Marines use WAN optimization to relocate Iraq HQ
- By Dan Campbell
- Jun 17, 2009
While relocating a command headquarters in Iraq, the Marine Corps used wide-area network optimization technology to increase transfer speeds via a satellite link to back up data.
The Multi-National Force–West (MNF-W), the highest command in the Marine Air-Ground Task Force, recently completed its headquarters relocation from Camp Fallujah to Al Asad Air Base with the assistance of Expand Networks’ WAN optimization technology. The company’s appliances helped the task force improve data transfer performance via the satellite network that connects the bases.
To complete the move, MNF-W executed a disaster recovery plan to electronically back up the Camp Fallujah data to the new facility. The backup required a transfer of 17T of data between the camps, a massive data replication process that would have been difficult if not impossible via the satellite network. Indeed, the Marines noticed performance problems with the data replication software, NetApp’s SnapMirror, without the Expand appliances in place.
After the Expand appliances were deployed, “the issue was immediately mitigated and we saw a throughput increase from around 120 [kilobits/sec] to 6 [megabits/sec],” said Capt. Criston Cox, data systems officer at MNF-W.
The military often uses satellites to cover its remote and mobile communication requirements. Geosynchronous satellites orbiting 22,300 miles above the Earth induce a natural round-trip latency on data traffic of about a half-second. Data traffic transmitted between military units might go through a central hub, causing two round-trips or a double hop, resulting in a full second or more of latency. Additionally, satellite communications suffer from atmospheric and environmental interference such as rain fade, which causes packet loss.
Latency and packet loss on an IP network dramatically reduce application performance and throughput, particularly for TCP-based applications that must reduce transmission speed to compensate for the impediments. WAN optimization technology mitigates the effects of latency and packet loss through techniques such as TCP acceleration and byte caching.
In TCP acceleration, the appliances at either end of the link provide local TCP acknowledgments for the end systems involved in the transaction, eliminating their perception of latency. In byte caching, elements of the data are stored locally so that repeat transmissions can be referenced and eliminated from the WAN link, improving performance and reducing the amount of traffic that must be transmitted over the network.
After the relocation and data transfer, the Marines used the optimization technology to solve problems with database replication time-outs for a critical application called the Biometric Automated Toolset System. The military uses BATS to store sensitive biometric information, such as retina scans and fingerprints, and to track and capture terrorists at military checkpoints. The application relies on synchronizing the databases between military units to ensure that the data is accurate and up-to-date. The replication process suffered due to the satellite latency and packet loss.
“Our throughput averaged 8 to 9 [kilobits/sec] with multiple time-outs over the TDMA satcom links,” Cox said.
The situation was so bad that MNF-W was forced to manually update new servers and fly them out to the remote locations via helicopter, a risky and costly venture filled with logistical hurdles, manpower issues and transport requirements.
The deployment of the Expand appliances improved the application’s performance so that “the BATS server interface indicated a constant transfer rate at 5.8 [megabits/sec], with no time-outs or data corruption,” Cox said.
The massive performance improvement was achieved via a physical 2 megabits/sec satellite link. The accelerators’ byte-caching and compression techniques reduce the amount of data that would otherwise have to be transferred over the satellite link, resulting in a perceived throughput greater than the actual link speed. The improved system eliminated the need to manually configure replicated servers and fly them to the remote sites.
Dan Campbell is a freelance writer with Defense Systems' sister publication, Government Computer News.