Re: EUnet GB policy on Cu-SeeMe and similar applications

Luk Van de Heyning (
Mon, 5 Jun 1995 19:45:40 +0200

Hi all,

remember me causing a 'black out" over here in Europe, just by using CuSeeme?

Here's a transcript from a message I just received from my Provider.

I think it is of interest to all CuSeeme-users...

>>> Damaging Video / Voice Traffic on the Internet
>>> ----------------------------------------------
>>> Eg: Cu-SeeMe and similar applications
>>> Summary:
>>> There are a number of Software and Hardware products
>>> that allow a variety of Audio and Video applications
>>> between LAN's over TCP/IP and therefore to run on
>>> Internet links.
>>> These applications, due to their unique requirements
>>> for a constant and high traffic stream, do not use the
>>> normal management layers of the Internet Protocol i.e TCP,
>>> and therefore have a very detrimental effect on other
>>> traffic - they are able to totally 'hog' links, no
>>> matter how large the link size.
>>> This has a very disruptive effect on the network
>>> performance as seen by other users, and can upset
>>> networks at any or many links worldwide between the two or
>>> more communicating application end-users.
>>> Internet Providers worldwide are concerned at the
>>> danger from indiscriminate use of these applications,
>>> and EUnet, like many others, will apply it's Terms
>>> and Conditions to prevent service impairment to it's
>>> networks and to those of other providers worldwide,
>>> in order to maintain a good service to all users.
>>> User Organisations must therefore make written requests to
>>> EUnet, and receive written confirmation that EUnet will allow
>>> such usage, in advance of using such Video / Audio
>>> applications across the Internet.
>>> Acknowledgement required
>>> ------------------------
>>> This situation is being taken very seriously in the context
>>> of maintaining an effective Internet service to users, and
>>> EUnet will require a written (email or other) acknowldedgement
>>> from all User Organisations that this message has been received and
>>> understood.
>>> Technical
>>> ---------
>>> Technically, it is UDP being transmitted in real
>>> time, large volume. This violates the fundamental
>>> design of the Internet, which is largely based on
>>> TCP (advanced, highly adaptive, robust, flow control)
>>> for high volume), and UDP (simple, crude, unreliable,
>>> no flow control) for single, occasional datagrams.
>>> Applications that need high volume, real time traffic
>>> currently have no option other than to use UDP.
>>> But the result can be, and usually is, devastating
>>> for TCP-based traffic. When a TCP connection detects
>>> packet loss, it immediately backs off. In the presence
>>> of high volume UDP traffic, the ensuing packet loss will
>>> cause TCP connections to slow down to a crawl.
>>> In brief, when TCP traffic is high on a link, all
>>> connections 'back-off' thus sharing equally the available
>>> bandwidth. UDP however, does not back-off in this controlled
>>> manner but will take all available bandwidth.
>>> These video/voice applications are new, 'exciting' and
>>> work fine on high bandwidth Local Area Networks or
>>> specialist high bandwidth Wide Area Networks such as JANET,
>>> where 34 MBits government financed links exist.
>>> The Worldwide InterNet, however, has a wide variety
>>> of links scaled to a capacity to handle well behaved TCP/IP
>>> traffic, but Audio and Video applications should not be used
>>> without permission from your Internet provider.
>>> Terms and Conditions
>>> --------------------
>>> It is in all our interest of both Internet Customers
>>> and Internet Providers worldwide that this policy is strictly
>>> observed, so that *all* users have the best possible service.
>>> EUnet's Terms and Conditions state:
>>> Section 4 para 4
>>> "Unless otherwise agreed in a service agreement,
>>> EUnet provides international bandwidth on an as-available
>>> basis, and User Organisation's bandwidth and other resource
>>> consumption must be commensurate with the type of service
>>> taken"
>>> It is apparent even from the pricing of Internet services worldwide,
>>> that users paying a fixed annual fee for eg a modem access, will
>>> at best slowly bankrupt Internet providers if they take full modem speed
>>> constant international bandwidth when connected. At worst they
>>> will cause Providers networks to very quickly become unusable
>>> by most users.
>>> Section 5
>>> "The User Organisation is assumed to be competent in making and
>>> maintaining an Internet connection, including where applicable
>>> Internet/ IP/ DNS/ system administration.
>>> "Where such administration is inadequate to prevent damaging traffic
>>> or effects on the EUnet network or external Internet, EUnet reserves the
>>> right to unilaterally apply packet filtering/ blocking and other menas to
>>> limit such damage or effects.
>>> "The User Organisation is liable for all expenses incurred by EUnet as a
>>> result of neglect, incompetenmce, wilful malice or other inappropraite
>>> behaviour or Internet/ IP/ DNS/ system administration on the User
>>> Organisations part, including but not limited to legal fees, technical fees
>>> and loss of income.
>>> In this context EUnet, in line with other providers,
>>> ask that written permission is obtained *prior* to use
>>> of these Video / Audio services.
>>> Other UDP applications
>>> ----------------------
>>> The above policy has been codified because we want to ensure that CuSeeMe
>>> and similar applications do not adversely affect the Internet. However
>>> there are other `non-dangerous' UDP applications, so if you are running
>>> or likely to run such applications please advise us both of the nature of
>>> these and of the ports used. This will help us to control damaging traffic
>>> while hopefully not harming `non-dangerous traffic'.
>>> Peter Houlder
>>> Technical Director - 3rd March 1995

Greatings / groetjes

Luk Van de Heyning

(-: PhD Internet-Addictions :-)