Datasheet

Data Sheet

Availability and Scalability

The Cisco Catalyst 2960 Series is equipped with a large set of features that allow for network

scalability and higher availability through multicast filtering as well as a complete suite of Spanning

Tree Protocol enhancements aimed to maximize availability in a Layer 2 network.

Enhancements to the standard Spanning Tree Protocol, such as Per-VLAN Spanning Tree Plus

(PVST+), UplinkFast, and PortFast, help to maximize network uptime. PVST+ allows for Layer 2

load sharing on redundant links to efficiently use the extra capacity inherent in a redundant design.

UplinkFast, PortFast, and BackboneFast all greatly reduce the standard 30- to 60-second

Spanning Tree Protocol convergence time. Flexlink provides bidirectional, fast convergence in less

than 100 milliseconds. The Loopguard and bridge protocol data unit (BPDU) guard enhancements

provide Spanning Tree Protocol loop avoidance.

Advanced QoS

The Cisco Catalyst 2960 Series offers superior multilayer QoS features to help ensure that

network traffic is classified and prioritized, and that congestion is avoided in the best possible

manner. Configuration of QoS is greatly simplified through automatic QoS (Auto QoS), a feature

that detects Cisco IP phones and automatically configures the switch for the appropriate

classification and egress queuing. This optimizes traffic prioritization and network availability

without the challenge of a complex configuration.

The Cisco Catalyst 2960 Series can classify, reclassify, police, mark, queue, and schedule

incoming packets and can queue and schedule packets at egress. Packet classification allows

the network elements to discriminate between various traffic flows and enforce policies based on

Layer 2 and Layer 3 QoS fields.

To implement QoS, the Cisco Catalyst 2960 Series Switch first identifies traffic flows or packet

groups, then classifies or reclassifies these groups using the differentiated services code point

(DSCP) field or the 802.1p class of service (CoS) field. Classification and reclassification can be

based on criteria as specific as the source or destination IP address, source or destination MAC

address, or the Layer 4 TCP or UDP port. At the ingress, the Catalyst 2960 Series also polices to

determine whether a packet is in or out of profile, marks to change the classification label, passes

through or drops out of profile packets, and queues packets based on classification. Control-plane

and data-plane ACLs are supported on all ports to help ensure proper treatment on a per-packet

basis.

The Cisco Catalyst 2960 Series supports four egress queues per port, giving network

administrators more control in assigning priorities for the various applications on the LAN. At

egress, the switch performs congestion control and scheduling, the algorithm or process that

determines the order in which queues are processed. The Catalyst 2960 Series Switch supports

Shaped Round Robin (SRR) and strict priority queuing. The SRR algorithm helps ensure

differential prioritization.

These QoS features allow network administrators to prioritize mission-critical and bandwidth-

intensive traffic, such as enterprise resource planning (ERP), voice (IP telephony traffic), and

computer-aided design and manufacturing (CAD/CAM), over applications such as FTP or e-mail.

For example, it would be undesirable to have a large file download destined to one port on a

switch increase latency in voice traffic destined to another port on this switch. This condition is

avoided by ensuring that voice traffic is properly classified and prioritized throughout the network.

Other applications, such as Web browsing, can be handled on a lower-priority basis.