Over the years, the discussion about achieving knowledge and discovering unknowns have attracted a lot of people and occasionally a news or text or short understanding of a new science absorbs scholars and people motivated to learn .looking in to the modern technology, we see new inventions and innovations which are unique .as an example, over the past years ,new technology has been created in computer networks of which metro Ethernet has had a Noticeable advance in urban communication. therefore the aim of this article is to provide and compile information regarding metro Ethernet technology. utilizing Ethernet in urban networks need the developing potential and strength that only exist in MPLS and IP levels. layer two and three joint networks are solutions that join simplicity and economy of Ethernet at IP/MPLS scale. Different transfer technologies have been used in metro so metro services should be given on a mixture of optic and data switches, MPLS have been developed for this work and using generalized-MPLScontrol surface that support both data and optic switches performs it .In the beginning theories about using metro technology to produce urban networks are explained. then a simulating called eNSP which is a suitable alternative for simulating metro Ethernet technology and at the end the result of the simulation will be presented. تفاصيل المقالة

One of looped networks that in recent years has been much noticed is standard known as IEEE 802.17 RPR ring network or the return packet. Architecture RPR ring network protocol that transmits data between nodes connected in a double ring structure to support. RPR has two single transit buffer structure (STB) and double transit buffer (DTB), respectively. Single transit buffer architecture, just a high-priority traffic buffering (HP) and low priority (LP) passing through the ring buffer architecture serves and double, two separate buffer for high-priority and low priority traffic is considered passing.Send information for scheduling algorithms used in network nodes RPR, queue priority (Priority-Queue), respectively. In this way, the separation of traffic based on priority and high priority traffic has absolute priority over lower priority traffic so that always the highest priority to transit buffer appropriated therefore of high priority traffic such as video packet, the nodes access to congested suffered numerous delays and instability vibration are ring (Jitter).In this thesis addition to scheduling priority queue, plans, schedules DRR and DRR + to increase the quality of service to traffic with high priority on congested node in a network with a ring structure with 10 nodes software Opnet simulation and the performance timing of passing information about at least two network nodes in the hub scenario (hUB) in which all the nodes transmit information to a node with video traffic conditions, congestion were examined happened and qualitative results were compared to that, the display shows the relative improvements in reducing delays and instability shaking changes in the timing of DRR and DRR + compared to the recommended standard. تفاصيل المقالة