非广播-多路来自访问网络(Non-Broadcast Multiple Access，NBMA)是OSPF通信协议中定义的四种网络类型的其中一种。 NBMA用来描述如X.25和帧中础福规有继这类本身并不具有支持广播和多播能力的多路访问网络。其他OSPF定义的网络类型有:广播网络、点对点网络和点对多点网络。OSPF邻居状态关系表示断所收争析标，只有Attempt会出现在NBMA协议中。

• 中文名称 非广播-多路访问网络
• 外文名称 Non-Broadcast Multiple Access,NBMA
• 简介 OSPF定义的四种网络类型其中一种
• 应用 网络通讯

　　在配置NBMA的情况下，OSPF在同一时刻向每一个路由器来自只会发送一个Hello包正数往但频树没去价(Hello包周期性发送，用于360百科建立和确定路由间企那地的邻居关系)而不是进行多播。Hello包的发送周期间隔的范围为10s~30s，而判断邻居失效(dead)的时间范围为40s~12资答清0s(4倍于Hello包发送间隔)。

　　NBMA (non胞龙眼弦诗现控亮-broadcast multiple acce免为英晚控ss)is one of four network types in the OSPF (Op育宗攻en Shortest Path First) communications protoco劳架市空待油义l. NBMA is used to accurately model X.25 and frame relay environments in multiple-access networks where there are no intrinsic broadcast and multicast capabilities. T源国子素有济计开推宁he other OSPF network types are: broadcast, point-to-point, and 宗个环觉服point-to-multip甲督oint. In an NBMA configuration, OSPF sen易苦世市今日停力ds HELLO packets (packets sent periodically to establish and confirm neighbor relationships between rou判菜基ters) to each router one at a time ra老群衣到ther than multicasting them. The HELLO timer (which tells the router how often to send HELLO pack跳钢色染正器花皇兵ets) is extended from 10 to 30 seconds and the dead router timer (which tells the router how long to wait before it decides that a neighboring router is not funct酒社指卫屋介伤饭投互ioning) is extend除哥包甲银树期笑ed from 40 to 120 seconds.