I really appreciate your help. Kindly look at my configures.
Router B is a simple configure. I started with reset configurations. I selected a standard router configuration with NAT and bridged all ports.
I added a new bridge. Rename the bridges into bridge-wan and bridge-lan. bridge-wan have eth1, eth2, and wlan1. All other ports belong to bridge-lan. My thought is to separate the traffic by using these two bridges.
In bridge-wan, eth1 is the wan port. eth2 is to direct internet to router A. bridge-wan are in the ip range 192.168.88.0/24.
in bridge-lan, only vlan-200 have an ip address 192.168.83.3. This is used to talk to the vlan in router A. This is done by a static router, dst-address 0.0.0.0/0 with gateway 192.168.83.2
Router A and Router B are connected by eth2.
I have CapsMAN enabled on Router A. When I connect APs on Router B ports, CapsMAN can register them.
Router B
[admin@MikroTik] /ip> /interface print
Flags: D - dynamic, X - disabled, R - running, S - slave
# NAME TYPE ACTUAL-MTU L2MTU MAX-L2MTU MAC-ADDRESS
0 R ether1 ether 1500 1598 4074 00:0C:42:F8:A5:77
1 RS ether2 ether 1500 1598 4074 00:0C:42:F8:A5:78
2 S ether3 ether 1500 1598 4074 00:0C:42:F8:A5:79
3 S ether4 ether 1500 1598 4074 00:0C:42:F8:A5:7A
4 S ether5 ether 1500 1598 4074 00:0C:42:F8:A5:7B
5 S ether6 ether 1500 1598 2028 00:0C:42:F8:A5:7C
6 S ether7 ether 1500 1598 2028 00:0C:42:F8:A5:7D
7 S ether8 ether 1500 1598 2028 00:0C:42:F8:A5:7E
8 S ether9 ether 1500 1598 2028 00:0C:42:F8:A5:7F
9 S ether10 ether 1500 1598 2028 00:0C:42:F8:A5:80
10 sfp1 ether 1500 1598 4074 00:0C:42:F8:A5:76
11 S wlan1 wlan 1500 1600 2290 00:0C:42:F8:A5:81
12 R bridge-lan bridge 1500 1594 00:0C:42:F8:A5:7A
13 R bridge-wan bridge 1500 1598 00:0C:42:F8:A5:78
14 RS vlan-200 vlan 1500 1594 00:0C:42:F8:A5:78
interface bridge print
0 R name="bridge-lan" mtu=auto actual-mtu=1500 l2mtu=1594 arp=enabled arp-timeout=auto mac-address=00:0C:42:F8:A5:7A protocol-mode=rstp fast-forward=no igmp-snooping=no auto-mac=yes ageing-time=5m priority=0x8000 max-message-age=20s forward-delay=15s transmit-hold-count=6 vlan-filtering=no
1 R name="bridge-wan" mtu=auto actual-mtu=1500 l2mtu=1598 arp=enabled arp-timeout=auto mac-address=00:0C:42:F8:A5:78 protocol-mode=rstp fast-forward=yes igmp-snooping=no auto-mac=no admin-mac=00:0C:42:F8:A5:78 ageing-time=5m priority=0x8000 max-message-age=20s forward-delay=15s transmit-hold-count=6 vlan-filtering=no
interface bridge port print
Flags: X - disabled, I - inactive, D - dynamic, H - hw-offload
# INTERFACE BRIDGE HW PVID PRIORITY PATH-COST INTERNAL-PATH-COST HORIZON
0 ether2 bridge-wan no 1 0x80 10 10 none
1 I ether3 bridge-wan no 1 0x80 10 10 none
2 I H ether4 bridge-lan yes 1 0x80 10 10 none
3 I H ether5 bridge-lan yes 1 0x80 10 10 none
4 I ether6 bridge-lan no 1 0x80 10 10 none
5 I H ether7 bridge-lan yes 1 0x80 10 10 none
6 I H ether8 bridge-lan yes 1 0x80 10 10 none
7 I H ether9 bridge-lan yes 1 0x80 10 10 none
8 I wlan1 bridge-wan 1 0x80 10 10 none
9 I ether10 bridge-lan no 1 0x80 10 10 none
10 vlan-200 bridge-lan 1 0x80 10 10 none
ip address
[admin@MikroTik] > /ip address print
Flags: X - disabled, I - invalid, D - dynamic
# ADDRESS NETWORK INTERFACE
0 192.168.88.1/24 192.168.88.0 bridge-wan
1 192.168.88.1/24 192.168.88.0 ether2
2 192.168.83.3/24 192.168.83.0 vlan-200
3 D 192.168.0.18/24 192.168.0.0 ether1
[admin@MikroTik] /ip> route print
Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, B - blackhole, U - unreachable, P - prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADS 0.0.0.0/0 192.168.0.1 1
1 A S 0.0.0.0/0 192.168.83.2 1
2 ADC 192.168.0.0/24 192.168.0.18 ether1 0
3 ADC 192.168.83.0/24 192.168.83.3 bridge-lan 0
4 ADC 192.168.88.0/24 192.168.88.1 bridge-wan 0