Fast Down Detection

Fast down detection or sub-second link failure detection is needed in a modern networks. Network operators of modern networks require that they can detect failure in sub-second and react to either soft or hard failures as quickly as possible.

The following are the two categories of fast down detection.

1. Polling

One of the method […]

MPLS VPN Hub and Spoke

Sometimes customer wants to implement MPLS VPN hub and spoke topology which allows the customer to control traffic between spokes and also to other resources like the Internet (access restriction). Therefore, the hub acts as a central transit point between spoke sites.

The MPLS VPN hub and spoke topology requires a special setup/configuration as shown […]

Inter-AS MPLS VPN: Back to Back VRF

Back to back VRF is one of the options to connect customer sites that are geographically dispersed and also connected to different service provider MPLS VPN backbones. This option is the simplest approach for allowing MPLS VPN providers to exchange VPN routing information for CE sites. The border provider edge routers residing in different AS […]

BGP No Route to Peer

Scenario is three routers – R1, R2 and R3; R1 and R3 are on AS100 and AS200 respectively. R1 and R3 have default route pointing to R2. R2 knows how to reach R1 and R3’s Loopback1 network via static route. R1 and R3 are peering to and sourcing BGP traffic from its Loopback1 IP address.