Orhan Ergun No Comments

Introduction to VPN (Virtual Private Network)

Introduction to VPN (Virtual Private Network)

Let’s start with the definition. VPN is a logical network and created over shared physical infrastructure.

Shared infrastructure can be private such as MPLS VPN of a Service Provider or over the Public infrastructure such as Internet.

There are many concepts to understand VPN in detail but in this article I will cover the definition, common design considerations, and some not well known concepts about it.

We can group VPNs into two categories. WAN and the Datacenter VPN Technologies.

WAN VPN Technologies

1.GRE

2.mGRE (Multipoint GRE)

3. IPSEC

4. DMVPN

5.GETVPN

6.L2TPV3

7.LISP

8. MPLS L3 VPN Read more

Orhan Ergun No Comments

BGP in MPLS Layer 3 VPN – BGP as a PE-CE Routing Protocol

BGP can be used as a PE-CE routing protocol in MPLS Layer 3 VPN. Also Service Providers run MP-BGP (Multiprotocol BGP) if they have MPLS Layer 3 VPN.

In this article, MP-BGP will not be explained since it has been explained here earlier in detail.

When BGP is used as a PE-CE routing protocol between the customer and its MPLS Layer 3 VPN Provider, it is important to say that there is no need to redistribute on the Service Provider PE. All the other routing protocol require redistribution from MP-BGP into the routing protocol and vice versa.

In this post, I will explained what are the design considerations when BGP is used as PE-CE routing protocol in MPLS Layer 3 VPN and the how you can mitigate possible routing loop problems.

Last but not least, I will share when CE (Customer Equipment) is multihomed to two PEs (Provider Edge Device), what would be the design considerations if BGP is used in MPLS Layer VPN. Read more