Cisco SM-ES3G-16-P= Gigabit Ethernet network switch module

Enhanced EtherSwitch SM, Layer 2/3 switching, 16x Gigabit Ethernet, PoE, Spare Cisco Enhanced EtherSwitch Service Modules for Cisco 2900 and 3900 Series Routers
The Cisco Enhanced EtherSwitch Service Modules greatly expands the router's capabilities by integrating industry-leading Layer 2 and Layer 3 switching with feature sets identical to those found in the Cisco Catalyst® 3560-E and Catalyst 2960 Series Switches. The new Cisco Enhanced EtherSwitch Service Modules are the first modules to take advantage of the increased capabilities on the Cisco 3900 and 2900 Series Integrated Services Routers. Additionally, these service modules enable Cisco's industry-leading power initiatives, Cisco EnergyWise®, Cisco Enhanced Power over Ethernet (ePoE), and per-port PoE power monitoring-all of which enhance the ability of the branch office to scale to next-generation requirements and still meet important initiatives for IT teams to operate a power efficient network. Furthermore, the Cisco Enhanced EtherSwitch Service Modules not only perform local line-rate switching and routing but also support direct service module-to-service module communication through the Integrated Services Router Generation 2 multigigabit fabric (MGF) which separates LAN traffic from WAN resources.

Secure Network Connectivity for Data, Voice, and Video
When inserted within a Cisco 2900 or 3900 Series Integrated Services Router, such as the Cisco 3945 (Figure 2), the Cisco Enhanced EtherSwitch Service Modules provide a fully integrated, secure networking and converged IP communications solution. From a single platform with an integrated switch, you can connect IP phones, wireless access points, and IP-based video cameras to your network and power them using the IEEE 802.3af, Cisco ePoE, or Cisco pre-standard PoE. With the optional integration of Cisco Unified Communications Manager Express, the router can also provide call-processing for the phones. As users attempt network access through the Cisco Enhanced EtherSwitch Service Module, the module can use IEEE 802.1x and a large number of Cisco 802.1x extensions to validate the credentials of the end device and place the user in the appropriate VLAN or Cisco TrustSec group. As the end-user data leaves the LAN, the router can encrypt the traffic and place it on a multitude of VPNs, securing communications between branch offices and central sites.
This high degree of convergence simplifies the network architecture and allows for cost-effective deployment of advanced services at the branch-office level. Furthermore, because the Cisco Enhanced EtherSwitch Service Modules support the same feature sets as the Cisco Catalyst 2960 and Catalyst 3560-E Switches, you can provide a ubiquitous configuration at headquarters and at the branch office to create a consistent experience throughout your network.