The Cisco Catalyst® 4948E and 4948E-F Ethernet Switches are the Cisco Catalyst 4900 Series data center switches built from the start to deliver best-in-class, full-featured server-access switching. The switches include identical features except that the Cisco Catalyst 4948E offers front-to-back cooling, and the Cisco Catalyst 4948E-F offers back-to-front cooling. Each switch offers forty-eight 10/100/1000-Gbps RJ45 downlink ports and four 1 and 10 Gigabit Ethernet uplink ports. The switches are designed to simplify data center architecture and operations by offering service provider-grade hardware and software in a one-rack-unit (1RU) form factor optimized for full-featured top-of-rack (ToR) data center deployments.The Cisco Catalyst 4948E and 4948E-F build on the advanced technology of the Cisco Catalyst 4948 Switches, the most widely deployed ToR switch in the industry, with more than 10 million ports deployed worldwide. The Cisco Catalyst 4948E and 4948E-F double the uplink bandwidth and offer true front-to-back and back-to-front airflow with no side or top venting. The airflow direction is controlled by the changing of fans. Optional front-to-back and back-to-front airflow management reduces data center operating costs by providing strict hot-aisle and cold-aisle isolation.Hot-aisle and cold-aisle deployment remains the widely adopted best practice for data center cabinet layouts today. Networking switches and computing servers mounted in a single cabinet need to maintain the separation of the inlet cold air and the exhaust hot air for efficient use of cooling resources. The Cisco Catalyst 4948E and 4948E-F switches provide the option of front-to-back airflow (Cisco Catalyst 4948E) and back-to-front airflow (Cisco Catalyst 4948E-F) for ToR switch deployments.Exceptional reliability and serviceability are delivered with optional internal AC and DC 1+1 hot-swappable power supplies and a hot-swappable fan tray with redundant fansScalability and Performance- Nonblocking server-to-server traffic with 176-Gbps aggregate throughput - Ease of migration from Gigabit Ethernet to 10 Gigabit Ethernet upstream with support for SFP and SFP+ optics - Large buffers optimized to handle microbursts with 17.5 MB of centralized buffering, helping ensure that business-critical packets are not lost due to insufficient buffering - Active queue management through dynamic buffer limiting for TCP throughput optimizations - Investment protection through data center design with dual-stack IP Versions 4 and 6 (IPv4 and v6) support - Advanced quality of service (QoS) with eight configurable queues for each port - Data center server virtualization support for larger Layer 2 domains with scalable MAC addresses - Support for a wide variety of optics connecting to the aggregation layer - Front-to-back and back-to-front airflow optionsEnhanced Manageability- Pay as you grow with software feature packages, from Layer 2 only (LAN Base) to full Layer 3 capability (Enterprise Services) - Reduced operating expenses (OpEx) with tools such as AutoInstall and Cisco IOS® Embedded Event Manager (EEM) that enable immediate availability - Data center automation with IP service-level agreement (SLA) and Smart Call Home - Data center optimization with true front-to-back and back-to-front airflow, including power suply cooling - Enhanced application visibility with smart flow logging - Enhanced manageability through eight bidirectional Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN) sessions - Network visibility through Cisco® NetFlow-Lite (future support)Resiliency- 1+1 AC or DC power supplies and hot-swappable fan tray with redundant fans for high availability for mission-critical applications - Optimized forwarding across all four uplinks with equal-cost multipath (ECMP) load sharing - Improved resiliency with protection from attacks with access control lists (ACLs), Control Plane Policing (CoPP), Address Resolution Protocol (ARP) inspection, and Dynamic Host Configuration Protocol (DHCP) snooping - Active queue management using dynamic buffer limiting (DBL) for increased security and network controlCisco IOS SoftwareCisco IOS Software is a proven network OS that offers best-in-class availability, manageability, and scalability.