MPLS and OC48c, FORE's technical leadership in this mkt segment.
-------- extract from the article:
"Last month, MCI launched an OC-48 link between Los Angeles and San
Francisco as part of the National Science Federation's vBNS research
network. The link features MPLS as its traffic engineering mechanism. What
MCI learns from this project could wind up in its commercial network."
================ full article below
March 15, 1999, Issue: 756
Section: News & Analysis
In Focus: IP Standards -- One Way To Play In Heavy Traffic
John Fontana
In life, the path less traveled often leads to the richest experiences. In
networking, it's the path most efficiently traveled that yields the greatest value
for end users.
A prominent signpost on that path is a maturing IETF standard called
Multiprotocol Label Switching (MPLS), which gives service providers and IT
managers a way to build connection-oriented paths across an IP network.
MPLS can be used to integrate IP and ATM, allow for traffic engineering and
result in virtual private networks that are more than just best-effort Internet
tunnels.
MPLS networks also are expected to be used for e-commerce, voice over
IP, true end-to-end quality of service (QoS) and Web conferencing. IT
managers will be able to buy guaranteed levels of bandwidth and service level
agreements. Coupled with other standards, most notably DiffServ, those
features could be extended into the LAN.
Carriers such as AT&T, MCI WorldCom and Uunet already are testing
MPLS. Mega-enterprises such as General Motors are eyeing the technology
for traffic engineering. And vendors such as Argon Networks Inc., Avici
Systems Inc., Cisco, Fore Systems, IBM, Lucent/Ascend and Newbridge
Networks Corp. are implementing MPLS in their hardware.
But MPLS suffers from one major issue: It is not completed. The most notable
omission is a protocol for constraint-based routing (CBR), similar to Private
Network-to-Network Interface (PNNI) in ATM.
The key to MPLS is that it separates the routing plane from the forwarding
plane, creating a software-based, label-switching plane, similar to ATM.
Changing the software that distributes the labels can change the way the
network behaves.
Simply stated, MPLS-enabled routers assign a 32-bit label that specifies a
packet's path through a network. The label contains information that routers in
conventional networks would have to calculate at each hop. Instead, each
device switches the packet based on the label and a table of paths. When the
packet exits the network, the label is removed.
"MPLS eliminates the need for dedicated connections, but retains their
reliability," said John Morency, an analyst at Renaissance WorldWide Inc.
"High performance is a given, but you also have more effective QoS across a
service provider network than in a conventional routed backbone."
Momentum is building, and the IETF's MPLS working group issued "last call"
Feb. 24 on the Label Distribution Protocol (LDP), the signaling mechanism
MPLS devices use to exchange label semantics such as destination address,
destination networks or bandwidth to destination networks. Drafts for MPLS
over ATM, as well as frame relay and MPLS encapsulation, are complete.
MPLS also is expected to let large enterprises engineer traffic and make IP
their protocol of choice while retaining the reliability and scalability they had
with SNA and other legacy protocols.
General Motors is doing just that. Once it can control IP routes, the company
can eliminate much of its legacy traffic and tunnel the rest through IP.
"In that sense, IP switching becomes important, and MPLS is the enabler of
that project," said Ajit Kapoor, director of network architecture and
standards at GM.
GM, which spends $1 billion annually on network support, hopes MPLS and
IP switching can cut that figure by 30 percent annually in the next three years.
Traffic engineering also has carriers salivating by lowering costs and reducing
network complexity, said Joe Skorupa, director of switching and routing at
RHK Inc., a consultancy. "It could help lower overall network costs by half,"
he said.
Last month, MCI launched an OC-48 link between Los Angeles and San
Francisco as part of the National Science Federation's vBNS research
network. The link features MPLS as its traffic engineering mechanism. What
MCI learns from this project could wind up in its commercial network.
AT&T is in beta with IP-enabled frame relay that uses MPLS and is a model
for future VPN services to the enterprise.
"The architecture can create tactical VPNs-ones that appear for a short time
and then go away," said Tom Nolle, president of consultancy CIMI Corp.
"We could see VPNs that last a couple of hours for NetMeeting sessions."
AT&T is using MPLS to leverage frame relay permanent virtual circuits
(PVCs) for IP applications. Currently, its enterprise customers require
hundreds of PVCs and complex routing tables to create a meshed network for
their IP applications over frame relay. But with MPLS, AT&T is moving that
complexity into its own network and allowing the enterprise to use just a single
PVC to provide secure, fully meshed connectivity to its network locations.
That lets customers establish a VPN for applications, such as enterprise
resource planning or e-mail. They also can retain their current IP addressing
and frame relay security.
Despite its promise, however, MPLS still needs refinement.
"The signaling is not nailed down yet, and there are issues around quick
response to failure and rerouting," said MCI's Rick Wilder, director of
advanced Internet technology.
The signaling protocol for both CBR and explicit path routing is missing. Both
routing methods can be used to optimize bandwidth and support differentiated
services. Two protocols are vying to be the standard: extensions to LDP and
the Resource Reservation Protocol (RSVP).
The signaling protocol is key because it enables connection-oriented paths
within IP. Also missing are hooks in the IP routing protocols to specify needed
bandwidth and check for its availability.
MCI sees a need for both RSVP and LDP but uses RSVP, which is backed
by vendors such as Cisco, Juniper Networks Inc. and Torrent Systems Inc.
"RSVP looks to be farther ahead in setting up a label-switched path by
specifying all the intermediate nodes and essentially doing source routing of the
signaling for the path," Wilder said.
Others, such as Nortel Networks, Ericsson and General DataComm Inc.,
recently completed the first constraint-based routing interoperability test using
LDP extensions.
Both LDP extensions and RSVP are likely to be approved as signaling
protocols. Last call on both are expected by early April. Until then, MPLS
provides no more than high-performance, best-effort routing without QoS
mechanisms. But most observers say that by early 2000, MPLS networks will
spring up. AT&T, GM and MCI all are shooting for that time frame.
"Everybody wants everything to look and smell like IP, and that means making
connectivity more and more the same," said Gene Cox, program director for
IBM's Network Hardware Division and business development.
Copyright ® 1999 CMP Media Inc. |
