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iterance n.反復,重復,重復申說。

iterate

In tranditional ip network , only the “ best effort ” service is provided , but the quality of service can not be guaranteed . though the interserv , deffserv and mpls are presented afterward to guarantee the qos for the ip network . but as a layer network , the realization of the qos function need span different layers ( such as rsvp protocol ) in the ip network , which may result in the function iterance and chaos 多媒體和實時業務的出現要求網絡能夠提供足夠的qos保證,在傳統的ip網絡中只能提供“盡量傳輸”的服務而不能保證服務質量,后來提出的綜合服務模型( interserv )以及區分服務模型( deffserv )以及mpls技術保證了ip網絡上的服務質量,但由于ip網絡是層次結構的網絡,因此對qos的支持需要跨層(如rsvp協議) ,這就可能引起功能的重復和混亂,而微通信元系統是無層次結構的網絡系統,就克服了這些的問題,變得簡單,效率更高。