Reverse Engineering Peering At Internet Exchange Points

Abstract

A technique for examining the relationships of autonomous systems (ASes) participating in an Internet Exchange Point (IXP) utilizes packet tracing servers proximate the IXPs. Where such packet tracing servers cannot be found in the participating ASes, the methodology identifies additional vantage points by looking at a list of ASes that are one hop away from the ASes at the IXP. The choice of one-hop away ASes is made judiciously by picking ones that have better connectivity, based on past-data. Plural-hop ASes may also be used where necessary.

What is claimed is: 
     
         1 . A network exchange point topology research server connected via a computer network to a plurality of autonomous systems subscribing to a network exchange point of the computer network, the topology research server comprising:
 a processor; and   non-transitory computer readable medium having computer readable instructions stored thereon that, when executed by the processor, perform operations for determining peering relationships of the plurality of autonomous systems, the operations comprising:
 selecting a vantage autonomous system from the plurality of autonomous systems, 
 determining that no packet tracing server is available within the vantage autonomous system; 
 determining that no packet tracing server is available in any autonomous system one hop from the vantage autonomous system; 
 identifying a packet tracing server in a second autonomous system located at least two hops from the vantage autonomous system, the second autonomous system not subscribing to the network exchange point; 
 identifying an IP address in a target autonomous system that is another of the plurality of autonomous systems subscribing to the network exchange point; 
 requesting a packet trace from the packet tracing server to the IP address; and 
 determining whether the vantage autonomous system and the target autonomous system have a peer relationship at the network exchange point based on whether the packet trace traverses the network exchange point. 
   
     
     
         2 . The network exchange point topology research server of  claim 1 , wherein the packet tracing server is a traceroute server. 
     
     
         3 . The network exchange point topology research server of  claim 1 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by consulting at least one reference selected from the group consisting of Packet Clearing House database, PeeringDB database and a network exchange point Web site.   
     
     
         4 . The network exchange point topology research server of  claim 1 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point utilizing an identifier contained in a DNS name of the network exchange point.   
     
     
         5 . The network exchange point topology research server of  claim 1 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by utilizing border gateway protocol tables.   
     
     
         6 . The network exchange point topology research server of  claim 1 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by utilizing traceroute data.   
     
     
         7 . The network exchange point topology research server of  claim 1 , wherein identifying a packet tracing server in a second autonomous system located at least two hops from the vantage autonomous system further includes:
 selecting the packet tracing server based at least in part on connectivity measured using past data.   
     
     
         8 . The network exchange point topology research server of  claim 1 , wherein selecting a vantage autonomous system from the plurality of autonomous systems further includes:
 selecting the vantage autonomous system based on a visibility of the autonomous system in a network.   
     
     
         9 . The network exchange point topology research server of  claim 1 , wherein selecting a vantage autonomous system from the plurality of autonomous systems further includes:
 selecting the vantage autonomous system based on a number of IP prefixes listed for the vantage autonomous system in a border gateway protocol table.   
     
     
         10 . The network exchange point topology research server of  claim 1 , further comprising:
 repeating the method, substituting another autonomous system from the plurality of autonomous systems as the vantage autonomous system.   
     
     
         11 . A network exchange point topology research server connected via a computer network to a plurality of autonomous systems subscribing to a network exchange point of the computer network, the topology research server comprising:
 a processor; and   non-transitory computer readable medium having computer readable instructions stored thereon that, when executed by the processor, perform operations for determining peering relationships of the plurality of autonomous systems, the operations comprising:
 selecting a vantage autonomous system from the plurality of autonomous systems, 
 determining that no packet tracing server is available within the vantage autonomous system; 
 identifying a packet tracing server in a second autonomous system located at least one hop from the vantage autonomous system, the second autonomous system not subscribing to the network exchange point; 
 identifying an IP address in a target autonomous system that is another of the plurality of autonomous systems subscribing to the network exchange point; 
 requesting a packet trace from the packet tracing server to the IP address; and 
 determining whether the vantage autonomous system and the target autonomous system have a peer relationship at the network exchange point based on whether the packet trace traverses the network exchange point. 
   
     
     
         12 . The network exchange point topology research server of  claim 11 , wherein the packet tracing server is a traceroute server. 
     
     
         13 . The network exchange point topology research server of  claim 11 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by consulting at least one reference selected from the group consisting of Packet Clearing House database, PeeringDB database and an network exchange point Web site.   
     
     
         14 . The network exchange point topology research server of  claim 11 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point utilizing an identifier contained in a DNS name of the network exchange point.   
     
     
         15 . The network exchange point topology research server of  claim 11 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by utilizing border gateway protocol tables.   
     
     
         16 . The network exchange point topology research server of  claim 11 , wherein the operations further include:
 identifying the plurality of autonomous systems subscribing to the network exchange point by utilizing traceroute data.   
     
     
         17 . The network exchange point topology research server of  claim 11 , wherein identifying a packet tracing server in a second autonomous system located at least two hops from the vantage autonomous system further includes:
 selecting the packet tracing server based at least in part on connectivity measured using past data.   
     
     
         18 . The network exchange point topology research server of  claim 11 , wherein selecting a vantage autonomous system from the plurality of autonomous systems further includes:
 selecting the vantage autonomous system based on a visibility of the autonomous system in a network.   
     
     
         19 . The network exchange point topology research server of  claim 11 , wherein selecting a vantage autonomous system from the plurality of autonomous systems further includes:
 selecting the vantage autonomous system based on a number of IP prefixes listed for the vantage autonomous system in a border gateway protocol table.   
     
     
         20 . The network exchange point topology research server of  claim 11 , further comprising:
 repeating the method, substituting another autonomous system from the plurality of autonomous systems as the vantage autonomous system.