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Cisco Catalyst 4948E and 4948E-F Ethernet Switches
Product Overview
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-ofrack (ToR) data center deployments (Figure 1).
Figure 1. Cisco Catalyst 4948E and 4948E-F Front Panel
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-tofront 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 fans (Figures 2 and 3).
Figure 2. Cisco Catalyst 4948E Front-to-Back Air-Cooled Switch Rear Panel
Figure 3. Cisco Catalyst 4948E-F Back-to-Front Air-Cooled Switch Rear Panel
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The Cisco Catalyst 4948E and 4948E-F switches offer:
Scalability and Performance
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Nonblocking server-to-server traffic with 176-Gbps aggregate throughput
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Ease of migration from Gigabit Ethernet to 10 Gigabit Ethernet upstream with support for SFP and SFP+
optics
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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
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Investment protection through data center design with dual-stack IP Versions 4 and 6 (IPv4 and v6) support
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Advanced quality of service (QoS) with eight configurable queues for each port
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Data center server virtualization support for larger Layer 2 domains with scalable MAC addresses
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Support for a wide variety of optics connecting to the aggregation layer
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Front-to-back and back-to-front airflow options
Enhanced Manageability
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Pay as you grow with software feature packages, from Layer 2 only (LAN Base) to full Layer 3 capability
(Enterprise Services)
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Reduced operating expenses (OpEx) with tools such as AutoInstall and Cisco IOS® Embedded Event
Manager (EEM) that enable immediate availability
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Data center automation with IP service-level agreement (SLA) and Smart Call Home
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Data center optimization with true front-to-back and back-to-front airflow, including power supply cooling
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Enhanced application visibility with smart flow logging
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Enhanced manageability through eight bidirectional Switched Port Analyzer (SPAN) and Remote SPAN
(RSPAN) sessions
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Network visibility through Cisco® NetFlow-Lite (future support)
Resiliency
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1+1 AC or DC power supplies and hot-swappable fan tray with redundant fans for high availability for missioncritical applications
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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 control
Cisco IOS Software
Cisco IOS Software is a proven network OS that offers best-in-class availability, manageability, and scalability.
The Cisco Catalyst 4948E and 4948E-F support three levels of Cisco IOS Software. The basic level is LAN Base,
developed for deployments that require data center-class hardware along with Layer 2 switching but not advanced
features such as routing and Cisco IOS EEM. The next level of software is IP Base; this level supports static routes,
Routing Information Protocol (RIP) Versions and 2, and Enhanced Interior Gateway Routing Protocol Stub (EIGRPStub) for limited routing. The top level of software is Enterprise Services; this level adds support for advanced routing
protocols such as Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), Intermediate System-to-
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Intermediate System (IS-IS) Protocol, and EIGRP. For a detailed list of supported software features, please refer to
the software release notes at
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/release/note/OL_23985.html.
Smart Top-of-Rack Design
Historically, data center design engineers have had to trade off access-layer features such as QoS, network visibility,
and security when moving from an end-of-row (EoR) to a ToR data center design. The Cisco Catalyst 4948E and
4948E-F offer the same features found on large EoR data center switches in a 1RU form factor optimized for ToR
deployments.
A few of the features specific to smart ToR switches are:
●
Server-rack-optimized switches with the option of front-to-back or back-to-front airflow
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Nonblocking hardware-based switching and routing
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Full support for access- and distribution-level Layer 3 routing
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Advanced QoS including a modular QoS command-line interface (CLI)
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Advanced security
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Extended MAC address support for virtual environments
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Network visibility (future support)
Data centers focused on the following applications should deploy smart ToR switches:
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High-performance technical computing (grid)
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Enterprise and service provider cloud
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Virtual desktop environments
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Network and server virtualized data centers
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Web services
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Enterprise IT
Cisco IOS Embedded Event Manager
Cisco IOS EEM is a unique subsystem within Cisco IOS Software that allows customers to create and
asynchronously run scripts directly on a router or switch. Scripts can be programmed using a simple CLI. Cisco IOS
EEM responds to real-time events to automate tasks or to take automatic action based on condition detection.
Customers can also use Cisco IOS EEM to create custom commands to reduce deployment and management
complexity. Scripts can enable simple to complex automated actions, such as entering a log item or changing a port
configuration in response to a security threat.
Visit the open Cisco IOS EEM scripting community, Cisco Beyond, for sample Cisco IOS EEM scripts.
Optimized for Multimedia Applications
The Cisco Catalyst 4948E and 4948E-F are optimized for multimedia applications, with advanced multicast support.
The switches support Protocol-Independent Multicast (PIM), Source-Specific Multicast (SSM), and Bidirectional PIM
(bidir-PIM), providing end users with additional scalability to support multimedia applications. Also supported are
Internet Group Management Protocol (IGMP) snooping and Multicast Listener Discovery (MLD) snooping in
hardware, enhancing performance and reducing network traffic by allowing a switch to dynamically add and remove
hosts from a multicast group.