目前保证 DHCP服务器没问题，网络畅通，应为接口下去掉mab认证，电话就能拿到地址
命令如下
interface FastEthernet0/24
switchport access vlan 516
switchport mode access
switchport voice vlan 205
authentication host-mode multi-auth
authentication order mab
authentication port-control auto
authentication timer restart 180
mab
spanning-tree portfa
查看log提示认证成功 ，实际上拿不到IP
Jan 22 15:16:44: %AUTHMGR-5-SUCCESS: Authorization succeeded for client (00a8.59f7.bbcc) on Interface Fa0/24 AuditSessionID 0A43070D0000027F483AB32C
