PPPoE WAN decrease speed after few days

Dear Sirs,
I've setup a PPPoE connection on WAN1 with EOLO ISP, first try everything was fine, test speed was 8.00Mbps .
After 2 days connection was still on but test speed was 1.2Mbps.
I've tried a disconnect then reconnect, still the same.
Reset routerboard to factory default with a blank conf, changed the port for the WAN and still the same.

Connected directly a PC first and another router and the speed was 8.00Mbps.

The ISP said can be a fautly mikrotik hardware,but I've tried today again with the routerboard and speed now is high.
Can someone please give me some advice?

oct/15/2015 15:08:44 by RouterOS 6.32.2

software id = LDRS-FM3M

/interface bridge
add comment="Internal Network" name=bridge-local
/interface ethernet
set [ find default-name=ether1 ] name=WAN1
set [ find default-name=ether2 ] comment=BACKUP name=WAN2
/ip neighbor discovery
set WAN2 comment=BACKUP
set bridge-local comment="Internal Network"
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa2-psk management-protection=allowed mode=
dynamic-keys name=wifi_security supplicant-identity=MikroTik
wpa2-pre-shared-key=wifipassword
add authentication-types=wpa-psk,wpa2-psk management-protection=allowed mode=
dynamic-keys name=test wpa-pre-shared-key=test
wpa2-pre-shared-key=test
/interface wireless
set [ find default-name=wlan1 ] mode=bridge security-profile=test ssid=test
/ip pool
add name=dhcp_pool1 ranges=192.168.1.11-192.168.1.20
/ip dhcp-server
add address-pool=dhcp_pool1 disabled=no interface=bridge-local lease-time=3d
name=dhcp1
/ppp profile
add change-tcp-mss=yes name=ppp-wan
/interface pppoe-client
add add-default-route=yes allow=pap default-route-distance=1 interface=WAN2
name=ppp-backup password=pwd profile=ppp-wan use-peer-dns=yes user=
userofpppoe
add add-default-route=yes allow=pap disabled=no interface=WAN1 name=ppp-wan
password=pwd profile=ppp-wan use-peer-dns=yes user=userofpppoe
/interface bridge port
add bridge=bridge-local interface=ether3
add bridge=bridge-local interface=ether4
add bridge=bridge-local interface=ether5
add bridge=bridge-local interface=wlan1
/ip address
add address=192.168.1.1/24 interface=bridge-local network=192.168.1.0
/ip cloud
set ddns-enabled=yes
/ip dhcp-server network
add address=192.168.10.0/24 dns-server=192.168.10.1 gateway=192.168.10.1
/ip dns
set allow-remote-requests=yes
/ip firewall filter
add action=drop chain=input comment="Drop Invalid connections"
connection-state=invalid
add chain=input comment="Allow Established connections" connection-state=
established
add chain=input comment="Allow ICMP" protocol=icmp
add action=drop chain=input comment="Drop Invalid connections"
connection-state=invalid
add chain=input comment="Allow Established connections" connection-state=
established
add chain=input comment="Allow ICMP" protocol=icmp
add chain=forward
/ip firewall nat
add action=masquerade chain=srcnat comment=nat-internet-access out-interface=
bridge-local
add action=masquerade chain=srcnat comment=nat-internet-access out-interface=
ppp-wan
add action=masquerade chain=srcnat comment=nat-internet-access out-interface=
bridge-local
/ip service
set telnet disabled=yes
set ftp disabled=yes
/system clock
set time-zone-name=Europe/Brussels
/system identity
set name=MK
/system leds
set 5 interface=wlan1

Actually there is a big problem of packet loss on the mikrotik, if I do a ping from a client, it report a percentage of 14.

Hi, I’m also new to Mikrotik with 2 pppoe WAN ports. Our local DSL settings requires us to specify Max-MRU=1480, Max-MTU=1480 MRRU=1600. These settings appear stable for us. Default MTU for ethernet is 1500. Worth a try? PPPoE specifies a maximum MTU of 1492. Best to check with your ISP.

Hi Chiara
Did you find what was?
A workaround for the packet loss was to change link from ether6 to ether4 (from FastEthernet to GEthernet) on a RB2011, but you already use the “right” port.

Hi, thanks for advices, it turned out that the device was under DoS attack… solved changing hw.