Switch users in for QoS cost surprise

By Jim Duffy and Robin Schreier Hohman
Network World, 3/23/98

As vendors tout their policy-based network capabilities, they're chomping at the bit to tell users about how they can guarantee quality of service (QoS).

But they're not anxious to tell users about another guarantee: The new features will require significant hardware upgrades that could cost tens of thousands of dollars.

Users looking to implement the IEEE 802.1p standard for QoS are going to have to replace current-generation LAN switches with new hardware, vendors and analysts acknowledged last week.

"It would require a forklift upgrade," said Kelly Carpenter, systems manager at Washington University's Genome Sequencing Research Center, in St. Louis, a large Cisco Systems, Inc. customer. "At some point you do have to bite the bullet and upgrade if it really is something that's going to help you out." Upgrades are also in the offingfor the 802.1Q virtual LAN (VLAN) protocol, but depending on the vendor, it may only entail software.

The 802.1Q specification is a four-byte field added to an Ethernet, token-ring or FDDI frame. It holds VLAN membership and security information. The 802.1p protocol - which is now in the IEEE's 802.1d committee - is a four-byte field that defines up to eight levels of transmission priority. It is intended for applications such as multicast video or real-time desktop videoconferencing and is expected to be ratified late
this year.

Both protocols are intended to enable multivendor Layer 2 switches to distinguish incoming traffic classes. In addition to interpreting 802.1p and 802.1Q bits, LAN switching equipment must support multiple priority queues. Most LAN devices do not have these capabilities, acknowledged Rick Forberg, product manager of ATM Internetworking at 3Com Corp..

But 3Com, which last year announced its TranscendWare policy-based network capabilities, said the newest generation of its CoreBuilder and SuperStack II switches support the Application Specific Integrated Circuits (ASIC) and multiple queues necessary for 802.1p and 802.1Q. Four of the seven models of those new switches are now shipping.

But six models of the older generation of SuperStack II switches and three models of the CoreBuilder family need upgrades or have to be replaced altogether if they are to process 802.1p and 802.1Q bits.

"There's always going to be a new generation of technology and there's going to be new capabilities in it. That's the way the world works," said Frank Fuller, 3Com's director of systems marketing.

That's a bitter pill for Lockheed Martin to swallow. Lockheed, in Pittsfield, Mass., bought $200,000 worth of CoreBuilder 5000s 18 months ago to support 1,200 users in 12 VLANs. But the company did not foresee an upgrade coming this soon, and 3Com didn't let on that there would be one, said Peter Bissonnette, a communication design analyst for Lockheed.

After asking about 802.1p and 802.1Q support in the CoreBuilder 5000, 3Com told him a hardware upgrade would be required and he would have to pay for it, Bissonnette said.

"If I were to go out and buy today I would absolutely insist on a tradeup to a compatible switch module when it's released," Bissonnette said. 3Com will support 802.1p and 802.1Q in a new Gigabit Ethernet downlink for the CoreBuilder 5000, but Fuller did not say when that would ship.

Hardware upgrades also are in the offing for some of Cisco's Catalyst switches. Cisco recently announced its CiscoAssure policy network plan.

"It is true that to get wire-speed [802.1p and 802.1Q] trunking, you have to embed the trunking capabilities in hardware," said Jayshree Ullal, Cisco's vice president of enterprise marketing. "There's no question of hardware change-out [in switches where] trunking was not offered as an option."

For 802.1Q support, Cisco has software that maps its proprietary InterSwitch Link protocol to 802.1Q without degrading the performance of Catalyst 3000 and 5000 switches, Ullal said. But 802.1p support will require new modules for these switches.

Bay Networks, Inc. users are in the same boat. Bay is shipping 802.1Q hardware in its new Accelar switches, but others will require a hardware or software upgrade, or both, said Paul Woodruff, Bay's director of product management.

Cabletron Systems, Inc.s SmartSwitch 6000 switch for the wiring closet and SmartSwitch 2000 for workgroups have been 802.1p- and 802.1Q-compliant since December, said Trent Waterhouse, a senior architect at Cabletron.

Users who bought either switch before December have been advised to download a firmware upgrade from Cabletrons Web site.