Routing network traffic

Abstract

A method may include receiving a domain name system (DNS) query at a network device, where the DNS query may be associated with a traffic flow identified for rerouting through an alternative path utilizing an alternative network device instead of a default path. The method may also include rewriting the DNS query such that the DNS query is routed through the alternative network device along the alternative path and to a DNS server associated with the alternative path. The method may additionally include receiving a DNS response from the DNS server, where a resource identified in the DNS response may be based on the DNS query coming through the alternative network device.

What is claimed is: 
     
         1 . A method, comprising:
 determining multiple paths from an origin of a traffic flow to a destination, each of the multiple paths including a first network domain path and a second network domain path;   obtaining first performance scores for the first network domain paths and the second network domain paths;   combining, for each path of the determined multiple paths, a first performance score for the first network domain path and a second performance score for the second network domain path;   designating a path with the best combined performance score as a primary path;   routing traffic along the primary path; and   rerouting traffic, in response the combined score of the primary path falling below a threshold, from the primary path to a backup path.   
     
     
         2 . The method of  claim 1 , further comprising:
 designating, after the combining and before the routing, a path other than the primary path as the backup path.   
     
     
         3 . The method of  claim 2 , wherein the designating comprises designating as the backup path a path with different initial edge network device than the primary path. 
     
     
         4 . The method of  claim 2 , wherein the rerouting traffic comprises rerouting traffic to the designated backup path. 
     
     
         5 . The method of  claim 1 , wherein the first network domain path is within an internal network domain, and the second network domain path is outside the internal network domain. 
     
     
         6 . The method of  claim 1 , wherein the first designating comprises:
 identifying at least two paths of the determined multiple paths to have identical best combined performance scores; and   applying equal cost multiple path routing to identifying the primary path.   
     
     
         7 . At least one non-transitory computer readable medium storing instructions which when executed by at least one processor, cause the at least one processor to:
 determine multiple paths from an origin of a traffic flow to a destination, each of the multiple paths including a first network domain path and a second network domain path;   obtain first performance scores for the first network domain paths and the second network domain paths;   combine, for each path of the determined multiple paths, a first performance score for the first network domain path and a second performance score for the second network domain path;   designate a path with the best combined performance score as a primary path;   route traffic along the primary path; and   reroute traffic, in response the combined score of the primary path falling below a threshold, from the primary path to a backup path.   
     
     
         8 . The at least one non-transitory computer readable medium of  claim 7 , further comprising instructions which when executed by the at least one processor, cause the at least one processor to:
 designate, after the combining and before the routing, a path other than the primary path as the backup path.   
     
     
         9 . The at least one non-transitory computer readable medium of  claim 8 , instructions which when executed by the at least one processor, cause the at least one processor to: designate as the backup path a path with different initial edge network device than the primary path. 
     
     
         10 . The at least one non-transitory computer readable medium of  claim 8 , wherein the reroute traffic comprises reroute traffic to the designated backup path. 
     
     
         11 . The at least one non-transitory computer readable medium of  claim 7 , wherein the first network domain path is within an internal network domain, and the second network domain path is outside the internal network domain. 
     
     
         12 . The at least one non-transitory computer readable medium of  claim 7 , instructions which when executed by the at least one processor, cause the at least one processor to:
 identify at least two paths of the determined multiple paths to have identical best combined performance scores; and   apply equal cost multiple path routing to identifying the primary path.   
     
     
         13 . A system, comprising:
 at least one processor;   a non-transitory computer readable medium storing instructions which when executed by the at least one processor causes the at least one processor:
 determine multiple paths from an origin of a traffic flow to a destination, each of the multiple paths including a first network domain path and a second network domain path; 
 obtain first performance scores for the first network domain paths and the second network domain paths; 
 combine, for each path of the determined multiple paths, a first performance score for the first network domain path and a second performance score for the second network domain path; 
 designate a path with the best combined performance score as a primary path; 
 route traffic along the primary path; and 
 reroute traffic, in response the combined score of the primary path falling below a threshold, from the primary path to a backup path. 
   
     
     
         14 . The system of  claim 13 , further comprising instructions which when executed by the at least one processor, cause the at least one processor to:
 designate, after the combining and before the routing, a path other than the primary path as the backup path.   
     
     
         15 . The system of  claim 14 , further comprising instructions which when executed by the at least one processor, cause the at least one processor to:
 designate as the backup path a path with different initial edge network device than the primary path.   
     
     
         16 . The system of  claim 14 , wherein the reroute traffic comprises reroute traffic to the designated backup path. 
     
     
         17 . The system of  claim 13 , wherein the first network domain path is within an internal network domain, and the second network domain path is outside the internal network domain. 
     
     
         18 . The system of  claim 13 , further comprising instructions which when executed by the at least one processor, cause the at least one processor to:
 identify at least two paths of the determined multiple paths to have identical best combined performance scores; and   apply equal cost multiple path routing to identifying the primary path.