Genie's Tech Blog

Where knowledge has no dimensions

BGP RT Constrained Route Distribution

For Handling unnecessary processing of prefixes of RT which are not imported on the PE routers we use the feature called Route-Target Constraint. With Route Target Constraint (RTC), the RR sends only those VPN4/6 prefixes to the PE that the PE has VRF importing those specific route-targets. [More]

Inter-AS MPLS VPN - Back to Back VRF

Hello All, Today, We are going to discuss about one of the very common topics on Inter-AS MPLS VPN's i.e. Inter-AS MPLS VPNs with Back to Back VRF. We are already aware of how Intra-AS MPLS VPN's work. This has been discussed deeply in one of our previous posts (Link Below). In Inter-AS VPN, Customers connect their sites across AS boundaries. The very first and basic type of Inter-AS deployment is Back to Back VRF. In this approach, the ASBR of both AS's connect each other through multiple sub-interfaces where in each sub-interface se... [More]

Inter-VRF Routing

Hello All, Today, I will be discussing about VRF-Lite and will also be discussing one of the designs using BGP which have been seen in real world deployments which is the Inter-VRF Routing. Lets first start by understanding what is VRF.  VRF: Virtual Router Forwarding, an IOS feature in which multiple forwarding tables are used, with the choice of which table to use is based upon additional data outside of a packet's IP header, such as the L3 input interface or an MPLS tag. VRF-Lite: An implementation of VRF on CE devices in which forwarding table selection is done based upon the L3 in... [More]

BGP-based VPLS Autodiscovery

Hello Everyone, I am back with yet another post on one of the topics which caught my interest on - VPLS Autodiscovery using BGP. Before we start digging in to it, lets first start by understanding what VPLS is? What is VPLS? Virtual - Multiple VPLSs can be offered over common packet switched network. Private - CE devices that belong to different VPLSs cannot interact LAN Service - CE devices that belong to given VPLS instance V, can interact through the SP network as if they were connected by a LAN. VPLS is an architecture which allows MPLS networks to provide Mu... [More]