Mikrotik 4 WAN Load Balancing using PCC method

Mikrotik 4 WAN Load Balancing using PCC method

Following is a complete script for Mikrotik to combine/Load Balance 4 WAN links OR DSL links , and the script idea is taken from
http://wiki.mikrotik.com/wiki/Manual:PCC#Example

In this example I have used MikrotikT RB750 5 ports router. 4 ports were connected with Four DSL Routers, and 5th port was connected with User LAN. All DSL lines have un-equal speed. Also don’t forget to rename the interface names accordingly.

In my personnel experience , If users request are directly hitting Mikrotik configured with PCC , then you will get good load balancing. Use src-address as classifier, this way you will get rid of problems like https/broken link, streaming issues etc. Load balancing using this PCC technique (src-address) will be effective and balanced approach when more and more connections (from clients) that occurred. I also recommend to use SQUID proxy server along with mikrotik , either parallel or in front or backend , for better response time and it will also increase good browsing experience to users.

If somehow you are not satisfied with the src-address approach,play with the PCC-Classifier,
Try both addresses and ports as the classifier. While this will randomize things the most and in theory give you the most fair allocation of bandwidth, BUT there is also a good chance that it will break certain things like banking web sites and some forums. This is because often times a HTTP requests will generate several connections, so there is a chance that some requests may go out a different route than the initial one, and that will break secure web sites. For that reason I usually stick with src-address PCC load balancing.

01	/ip address

02	add address=192.168.0.1/24 network=192.168.0.0 broadcast=192.168.0.255 interface=Local

03	add address=192.168.1.2/24 network=192.168.1.0 broadcast=192.168.1.255 interface=WAN1

04	add address=192.168.2.2/24 network=192.168.2.0 broadcast=192.168.2.255 interface=WAN2

05	add address=192.168.3.2/24 network=192.168.3.0 broadcast=192.168.3.255 interface=WAN3

06	add address=192.168.4.2/24 network=192.168.4.0 broadcast=192.168.4.255 interface=WAN4

07

08	/ip firewall mangle

09	add chain=input in-interface=WAN1 action=mark-connection new-connection-mark=WAN1_conn

10	add chain=input in-interface=WAN2 action=mark-connection new-connection-mark=WAN2_conn

11	add chain=input in-interface=WAN3 action=mark-connection new-connection-mark=WAN3_conn

12	add chain=input in-interface=WAN4 action=mark-connection new-connection-mark=WAN4_conn

13

14	add chain=output connection-mark=WAN1_conn action=mark-routing new-routing-mark=to_WAN1

15	add chain=output connection-mark=WAN2_conn action=mark-routing new-routing-mark=to_WAN2

16	add chain=output connection-mark=WAN3_conn action=mark-routing new-routing-mark=to_WAN3

17	add chain=output connection-mark=WAN4_conn action=mark-routing new-routing-mark=to_WAN4

18

19	add chain=prerouting dst-address=192.168.1.0/24 action=accept in-interface=Local

20	add chain=prerouting dst-address=192.168.2.0/24 action=accept in-interface=Local

21	add chain=prerouting dst-address=192.168.3.0/24 action=accept in-interface=Local

22	add chain=prerouting dst-address=192.168.4.0/24 action=accept in-interface=Local

23

24	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/0 action=mark-connection new-connection-mark=WAN1_conn passthrough=yes

25	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/1 action=mark-connection new-connection-mark=WAN2_conn passthrough=yes

26	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/2 action=mark-connection new-connection-mark=WAN3_conn passthrough=yes

27	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/3 action=mark-connection new-connection-mark=WAN4_conn passthrough=yes

28	add chain=prerouting connection-mark=WAN1_conn in-interface=Local action=mark-routing new-routing-mark=to_WAN1

29	add chain=prerouting connection-mark=WAN2_conn in-interface=Local action=mark-routing new-routing-mark=to_WAN2

30	add chain=prerouting connection-mark=WAN3_conn in-interface=Local action=mark-routing new-routing-mark=to_WAN3

31	add chain=prerouting connection-mark=WAN4_conn in-interface=Local action=mark-routing new-routing-mark=to_WAN4

32

33

/ip route

34	add dst-address=0.0.0.0/0 gateway=192.168.1.1 routing-mark=to_WAN1 check-gateway=ping

35	add dst-address=0.0.0.0/0 gateway=192.168.2.1 routing-mark=to_WAN2 check-gateway=ping

36	add dst-address=0.0.0.0/0 gateway=192.168.3.1 routing-mark=to_WAN3 check-gateway=ping

37	add dst-address=0.0.0.0/0 gateway=192.168.4.1 routing-mark=to_WAN4 check-gateway=ping

38

39	add dst-address=0.0.0.0/0 gateway=192.168.1.1 distance=1 check-gateway=ping

40	add dst-address=0.0.0.0/0 gateway=192.168.2.1 distance=2 check-gateway=ping

41	add dst-address=0.0.0.0/0 gateway=192.168.3.1 distance=3 check-gateway=ping

42	add dst-address=0.0.0.0/0 gateway=192.168.4.1 distance=4 check-gateway=ping

43

44	/ip firewall nat

45	add chain=srcnat out-interface=WAN1 action=masquerade

46	add chain=srcnat out-interface=WAN2 action=masquerade

47	add chain=srcnat out-interface=WAN3 action=masquerade

48	add chain=srcnat out-interface=WAN4 action=masquerade

Now Configure DNS server so users can resolve hostnames,

1	/ip dns set allow-remote-requests=yes cache-max-ttl=1w cache-size=5000KiB max-udp-packet-size=512 servers=221.132.112.8,8.8.8.8

All Done ! Now Test the link by putting user load, the more multiple users load you put on it, the better Load Balance result you will get 

PCC WITH UN-EQUAL WAN LINKS

If you have Un-Equal WAN Links, for example WAN,1,2,3 are of 4MB and WAN,4 is of 8 Mb, and you want to force MT to use WAN4 link more then other because of its capacity, Then you have to Add more PCC rules assigning the same two marks to a specific link i.e WAN4 , something like

Code:

1	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/0 action=mark-connection new-connection-mark=WAN1_conn passthrough=yes

2	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/1 action=mark-connection new-connection-mark=WAN2_conn passthrough=yes

3	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/2 action=mark-connection new-connection-mark=WAN3_conn passthrough=yes

4	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/3 action=mark-connection new-connection-mark=WAN4_conn passthrough=yes

5	add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses-and-ports:4/4 action=mark-connection new-connection-mark=WAN4_conn passthrough=yes

Source: http://aacable.wordpress.com/2011/06/04/mikrotik-4-wan-load-balance-pcc-complete-script-by-zaib/#