Cisco WS-C2960-8TC-L Specifications download pdf (Page 5)

Data Sheet

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 LAN Base 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 LAN Base 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 LAN Base 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 Cisco Catalyst 2960 LAN Base

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 LAN Base 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 Cisco Catalyst 2960 LAN Base 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

making sure 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.

The Cisco Catalyst 2960 Series LAN Base can perform rate limiting through its support of the

Cisco committed information rate (CIR) function. Through CIR, bandwidth can be guaranteed in

increments as small as 1 Mbps. Bandwidth can be allocated based on several criteria, including

MAC source address, MAC destination address, IP source address, IP destination address, and

TCP or UDP port number. Bandwidth allocation is essential when network environments require

service-level agreements or when it is necessary to control the bandwidth given to certain users.

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Cisco WS-C2960-8TC-L Specifications Page 5