Multidwelling Network Using Catalyst 3550 Switches - Cisco Catalyst 3550 series Software Configuration Manual

Chapter 1 Overview
Network Configuration Examples

Multidwelling Network Using Catalyst 3550 Switches

A growing segment of residential and commercial customers are requiring high-speed access to Ethernet
metropolitan-area networks (MANs). Figure 1-4 shows a configuration for a Gigabit Ethernet MAN ring
using Catalyst 3550 multilayer switches as aggregation switches in the mini-point-of-presence (POP)
location. These switches are connected through 1000BASE-X GBIC ports.
The resident switches can be Catalyst 3550 switches, providing customers with high-speed connections
to the MAN. Catalyst 2900 LRE XL or 2950 LRE Layer 2-only switches also can be used as residential
switches for customers requiring connectivity through existing phone lines. The Catalyst LRE switches
can then connect to another residential switch or to an aggregation switch.
All ports on the residential Catalyst 3550 switches (and Catalyst LRE switches if they are included) are
configured as 802.1Q trunks with protected port and STP root guard features enabled. The protected port
feature provides security and isolation between ports on the switch, ensuring that subscribers cannot
view packets destined for other subscribers. STP root guard prevents unauthorized devices from
becoming the STP root switch. All ports have IGMP snooping or CGMP enabled for multicast traffic
management. ACLs on the uplink ports to the aggregating Catalyst 3550 multilayer switches provide
security and bandwidth management.
The aggregating switches and routers provide services such as those described in the previous examples,
"Small to Medium-Sized Network Using Mixed Switches" section on page 1-13 and "Large Network
Using Only Catalyst 3550 Switches" section on page 1-15.
Catalyst 3550 Multilayer Switch Software Configuration Guide
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