How Traffic Engineering Can Solve the Problem of Circuit Saturation.

摘要

The dynamics of U.S. military communications in the Afghanistan Theater has changed dramatically over the last few years. There have been significant upgrades in bandwidth from the typical 8 Mbps satellite circuits to 10 Gbps fiber optic solutions. The capability to support increased customer requirements and efficiency provided by IP-based transport were the initial drivers to facilitate a migration from legacy TDM to the IP-based infrastructure found in the Afghanistan Black Core Network (BCN) today. The BCN was introduced into production in early 2010 and modeled after the DISA backbone infrastructure. The BCN in Afghanistan continues to grow and mature as the primary method of transporting secure communications. The introduction of Multiprotocol Label Switching (MPLS) to the BCN allowed for each customer's traffic to be isolated into its own virtual circuit. Separation of customer traffic is made possible by maintaining a separate routing table on the BCN for each virtual circuit. In certain parts of Afghanistan, mission critical traffic has competed for bandwidth on congested links. In the aggregate, throughput requirements exceeded allocated bandwidth. Even though there are other paths available on the BCN, standard routing techniques required all traffic, including SIPR, NIPR, and coalition networks to transit through a single primary path. As the BCN transport system grew to include additional customers outside of NIPR, SIPR & CX-I, the need to prioritize traffic based upon operational impact began to emerge. To overcome the limitations imposed by standard IP routing techniques, network engineers in Afghanistan began employing MPLS 'Traffic Engineering' (MPLS-TE). MPLS-TE allows for the routing of data across multiple transmission media concurrently. It can enable the concurrent transmission of data across fiber optic links, satellite links, and Line of Sight links.