Cisco Catalyst 3550 series Software Configuration Manual page 50

Network Configuration Examples
Bandwidth alone is not the only consideration when designing your network. As your network traffic
profiles evolve, consider providing network services that can support applications for voice and data
integration, multimedia integration, application prioritization, and security.
network demands and how you can meet those demands.
Table 1-2 Providing Network Services
Network Demands
Efficient bandwidth usage for
multimedia applications and
guaranteed bandwidth for critical
applications
High demand on network redundancy
to provide always on mission-critical
applications
An evolving demand for IP telephony
A growing demand for using existing
infrastructure to transport data and
voice from a home or office to the
Internet or an intranet at higher
speeds
Figure 1-1
•
Catalyst 3550 Multilayer Switch Software Configuration Guide
1-10
Suggested Design Methods
Use IGMP snooping to efficiently forward multimedia and multicast traffic.
•
Use other QoS mechanisms such as packet classification, marking, scheduling,
•
and congestion avoidance to classify traffic with the appropriate priority level,
thereby providing maximum flexibility and support for mission-critical, unicast,
and multicast and multimedia applications.
Use optional IP multicast routing to design networks better suited for multicast
•
traffic.
Use MVR to continuously send multicast streams in a multicast VLAN, but to
•
isolate the streams from subscriber VLANs for bandwidth and security reasons.
Use HSRP for router redundancy.
•
Use VLAN trunks, cross-stack UplinkFast, and BackboneFast for traffic-load
•
balancing on the uplink ports so that the uplink port with a lower relative port cost
is selected to carry the VLAN traffic.
Use QoS to prioritize applications such as IP telephony during congestion and to
•
help control both delay and jitter within the network.
Use switches that support at least two queues per port to prioritize voice and data
•
traffic as either high- or low-priority, based on 802.1P/Q.
Use voice VLAN IDs (VVIDs) on the Catalyst 2900 XL and 3500 XL switches to
•
provide separate VLANs for voice traffic.
Use the Catalyst 2900 LRE XL and Catalyst 2950 LRE switches to provide up to
15 Mb of IP connectivity over existing infrastructure, such as existing telephone lines.
Long-Reach Ethernet (LRE) is the technology used in the Catalyst 2900 LRE
Note
XL and Catalyst 2950 LRE switches. Refer to the switch documentation sets
about these switches and the LRE technology.
shows three configuration examples of using Catalyst switches to create the following:
Cost-effective wiring closet—A cost-effective way to connect many users to the wiring closet is to
connect a Catalyst switch cluster of up to nine Catalyst 3550 XL switches (or with a mix of
Catalyst 3550, Catalyst 2950, Catalyst 3500 XL, and Catalyst 2900 XL switches) through
GigaStack GBIC connections. To preserve switch connectivity if one switch in the stack fails,
connect the bottom switch to the top switch to create a GigaStack loopback, and enable cross-stack
UplinkFast on the cross-stack Gigabit uplinks.
You can have redundant uplink connections, using Gigabit GBIC modules, from the GigaStack
cluster to a Gigabit backbone switch such as the Catalyst 3550-12T or Catalyst 3550-12G switch.
You can also create backup paths by using Fast Ethernet, Gigabit, or EtherChannel links. If one of
the redundant connections fails, the other can serve as a backup path. You can configure the
Catalyst 3550-12T or Catalyst 3550-12G switch as a switch cluster manager to manage stack
members through a single IP address. The Catalyst 3550-12T or Catalyst 3550-12G switch can be
connected to a Gigabit server through a 1000BASE-T connection.
Chapter 1 Overview
Table 1-2 describes some
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