FW: FYI - Internet delays and RA
Dan Kohn (email@example.com)
Tue, 21 Jan 1997 16:27:00 -0800
>Sent: Tuesday, January 21, 1997 4:01 PM
>To: Marketing Team
>Subject: Fwd: FYI - Internet delays and RA
> Bogus Messages Snarling the 'Net
> By JEFF CARUSO and AMY ROGERS
> Experiencing Internet delays? You can probably feel safe blaming the
> A huge percentage of Internet routing control messages may be
> nonsensical or redundant, according to a project funded by the
> National Science Foundation. While this can have significant
> performance and reliability implications for network and IS
> managers, the complex nature of the Internet makes it tough to
> pinpoint exactly where or why a bottleneck occurs.
> According to researchers, unnecessary routing control
> messages--and the routers handling them--occasionally turn the
> Internet into the World Wide Wait.
> For end users, the problems may amount to no more than an
> occasional performance delay. But the same kind of congestion
> that has moved some America Online users to file lawsuits may
> spur Internet service providers to take a harder look at their own
> router and backbone configurations, to ensure the stability of their
> customers' connections.
> Internet routers suffer from mysterious "pathological behavior" that
> sometimes causes them to lose users' packets, increase delay and, in
> extreme cases, shut down, according to Craig Labovitz, leader of the
> Routing Arbiter (RA) project, the effort funded by the National
> Science Foundation that discovered the problem last year. According
> to the study, more than 90 percent of the routing updates that
> Internet routers send to each other are needless.
> Sending extraneous updates at the very least burns router
> processor cycles and causes "routing instability" as routers
> update their topology maps. Labovitz said it is "common
> knowledge" among engineers that routing instability leads to
> packet loss and delay, though no one has been able to quantify
> the impact in a network as fast and complex as the Internet.
> "This is an ISP issue," said Joel Halpern, the Internet Engineering
> Task Force's routing area director and principal systems engineer at
> Newbridge Networks. "Anyone running the core Net has to think about
> it. Customers of ISPs don't have to deal with this problem per se,
> but we are all affected by any kind of instabilities."
> ISPs are cognizant of the problems. Robert Berger, chief
> technology officer at Internex Information Services Inc., a Santa
> Clara, Calif.-based ISP, called for increasing the number of North
> American network access points. He also hopes that IP version 6 will
> support additional exterior gateway protocols beyond Border Gateway
> Protocol, to stabilize the Net. These "pathological" messages are all
> based on BGP.
> Despite the potential problems and how they can impact users'
> Internet efforts, network and IS managers noted there are a
> number of proactive steps they can take to prevent performance
> For example, Viacom Inc. is working to ensure acceptable
> access-speed levels for its Web sites' visitors through special
> service arrangements with its ISP, Uunet, as well as regular
> evaluation of its Internet servers and the efficiency with which
> incoming hits are handled, said Steve Plastrik, vice president of
> technical operations at New York-based Viacom.
> "All of us who run networks today know that there are always
> things you can do to clean them up," said Jeffrey Burgan, a
> director for the IETF's Internet area and manager of the ISP
> development group at Bay Networks. "The onus is on the ISPs,"
> he continued. Unfortunately, "A lot of them are stretched as far as
> they can go, where resources are concerned, and a lot of them may not
> have the expertise that others have."
> RA project directors have no clear idea what is causing routers to
> send so many updates, but have developed some theories. One discovery
> revealed that when a Net router sends out a topology update, there is
> a high probability a duplicate message will follow in 30 seconds.
> This results in millions of superfluous messages traversing the Net
> Routers issue updates, or "announcements," to let their neighbors
> know to which destinations they can send user data. But the problem
> seems especially pronounced with "withdraws," or messages that let
> others know that the router can no longer reach a particular
> The problem also could be rooted in a vendor-specific hardware
> or software bug. But Cisco, the largest router vendor, said it could
> not duplicate any discovered problems in test scenarios. Yet Cisco
> has adjusted its interpretation of BGP slightly in an attempt to
> address some of the study's concerns. "It hasn't been a real active
> concern of ours, because we're not hearing any complaints from
> customers," a Cisco representative said.
> The 30-second periodic nature of the problem suggests another
> theory: that routers aren't interacting well with telephone company
> The phone companies sometimes drop lines for a fraction of a
> second--too short a time for people on a phone conversation to
> notice but perhaps long enough on a leased line for data
> networking equipment to issue a withdraw message, RA's
> Labovitz said.
>Also in this issue:
>Congestion is a way of life on the Internet
>First Telco Deploys Nortel's "Internet Thruway"
>Online students fare better
>Prof fights for right to Net porn
>California Enacts Internet Consumer Protection Provision
>Excerpt from the CSS INTERNET NEWS
>For subscription details e-mail
>-----End of forwarded message-----