The 8510 challenges Bay Networks' Accellar 1200, Cabletron Systems' SmartSwitch Router, Extreme Networks' Summit switches, Foundry Networks' NetIron and 3Com Corp.'s CoreBuilder 3500. The first in the Catalyst 8500 series, this five-slot chassis remarkably resembles a Cisco LightStream 1010 ATM switch. I was not surprised by this coincidence: The 8510 uses the same 10-Gbps backplane.

However, the similarities stop at looks. Instead of a cell-switching fabric, the Catalyst 8510 features a 10-Gbps frame-switching architecture. New Catalyst 8500 series switching modules now reside in place of CAMs (Carrier Modules) and PAMs (Port Adapter Modules).

Backwards Backstroke One of the Catalyst 8510's most notable features is its backward-compatibility with the Catalyst 5500 line. Catalyst 5500 owners will be pleased that they can upgrade their switches to take advantage of the 8510 switching architecture. You can plug Catalyst 8510 line modules into four of the five lower slots of the Catalyst 5500 in lieu of ATM modules. This added investment protection is a great boon for users who invested in the 5500 as a frame switch. A module will be available in late summer to bridge the gap between the 8500 switch processor and the Catalyst 5500's existing backplane.

The 8510 chassis initially will support 10/100BASE-TX and ŭFX, as well as Gigabit Ethernet. ATM OC-3 and OC-12 will be available shortly after the product ships, letting you integrate ATM LANs and Packets Over Sonet into your Layer 3 switched network. Each Fast Ethernet module contains eight 10/100BASE-TX connections. Gigabit Ethernet will be provided in one-port modules, primarily intended for uplinks into your backbone network.

The configuration I tested included four eight-port 10/100 line cards and a 8510 switching engine. Although I ran into some significant bugs with 10/100 autonegotiation, I was still able to test the Catalyst 8510 hardware and software's performance and functionality.

To test hardware performance, I used two Netcom Systems' Smartbits analyzers to generate 32 streams of wire speed 100-Mbps Layer 3 traffic. I directed each pair of streams across the 8510's backplane, ensuring that the test traffic fully utilized the switching fabric. The Catalyst 8510 forwarded all 32 streams at wire speed--a total of 4,761,760 packets per second--without dropping a single frame. In addition to wire-speed IP routing, the Catalyst 8510 performs wire-speed IPX routing. This functionality was complete in the product I tested, but lack of time restricted us from testing this feature.

The Catalyst 8510 exhibits a nonblocking shared memory architecture. Cisco could have squeezed 12 ports on each line module, but that would have caused switch-performance bottlenecks. Cisco makes no performance compromises with the 8500 series; no combination of boards can oversubscribe the switching fabric.