Evolving from Legacy P-OTN to SR-MPLS Based IPoDWDM Networks with OcNOS

Networks built on 2nd-generation Packet-Optical Transport Network (P-OTN) technology face a structural refresh challenge. Many OTN platforms are at or approaching end-of-life, spare parts are becoming scarce, and the technology itself predates modern SR-MPLS and coherent optical standards that offer dramatically better scalability, flexibility, and economics.

The migration path from P-OTN to SR-MPLS based IPoDWDM is not a single cutover event. It is a phased architectural evolution that can be executed without service disruption. OcNOS 7.0 provides the migration platform with full SR-TE, SR-MPLS, and IPoDWDM support on a single NOS.

Why P-OTN Networks Need to Evolve

Migration Architecture: Three Phases

Phase 1: SR-MPLS Overlay on Existing Infrastructure

! OcNOS 7.0 -- Phase 1: Enable IS-IS SR on existing nodes
! OTN circuits remain as transport; SR-MPLS operates as overlay
!
router isis TRANSPORT
  net 49.0003.0000.0000.0001.00
  is-type level-2-only
  segment-routing mpls
  !
  ! BGP-Free Core: remove BGP from transit nodes
  ! PE nodes retain BGP; P nodes use SR labels only
  !
  fast-reroute ti-lfa level-2 proto ipv4    ! Replace OTN 1+1 protection
!
interface lo
  ip address 10.100.0.1/32
  ip router isis TRANSPORT
  prefix-sid index 1
!
commit
end
!
! Verify SR is active (OTN circuits still carrying traffic):
show isis segment-routing state
show mpls forwarding-table

• IPoDWDM Deployment Simplified
• LDP to SR Migration Guide
• IPoDWDM Solution Page
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IP Infusion Engineering Team