--- 1/draft-ietf-cdni-request-routing-extensions-00.txt 2019-02-03 07:13:31.674517952 -0800 +++ 2/draft-ietf-cdni-request-routing-extensions-01.txt 2019-02-03 07:13:31.698518537 -0800 @@ -1,19 +1,19 @@ Network Working Group O. Finkelman Internet-Draft Qwilt Intended status: Standards Track S. Mishra -Expires: April 20, 2019 Verizon - October 17, 2018 +Expires: August 7, 2019 Verizon + February 3, 2019 CDNI Request Routing Extensions - draft-ietf-cdni-request-routing-extensions-00 + draft-ietf-cdni-request-routing-extensions-01 Abstract The Open Caching working group of the Streaming Video Alliance is focused on the delegation of video delivery requests from commercial CDNs to a caching layer at the ISP. In that aspect, Open Caching is a specific use case of CDNI, where the commercial CDN is the upstream CDN (uCDN) and the ISP caching layer is the downstream CDN (dCDN). The extensions specified in this document to the CDNI Metadata and FCI interfaces are derived from requirements raised by Open Caching @@ -33,25 +33,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 20, 2019. + This Internet-Draft will expire on August 7, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -62,26 +62,26 @@ 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Redirect Target Address Capability Object . . . . . . . . . . 3 2.1. DnsTarget . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2. HttpTarget . . . . . . . . . . . . . . . . . . . . . . . 6 3. Fallback Target Address Metadata . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 4.1. CDNI Payload Types . . . . . . . . . . . . . . . . . . . 9 4.1.1. CDNI FCI RedirectTarget Payload Type . . . . . . . . 9 4.1.2. CDNI MI FallbackTarget Payload Type . . . . . . . . . 9 - 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 - 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 + 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 + 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 - 8.2. Informative References . . . . . . . . . . . . . . . . . 10 + 8.2. Informative References . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction This document defines objects needed for Open Caching request routing. For that purpose it extends CDNI metadata [RFC8006] and CDNI Footprint and Capabilities [RFC8008]. For consistency, this document follows the CDNI notation of uCDN (the commercial CDN) and dCDN (the ISP caching layer). @@ -139,55 +139,61 @@ The Redirect Target capability object is used to indicate the target address the uCDN should use in order to redirect a client to the dCDN. A target may be attached to a specific uCDN host, a list of uCDN hosts, or it can be set globally for all the hosts of the uCDN. When dCDN is attaching the redirect target to a specific uCDN host or a list of uCDN hosts, the dCDN MUST advertise the hosts within the Redirect Target Capability object as "redirecting-hosts". In that case, the uCDN can redirect to that dCDN address, only if the request - is of one of these uCDN hosts. + was directed to one of these uCDN hosts. - A redirect target for DNS redirection is the FQDN to be used as a - CNAME for the uCDN host (see [RFC1034]). + A redirect target for DNS redirection is an IP address used as an A + record response or a FQDN used as an alias in a CNAME record response + (see [RFC1034]) of the uCDN DNS router. Note that DNS routers take + routing decisions based on either the DNS resolver's IP address or + the client IP address when EDNS0 client-subnet is used (see + [RFC7871]). The dCDN may choose to advertise redirect targets and + footprints to cover both cases. A uCDN DNS router implemenation + SHOULD prefer routing based on client IP address when it is + available. - A redirect target for HTTP redirection is the hostname to be used as - the first path segment in an absolute URI which is used as the - Location header of the HTTP rediret response (see section 7.1.2 of - [RFC7231]). + A redirect target for HTTP redirection is the URI to be used as a + value of the Location header of a HTTP redirect 3xx response, + typically a 302 (Found) (see section 7.1.2 of [RFC7231] and section + 6.4 of [RFC7231]). Property: redirecting-hosts Description: One or more uCDN hosts to which this redirect target is attached. A redirecting host SHOULD be a host that was published in a HostMatch object by the uCDN as defined in section 4.1.2 of [RFC8006]. Type: A list of Endpoint objects (see section 4.3.3 of [RFC8006]) Mandatory-to-Specify: No. If not present, or empty, the redirect target applies to all hosts of the redirecting uCDN. Property: dns-target - Description: Target address for DNS CNAME delegation. + Description: Target address for DNS A record or CNAME record. Type: DnsTarget object (see Section 2.1) Mandatory-to-Specify: No. but at least one of "dns-target" or "http-target" MUST be present and non empty. Property: http-target - - Description: Target URL for HTTP redirect. + Description: Target URI for HTTP redirect. Type: HttpTarget object (see Section 2.2) Mandatory-to-Specify: No. but at least one of "dns-target" or "http-target" MUST be present and non empty. Example of Redirect Target Capability object that advertises a dCDN target address that is attached to a specific list of uCDN "redirecting-hosts". A uCDN host that is included in that list can redirect to the advertised dCDN redirect target. @@ -210,31 +216,31 @@ }, "footprints": [ ] } ] } 2.1. DnsTarget - The DnsTarget object is the target address for CNAME delegation from - the uCDN to the dCDN. + The DnsTarget object gives the instructions to construct the target + address for the DNS response for delegation from the uCDN to the + dCDN. Property: host - Description: The host property is a hostname, without a port - number. + Description: The host property is a hostname or an IP address, + without a port number. Type: Endpoint object as defined in section 4.3.3 of [RFC8006] - with the limitation that it MUST only be a hostname, and it - MUST NOT include a port number. + with the limitation that it MUST NOT include a port number. Mandatory-to-Specify: Yes. Example of DnsTarget object: { "host": "service123.ucdn.example.dcdn.com" } Example of a DNS query for uCDN address @@ -244,54 +250,56 @@ Query: a.service123.ucdn.example.com: type A, class IN Response: a.service123.ucdn.example.com: type CNAME, class IN, cname service123.ucdn.example.dcdn.com 2.2. HttpTarget - The HttpTarget object is the target address for http redirection from - the uCDN to the dCDN. + The HttpTarget object gives the instructions to construct the target + Location URI for http redirection from the uCDN to the dCDN. Property: host - Description: Hostname or IP address and optional port, i.e., - the host and port as described in section 3.2 of [RFC3986]. + Description: Hostname or IP address and an optional port, i.e., + the host and port of the authority component of the URI as + described in section 3.2 of [RFC3986]. Type: Endpoint object as defined in section 4.3.3 of [RFC8006]. Mandatory-to-Specify: Yes. Property: path-prefix - Description: A path prefix for the HTTP redirect. The original - path is appended after this prefix. + Description: A path prefix for the HTTP redirect Location + header. The original path is appended after this prefix. Type: A prefix of a path-absolute as defined in section 3.3 of [RFC3986]. The prefix MUST end with a trailing slash, to indicate the end of the last path segment in the prefix. Mandatory-to-Specify: No. If this property is absent or empty, the uCDN MUST NOT prepend a path prefix to the original content - path. + path, i.e. the original path MUST appear in the location URI + right after the authority component. Property: include-redirecting-host Description: A flag indicating whether or not to include the redirecting host as the first path segment after the path- prefix. In case this flag is true and a "path-prefix" is used, the uCDN redirecting host MUST be added as a separate path segment after the path-prefix and before the original URL path. In case this flag is true and there is no path-prefix, the uCDN - redirecting host MUST be perpended as the first path segment in + redirecting host MUST be prepended as the first path segment in the redirect URL. Type: Boolean. Mandatory-to-Specify: No. Default value is False. Example of HttpTarget object with a path-prefix and include- redirecting-host: { @@ -317,56 +325,60 @@ 3. Fallback Target Address Metadata Open Caching requires that the uCDN should provide fallback target server to the dCDN to be used in cases where the dCDN cannot properly handle the request. To avoid redirect loops, the fallback target server's address at the uCDN MUST be differnet than the original address at the uCDN from which the client was redirected to the dCDN. The uCDN MUST avoid further redirection when receiving the client request at the fallback target. The fallback target is defined as a generic metadata object (see section 3.2 of [RFC8006]) - Use cases o Failover: A dCDN request router receives a request but has no caches to which it can route the request. This can happen in the - case of failures or temporary network overload. In these cases, - the router may choose to redirect the request back to the uCDN - fallback address. + case of failures or temporary network overload. + + o No coverage: A dCDN request router receives a request from a + client located in an area inside the footprint but not covered by + the dCDN caches, or a client located outside the dCDN footprint + coverage. In such cases, the router may choose to redirect the + request back to the uCDN fallback address. o Error: A cache may receive a request that it cannot properly serve, for example, some of the metadata objects for that service were not properly acquired. In this case, the cache may resolve to redirect back to uCDN. The Fallback target metadata object is used to indicate the target address the dCDN should use in order to redirect a client back to the uCDN. Fallback target is represented as endpoint objects as defined in section 4.3.3 of [RFC8006]. - The uCDN fallback target address may be used as a DNS CNAME in case - of DNS redirection mode or a host name for HTTP redirect. + The uCDN fallback target address may be used as a DNS A record or + CNAME record in case of DNS redirection mode or a host name for HTTP + redirect. When using HTTP redirect to route a client request back to the uCDN, it is the dCDN's responsibility to use the original URL path as the client would have used for the original uCDN request, stripping, if needed, the dCDN path-prefix and the uCDN host name from the redirect URL that may have been used to request the content from the dCDN. Property: host Description: Target address to which the dCDN can redirect the client. Type: Endpoint object as defined in section 4.3.3 of [RFC8006] - with the limitation that in case of DNS delegation, it MUST - only be a hostname, and it MUST NOT include a port number. + with the limitation that in case of DNS delegation, it MUST NOT + include a port number. Mandatory-to-Specify: Yes. Example of a MI.FallbackTarget Metadata object that designates the host address the dCDN should use as fallback address to redirect back to the uCDN. { "generic-metadata-type": "MI.FallbackTarget", "generic-metadata-value": @@ -474,20 +486,25 @@ [RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed., "Framework for Content Distribution Network Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336, August 2014, . [RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI) Media Type Registration", RFC 7736, DOI 10.17487/RFC7736, December 2015, . + [RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W. + Kumari, "Client Subnet in DNS Queries", RFC 7871, + DOI 10.17487/RFC7871, May 2016, + . + Authors' Addresses Ori Finkelman Qwilt 6, Ha'harash Hod HaSharon 4524079 Israel Phone: +972-72-2221647 Email: orif@qwilt.com