Cisco Catalyst 2955T WS-C2955T-12 Hoja De Datos

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services based on time periods. ACPs can also be applied to filter traffic based on differentiated services code point

(DSCP) values. Port security provides another means to ensure that appropriate users are on the network, by limiting

access based on MAC addresses.

For authentication of users with a Terminal Access Controller Access Control System (TACACS+) or RADIUS server,

802.1x provides port-level security. 802.1x in conjunction with a RADIUS server allows for dynamic port-based user

authentication. 802.1x-based user authentication can be extended to dynamically assign a virtual LAN (VLAN)

based on a specific user, regardless of where that user connects on the network. This intelligent adaptability provides

greater flexibility and mobility to the network’s stratified user populations. By combining access control and user

profiles with secure network connectivity, services, and applications, customers can more effectively manage user

mobility and drastically reduce the overhead associated with granting and managing access to network resources.

With multilayer Cisco Catalyst 2955 Series switches, network managers can implement high levels of console

security. Multilevel access security on the switch console and a Web-based management interface prevent

unauthorized users from accessing or altering switch configurations. TACACS+ or RADIUS authentication enable

centralized access control of the switch and restrict unauthorized users from altering the configuration. Deploying

security can be done through Cisco CMS Software Security Wizards, which ease the deployment of security features

that restrict user access to a server, a portion of the network, or the entire network.

Cisco Catalyst 2955 Series switches offer superior and highly granular QoS based on Layers 2-4 information, to help

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

These switches can classify, reclassify, police (determine if the packet is in or out of predetermined profiles and affect

actions on the packet), and mark or drop the incoming packets before the packet is placed in the shared buffer. Packet

classification allows the network elements to discriminate between various traffic flows and to enforce rate-limiting

policies based on Layer 2 and Layer 3 QoS fields.

To implement QoS, these switches first identify traffic flows or packet groups. They classify or reclassify these groups

using the DSCP field in the IP packet and/or the 802.1p class of service (CoS) field in the Ethernet packet.

Classification and reclassification can also be based on criteria as specific as the source or destination IP address,

source or destination MAC address, or the Layer 4 TCP/UDP ports. At the ingress (incoming port) level, Cisco

Catalyst 2955 Series switches can also perform policing and marking of the packet.

After the packet goes through classification, policing, and marking, it is assigned to the appropriate queue before

exiting the switch. Cisco Catalyst 2955 Series switches support four egress (outgoing port) queues per port, allowing

the network administrator to be more discriminating and specific in assigning priorities for the various applications

on the network. At the egress level, the switch performs scheduling—an algorithm that determines the order in which

the queues are processed. The switches support Weighted Round Robin (WRR) scheduling, strict priority queuing or

strict priority scheduling. The WRR scheduling algorithm ensures that lower-priority packets are not entirely starved

for bandwidth and are serviced without compromising the priority settings administered by the network manager.

Strict priority scheduling ensures that higher-priority packets will always get serviced first, ahead of other traffic in

lower-priority queues.

These features allow for prioritization of mission-critical, such as motion-control traffic, critical I/O or sensor data,

video monitoring of security areas over voice (IP telephony traffic), ERP (Oracle, SAP, etc.), and CAD/CAM, which,

in turn, would be scheduled to have precedence over less time-sensitive applications such as FTP or e-mail (SMTP).