The MPLS Internet protocol allows the transmitter to mark packets and establish priorities for service. The edge routers in a network mark packets are in a fixed length label that contains information about the route and the priority of service.
MPLS Internet has a wide range of service classes, but it can only provide QoS in an MPLS domain and not end-to-end. Therefore, the use of MPLS Internet for QoS is very limited.
Layer 2 Solutions for QoS. A very effective method of implementing QoS in a network is to use layer 2 protocols to prioritize traffic. Control of media access control (MAC) layer, the 802nd p standard provides specifications for layer 2 switches, which creates the eight classes of traffic. Both Virtual Local Area Network (VLAN) and VPLS (Virtual Private LAN Service) will support the 802nd p to establish virtual circuits that are prioritized according to the type of content. Layer 2 solutions for QoS can be the most effective means to deliver high quality and priority service over an IP network. However, layer 2 solutions are normally only used in Intranets and VLAN, which are controlled by a single system administrator. Over the global MPLS Internet, it may not be possible to use the layer 2 QoS solutions when accessing public websites.
The early methods for QoS in IP networks such as TCP flow control and FIFO buffers are not adequate for today's high speed Internet applications. There are improved methods of MPLS Internet for QoS necessary to support real time applications such as video and voice over IP.
There are three levels of QoS: Best effort differentiated service and warranty service. The best possible action offers no QoS protocols other than TCP flow control and can only be used for bursty IP traffic. Differentiated service classifies and prioritizes traffic flows so that higher priority traffic has precedence in the network. The guaranteed service levels for QoS provides the best QoS by reserving resources in the entire network for high priority traffic flows. Guaranteed service levels can only be given when the network has sufficient bandwidth to support traffic. Implementing Layer 2 QoS is very effective when a single system administrator controls the network. With VLAN, virtual circuits can prioritize traffic and establish a high level of QoS.
The future of the MPLS Internet will depend on effective Quality of Service (QoS) methods. To support future real-time applications over the global Internet, the reliable transmission methods are needed along with the ability to classify and prioritize traffic on one end to the base. QoS methods described in this document provides a framework for implementing QoS in IP networks. Layer 2 solutions will serve Intranet, while standards and common solutions must be decided on the public Internet. Get connected to MPLS now!
