發送短信 : Geographic routing with cross links

 ______     _____    _    _     _____     ______  
|      \\  |  ___|| | || | ||  |  ___||  /_   _// 
|  --  //  | ||__   | || | ||  | ||__      | ||   
|  --  \\  | ||__   | \\_/ ||  | ||__     _| ||   
|______//  |_____||  \____//   |_____||  /__//    
`------`   `-----`    `---`    `-----`   `--`