ection (single port). The C48 connects to the 64Gu by two HSS links. It is interesting to note that the C192 can also be connected to the PowerPRS 64Gu, SO IBM's customers can have 10 Gbps pipes (eliminating the need for the SCIC, as was the case with the PRS-64G). To support redundancy over two switching planes and to enable either load sharing or packet-lossless switchover in case of maintenance or trouble, the 64Gu offers native support for an alternative/redundant switching path, which is implemented through the help of either the C48 or C192 chips. As mentioned in the section about shared memory switches, the 64Gu implements data striping (byte slicing) and opts for a graceful degradation instead of penalizing links in multicast traffic cases. The 64Gu generally continues IBM's powerful platform for multicasting combined with QoS, where a packet is stored once in shared memory and then multiple copies will be transmitted to the corre- sponding outputs, where the memory indexes (pointers) reside. In terms of QoS, it offers four levels of traffic priority and programmable threshold levels for flow control. The 64Gu is housed in a 624-ball CBGA package and consumes between 13 and 19 watts, the lat- ter representing 100 percent of traffic capacity. AGERE SWITCH FABRICS Agere Systems is one of very few vendors that can provide a complete solution from fiber to fabric. Therefore, it would be unfair not to briefly mention the latest technology that the company has to offer in the area of switch fabrics. Agere Systems has a presence in the TDM fabric realm as well as in the ATM and IP network areas. In the TDM realm, it offers crossconnect TDM switches for high-capac- ity OC-3 and OC-12 systems, access concentrators handling OC-48 capacities, T1/E1 multiplexors, digital loop carriers (DLCs), and cellular infrastructure. In the ATM and IP network areas, until recently, it offered switching fabrics with throughputs of 5 Gbps expandable up to 25 Gbps for ATM, TDM, and IP. Downloaded from Digital Engineering Library @ M