NASA team tests switches, routers for Net's successor
- By John Breeden II
- Sep 29, 1997
BOSTON--The tools that make up the Next Generation Internet are not
all vaporware. An entire NASA division is devoted to testing the technologies for the
backbone of a future Internet 100 times faster than today's.
The current focus of NGI testing is on routers and switches, said NASA computer
specialist Paul Grams, who works with a team of NASA testers in the NGI Division at Ames
Research Center in Moffett Field, Calif. The center is reviewing three new kinds of router
management software that might speed up transfer rates on existing equipment.
"The growth of the Internet and increasing client-server computing are causing
network congestion," Grimes said last week at the Technology 2007 conference.
"New applications such as video, multimedia and network audio are very
delay-sensitive," he said. "Standard router-based networks do not provide
guaranteed quality of service required by these delay-sen-sitive applications." But
the addition of more routers and expensive networks will not eliminate the bandwidth clogs
cost-effectively, he said.
That's where NASA's NGI team takes over.
The NGI team accepts proposals from industry to field test products at Ames. Grimes
said products start with tests in the lab, then move to a few buildings and, if they pass
the preliminary tests, to Ames' 7,000 users. NASA then reports the advantages and
disadvantages of a tool for potential NGI use.
Grimes said routers slow Internet traffic because they have to read each packet of data
before sending it to the next router in the chain, which must do the same.
"The current routers were designed to handle 80 percent local traffic and 20
percent remote," he said. "Today, the opposite is true."
One of the three router software applications NASA is testing is IP switching from
Ipsilon Networks of Sunnyvale, Calif. The software creates IP ability in asynchronous
transfer mode network hardware.
An ATM switch with IP software acts as a router for low-duration traffic and as an ATM
switch for long-duration flows such as file transfer. IP switching software is designed to
run on top of ATM hardware and lets network administrators determine how short a
transaction should be to activate IP instead of ATM.
NASA's simulation studies based on Internet traffic have determined that 84 percent of
the data packets would be IP-switched.
A second way to speed existing hardware is tag switching, a technology developed by
Cisco Systems Inc. of San Jose, Calif.
Tag switching simplifies a router's job and works with ATM networks. The software tags,
or maps, the current network and stores the data in routers. Data packets are also tagged
and switched as they leave their starting points.
Tags eliminate the need for routers by letting the network plot a course through ATM
backbones. By scanning the tag, the switches send the packet to the next step in the
IP routers normally do not have to know the complete path to a destination, but
switches need to know the whole destination, or at least the destination to an edge
router. This can cause network drag as each device has to plot a course through the
Tags can also be given higher priority based on the application or computer that sends
the file, so less-important traffic waits for packets with higher priority.
The tag switching network idea currently works only with Cisco equipment.
The third software NASA plans to test for NGI is an application for multiprotocol over
ATM (MPOA). MPOA is nonproprietary software supported by the ATM Forum, a coalition of
companies that develop routing software. It is also the only one of the three technologies
that is not ready for testing.
MPOA is supposed to work by establishing a switched ATM link between systems, instead
of routers processing data packets individually. The network initiating a file would find
the ATM address of the destination system and create a switched direct ATM connection.
MPOA uses LAN emulation to find ATM addresses when a communication begins. Then it
monitors the network traffic. It uses Next Hop Resolution Protocol to establish a direct
ATM channel for all subsequent traffic, eliminating the need to set up an ATM channel for
John Breeden II is a freelance technology writer for GCN.