RSVP Auto Bypass on OcNOS: Automating MPLS Resiliency at Scale

In traditional MPLS networks running RSVP-TE, protecting every LSP against link and node failures requires manually pre-configuring bypass tunnels for each potential failure scenario. In a network with dozens of nodes, this means hundreds of manually engineered tunnels — each requiring careful path specification, ongoing maintenance as the topology changes, and operational expertise to troubleshoot when something goes wrong.

RSVP Auto Bypass solves this problem. OcNOS dynamically discovers protected LSPs traversing each interface, automatically creates the optimal bypass tunnel for each failure scenario, and maintains these tunnels as the network topology evolves. The result is sub-50ms failover coverage without a single manually configured bypass tunnel.

How RSVP Auto Bypass Works

Configuring RSVP Auto Bypass on OcNOS

! OcNOS -- RSVP-TE with Auto Bypass enabled
!
! Step 1: Enable MPLS and RSVP-TE globally
mpls traffic-eng tunnels
!
router ospf 1
  mpls traffic-eng router-id Loopback0
  mpls traffic-eng area 0
!
! Step 2: Enable RSVP on all core interfaces
interface eth-0-1
  ip rsvp bandwidth 1000000      ! Reserve up to 1 Gbps for RSVP-TE
  ip rsvp signalling hello        ! Enable RSVP hello for fast failure detection
!
interface eth-0-2
  ip rsvp bandwidth 1000000
  ip rsvp signalling hello
!
! Step 3: Enable Auto Bypass on protected interfaces
! OcNOS automatically creates bypass tunnels for any LSP
! traversing these interfaces
interface eth-0-1
  mpls traffic-eng backup-path auto-backup
  mpls traffic-eng fast-reroute protect link    ! Link protection
  mpls traffic-eng fast-reroute protect node    ! Node protection (stronger)
!
interface eth-0-2
  mpls traffic-eng backup-path auto-backup
  mpls traffic-eng fast-reroute protect link
  mpls traffic-eng fast-reroute protect node

! OcNOS -- Head-end LSP configured for Fast Reroute
! The LSP requests FRR protection; bypass tunnels are auto-created by transit nodes
!
interface Tunnel0
  ip unnumbered Loopback0
  tunnel destination 10.0.0.4          ! Tail-end: R4
  tunnel mode mpls traffic-eng
  tunnel mpls traffic-eng fast-reroute ! Request FRR protection
  tunnel mpls traffic-eng priority 5 5
  tunnel mpls traffic-eng path-option 10 dynamic

Verification Commands

! OcNOS -- RSVP Auto Bypass verification
!
! View all auto-created bypass tunnels:
show mpls traffic-eng tunnels backup
! Expected: auto-bypass tunnels listed with protect type (link/node)
! and protected interface, PLR node, and MP node

! Check FRR state per protected interface:
show mpls traffic-eng fast-reroute database
! Shows: protected LSPs, bypass tunnel assigned, FRR state (Ready/Active)

! Verify bypass tunnel path:
show mpls traffic-eng tunnels tunnel0 detail
! Shows: explicit path used by bypass, RSVP reservation, bandwidth

! Simulate failure and verify bypass activates:
! (Shut eth-0-1 on R2, then check)
show mpls traffic-eng fast-reroute database
! Expected: FRR state changes from Ready to Active for affected LSPs

! RSVP statistics:
show ip rsvp interface
show ip rsvp neighbor

Auto Bypass vs. Manual Bypass vs. SR TI-LFA

For new deployments, Segment Routing with TI-LFA is the recommended fast-reroute mechanism — simpler, stateless, and 100% coverage. RSVP Auto Bypass is the right choice for operators with existing RSVP-TE deployments who need automated protection without migrating to SR.

• ISIS-SR with TI-LFA: Fast Reroute Guide
• LDP to SR Migration Guide
• OcNOS-SP Product Page
• Contact IP Infusion

IP Infusion Engineering Team