MLPPP With 2 T1

Posted on 2003-11-15
Last Modified: 2008-03-17
WE have a hub and spoke frame relay network. I want to add a secondary T1 to double bandwidth.. I do not want to use load balancing but want to bond the 2 T1's together. I know I can use MLPPP to bond the T1's. I am confuse on how to configure the interface for frame relay....
Question by:elliealfonso
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LVL 79

Expert Comment

ID: 9754290
You have to work with your telco to get bonded T1 multi-link frame-relay. You simply cannot do it on just your end. Typically, the telco will bring in an imux that will connect to your router by either HSSI or v.35.
Either that, or they will use IMA to bond ATM T1's together at the router and not use frame-relay at your end.


Author Comment

ID: 9754915
Telco said they are going to split the primary PVC going to the frame relay hub  between the the 2 T1's. Does that mean they are already doing inverse multiplexing of the T1's and if they are I have a problem because I am planning on using my PA-MC-4T1 card on my 7206 to do this and I do not have a budget to buy a different card.  Also, right now I have multipoint on the hub and point-to-point on the spokes configure on my frame network, I want to change it to point-to-point on the hub so I can monitor my connection to each site since it will have a subinterface going to each spoke on the network. Is this a good idea?
LVL 79

Expert Comment

ID: 9755045
I would understand splitting the PVC as meaning giving you two PVC's to two different T1's, NOT combining in a multilink.
You can do your own load-sharing/load-balancing between the two PVC's.

It is always better to have multiple point-to-point subinterfaces rather than point-to-multipoint.
You can do a lot more things with interfaces than you can routes. Connection monitoring and bandwidth monitoring/restricting among the many...
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Author Comment

ID: 9755158
If they are providing 2 PVC. Will I be able to use Cisco MLPPP to do load sharing, as far I can undestand with MLPPP you have to use a group and assign your T1 interfaces into this group. How do I configure do I configure the serial interface to use this group ?
LVL 79

Accepted Solution

lrmoore earned 250 total points
ID: 9755180
My advise is not to even try to use MLPPP to load share.
Use CEF and equal-cost routes.
MLPPP causes every packet to be process-switched, while CEF and equal-cost paths use fast-switching. The performance difference is incredible.
All you have to do to enable it is a global command
router(config)#ip cef

If you are using EIGRP or OSPF, you should automatically get equal-cost routes through the route updates. As long as you have equal cost routes, then you have the automatic default packet-by-packet load sharing with automatic failover if one link goes down.

There is no technical reason to go through the trouble of trying to create a multi-link PPP connection, especially over frame-relay sub-interfaces. It just does not make sense.


Assisted Solution

RonaldLeibfreid earned 250 total points
ID: 9930643
Actually, your ISP may be doing the best possible method - MLFR or MFR - Multi-link Frame Relay.  7206 VXR and the card you have should work fine, but you'll need to ensure the IOS is adequate for MFR.  It requires IP-Plus.  I think 12.2(8) T5 should be adequate.

Author Comment

ID: 9931136
Thanks for the help. I have another question can I have all the remote sites configure to have all the same DLCI number and create subinterfaces in the HUB with different DLCI number for each subinterfaces ?
LVL 79

Expert Comment

ID: 10752905
Are you still working on this? Can you close out the original question?


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