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Load Balancing 2 T1's, with 2 differant ISP's using a Cisco Router

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ACSNS asked
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Last Modified: 2013-11-30
All,

Is it possible to load balance 2 T1's from two differant ISP's.  If so, what protocol would be needed and how efficient is it?  Any other points of interested would be greatly appreciated.

Thanks,
Andy
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Commented:
That link's not so good.

Typically, you could use a route map to divide the traffic between two different ISPs.

I think there is also an option within the route map syntax to check to see if the link is still alive. If the link is not alive, then the route map sends everything to the live ISP link.

Commented:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/qos_c/qcpart1/qcpolicy.htm

Here's a real good link, (search for "equal access example"), but it doesn't show how to fail-over. Maybe route maps can't detect failures.
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Commented:
Do you want to load blance both inbound and outbound traffic?  If so, you MUST talk to your ISP's.  You can load blance your outbound traffic, but the ISP's must work to gether to load balance your inbound traffic.

Commented:
you can load balance uplinks with the commands

ip route 0.0.0.0. 0.0.0.0. x.x.x.x
ip route 0.0.0.0. 0.0.0.0  y.y.y.y

and use no ip route-cache so router will throw a packet to each line and if you monitor using solarwinds or mrtg you will find up link equal

about downlink this can be done using through you  provider through the same steps
You need carefully implement what you are doing.  Basically you will have two different gateways and thewre a number of ways to do this.  You can send one packet to one gateway and one packet to the other gateway, AKA load balancing.  Sometimes that will not work because some applications require the same gateway for the full session.  Another way is to subnet your network so each one has there own gateway for outbound traffic, AKA load or traffic splitting.  Note that with load splitting traffic is necessarily balanced.  In either case, if you have a firewall the configuration becomes more complex.

Remember if you balance or split outbound traffic, to get the full benefit you will also need to fo the same for inbound traffic.  If you want inbound traffic to be either balanced or split, you will need to contact each ISP and have them implement an exterior routing protocol, BGP.  You will also need an AS Number which is not hard to get from ARIN.

Thanks.    
http://www.fatpipeinc.com/

One of these will do inbound & outbound load-balancing (and lots more) without any need to even speak to the ISP.

Theres lots of different models, but the low end Warp is suitable for most peoples purposes.

It can also aggregate ADSL, ISDN, etc (anything with an IP address & ethernet connection really)

I work for a UK distributor, and can supply you further details if you want to email.

Cheers


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Commented:
heathcote123, not it won't.  You MUST talk to your ISP(s) to balance inbound traffic.   Inbound traffic is based on routing tables in the Internet.  How is it going to change routing tables within the Internet?
No really, it will.

It depends on what you want to achieve. If you have control of your dns records then generally there is no need to speak to them or arrange changing in routing tables.

Some models have 'smart dns', allowing you to delegate records to the various interfaces on the box and let it do the incoming load balancing.

http://www.fatpipeinc.com/brochures/warp_brochure.pdf

Would be useful if the OP could post a bit more about his requirements.
 
 

Completely missed the reference to Cisco in the original question - apologies to the OP.
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Commented:
What fatpipe will do is balance traffing into a server, but not into a site.  If I have two T1's from the same or different ISP's, it will not balance traffic from the internet across the T1's inbound to me.   Once the traffic hits the fatpipe, it will balance across mutliple internal connections that are between the fatpipe and my servers, and it will balance the outbound responses across the T1's.
"Once the traffic hits the fatpipe, it will balance across mutliple internal connections that are between the fatpipe and my servers, and it will balance the outbound responses across the T1's."

No wrong again. That would be pretty pointless in the days

When a DNS request hits the FP, it will reply with the IP that is least loaded. Hence connections will come down that pipe from that client.

Please take the time to read the link before contradicting any more statements :) Theres more than one way to skin a cat you know ....
Some how didnt finish that 2nd sentence - That would be pretty pointless load balancing a couple of T1's on a gigabit lan.

Author

Commented:
Thank you to those who actually address my question instead of wasting my time with this fatpipe nonsense.
I guess you missed this post:

Completely missed the reference to Cisco in the original question - apologies to the OP.

I read the question:

Is it possible to load balance 2 T1's from two differant ISP's.  If so, what protocol would be needed and how efficient is it?  Any other points of interested would be greatly appreciated.


Sorry for the nonsense - only trying to help.
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Commented:
Opps, we just cross posted.  No problem.

In order to have traffic from the Internet to you load balanced across two different ISP's connections, you must have one of your ISPs get what is called a Autonomous System number (ASN or AN) for you (if you are really large and own your own IP subnet I beleive you can get one on you own ASN).  Then all ISP's you have have to setup internal routing tables for this AS and all IP subnets on the AS.

Using my prior information, say I go to talk to a host in 1.1.1.0/24, well now the core part of the internet also knows that it can get to this address through ISP2 and ISP2 will be setup to route traffic for 1.1.1.0/24 over ISP2T1.  This will allow traffic from the Internet to be sent inbound to you from different ISP's.



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Commented:
Don't get me wrong, FP is a great box.  I would really love to have one, its just in our current enviroment one does not make sense for us.  Our backend server is a single mainframe and we only have two T1's from a single ISP.  Most of our requests are small amounts of inbound data, lots of reading data in a database, and then little bits of data out.


I appreciate they are not suitable for every situation - but they are a good option for many.

I'm gonna shoot off now before we waste any more of Andys time. :)

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