Chapter 1 Overview
Network Configuration Examples
1-16
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-05
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, which serves as a single point for
monitoring and controlling the network. You can use a Catalyst 4908G-L3 switch,
as shown, or a Catalyst 3508G XL switch to create a Gigabit backbone. A
Catalyst 4908G-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 CMS 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 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/Q 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 3524-PWR XL switches and to the 10/100 ports on the
Catalyst 2900 XL and Catalyst 3500 XL switches. These multiservice switch
ports automatically detect if an IP phone is 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,
where the IP network supports both voice and data.
