Content providers were using centralized traffic flow optimization together with MPLS TE for at least 15 years (some of them immediately after Cisco launched the early MPLS-TE implementation in their 12.0(5)T release), but it was always hard to push the results into the network devices.

PCEP and BGP-LS all changed that – they give you a standard mechanism to extract network topology and install end-to-end paths across the network, as Julian Lucek of Juniper Networks explained in Episode 43 of Software Gone Wild.

We started with easy questions like “What is the Juniper's NorthStar controller and what can it do” but as always our discussion quickly turned into a deep dive during which we covered these topics:

• How does an MPLS-TE controller discover the network topology?
• What does the controller do once it knows the network topology?
• How does it install new MPLS-TE tunnels?
• How does it deal with changing bandwidth requirements or changes in network topology?
• How could it replace the messy inter-area MPLS-TE with PCEP-signaled tunnels?
• How would you integrate the NorthStar controller with an orchestration system (or user-facing portal)?
• What happens when the controller fails?