COMMUNICATIONS TEST: Probe and protocol analysis rolls for 2.5-Gbit serial links

Colorado Springs, Colo. — Agilent Technologies Inc. is making a multipronged assault on high-speed serial interconnect, addressing buses and backplanes of 2.5 Gbits/second and beyond. The effort by Agilent's digital verifications solutions group involves pulse-generation systems and bit-error-rate testers from the high-speed digital test group, as well as protocol analyzers covering a gamut of storage-area network (SAN) test and specific buses such as PCI Express.

Agilent last month began shipping a serial pulse generator with stimulus frequencies of up to 7 GHz, intended for checking signal integrity in devices and subsystems. The launch of the 81141A pulse generator is merely the first step in an effort that will upgrade serial bit-error-rate test and parallel BERT systems for next-generation PCI Express board designs, said BERT marketing manager Michael Droemmer.

Serial and parallel
The N4900 Serial BERT is used in testing individual multigigabit channels, while the 81250 ParBERT offers more advanced multichannel testing for multiplexing/demultiplexing environments. The ParBERT's role in analyzing multiple sources of jitter in enterprise and data center systems carries a certain irony — just as the BERT market in telecom equipment transport was cooling off, designers of 10-Gbit/s enterprise networks re-quired the same capability in LANs and in-system buses.

Agilent's probe and protocol analysis introductions this year are aimed at the PCI Express Advanced Switching Interconnect (ASI) and the Advanced Telecommunications Computing Architecture (AdvancedTCA), though some system strategies will build off the company's Fibre Channel and SAN analysis work. While there is not a direct relationship between PCI Express ASI and the AdvancedTCA standard — many adherents of the Rapid I/O serial standard are adopting AdvancedTCA, for example — AdvancedTCA is considered the primary mechanical form factor for ASI signals, and Intel Corp. and several partners are driving the ASI Special Interest Group and AdvancedTCA as related standards.

At an ASI SIG event at the recent Supercomm show, Agilent announced the first AdvancedTCA probe cards, meeting the PCI Industrial Computer Manufacturers Group's standard for an Advanced Mezzanine Card for AdvancedTCA. This minicard is the form factor of choice for the new MicroTCA extension to the AdvancedTCA spec.

At Supercomm, Agilent simultaneously introduced active and passive interposer boards for AdvancedTCA, the E2943A and E2944A, respectively. Passive systems connect to system buses via a midplane bus used in previous Agilent test equipment.

The active probe board links to an AdvancedTCA backplane to let an exerciser emulate PCI Express Advanced Switching designs, while the passive probe is used to capture ASI transactions nonintrusively between two line cards in an AdvancedTCA system.

Configurable module
As the ASI/AdvancedTCA exerciser boards have moved to customer shipment, Agilent has introduced a test module, configurable as either a Fibre Channel test module or active SAN tester, that handles Fibre Channel protocols at 1, 2 and 4 Gbits/s.

The 1735A system is defined by its software as either a protocol analyzer or full active SAN tester with traffic generation. In the future, add-in hardware modules and multiprotocol software will let systems in form factors similar to the 1735A test a range of serial protocols used in SANs and data center serial interconnects.

Agilent said it will work with third parties for expanded software capabilities. Lamprey Networks (Durham, N.H.), which partnered with Agilent for Infiniband solutions, will provide software for PCI compliance testing, and will play an active role in future plugfest events on ASI and AdvancedTCA.