Containers (Docker) - OS Virtualization

Lately I have been looking at some application virtualization stuff. Majority of us are aware of  how server virtualization works however the concept of application virtualization is relatively new.

To understand what it is, let's first see what server virtualization is. In the old days, organizations used to keep physical servers to run their applications. Normally one physical server would be used to run one or two specific applications. Depending on the number of applications, companies had to maintain server farms which meant management of multiple Hardwares and Softwares, paying for CoLo space and electricity bill for all the physical devices.

Migration Methods

In this post, we will discuss various options to migrate customer's network from one service provider to other service provider. 

Let's assume that you work for an enterprise customer with three sites. All the sites are currently connected through a Layer 3 IPVPN solution provided by service provider A.

MPLS Traffic Engineering

In this post, we will discuss about MPLS Traffic Engineering. To understand where it can be used and what problems it can resolve, let's look at the below topology.

The CE1 and CE2 are customer edge devices with LAN subnet of 1.1.1.1/32 and 7.7.7.7/32 respectively. They are connected with corresponding PE1 and PE2. We are running OSPF and LDP in the service provider core. Both the PE devices exchange VPN labels via MP-BGP and transport label via LDP. 

BGP PIC EDGE

Continuing from our previous post, we will now see how BGP PIC EDGE works. We will use the same topology. The only difference is that I have removed R4 as route-reflector. All the PEs have full mesh IBGP neighbourship. 

At the moment R2 learns 8.8.8.8/32 from R6 and R7. It prefers the path with the next-hop of 6.6.6.6 over 7.7.7.7.

BGP PIC CORE

Happy New Year Folks!

In one of the previous posts, we looked at EIGRP FRR and OSPF LFA feature which helps achieving fast convergence.

There is a similar feature  in BGP which is called PIC (Prefix Independent Convergence). It speeds up the convergence of the FIB in failover conditions. BGP works differently than any IGP. It is designed to carry hundreds of thousands routes in the routing table hence fast failover works differently in BGP. There are couple of ways to implement PIC in BGP. They are "PIC Core" and "PIC Edge". We will look into both of these options.

Let's look at the below topology.