3Com to meld Ethernet, ATM QoS

By Jim Duffy
Network World Fusion, 05/27/99

3Com next week will make good on its pledge to map Ethernet-to-ATM quality of service (QoS) when it unveils new modules for its SuperStack II and CoreBuilder LAN switches.

The new modules will sport new Application Specific Integrated Circuits (ASIC) - called ZipChip 3 and FIRE - that will enable users to enforce policies for ensuring consistent QoS in mixed Ethernet and ATM networks. The modules were expected.

3Com's Ethernet-to-ATM QoS mapping strategy is intended to deliver consistent QoS across different network media, which is vital to voice, data and video convergence. Ethernet connections dominate the desktop, while ATM seems to be the media of choice for convergence in the core of enterprise networks.

If QoS fluctuates between different media types, the result is poor service that negates the other chief benefits of convergence - reduced equipment and service costs. 3Com's ASICs map 802.1p Ethernet priority bits to one of four ATM QoS features - variable, constant, available or unspecified bit rate.

The ZipChip 3 modules include OC-3 and OC-12 blades for 3Com's SuperStack II 1100 and 3300 switches, and 10/100M bit/sec Ethernet cards for the company's CoreBuilder 7000HD switch. The OC-3/OC-12 module features a single ATM port that is software configurable to operate at either 155M bit/sec OC-3 or 622M bit/sec OC-12. It is intended to serve as a single uplink for SuperStack II 1100s and 3300s to a 3Com CoreBuilder 9000 ATM backbone switch.

The 10/100 Ethernet card is called the 7900 High-Density 10/100 Fast Ethernet Interface Module. The 7900 sports 36 10/100 copper ports with RJ-45 connectors. It is designed to connect desktops to ATM building, campus and metropolitan area backbone networks anchored by the CoreBuilder 9000.

The FIRE ASIC-based modules are OC-3 and OC-12 ATM cards for 3Com's CoreBuilder 3500 Layer 3 switch. The modules support either two OC-3 ports or one OC-12 interface. They are designed to route traffic between ATM emulated LANs with or without the Multi-protocol over ATM (MPOA) standard.

MPOA, which requires a software upgrade to the FIRE ASIC boards, establishes switched connections between ELANs in different IP subnets. This is intended to increase performance by bypassing router hops. FIRE ASIC-based ATM switching modules, such as those in the CoreBuilder 3500, function as MPOA servers, while ZipChip 3-based ATM cards, such as those in the SuperStack II 1100 and 3300 - serve as MPOA clients that request switched paths from the server.

3Com also announced Ethernet 802.1p-to-ATM QoS mapping software for its Pathbuilder ATM WAN access switch as well as four-port OC-3 copper modules for the CoreBuilder 9000. The QoS mapping software is intended to let users extend Ethernet/ATM QoS across the WAN. The new CoreBuilder 9000 cards let users deploy lower cost copper cabling for ATM networking.

Missing from 3Com's Ethernet-to-ATM QoS mapping program are ZipChip 3-based Ethernet modules for the CoreBuilder 9000. This would let users connect to the ATM backbone using Ethernet uplinks instead of ATM. 3Com officials say these modules will emerge early next year.

The ZipChip 3 module for the SuperStack II 1100 and 3300 switches costs $5,995 and will be available in July. The 7900 module costs $14,995 and will be available in the fourth quarter. The FIRE modules for the CoreBuilder 3500 cost $9,995 for OC-3 and $11,995 for OC-12, both will be available in August.