GNS3 Topology: MPLS Traffic Engineering

Traditional IP-forwarding leads to suboptimal use of available bandwidth between pair of routers in the SP network. The suboptimal paths are under-utilized in IP networks. To avoid packet drops because of inefficient use of available bandwidth, TE is employed to steer some of the traffic, and to enable better bandwidth management and utilization between pair of routers

TE tunnels configured on routers are unidirectional, which means we need to configure a pair of TE tunnel between routers if we want to implement bidirectional TE tunnel.

OSPF or IS-IS with extensions for TE is used to carry information pertaining to the tunnel configured on a router.In OSPF, the LSA type 10 provides information about resource and link status. The inspiration behind MPLS TE is Constraint Based Routing (CBR) and CBR requires IGP like IS-IS or OSPF (IGP must be link-state routing protocol) for its operation. Resource availability and link status information are calculated using a constrained SPF (CSPF) calculation in which factors such as the bandwidth, policies, and topology are taken into consideration to define probable paths from a source to destination.

"Lobo L, Lakshman U, 2005, MPLS Configuration on Cisco IOS Software, Cisco Press"



PART 1 (enabling MPLS and configuring routers for TE support)

PART 2 (configuring headend router, verification and unequal cost load balancing using TE)