WEIRD Hot Topic: Current IETF Activities in Wireless Internet
By Chris Burke, Chairman, IETF Web Elucidation of Internet Related Developments WG
At this writing (February 8, 2000) the IETF has more than 100 active working groups clustered in 8 areas of specialization. No area of specialization deals specifically with "wireless internet", but activities related to wireless internetworking can be found in each of the areas.
In this article I’ll define "wireless internet", identify some uniquely wireless issues in internet standardization, and survey the work of the IETF that has, in my opinion, the greatest impact on evolution and deployment of wireless internet.
What’s "Wireless Internet"?
"Wireless" refers to ways of transmitting information using radio signals or light traveling through space (no wires or fiber-optics). "Internet" refers to the global information system that:
"(i) is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons;
(ii) is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-compatible protocols; and
(iii) provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein"
"Wireless internet" is simply that part or parts of the internet, for which the communications and related infrastructure described in item (iii) above, are provided using wireless data transmission media such as radio signals or light.
Uniquely Wireless Internet Issues
The wireless internet is part of the internet, and so nearly every activity, RFC, and standard of the IETF applies to the wireless internet. Exceptions include certain IETF Internet Area activities related to transmission of internet protocols over specific non-wireless media such as fiber-channel or IEEE 1394 "firewire".
Engineering the wireless internet presents unique technical challenges. The frequencies used for radio transmission are a scarce resource – so scarce that most governments around the world carefully regulate their use for information transmission.
Wireless internet signals travel freely through space, but their travel is limited by government regulations on transmitter power and the signals can be blocked or corrupted unintentionally by walls, moving vehicles, mountains, or even bad weather. Signals can arrive at unintended receivers, causing interference with other means of communication, or duplication of data. Wireless communication also presents a security challenge - anyone with the right equipment can eavesdrop on unsecured wireless internet signals without "tapping a wire".
One very important internet protocol, Transmission Control Protocol (TCP), relies on assumptions that are not valid on some wireless networks. TCP includes a congestion control mechanism intended to prevent network gridlock during periods of high usage. However, this mechanism uses packet loss (failure of information to arrive when expected) as an indicator of congestion. In wireless neworks packet loss commonly occurs for a variety of reasons unrelated to congestion. TCP reacts to packet loss by trying "less hard" to send data, when a more appropriate response on a wireless network might be just the opposite.
In many cases, the engineer’s goal in choosing a wireless transmission medium is to achieve mobility; those using the wireless internet want to move around while doing so, without interrupting their interaction with high level services like web browsing, e-mail, group collaboration, or gaming. The desire for mobility leads to requirements on networking technology and also limits the compute-power and program storage available to implement internet protocols.
Some wireless transmission media, such as satellites, time-delay data significantly. Other wireless media, such as narrow-band packet radio, transmit data slowly in comparison with typical dial-up internet access.
Wide-are wireless internets are often operated for profit, by the same companies that operate cellular telephony systems. The wireless medium itself is scarce, and the opportunity cost of using the medium for wireless internet access is often high: a customer might pay $12 / hour to talk over a cell phone using network resources that might otherwise enable wireless internet access. To meet the needs of end users, engineers designing applications for use on the wireless internet often prioritize minimizing the amount of network resource used by the application over creating rich functionality. This has a direct impact on the engineering of transport, security, and application-layer protocols.
The unique challenges and resource costs of building the wireless internet can cause engineers designing wireless internets, and engineers designing wired internets, to find different solutions and architectures optimal. When such engineers meet in IETF working groups, their challenge is to find solutions that meet the common need without over-compromising either.
An Area Index
Here’s a quick guide to what’s happening in each of the IETF Areas that could be of special interest to engineers developing the wireless internet. More information on each of these activities is available on the IETF web site athttp://www.ietf.org/html.charters/wg-dir.html.
The wireless internet is part of the internet, and so nearly every activity, RFC, and standard of the IETF applies to the wireless internet. The working groups highlighted here indicate only my own perspective – the subjects that I, as a wireless internet engineer, find to have the greatest potential impact on deployment of wireless internets.
The Applications Area of the IETF is concerned with protocols used to implement high level services on the internet. Some of these high level services have strong functional similarity to services like paging and voice telephony that have traditionally been offered over dedicated wireless networks.
IETF work on high level services creates both competitive alternatives and an evolutionary path for traditional wireless services. Applications Area work of particular interest to engineers working on the wireless internet includes:
Currently the General Area of the IETF has only one working group. Known as poisson (Process for Organization of Internet Standards ONg), this group discusses and documents the standards development process of the IETF, including IETF policy for interaction with other standards bodies such as ETSI and TIA.
Working groups in the IETF Internet Area may meet to agree on standards for transmission of IP datagrams over specific media types. Currently, working groups are discussing IP Over Fiber Channel, IP Over IEEE 1394, and IP Over Cable Data Network. None of the current discussions are specific to wireless media.
Several working groups in the Internet Area are discussing issues about which engineers working on wireless internet deployment might have a unique view of requirements. These include:
Operations and Management Area
The Operations and Management Area of the IETF forms working groups to develop network management standards.
Many of the working groups in this area meet to specify Simple Network Management Protocol (SNMP) Management Information Blocks (MIBs) that provide management information about specific data transmission media – including, potentially, wireless media.
Another large set of Operations and Management Area working groups meet to specify management techniques for making Quality of Service (QoS) guarantees and optimizations in wired and wireless internets.
The work of the Operations and Management area includes all aspects of internet network management. Working groups discussing topics of special interest to wireless internet engineers include:
Working groups in the IETF Routing Area discuss and specify techniques for moving information around in the internet (routing) based on IP addresses and other criteria. Working groups of special interest to wireless internet engineers include:
The IETF Security Area addresses protocol security issues for all of the other areas. Security is important in all aspects of internet communication, but is of special interest to wireless internet engineers due to the relative ease of intercepting, spoofing, or interfering with a radio signal.
Security Area working groups that might be of special interest to wireless internet engineers include:
Transport Area working groups discuss issues and author standards related to transmitting streams of data over wired and wireless internets. This is a very rich area, with many topics of special interest to wireless internet engineers, including:
User Services Area
Unlike other IETF areas, the User Services Area does not develop internet standards. Rather, it serves as an end-user advocate and identifies methods to improve the quality of information available to users of the Internet, and initiates projects designed to assist individuals and organizations that support Internet users.
The Web Elucidation of Internet Related Developments (weird) working group that wrote this document on wireless internet issues is part of the User Services Area.
A Subject Index
Here are 10 topics of interest to engineers developing wireless internets, a brief description of each, and a list of current IETF activities related to each topic.
Note that the Internet Research Task Force (IRTF) is a forum for discussion of pre-standardization research in many of these areas. For more information, consult the IRTF home page at http://www.irtf.org/.
(THIS SECTION NOT FINISHED – OUTLINE ONLY)
Matching Internet Protocol Requirements to Bandwidth, Delay, Jitter, Time-Variance, and Error Rate of the Medium
Optimal Network Resource Allocation
Usage Metrics for Cost Recovery
Security of All Parties
Mobility and Dynamic Network Topology
Small Internet Hosts
Emulation of High Level Services that Predate the Internet
Interworking with Legacy Wireless Telecommunication Systems
New High Level Services
IETF Policies, Alliances, Liaisons, and Sharing of Responsibility With Other Wireless Telecommunication Industry Standards Development Organizations
Is There a BOF In Your Future?
Birds-Of-a-Feather (BOF) is a name given by the IETF to an open meeting to discuss creation of new IETF working groups.
If you are working on any aspect of wireless internet that would benefit from the IETF standards process, but don’t see an IETF working group discussing your issues, why not host a BOF at an IETF meeting to find out who else around the world shares your goals?
In the interest of attracting the largest group of interested parties, BOF meetings are formal agenda items at IETF meetings, and must be sponsored by one of the IETF Area Directors. Instructions for requesting a BOF on the IETF meeting agenda are on-line at http://www.ietf.org/meetings/1bof-procedures.txt.
WEIRD is the Web Elucidation of Internet Related Developments working group of the Internet Engineering Task Force. WEIRD provides information through its web site to raise engineering community and end-user awareness of IETF activities.
We chose the unorthodox name, WEIRD, to reflect the unusual structure and deliverables of the working group. Most IETF working groups have a fixed period of existence in which to develop specific standards-related deliverables known as RFCs. In contrast, the WEIRD working group uses web media to report on current IETF working group and pre-working-group (known as BOF) activities, dependencies and interrelationships among specific IETF WG and BOF activities, IAB / IESG / Secretariat issues and topics of interest to the internet engineering community.
For more information on WEIRD, or to volunteer to write an article for WEIRD, see our IETF home page athttp://www.ietf.org/html.charters/weird-charter.html