juniper接口打环测试

官网都有！

SDH口：

http://www.juniper.net/techpubs/en_US/junos14.2/topics/topic-map/sonet-interfaces-loopback-testing.html

FE/GE/XE口：

http://www.juniper.net/techpubs/en_US/junos14.2/topics/topic-map/ethernet-fast-and-gigabit-loopback-testing.html

T3口：

http://www.juniper.net/techpubs/en_US/junos14.2/topics/topic-map/t3-interfaces-loopback-testing.html

T1口：

http://www.juniper.net/techpubs/en_US/junos14.2/topics/topic-map/t1-interfaces-loopack-testing.html

ATM口：

http://www.juniper.net/techpubs/en_US/junos14.2/topics/topic-map/atm-interface-loopback-testing-use.html