1-14
Catalyst 2960 Switch SoftwareConfiguration Guide
78-16881-01
Chapter1 Overview
Network Configuration Examples
Figure 1-2 Server Aggregation
Small to Medium-Sized Network Using Catalyst 2960 Switches
Figure 1-3 shows a configuration for a network of up to 500 empl oyees. This network uses Catalyst 2960
switches with high-speed connections to two routers. For network reliability and load balancing, this
network has HSRP enabled on the routers. This ensures connectivity to the Internet, WAN, and
mission-critical network resources in case one of the routers fails. The switches are using EtherChannel
for load sharing.
The switches are connected to workstations, local servers, and IEEE 802.3af compliant and
noncompliant powered devices (such as Cisco IP Phones). The server farm includes a call-processing
server running Cisco CallManager software. Cisco CallManager controls call processing, routing, and
Cisco IP Phone features and configuration. The switches are interconne cted through Gigabit interfaces.
This network uses VLANs to logically segment the network into well-defined broadcast groups and fo r
security management. Data and multimedia traffic are configured on the same VLAN. Voice traffic from
the Cisco IP Phones are configured on separate VVIDs. If data, multimedia, and voice traffic are
assigned to the same VLAN, only one VLAN can be configured per wiring closet.
When an end station in one VLAN needs to communicate with an end station in another VLAN, a router
routes the traffic to the destination VLAN. In this network, the routers are providing inter-VLAN
routing. VLAN access control lists (VLAN maps) on the switch provide intra-VLAN security and
prevent unauthorized users from accessing critical areas of the network.
In addition to inter-VLAN routing, the routers provide QoS mechanisms such as DSCP priorities to
prioritize the different types of network traffic and to deliver high-priority traffic. 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 Ca talyst PoE switches,
IEEE 802.1p/Q QoS gives voice traffic forwarding-priority over data traffic.
89376
Campus
core
Catalyst
6500 switches
Catalyst 3750
StackWise
switch stacks
Access-layer
Catalyst
switches
Server racks