And no hierarchial QoS, which was requirement of the original poster, of course 3550 offer no such either.
IIRC, the only switch to currently support HQF is the 3750 Metro Series: http://www.cisco.com/en/US/products/hw/switches/ps5532/products_qanda_item09... """ Q. What is the difference between the Cisco Catalyst 3750 Metro Series and the Cisco Catalyst 3750 Series? The Cisco Catalyst 3750 Metro Series is built for Metro Ethernet access in a customer location, enabling the delivery of more differentiated Metro Ethernet services. These switches feature bidirectional hierarchical QoS and Traffic Shaping; intelligent 802.1Q tunneling with class-of-service (CoS) mutation; VLAN translation; MPLS, EoMPLS, and Hierarchical Virtual Private LAN Service (H-VPLS) support; and redundant AC or DC power. They are ideal for service providers seeking to deliver profitable business services, such as Layer 2, Layer 3, and MPLS VPNs, in a variety of bandwidths and with different SLAs. With flexible software options, the Cisco Catalyst 3750 Metro Series offers a cost-effective path for meeting current and future service requirements from service providers. The standard Cisco Catalyst 3750 Series is an innovative product line for midsize organizations and enterprise branch offices. Featuring Cisco Systems(r) StackWise™ technology, Cisco Catalyst 3750 Series products improve LAN operating efficiency by combining industry-leading ease of use and high resiliency for stackable switches. """
32Gbps Backplane (Counted packet-in, packet-out, each direction, with all packets the same size, multicast?) and 52 GE interfaces. Not exactly non-blocking. Gotsta do the CiscoMath.
The 1U with the best blocking ratio is the 4948: http://www.cisco.com/en/US/products/ps6021/products_data_sheet0900aecd8017a7... "96 Gbps nonblocking switch fabric" However, I'm unsure of the details of its QoS support? Regards, ~Aaron