生成树算法的网桥协议STP(Spanning Tree Protocol) 它通过生成生成树保证一个已知的网桥在网络拓扑中沿一个环动态工作。网桥与其他网桥交换BPDU消息来监测环路，然后关闭选择的网桥接口取消环路，统指IEEE802·1生成树协议标准和早期的数字设备合作生成树协议，该协议是基于后者产生的。IEEE版本的生成树协议支持网桥区域，它允许网桥在一个扩展本地网中建设自由环形拓扑结构。IEEE版本的生成树协议通常为在数字版本之上的首选版本。
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SpanningTree .classpath .project .settings bin src
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.303902s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.267676s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.012170s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.003522s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.005336s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003039s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000887s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003600s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.016874s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001187s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 329700 [ RunTime:0.015933s ]
