Hello

The Catalyst 6500 and 4500 has different design. The 6500 has all hardware related buffers on his line modules. Each type of line modules has own intelligence and functionalities. Depend the mix of Supervisors and modules you have different capabilities. Top Sup720 and line modules 67xx come up to 80 Gigabit per slot. The other end are Sup1 and Sup2 without switch fabric and with line modules 61xx-63xx has only 4x8gigabit channels common for all slots on the chassis.

The 4500 has a shared memory as central switching instance. The line cards are just interfaces without any intelligence. All intelligence and functionalities are done by the supervisor. Each line card is via 6 channels 1gigabit of each connected to the supervisors. Depend the line cards you have different rates of oversubscriptions from 1:1 (4506) up to 8:1 (4x48). More information you will found in the following sheet:

Cisco Catalyst 4500 Series Line Cards Data Sheet

http://www.cisco.com/en/US/products/hw/switches/ps4324/products_data_sheet0900aecd802109ea.html

Table 1. Port Information for Line Cards, see the column wire rate

General QoS information can be fond at:

Configuring Quality of Service

Catalyst 4500 Series Switch Cisco IOS Software Configuration Guide, 12.2(37)S

http://www.cisco.com/en/US/products/hw/switches/ps4324/products_configuration_guide_chapter09186a008082a29d.html

Configuring QoS

Catalyst 3750 Switch Software Configuration Guide, 12.2(37)S

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a008081df7e.html

Andy