Monday, October 8, 2012

IETF: DPI/Policy Enforcement, Re-direction and Caching IPv6 Challanges

An IEFT document by Roberta Maglione (pictured), Telecom Italia and Wojciech Dec, Cisco from the Softwire, working group that is currently discussing both encapsulation and translation based stateless IPv4/IPv6 solutions in order to be able to provide IPv4 connectivity to customers in an IPv6 only environment.

The group presents a use-case for the Application of Service Policies to the subscriber’s sessions, Application of web-redirection policies and Caching.

"With the continuing growing of video traffic, especially considering the increase of http video traffic (you tube like,) it is useful for the Service Providers to be able to cache the video stream at the Edge of the network in order to save bandwidth in upstream links. Using cache devices together with tunnel solutions would introduce similar challenges/issues as the ones described for DPI scenarios, in particular it would require applying caching functionality after the decapsulation point. Obviously this would not eliminate the benefits of the cache. Instead a MAP-T approach would allow caching the subscriber traffic at the edge of the network and gaining the bandwidth savings introduced by the caching. Crucially, any native IPv6 web-caches would be capable of processing IPv6 MAP-T traffic as fully native traffic.

In addition in some deployments today, Web Cache Control Protocol (WCCP) feature is used in order to redirect subscriber’s traffic to the cache devices. When a subscriber requests a page from a web server (located in the Internet, in this case), the network node where the WCCP is active, sends the request to a Cache Engine. If the cache engine has a copy of the requested page in storage, the engine sends the user that page. Otherwise, the engine gets the requested page and the objects on that page from the web server, stores a copy of the page and its objects (caches them), and forwards the page and objects to the user. WCCP is another example of web redirect thus, the same considerations described in section Section 2.3 and the benefits introduced by MAP-T also apply here". 

See "Uses cases for MAP-T" - here.

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