I recently attended a conference in Japan where the attendee network offered IPv6 service only. In the past, conferences such as the Asia Pacific Regional Conference on Operational Technologies (APRICOT) and meetings of the Internet Engineering Task Force (IETF) have conducted IPv6 experiments, but these have all been “opt-in” events. The conference in Japan was different: there was no IPv4 service available. Making this work involved a few manual configuration steps, but for the most part everything worked more or less the same as it did under IPv4. Some applications, including my instant message client and Skype did not work, and all connections to IPv4-only hosts needed to use Fully Qualified Domain Names (FQDNs) instead of IP addresses, but overall the experience gave me confidence that IPv6 is becoming a reality. As you might expect, this IPv6-only experiment also uncovered a number of bugs and incompatibilities that were duly reported to developers around the world.
Our first article is an overview of TRansparent Interconnection of Lots of Links (TRILL). TRILL uses Layer 3 routing techniques to create a large cloud of links that appear to IP nodes to be a single IP subnet. The protocol has been developed in the IETF and is currently being refined and enhanced in the TRILL working group. The article is by Radia Perlman and Donald Eastlake.
Developments in Internet technologies have lead to changes that go beyond the Internet itself. Not only is Voice over IP (VoIP) often used in place of traditional circuit-switched telephony, the telecommunication networks themselves are evolving to incorporate IP routers in place of traditional telephone switches. This evolution also applies to cellular telephone networks, specifically to what is known as backhaul—the transportation of voice and data from the cell sites to the mobile operators’ core networks. Jeff Loughridge explains more in “The Case for IP Backhaul.”
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by Radia Perlman, Intel Labs, and Donald Eastlake, Huawei Technologies
Transparent Interconnection of Lots of Links (TRILL) is an Internet Engineering Task Force (IETF) protocol standard that uses Layer 3 routing techniques to create a large cloud of links that appear to IP nodes to be a single IP subnet. It allows a fairly large Layer 2 cloud to be created, with a flat address space, so that nodes can move within the cloud without changing their IP addresses, while using all the Layer 3 routing techniques that have evolved over the years, including shortest paths and multipathing. An early problem and applicability statement for TRILL can be found in . Additionally, TRILL supports Layer 2 features such as Virtual Local-Area Networks (VLANs), the ability to autoconfigure (while allowing manual configuration if so desired), and multicast/broadcast with no additional protocol.
by Jeff Loughridge, Brooks Consulting LLC
In any hierarchical network, designers must specify how the access layer delivers traffic to the core. In Mobile Network Operator (MNO) networks, the transport of voice and data from the cell sites to the wireless MNOs’ core networks is called backhaul. Time Division Multiplexing (TDM) backhaul has dominated backhaul deployments since the inception of wireless communication. Leasing the backhaul access of multiple T1s/E1s for every cell site becomes prohibitively expensive in terms of operating expenses, particularly for providers that do not own the last mile. Today’s 3G/4G cellular technologies have spurred a major change in the backhaul network: the transition from TDM to packet backhaul.
The Internet Protocol Journal (IPJ) is published quarterly by Cisco Systems. The journal is not intended to promote any specific products or services, but rather is intended to serve as an informational and educational resource for engineering professionals involved in the design, development, and operation of public and private internets and intranets. The journal carries tutorial articles (“What is…?”), as well as implementation/operation articles (“How to…”). It provides readers with technology and standardization updates for all levels of the protocol stack and serves as a forum for discussion of all aspects of internetworking.