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design question for MPLS WAN redundancy

david contreras
Level 1
Level 1

We have an MPLS WAN with 2 DS3 routers.  The routers are not connected to each other.  I want to load balance the traffic across the DS3's.  Right now traffic is just taking the best path according to BGP. 

Will I need to run GLBP on the front side (ethernet/lan side)?

I found a configuration to run for BGP to load balance.

      

The MPLS provider is the same carrier for both connections. 

9 Replies 9

Collin Clark
VIP Alumni
VIP Alumni

You can run iBGP between your two routers. You can then tweak the attributes in BGP and "load balance" and provide WAN link redundnacy. Note that perfect load balancing in BGP is not really possible. GLBP is an option, but you could also use HSRP or VRRP. iBGP will take care of routing to the MPLS cloud.

So with iBGP, just make a /30 and connect both routers via these links.  I can use a 192.168.x.x/30 subnet?

What attibutes in BGP need to be tweaked for the load balance.  It does not have to be perfect load balancing.  Its just that now one of our DS3's is hitting 90% and the other one is at about 10%.  Thanks

Joseph W. Doherty
Hall of Fame
Hall of Fame

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

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Posting

If supported by your platforms, Cisco PfR will dynamically load balance.

If used, PfR load balances over time, so something like GLBP might be used is get rough egress load balancing, and then PfR can "fine tune".

What IOS is needed for PfR?

I was using a 7206 with 12.4.24 T8 on dynamips/GNS3....but no pfr master command.  I did the key chain commands.  Do I need to use 15.x?

Thanks,

We have 7206vxr's in production, running 12.4.4T1

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

I recall PfR came out in 12.4T (and OER in 12.4), so there's a good chance your IOS versions support one or the other.  However, I don't think either is in the IP Base feature set.

Jami Bailey
Level 1
Level 1

Adjusting BGP Maximum paths will allow BGP to load balance, but PfR would be ideal for your scenario.

We have 2 -7206VXRs running AdvEnterprise IOS 12.4.4.  I tried 12.4.24 AdvEnt on dynamips, it does not do PfR.  I think that we would need 15.x.  I have not heard good things with the 15.x and the 7206VXR.

My understanding is maximum-paths works if we have a single router with the 2 BGP connections.  Is that correct?

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

As noted in my prior post, PfR arrived with 12.4T.  12.4 should have OER, but I don't recall what release it arrived with (if not release 1).


MPLS-redundancy.jpg

Can I run maximum-paths on the 2-MPLS 7206's?  I heard it would only work for a single router with 2 ISP connections.  Anyone know?      

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