Load Balanced Dual T1's - Same default gateway for both CSU/DSU's?

Gleb Smirnoff glebius at cell.sick.ru
Tue Apr 27 23:28:32 PDT 2004

On Tue, Apr 27, 2004 at 10:19:59PM -0500, Steven N. Fettig wrote:
S> I know this is possible using a Cisco router with two or dual CSU/DSU's 
S> for data T1's, but I am struggling to figure out how to get this to work 
S> with FreeBSD: 
S> I have a Sangoma Dual T1 (CSU/DSU) card in a FreeBSD box I want to use 
S> as the router and firewall for.  Global Crossing has provided me with 
S> two T1's that they are "load balancing" on their end (they will not 
S> employ multilink ppp) - traffic will be distributed "evenly" across both 
S> T1's - one is not a main vs. backup - they are both mains and if one 
S> goes down, both go down.  I need to somehow tell the gateway/router to 
S> use two different pipes as the default gateway.  I.e. the far side of 
S> the wan is for T1-1 and for T1-2.  I can only 
S> add a default route for one and not set it to both.  Is there a way to 
S> either use ipfw or simple routing to make this work?  otherwise, I guess 
S> Cisco is it...

Surely, the best way ever is multilink PPP. You can also try this hack:

route delete default
route add
route add

Does Sangoma has a netgraph driver? If it does you can try to use ng_one2many.

Totus tuus, Glebius.

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