BGP AS-PATH manipulation techniques: local-as, prepending, allowas-in, as-override
The AS-PATH is one most interesting BGP path attribute. It's a well known, mandatory, and transitive path attribute, so it must be included in every…
Read more →Welcome to my website!
This is my blog, I've been preparing for my CCNP exam, so I mostly write posts about networking stuff recently: Routing/switching, BGP, OSPF, Multicast, MPLS VPNs, Security, QoS etc. Currently I have the CCNP ENARSI, the CCNA and the Linux+ certifications, I also have a degree in telecommunication.
I sometimes create educational videos, check out my YouTube Channel: Networking Explained
Implementing Unified MPLS
Because of scalability reasons we might have multiple IGP processes running within our core network. If we have many routers and prefixes we might have…
Read more →Crating a Python script to control the GPIO of my Raspberry Pi
To practice for my CCNP ENCOR I've been creating simple Python scripts recently. I've got a few Raspberry Pis and temperature sensors lying around at…
Read more →Implementing MPLS-TE: VPN over the TE tunnel from PE to PE, TE metric, explicit-path
By default the IGP metric (ISIS/OSPF cost) determines how the packets are forwarded within the MPLS core. With MPLS Traffic Engineering (TE) we can be…
Read more →Ethernet Flow Point: VLAN tag manipulation for the VPLS service
We continue one of my previous VPLS topology: this time we're going to take a look at what happens from the perspective of the service…
Read more →Implementing Site-to-Site IPsec VPN: GRE over IPsec and MTU issues (Part 3)
In the previous post I created the VPN tunnel between the two sites with a crypto map. This implementation is very static, the ACLs define…
Read more →Implementing Site-to-Site IPsec VPN with crypto map (Part 2): Troubleshooting
We continue the previous IPsec lab with basic troubleshooting. If you haven't read part 1, read that post first before you continue. So what are…
Read more →Implementing Site-to-Site IPsec VPN with crypto map (Part 1)
In this lab we're going to establish secure communication between two private subnets located at two different sites over an unsecure network (the internet for…
Read more →Multicast over MPLS: mVPN Profile 1 and Profile 13
After going through how we can configure Profile 0, this time we're going to take a look at two other profiles which both require mLDP.
Read more →Multicast over MPLS: mVPN Profile 0 (Draft Rosen)
Previously I wrote a few posts about how multicast works but only within an enterprise environment without MPLS. This time we're going to take a…
Read more →Configuring multi-area OSPF with Ansible
This time we're going to configure OSPF, but not with the CLI, we're going to use a network automation tool called Ansible. I'm going to…
Read more →Carrier Supporting Carrier (CSC) MPLS L3VPN
After going through inter-AS Option A, B and C, this time we take a look at the CSC implementation. This is very similar to the…
Read more →Implementing High Availability with Bidirectional Forwarding Detection (BFD)
How can a router detect when a BGP neighbor, or just any kind of IGP neighbor device goes down? If the two devices are directly,…
Read more →Implementing OSPF Sham-link
We're going to continue the previous inter-AS L3VPN Option C lab, and in this post we're going to be focusing on customer GREEN who runs…
Read more →Implementing Inter-AS MPLS L3VPN services with Option C
We finish the inter-AS L3VPN series with Option C: As I foreshadowed in the end of the of the Option B post, Option C is…
Read more →Implementing Inter-AS MPLS L3VPN services with Option B
In the previous post we've seen how we can set up an inter-AS L3VPN with Option A. We continue this lab, but this time we'll…
Read more →Implementing Inter-AS MPLS L3VPN services with Option A
What if a single customer wants to have an MPLS L3VPN service, but he has to connect with his CE routers to two different service…
Read more →BGP on IOS-XR: Route Policy Language (RPL)
I've been learning BGP on IOS-XR recently. Configuring inbound or outbound BGP policies on IOS-XR is quite different than on IOS-XE or regular IOS. On…
Read more →BGP Route Reflector Design Options (Part 2): Hierarchical 2-tier Route Reflectors, MCIDs
The issue of the previous Route Reflector (RR) design is that it is not protected from a single point of failure: if a RR goes…
Read more →BGP Route Reflector Design Options (Part 1): Inter-Cluster Peerings
If we have many iBGP routers within an AS, to solve the scalability issue of the full-mesh requirement we can deploy one (or more) iBGP…
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