The Greenbay VPN product has proved to be a secure method for Australian Small Business and Corporate clients to provide cost effective data transmission to their diverse locations. The introduction of Quality of Service (QoS) capabilities across this VPN product is now enabling a new set of business applications to be extended from the Corporate Head office to branch locations with the same predictability of their private network.

Interactive applications such as Citrix and telnet based interfaces can now leverage the differentiation of traffic classes to provide time-sensitive data transmission. Voice over IP (VoIP) can now also be considered as a viable alternative to provide low cost on-network telephony to all VPN serviced corporate sites.

Without Quality of Service (QoS) features enabled on a VPN network, all packets have equal access to the broadband interface, regardless of the type of traffic. For example, Voice over IP (VoIP) packets get placed in the same buffer as HTTP (web) or FTP (file download) data packets. Furthermore, in the event of congestion (that is, oversubscription of an interface), all traffic is equally subject to discard. Basically packets are serviced in the order in which they were received, and if the buffer is full, all subsequent packets are dropped. This is known as First In, First Out (FIFO) queuing with tail-drop.

With the introduction of QoS enabled VPNs, the interface capacity is carved into one or more individual queues. Each queue has one or more drop thresholds associated with it. The combination of multiple queues within a buffer, and the drop thresholds associated with each queue, allow QoS enabled VPN devices to make intelligent decisions when faced with congestion. Traffic sensitive to jitter and delay variance, such as VoIP packets, can be moved to the head of the queue for transmission, while other less important or less sensitive traffic can be buffered or dropped.

With converging networks, congestion management is critical. Latency sensitive traffic like voice and video can be severely impacted if delays are incurred. The VPN QoS product is implemented by enabling QoS features on the Greenbay managed CPE devices and optionally on the Core Network infrastructure within the Greenbay aggregated network.

Product Resources

• Greenbay VPN with QoS Detail