deciding what traffic to split at second isp setup

[baselzind]

my workplace are getting a second isp to blanace the network load , assuming i have the following traffic " please add any if i missed some in a normal network environment"

-web browsing traffic "for employees"

-servers traffic "oracle,exchange,..etc"

-video conference units traffic "video calls"

-vcs expressway traffic "jabber"

assuming both isp have the same speed how should the traffic types be split amongst the two? bear in mind the video conference unit are standalone and makes call natted through the fw and please advice if some application are better not to be disturbed?

[Francesco Molino]

Hi

If you want to loadbalance some traffic on ISP1 and others on ISP2, you can do that by using Policy-Based routing.

You need to create ACL, and route-maps in order to classify traffic and set the next-hop that would be ISP1 or ISP2.

If you have some traffic coming from outside to inside, you need to be careful to not create asymmetric traffic for the return traffic.

Hope this answered your question.

Thanks

PS: Please don't forget to rate and mark as correct answer if this solved your issue

[Richard Burts]

Doing load balancing of traffic to and from the Internet is pretty tricky. You really need to consider how to balance outbound traffic and balance inbound traffic as separate things since the mechanism that performs one does not do the other.

As suggested in the previous post it is easier to balance outbound traffic, especially if both ISP are connected to a single router in your network. You could configure Policy Based Routing to send some types of traffic to ISP 1 and other types to ISP 2 and could configure PBR to provide failover if one of the ISP goes down.

The significant challenge is in how to balance the inbound traffic. Think about a situation in which user A has sent Web Browser traffic out through ISP 1 and has sent video conference call out through ISP 2. How do you balance the returning traffic? The ISP is not able to use PBR to match your traffic types. So how do you handle the response traffic in a way that does not create asymmetric traffic?

In my experience it frequently works better if you balance traffic based on the address of the inside host. If you arrange PBR so that the first half of your hosts use ISP 1 and the second half of your hosts use ISP 2 then it might be possible to arrange routing so that the Internet uses ISP 1 for the first half and uses ISP 2 for the second half.

HTH

Rick

[baselzind]

i believe all these action will be done on the firewall? as the network is located behind a firewall which in turn connects to the isp routers?

[Richard Burts]

It is not clear to me which actions you are talking about which would be done on the firewall. For outbound traffic, if the firewall supports PBR the balancing of outbound traffic could be done on the firewall. But how would the firewall balance inbound traffic?

HTH

Rick

[baselzind]

im not sure as im not handling the firewall part , my question is basically is what traffic type to assign to which isp not how technically to do so 

[Francesco Molino]

For outbound traffic, there is no recommendation of what type of traffic to load balance. 

However as I've said and as Richard said, you need to know whic traffic is allowed inbound. 

In that case, everything that needs to be natter inbound should stay with ISP1 and all other traffic could go through ISP2.    

Thanks

PS: Please Don't Forget to rate and mark as correct answer if this solved your issue