A routing mechanism, service or system operable in a distributed
networking environment. One preferred environment is a content delivery
network (CDN) wherein the present invention provides improved
connectivity back to an origin server, especially for HTTP traffic. In a
CDN, edge servers are typically organized into regions, with each region
comprising a set of content servers that preferably operate in a
peer-to-peer manner and share data across a common backbone such as a
local area network (LAN). The inventive routing technique enables an edge
server operating within a given CDN region to retrieve content
(cacheable, non-cacheable and the like) from an origin server more
efficiently by selectively routing through the CDN's own nodes, thereby
avoiding network congestion and hot spots. The invention enables an edge
server to fetch content from an origin server through an intermediate CDN
server or, more generally, enables an edge server within a given first
region to fetch content from the origin server through an intermediate
CDN region. As used herein, this routing through an intermediate server,
node or region is sometimes referred to as "tunneling."