Containers and DNS. I did something like this before but they were no docker containers in CML then. I love labs like this.
#cisco #ciscomodelinglabs #cml #NAT #OSPF #Docker #Containers
#cisco #ciscomodelinglabs #cml #NAT #OSPF #Docker #Containers
Attached is a simple GRE Tunnel. The screenshots show that if you overlay a typical network, you will observe that you will get an additional IPv4 header encapsulated in a GRE header. This is all shown in the Wireshark packet capture.
#cisco #ciscomodelinglabs #cml #GRE
#cisco #ciscomodelinglabs #cml #GRE
October 20, 2025 at 10:03 AM
Attached is a simple GRE Tunnel. The screenshots show that if you overlay a typical network, you will observe that you will get an additional IPv4 header encapsulated in a GRE header. This is all shown in the Wireshark packet capture.
#cisco #ciscomodelinglabs #cml #GRE
#cisco #ciscomodelinglabs #cml #GRE
Having trouble with DNSMASQ in CML v2.9? Watch my new video.
👇👇👇
youtu.be/hH_SYGbTTMc
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #DOCKER #DNSMASQ
👇👇👇
youtu.be/hH_SYGbTTMc
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #DOCKER #DNSMASQ
Cisco Modeling Labs - DNSMASQ Container
YouTube video by Alexei Cherubin
youtu.be
September 1, 2025 at 7:16 AM
Having trouble with DNSMASQ in CML v2.9? Watch my new video.
👇👇👇
youtu.be/hH_SYGbTTMc
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #DOCKER #DNSMASQ
👇👇👇
youtu.be/hH_SYGbTTMc
Feel free to like and subscribe.
#cisco #ciscomodelinglabs #cml #DOCKER #DNSMASQ
I got the DNSMASQ container to work. However, the DHCP and TFTP functionality seems to be difficult. I'll keep working on this.
#cisco #ciscomodelinglabs #cml #DNSMASQ
#cisco #ciscomodelinglabs #cml #DNSMASQ
August 22, 2025 at 5:44 PM
I got the DNSMASQ container to work. However, the DHCP and TFTP functionality seems to be difficult. I'll keep working on this.
#cisco #ciscomodelinglabs #cml #DNSMASQ
#cisco #ciscomodelinglabs #cml #DNSMASQ
In this short video I go through the functionality of the new docker containers in CML v2.9. Feel free to like and subscribe.
youtu.be/CMUrmWoA_nw
#cisco #ciscomodelinglabs #cml #DOCKER #containers
youtu.be/CMUrmWoA_nw
#cisco #ciscomodelinglabs #cml #DOCKER #containers
Cisco Modeling Labs - Basic Network Lab with Containers
YouTube video by Alexei Cherubin
youtu.be
August 14, 2025 at 4:30 AM
In this short video I go through the functionality of the new docker containers in CML v2.9. Feel free to like and subscribe.
youtu.be/CMUrmWoA_nw
#cisco #ciscomodelinglabs #cml #DOCKER #containers
youtu.be/CMUrmWoA_nw
#cisco #ciscomodelinglabs #cml #DOCKER #containers
I try to get in as much IPv6 work as possible these days. In the screenshots I created a IPv6 Tunnel Lab which uses docker containers. The Chrome container takes the IPv6 address notation of [2001:db8:1::2]. The brackets are necessary for Chrome to understand it is an IPv6 address.
#cml #IPV6
#cml #IPV6
August 1, 2025 at 4:48 AM
You have to update to CML v2.9. So much new features in this release.
July 24, 2025 at 7:49 AM
You have to update to CML v2.9. So much new features in this release.
In the attached screenshot I use the Firefox, Chrome and NGINX docker containers to see the translations involved in a web page transaction. You can clearly see port 80 on the NGINX container being accessed by the Chrome container.
July 21, 2025 at 12:15 PM
In the attached screenshot I use the Firefox, Chrome and NGINX docker containers to see the translations involved in a web page transaction. You can clearly see port 80 on the NGINX container being accessed by the Chrome container.
Here is a router on a stick lab I just finished. I use the Firefox, Chrome and NGINX docker containers. The two "browser" containers access the NGINX server from VLAN 10, which is dedicated to Management. the NGINX server is on VLAN 20.
July 21, 2025 at 12:09 PM
Here is a router on a stick lab I just finished. I use the Firefox, Chrome and NGINX docker containers. The two "browser" containers access the NGINX server from VLAN 10, which is dedicated to Management. the NGINX server is on VLAN 20.
Here are the Cisco Modeling Labs v2.9 release notes. It details everything about installing, configuring, and utilizing CML v2.9.
developer.cisco.com/docs/modeling-…#ciscoc#ciscomodelinglabsb#cmlml
developer.cisco.com/docs/modeling-…#ciscoc#ciscomodelinglabsb#cmlml
https://developer.cisco.com/docs/modeling-…
July 21, 2025 at 12:06 PM
Here are the Cisco Modeling Labs v2.9 release notes. It details everything about installing, configuring, and utilizing CML v2.9.
developer.cisco.com/docs/modeling-…#ciscoc#ciscomodelinglabsb#cmlml
developer.cisco.com/docs/modeling-…#ciscoc#ciscomodelinglabsb#cmlml
I made some adjustments to the OSPF lab I was building. I introduced "Area 1" to show OSPF inter-area routing. the OSPF database is now populated with Area 1 entries. Also, the routing table now has "O IA" next to some of the routes to show that they are inter-area.
July 19, 2025 at 6:12 AM
I made some adjustments to the OSPF lab I was building. I introduced "Area 1" to show OSPF inter-area routing. the OSPF database is now populated with Area 1 entries. Also, the routing table now has "O IA" next to some of the routes to show that they are inter-area.
Here is another screenshot of a simple OSPF lab. It shows the OSPF database. The "show ip ospf database" command displays the contents of the OSPF database on a Cisco router.
#cisco #ciscomodelinglabs #cml #OSPF
#cisco #ciscomodelinglabs #cml #OSPF
July 18, 2025 at 5:12 AM
Here is another screenshot of a simple OSPF lab. It shows the OSPF database. The "show ip ospf database" command displays the contents of the OSPF database on a Cisco router.
#cisco #ciscomodelinglabs #cml #OSPF
#cisco #ciscomodelinglabs #cml #OSPF
Here's another look at the OSPF lab I was working on. I'm using an Alpine Linux node (PC1) to ping and traceroute to the far end of the network. R2 is the designated router (DR) and is receiving routes from R1 and R3.
#cisco #ciscomodelinglabs #cml #OSPF
#cisco #ciscomodelinglabs #cml #OSPF
July 14, 2025 at 7:38 AM
Here's another look at the OSPF lab I was working on. I'm using an Alpine Linux node (PC1) to ping and traceroute to the far end of the network. R2 is the designated router (DR) and is receiving routes from R1 and R3.
#cisco #ciscomodelinglabs #cml #OSPF
#cisco #ciscomodelinglabs #cml #OSPF
July 7, 2025 at 2:37 AM
I just finished uploading a video in YouTube which shows how NGINX can be used in CML to investigate ports in NAT translations. It is a fairly easy lab that I hope you can enjoy.
Have a look: 👇
youtu.be/q_wdwouYeNk
Have a look: 👇
youtu.be/q_wdwouYeNk
Cisco Modeling Labs - NAT Lab with NGINX
YouTube video by Alexei Cherubin
youtu.be
June 30, 2025 at 3:34 AM
I just finished uploading a video in YouTube which shows how NGINX can be used in CML to investigate ports in NAT translations. It is a fairly easy lab that I hope you can enjoy.
Have a look: 👇
youtu.be/q_wdwouYeNk
Have a look: 👇
youtu.be/q_wdwouYeNk
Here's a look at my NGINX lab again. When I attempt to view the webpage on my NGINX server from the Desktop PC, I get a log on my NGINX server that points to the outside NAT IP 200.64.0.1. This is expected.
It brings back memories of when I was a network administrator. Good times.
#cisco
It brings back memories of when I was a network administrator. Good times.
#cisco
June 23, 2025 at 3:49 PM
Here's a look at my NGINX lab again. When I attempt to view the webpage on my NGINX server from the Desktop PC, I get a log on my NGINX server that points to the outside NAT IP 200.64.0.1. This is expected.
It brings back memories of when I was a network administrator. Good times.
#cisco
It brings back memories of when I was a network administrator. Good times.
#cisco
In this lab, I use a Desktop node to show a basic web page ("Hello World!") I put on a NGINX Server. The NGINX server represents a web server on the internet. It is located outside the NAT router and the translation is clearly seen.
#cisco #ciscomodelinglabs #cml #NGINX #NAT
#cisco #ciscomodelinglabs #cml #NGINX #NAT
June 19, 2025 at 1:33 PM
In this lab, I use a Desktop node to show a basic web page ("Hello World!") I put on a NGINX Server. The NGINX server represents a web server on the internet. It is located outside the NAT router and the translation is clearly seen.
#cisco #ciscomodelinglabs #cml #NGINX #NAT
#cisco #ciscomodelinglabs #cml #NGINX #NAT
I came across the "Netmiko" Python Library today and decided to try it out. The attached shows the code I used and the output in the terminal. A simple 'show ip int brief'.
#cisco #ciscomodelinglabs #cml #netmiko #python
#cisco #ciscomodelinglabs #cml #netmiko #python
June 11, 2025 at 1:56 PM
I came across the "Netmiko" Python Library today and decided to try it out. The attached shows the code I used and the output in the terminal. A simple 'show ip int brief'.
#cisco #ciscomodelinglabs #cml #netmiko #python
#cisco #ciscomodelinglabs #cml #netmiko #python
I'm still busy coding in my RESTCONF lab. The attached shows the topology of the lab I'm working on. Also shown is some code in "vs code". You can use a Linux node within CML or vs code in Windows to fiddle with your RESTCONF code.
#cisco #ciscomodelinglabs #cml #restconf #python #vscode
#cisco #ciscomodelinglabs #cml #restconf #python #vscode
June 11, 2025 at 1:55 PM