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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 1 Overview
Network Configuration Examples
Servers are connected to the GBIC module ports on the switches, allowing 1-Gbps throughput to users
when needed. When the switch and server ports are configured for full-duplex operation, the links
provide 2 Gbps of bandwidth. For networks that do not require Gigabit performance from a server,
connect the server to a Fast Ethernet or Fast EtherChannel switch port.
Connecting a router to a Fast Ethernet switch port provides multiple, simultaneous access to the Internet
through one line.
Collapsed Backbone and Switch Cluster Configuration
Figure 1-3 shows a configuration for a network of approximately 500 employees. This network uses a
collapsed backbone and switch clusters. A collapsed backbone has high-bandwidth uplinks from all
segments and subnetworks to a single device, such as a Gigabit switch, that serves as a single point for
monitoring and controlling the network. You can use a Catalyst 3550-12T-L3 switch, as shown, or a
Catalyst 3508G XL switch to create a Gigabit backbone. A Catalyst 3550-12T-L3 backbone switch
provides the benefits of inter-VLAN routing and allows the router to focus on WAN access.
The workgroups are created by clustering all the Catalyst switches except the Catalyst 4908G-L3 switch.
Using Network Assistant and Cisco switch clustering technology, you can group the switches into
multiple clusters, as shown, or into a single cluster. You can manage a cluster through the IP address of
its active and standby command switches, regardless of the geographic location of the cluster members.
This network uses VLANs to segment the network logically into well-defined broadcast groups and for
security management. Data and multimedia traffic are configured on the same VLAN. Voice traffic from
the Cisco IP Phones are configured on separate voice VLAN IDs (VVIDs). You can have up to
four VVIDs per wiring closet. If data, multimedia, and voice traffic are assigned to the same VLAN, only
one VLAN can be configured per wiring closet. For any switch port connected to Cisco IP Phones,
802.1p or 802.1Q QoS gives forwarding priority to voice traffic over data traffic.
Grouping servers in a centralized location provides benefits such as security and easier maintenance. The
Gigabit connections to a server farm provide the workgroups full access to the network resources (such
as a call-processing server running Cisco CallManager software, a DHCP server, or an IP/TV multicast
server).
Cisco IP Phones are connected—using standard straight-through, twisted-pair cable with RJ-45
connectors—to the 10/100 inline-power ports on the Catalyst 3550-24PWR switches and to the
10/100 ports on the Catalyst 2950 switches. These multiservice switch ports automatically detect any IP
phones that are connected. Cisco CallManager controls call processing, routing, and IP phone features
and configuration. Users with workstations running Cisco SoftPhone software can place, receive, and
control calls from their PCs. Using Cisco IP Phones, Cisco CallManager software, and Cisco SoftPhone
software integrates telephony and IP networks, and the IP network supports both voice and data.
Each 10/100 inline-power port on the Catalyst 3550-24PWR switches provides –48 VDC power to the
Cisco IP Phone. The IP phone can receive redundant power when it is also connected to an AC power
source. IP phones not connected to the Catalyst 3550-24PWR switches receive power from an AC power
source.