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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 1 Overview
Network Configuration Examples
Service-Provider Central-Office Configuration
Figure 1-5 shows the Catalyst 2950ST-24 LRE 997 switches in a service-provider central-office network
environment. The Catalyst 2950ST-24 LRE 997 switches have DC-input power supply and are compliant
with the VDSL 997 band plan. The Catalyst 2950 LRE switches are located in a central office and are
connected to the Cisco 576 LRE 997 CPE devices located in different buildings. The switches also
connect to a Cisco 7500 router.
You can use a POTS splitter to connect the switches to the CPE devices. The splitter routes data
(high-frequency) to a Catalyst 2950 LRE switch and voice (low-frequency) traffic from the telephone
line to a PSTN.
Connected to the telephone line in each office is an Cisco 576 LRE 997 CPE device. The LRE CPE
device provides:
• Two RJ-11 ports, one for connecting to the telephone jack on the wall and one for connecting to a
POTS telephone.
• One RJ-45 Ethernet port for connecting to devices such as a customer’s laptop, the office’s IP phone,
the television set-top box, or a office environmental control device. A Cisco 576 LRE 997 provides
one Ethernet connection.
When connected to the CPE device, the Ethernet devices and office telephone share the same telephone
line.
Note All telephones not directly connected to the office CPE device require microfilters with a 300-ohm
termination. Microfilters improve voice call quality when voice and data equipment are using the same
telephone line. They also prevent nonfiltered telephone rings and nonfiltered telephone transitions (such
as on-hook to off-hook) from interrupting the Ethernet connection.
Note Cisco LRE products can share lines with analog telephones and Integrated Services Digital Network
(ISDN) telephone network that use the 0 to 120 kHz frequency range.
Data to and from the office devices (such as e-mail for the laptop and IP multicast traffic for the
television) are transferred through the LRE link, which is established between the CPE RJ-11 wall port
and the LRE port on an LRE switch. The upstream and downstream rates on the LRE link are controlled
by a profile configured on each LRE port.
The Catalyst 2950 LRE switches are cascaded through their 10/100/1000 switch ports. Each switch also
has a 10/100/1000 connection to an aggregation switch, such as a Catalyst 3550-12G switch or
Cisco 7600 router.
You can manage the switches as a switch cluster and through Network Assistant. You can also manage
and monitor the individual CPE devices from the LRE switches to which they are connected. The
Catalyst 2950 LRE switch ports support the same software features as 10/100/1000 switch ports. For
example, you can configure port-based VLANs on the LRE ports to provide individual port security and
protected ports to further prevent unwanted broadcasts within the VLANs.
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