A joint "packet-optical" layer restoration mechanism protects against
single, packet-layer router failures by managing network resources from
both the packet layer and the optical transport layer in a synergistic
manner. It reuses packet-layer router service-ports and/or
transport-layer service wavelengths associated with optical switch-ports
instead of reserving additional standby packet-layer router
service-ports. It can reuse resources from primary paths that are
unaffected by router failures and paths that exist for link-failure
protection at the optical layer. Embodiments feature a modified node
structure that includes both an IP router and a dynamically
reconfigurable OXC, which dynamically establishes connectivity between
IP-router ports and transport-layer optical fibers. The joint-layer
router provides fine-granularity grooming at the IP layer and
full-fledged wavelength networking via dynamic wavelength switching
and/or wavelength translation at the optical layer. The latter can change
the wavelength cross-connections on-demand to perform restoration or to
modify the connectivity between IP routers in the network.