Two Links, balance traffic

[Francisco Sanchez]

Hi Guys

I want to balance traffic using two links.

What is the best practice for balance traffic ???

I use routing EIGRP and Tunnels GRE,

I try with EIGRP LEAK but I do not is the best option.

Regards.

[paul driver]

Hello

load sharing in eigrp can be either equal or unequal 

Can you provide additional information regards your topology and exactly what you wish to achieve 

res

Paul

[Francisco Sanchez]

 I want is to balance the traffic, use both links.

Use the both IPS.

[paul driver]

Hello

unfortunately this isn't enough information to provide a solution

Can you share a topology of your network how it is presently and the current  traffic path from your clients

res

Paul

[Francisco Sanchez]

Yes, attach a similar topology.

 configuration

conf t

router eigrp 1

network 192.168.0.0 0.0.255.255 -> LAN

passive-interface default
 no passive-interface Tunnel27
 no passive-interface Tunnel28

exit

!

interface tunnel 27

Description *** ISP_1 *** -> LAYER 2 bandwidth 10000
 ip address 10.10.5.2 255.255.255.252
 load-interval 30
 delay 1
 keepalive 10 3
 tunnel source 172.16.0.90
 tunnel destination 172.16.0.89

!

interface tunnel 28

 description *** ISP_2 *** ->LAYER 3
 bandwidth 5000
 ip address 10.9.1.2 255.255.255.252
 load-interval 30
 delay 1
 keepalive 10 3
 tunnel source 172.20.5.246
 tunnel destination 10.10.1.50

I want to pass traffic for both tunnel

[Amit Goyal]

Hi Francisco,

You can use either PBR (Simplest method) or make use of PFR which is the smartest way (but little tough to implement) of doing load balancing.

HTH

-Amit

[Francisco Sanchez]

Hi Amit

Do you have example configuration of both protocols?

What protocol are you recommend?

[Amit Goyal · Accepted solution]

Hi Francisco,

PFR is always a best option but since it is difficult to implemet, you may end up with nothing. So i would recommend you to implement PBR. Below is the link whic can help you.

http://www.cisco.com/c/en/us/support/docs/ip/ip-routed-protocols/48003-pbrtracking.html

Above link describes the steps of applying PBR using track mechanism to check the status of ISP link. If ISP1 is good keep sending traffic to ISP1 for all traffic matched in ACL 10. If ISP1 fails, traffic will start moving over ISP2. Similarly you can add one more statement in route-map matching ACL 20 and preferred ISP2 for this and ISP1 as  

Interface <LAN interface>

ip policy route-map alphaback up.

route-map alpha permit 10

match ip address 10

set ip next-hop verify-availability  <IP of ISP1> track 123

set ip next-hop verify-availability  <IP of ISP2> track 124

route-map alpha permit 20

match ip address 20

set ip next-hop verify-availability  <IP of ISP2> track 124

set ip next-hop verify-availability  <IP of ISP1> track 123

ip access-list standard 10

permit ip <permit subnet which you want to pass via ISP1>

ip access-list standard 20

permit ip <permit subnet which you want to pass via ISP2>

You can also refer to the discussion on below link for the same requirement with 3xISP links.

https://supportforums.cisco.com/discussion/12391981/bgp-redundancy

HTH

-Amit

[paul driver]

Hello

Are those Bw and Delay values historical or have you set them to try and acheive LB?

Can you share

Sh ip route eigrp
sh ip eigrp topology

Applying equel LB to a current unequal LB senario can be done -

Example:

Sh ip route x.x.x.x.
sh ip eigrp topology x.x.x.x.| in Composite

Of the two entries in the eigrp topology table for this route you will see the coompostic metrics , these need to be divided
   
    Composite metric is (409600/128256), Route is Internal
    Composite metric is (5273600/128256), Route is Internal

5273600 / 409600  - 12.875  -  Round this up the nearest full value  = 13

router eigrp xxx
varience 13

sh ip route  x.x.x.x | in traffic
 Route metric is 409600, traffic share count is 240
 Route metric is 5273600, traffic share count is 19


290 / 19 = 12.6

sh ip route eigrp x.x.x.x

D       x.x.x.x [90/409600] via 10.1.13.3, 00:01:55, FastEthernet0/1
                            [90/5273600] via 10.1.12.2, 00:01:55, FastEthernet0/0

res
Paul

[Francisco Sanchez]

Hi

If the bandwight is different I can configure PRB??

Do you kneo CEF es great option or not?

[paul driver]

Hello

you can do for eigrp unequal load sharing also

PLease share your 

Show ip eigrp topology 

res

paul

[MANI .P]

PBR is the best option ....

[Joseph W. Doherty]

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Posting

If your two paths are equal bandwidth, or close to being equal, EIGRP ECMP would be an easy solution.

If your two paths vary much in bandwidth, EIGRP support unequal path load balancing, although another poster, in other posts, says EIGRP doesn't do it very efficiently.  (I.e. it might drive up CPU.)  This is also rather easy to config.

If your devices support PfR with PIRO, it might be used to do dynamic load balancing, and it can support both equal or unequal bandwidth paths.  This is the most optimal solution but requires learning a whole new technology.

As others have already noted, you could also use PBR, but it's often a bear to maintain, and you need to be careful with your config to deal with a path failure.