OPTICALLY-AWARE ROUTING

Manage Your Risk

   

Protecting Connection Diversity Policies by Identifying Shared Optical Links

OpticallyAwareRouting LIGHT

What It Does

  • Automatically creates an accurate shared-risk link group (SRLG) table for the entire network
  • Updates the IP/MPLS layer SRLGs with every network change
  • Alerts when connections that are supposed to be independent share a risk
  • Proactively establishes more optical link diversity by rerouting the optical path for IP links when necessary

Operator Benefits

  • Boost IP/MPLS layer resiliency
  • Avoid traffic loss during failures
  • Ensure premium services with strict SLAs are maintained
  • Automate engineering-intensive tasks

 

Sedona’s Optically-Aware Routing application leverages cross-layer mapping information to improve IP/MPLS layer performance in two ways.

  • Tactical: Avoid routing MPLS LSPs that should be diverse over IP links that ultimately use the same fiber
  • Strategic: Improve overall IP/MPLS layer resiliency by proactively establishing more diversity in its optical paths

High-availability services typically require a pair of MPLS LSPs that are routed over diverse fiber links. That way, if one of the LSPs fails, its traffic switches quickly to the other one so high-availability SLAs can be maintained.

But what if the two IP links unknowingly share a segment in their optical paths? This risk is very real because many IP links are physically routed through a smaller set of fibers and because cross-layer awareness is very limited in existing network topologies. A single fiber cut might expose the fact that a pair of connections is not actually independent, resulting in SLA violations.

Existing routers can be configured to know which connections should have independent optical links and assign it to an SRLG. Once set, the control plane avoids using links with the same SRLG for both primary and secondary LSP paths. However, operators rarely use this capability since it is time consuming and difficult to provision SRLGs accurately, and even harder to maintain them dynamically. This is where Sedona’s Optically-Aware Routing application comes into play. All of this SRLG provisioning is automatic and accurate.

Accurate SRLGs

Sedona’s NetFusion platform has an accurate view of the network at all times. It understands exactly how each IP link is mapped to an optical link. Thus, it can accurately provision the SRLGs at all times. When the optical routing of an IP link changes, NetFusion re-provisions the SRLGs to reflect the change.

More strategically, instead of just making do with limited diversity of optical paths used by existing IP links, the application can improve overall IP/MPLS layer resiliency by proactively auditing the entire network and rerouting the optical paths of IP links in a more diverse manner. This reduces the overall impact of a fiber cut. It is done in a coordinated fashion to ensure there is no traffic hit during the process.

Our Optically-Aware Routing application empowers the control plane to route LSPs in a truly diverse manner so that service providers can offer high-availability services without risking SLA violations.