BRAS子接口配置DHCP服务器终端无法获取地址

我在BRAS的子接口上配置了DHCP，但在交换机的终端却获取不到地址，请大神帮我分析一下。

BRAS配置如下：

[YLGD_BRAS_01-dhcp-pool-onu-manager]dis th

#

dhcp server ip-pool onu-manager

 gateway-list 110.197.128.1

 network 110.197.128.0 mask 255.255.128.0

 dns-list 172.31.183.8

 forbidden-ip 110.197.128.1

#

return

[YLGD_BRAS_01-dhcp-pool-onu-manager]quit

[YLGD_BRAS_01]int Route-Aggregation11.8

[YLGD_BRAS_01-Route-Aggregation11.8]dis th

#

interface Route-Aggregation11.8

 description TO-onu-manager

 ip address 110.197.128.1 255.255.128.0

 vlan-type dot1q vid 3401

 dhcp server apply ip-pool onu-manager

交换机配置如下:

<YLGD-DFDS-S7606>sys

System View: return to User View with Ctrl+Z.

[YLGD-DFDS-S7606]vlan 3401

[YLGD-DFDS-S7606-vlan3401]int b1

[YLGD-DFDS-S7606-Bridge-Aggregation1]dis th

#

interface Bridge-Aggregation1

 description TO-UPlink-BRAS-SR8808

 port link-type trunk

 undo port trunk permit vlan 1

 port trunk permit vlan 7 43 101 300 to 499 501 510 513 to 516 518 580 709 to 998 

 port trunk permit vlan 1200 to 1399 3401 4000

#

return

[YLGD-DFDS-S7606-Bridge-Aggregation1]int g

[YLGD-DFDS-S7606-Bridge-Aggregation1]int g1/4/0/13

[YLGD-DFDS-S7606-GigabitEthernet1/4/0/13]dis th

#

interface GigabitEthernet1/4/0/13

 port link-mode bridge

 port access vlan 3401

交换机下面13口的终端无法获取IP地址，请大神帮我分析一下到底哪里出错了。