The Cisco 36-port 10/100 EtherSwitch modules offer branch office customers the option to integrate switching and routing in one platform. Combining robust Layer 3 flexible WAN routing with low-density line-rate Layer 2 switching, the EtherSwitch modules provide straightforward configuration, easy deployment and integrated management in a single platform. The 36-port high-density service module (HDSM) utilizes the extra capacity from the wider interface form factor available only on the Cisco 3700 and Cisco 3660 routers to increase the port densities. The combination of Cisco 3600 or 3700 Series routers and the EtherSwitch modules utilize the powerful features available in both Cisco IOS software and Catalyst switching. The EtherSwitch module hardware supports 802.1p Layer 2 prioritization, while Cisco IOS software supports Layer 3 DiffServ and Class of Service (CoS) markings for critical business data.