Networking's greatest debates in LANS + WANS

Including IPv4 vs. IPv6, routing vs. switching, Packet switching vs. circuit switching, Ethernet vs. Token Ring, and Cisco vs. the rest,

Ethernet vs. MPLS in the WAN

They began as totally separate and distinct technologies: Ethernet as the standard in the LAN, and MPLS VPNs as an attractive alternative to frame relay and ATM services in the WAN.

But now they are starting to collide. Service providers are turning up Layer 2 Ethernet VPNs based on an MPLS derivative called Virtual Private LAN Services (VPLS) on a regional, national and eventually, global basis. And while some carriers say VPLS Ethernet is a complementary access or metro technology to MPLS national and global services, some acknowledge that users are reconsidering their Layer 3 VPN decisions.

VPLS is intended for businesses that prefer to maintain control of their routing, for security and staffing purposes, rather than share it with their service provider. Layer 3 MPLS VPN users choose to let the service provider manage the routing domain.

This will usually be the chief determinant of whether an enterprise selects a Layer 2 or Layer 3 VPN service, carriers say. But some users have also cited the ability to scale multicasts as a benefit of Layer 3 MPLS VPNs, especially as they migrate to service-oriented architectures.

MPLS VPNs have been around a few years longer than VPLS. But as VPLS continues to mature and become more functionally complete, the decision to pick one over the other will become harder -- and the ability of carriers to keep one from cannibalizing the other will be tougher as well.

"I don't think it's a zero-sum game," said Josh Holbrook of the Yankee Group. "I don't think one of those services will prevail over the other."
Jim Duffy

IPv4 vs. IPv6

The argument about how best to upgrade the Internet's main communications protocol raged in the Internet Engineering Task Force in the early 1990s. By then, experts realized that the Internet would eventually run out of address space with the original version of the Internet Protocol, known as IPv4.

The issue of what direction to take with the next-generation of IP came to a head at a 1994 IETF meeting in Toronto. Ultimately, the IETF decided to replace the 32-bit addressing scheme in IPv4 with a 128-bit addressing scheme in IPv6. The standards body tried to create other reasons to upgrade to IPv6, including built-in security with IPsec and easier management through autoconfiguration of devices.

Nearly a decade after IPv6 was finalized, the network industry has yet to embrace the new protocol. That's because a forklift upgrade to IPv6 is too expensive and time consuming for a carrier or enterprise, with little measurable return. Instead, the network industry anticipates a gradual transition to IPv6, which will likely run side by side with IPv4 for many years to come.

Now it appears that IPv6 is finally winning this argument. The American Registry for Internet Numbers recommended in May that the Internet community start migrating to IPv6.

In fact, some industry experts predict that there are only around 1,200 days left until the Internet runs out of IPv4 addresses. Leading the charge to IPv6 is the U.S. federal government, which has mandated that all agencies support the new protocol in their backbone networks by June 2008.
Carolyn Duffy Marsan

K56flex vs. x2 56Kbps modems

In this argument over technologies the winner is not a technology at all, it's its inventor Brent Townshend.

He ultimately prevailed in his legal claim as inventor of the modem that capitalizes on a vagary of the public phone network that makes it possible to send data to a dial-up modem at 56Kbps, faster than the 33.6Kbps limit on sending data from that same machine.

In 1997, when broadband Internet access hadn't been invented, the 56K modem was a major advance that industry heavyweights laid claim to, most importantly U.S. Robotics, touting its x2 technology, and Lucent, backing K56flex.

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Network World staff

Network World

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