# US 2014/0156822 A1 · Method of request routing re-direction with loop detection and prevention > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0156822 A1 - Document ID: US20140156822A1 - Status: Published application - Kind: A1 - Application number: 14/080,874 - Filed: 2013-11-15 - Published: 2014-06-05 - Earliest claimed: 2012-11-15 - Assignees: Electronics and Telecommunications Research Institute; LG Uplus Corp.; SK Telecom Co., Ltd.; Solbox Inc. - Applicants: Electronics and Telecommunications Research Institute; LG Uplus Corporation; SK Telecom Co., Ltd.; Solbox Inc. - Inventors: Taesang CHOI; John Dongho SHINN; Jong Min LEE; Ja-Ryeong KOO - Web page: https://patentgrep.com/patent/US20140156822A1 ## CPC - H04L 61/4511: using domain name system [DNS] - H04L 67/289: Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network - H04L 67/568: Storing data temporarily at an intermediate stage, e.g. caching - H04L 2101/30: Types of network names - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method of request routing redirection includes: receiving, by a first content delivery network (CDN) among a plurality of CDNs connected by CDN interconnection (CDNi), a domain name system (DNS) request including a list of CDN-provider-identifications (IDs) of higher CDNs, from a client; determining whether the client's request is processable; and when the client's request is not processable, redirecting the request, while preventing a loop of the request routing on the basis of the list of the CDN-provider-IDs. ## Claims ### Claim 1 A method of request routing redirection, comprising: receiving, by a first content delivery network (CDN) among a plurality of CDNs connected by CDN interconnection (CDNi), a domain name system (DNS) request including a list of CDN-provider-identifications (IDs) of higher CDNs of the first CDN, from a user terminal; determining whether the request is processable; and when the request is not processable, redirecting the request, while preventing a loop of the request routing on the basis of the list. ### Claim 2 (depends on 1) The method of claim 1, further comprising, when the request is processable, transmitting an IP address of a delivery node to the user terminal. ### Claim 3 (depends on 1) The method of claim 1, further comprising, when a CDN-provider-ID of the first CDN is included in the list, stopping redirecting of the request routing. ### Claim 4 (depends on 1) The method of claim 1, wherein the CDN-provider-IDs each comprise a name of a CDN provider and a maximum number of redirection hops. ### Claim 5 (depends on 4) The method of claim 4, further comprising, when the maximum number of redirection hops is 0, stopping redirecting of the request routing. ### Claim 6 (depends on 4) The method of claim 4, wherein the name of the CDN provider comprises an autonomous system number and a pair of additional identifiers. ### Claim 7 (depends on 1) The method of claim 1, wherein the redirecting of the request comprises: determining whether CDN-provider-IDs of lower CDNs of the first CDN are included in the list; when the CDN-provider-IDs of the lower CDNs are not included in the list, selecting a candidate CDN among the lower CDNs; and when CDN-provider-IDs of some of the lower CDNs are included in the list, selecting a candidate CDN among the remaining lower CDNs other than the some CDNs. ### Claim 8 (depends on 7) The method of claim 7, wherein the redirecting of the request further comprises delivering a name server (NS) record including the CDN-provider-ID of the first CDN, the CDN-provider-IDs of the higher CDNs, and a CDN-provider-ID of the candidate CDN, to the user terminal. ### Claim 9 A method of request routing redirection comprising: receiving, by a first content delivery network (CDN) among a plurality of CDNs connected by CDN interconnection (CDNi), a domain name system (DNS) request including a list of CDN-provider-identifications (IDs) of higher CDNs of the first CDN, from a user terminal; returning an Internet protocol (IP) address of a request router of the first CDN to the user terminal; receiving a hypertext transfer protocol (HTTP) request from the user terminal; determining whether the HTTP request is processable; and when the HTTP request is not processable, redirecting the request, while preventing a loop of the request routing on the basis of the list. ### Claim 10 (depends on 9) The method of claim 9, wherein when the request is processable, transmitting an IP address of a delivery node to the user terminal. ### Claim 11 (depends on 9) The method of claim 9, wherein when a CDN-provider-ID of the first CDN is included in the list, stopping redirecting of the request routing. ### Claim 12 (depends on 9) The method of claim 9, wherein the CDN-provider-IDs each comprise a name of a CDN provider and a maximum number of redirection hops. ### Claim 13 (depends on 12) The method of claim 12, wherein when the maximum number of redirection hops is 0, stopping redirecting of the request routing. ### Claim 14 (depends on 12) The method of claim 12, wherein the name of the CDN provider comprises an autonomous system number and a pair of additional identifiers. ### Claim 15 (depends on 9) The method of claim 9, wherein the redirecting of the request comprises: determining whether CDN-provider-IDs of lower CDNs of the first CDN are included in the list; when the CDN-provider-IDs of the lower CDNs are not included in the list, selecting a candidate CDN among the lower CDNs; and when CDN-provider-IDs of some of the lower CDNs are included in the list, selecting a candidate CDN among the remaining lower CDNs other than the some CDNs. ### Claim 16 (depends on 15) The method of claim 15, wherein the redirecting of the request comprises: delivering an HTTP redirection message including a CDN domain of the candidate CDN, a CDN domain of the first CDN, CDN domains of the higher CDNs, and a CDN-provider-ID of the first CDN, to the user terminal. ### Claim 17 A method of request routing redirection, comprising: delivering a domain name system (DNS) request including a list of CDN-provider-identifications (IDs) of higher content delivery networks (CDNs) of a first CDN to the first CDN, among a plurality of CDNs connected by CDN interconnection (CDNi); when the first CDN cannot process the request, receiving a DNS request further including CDN-provider-identifiers (ID) of candidate CDNs selected from lower CDNs of the first CDN in the list; and redirecting the request to a second CDN among the candidate CDNs. ### Claim 18 (depends on 17) The method of claim 17, further comprising, when the connection to the second CDN fails, redirecting the request to a third CDN among the candidate CDNs. ### Claim 19 (depends on 17) The method of claim 17, further comprising: receiving an address of an Internet protocol (IP) of a request router of the first CDN; and transmitting a hypertext transfer protocol (HTTP) request to the request router of the first CDN. ### Claim 20 (depends on 19) The method of claim 19, further comprising, when the connection to the second CDN fails, redirecting the request to a third CDN among the candidate CDNs.