Large Network Using Catalyst 3750 Switches - Cisco WS-C3750-48PS-S Software Configuration Manual

Network Configuration Examples
In addition to inter-VLAN routing, the multilayer switches provide QoS mechanisms such as DSCP
priorities to prioritize the different types of network traffic and to deliver high-priority traffic in a
predictable manner. If congestion occurs, QoS drops low-priority traffic to allow delivery of
high-priority traffic.
For pre-standard and IEEE 802.3af-compliant powered devices connected to Catalyst PoE switches,
802.1p/Q QoS gives voice traffic forwarding-priority over data traffic.
Catalyst PoE switch ports automatically detect any Cisco pre-standard and IEEE 802.3af-compliant
powered devices that are connected. Each PoE switch port provides 15.4 W of power per port. The
powered device, such as an IP phone, can receive redundant power when it is also connected to an AC
power source. Powered devices not connected to Catalyst PoE switches must be connected to AC power
sources to receive power.
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.
With the multilayer switches providing inter-VLAN routing and other network services, the routers
focus on firewall services, Network Address Translation (NAT) services, voice-over-IP (VoIP) gateway
services, and WAN and Internet access.
Figure 1-6
Catalyst 3750
StackWise
switch stack

Large Network Using Catalyst 3750 Switches

Switches in the wiring closet have traditionally been only Layer 2 devices, but as network traffic profiles
evolve, switches in the wiring closet are increasingly employing multilayer services such as multicast
management and traffic classification.
Catalyst 3750 multilayer switch stacks in the wiring closets and two backbone switches, such as the
Catalyst 6500 switches, to aggregate up to ten wiring closets.
Catalyst 3750 Switch Software Configuration Guide
1-18
Catalyst 3750 Switch Stack in a Collapsed Backbone Configuration
Cisco 2600 or
3700 routers
multilayer
IP IP
Cisco IP
phones
Internet
Aironet wireless
access points
Workstations
running
Cisco SoftPhone
software
Figure 1-7 shows a configuration for a network that only use
Chapter 1 Overview
Gigabit
servers
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