a router connected to more than one autonomous system (AS), and which exchanges routing information with routers in other ASs
                                                            
                                                     
                        
                                                
                        
                        
                            autonomous system boundary router. A router that exchanges routing information with routers that belong to other autonomous systems. The AS boundary router then advertises external routes throughout the autonomous system. AS boundary routers can be internal or area border routers, and migh or might not be connected to the backbone.
                                                            
                                                     
                        
                                                
                        
                        
                            Autonomous system boundary router. In OSPF, a router that exchanges routing information with routers in other ASs.