+----------------------------+    +---------------------------+   
|                            |    |                           |     
                             |    |                      
|                          "internet"                         |     
                                |                          
|                               |                             |     
                                |
|                               |                             |     
                           24.12.1.20                       
|                              xl1                            |   
                                |                               
|               +-----------------------------+               |
                |          San Antonio        |
|               +-----------------------------+               |   
                 |            |              |  
|               xl0(T-1)    fxp0            dc0               |   
              10.0.1.1     192.168.1.1    192.168.2.2
|                |                           |                |   
                 |                           |  
|                |                           |                |   
                 |                           |
|                |                           |                |   
              10.0.1.2                    192.168.2.1
|          (T-1)xl1 192.168.3.1             dc0               |   
                 |   fxp0                    |
|           +----------|-+              +------------+        |   
            |   Houston  |              |   Dallas   |
|           +------------+              +------------+        |   
              |         |                 |         |
|            dc0        xl0(T-1)     (T-1)xl1      xl0        |   
     24.100.100.12   10.0.0.5       10.0.0.6  24.155.100.66  
|             |         |                 |         |         |   
              |         |                 |         |
|             |         +-----------------+         |         |   
              |                                     |           
|             |                                     |         |   
+-------------+                                     +---------+ 

The internet IPs are fake, but there will need to be a VPN 
tunnel from Houston to SA and one from Dallas to SA as a 
fail over if the the other lines go down. Right now Houston
is the only router which has both Dallas and SA as a neighbor.