Preparing to Install the Content Router

This chapter contains network topology tips and important safety information you should know before working with the Content Router. Use the safety warnings and guidelines to ensure your own personal safety and to help protect your Content Router from potential damage.

Read the Regulatory Compliance and Safety Information for the Cisco Content Router 4400 document and the Site Preparation and Safety Guide that came with your Content Router before you begin the installation.

Warning Read the installation instructions before you connect the system to its power source.

Network Topology Considerations

Network topology should be considered in order to optimize the performance of your Content Delivery Network. To reduce the overall time needed for the content download, place the content routing agents and any Cache Engines "close to" the location where the largest number of requests is expected. The second priority is to locate the Content Router at a site with minimum delay to the farthest agent. The latency from the Content Router to each agent should be minimized by avoiding high-latency connections such as a satellite link.

Another point to consider for optimization is the amount of bandwidth required by the Content Router to forward all the DNS requests to each agent. These packets will average 112 bytes in size. To approximate the bandwidth requirements, the packet size is multiplied by the number of DNS queries per second expected to be serviced, and again multiplied by the number of clients sharing the given link (route). If this link is also shared with the origin server, cache miss updates must also be accounted for in the bandwidth requirements.

Safety Warnings

Before you install the Content Router, observe the following safety warnings.

Warning Before working on a system that has an on/off switch, turn OFF the power and unplug the power cord.

Warning The device is designed to work with TN power systems.

Warning This unit is intended for installation in restricted access areas. A restricted access area is where access can only be gained by service personnel through the use of a special tool, lock and key, or other means of security, and is controlled by the authority responsible for the location.

Warning To avoid electric shock, do not connect safety extra-low voltage (SELV) circuits to telephone-network voltage (TNV) circuits. LAN ports contain SELV circuits, and WAN ports contain TNV circuits. Some LAN and WAN ports both use RJ-45 connectors. Use caution when connecting cables.

Warning This product relies on the building's installation for short-circuit (overcurrent) protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15A U.S. (240 VAC, 10A international) is used on the phase conductors (all current-carrying conductors).

Warning This equipment is intended to be grounded. Ensure that the host is connected to earth ground during normal use.

Warning Do not work on the system or connect or disconnect cables during periods of lightning activity.

Warning Before working on equipment that is connected to power lines, remove jewelry (including rings, necklaces, and watches). Metal objects will heat up when connected to power and ground and can cause serious burns or weld the metal object to the terminals.

Warning Ultimate disposal of this product should be handled according to all national laws and regulations.

Warning Only trained and qualified personnel should be allowed to install, replace, or service this equipment.

Warning The safety cover is an integral part of the product. Do not operate the unit without the safety cover installed. Operating the unit without the cover in place will invalidate the safety approvals and pose a risk of fire and electrical hazards.

Warning Blank faceplates and cover panels serve three important functions: they prevent exposure to hazardous voltages and currents inside the chassis; they contain electromagnetic interference (EMI) that might disrupt other equipment; and they direct the flow of cooling air through the chassis. Do not operate the system unless all cards, faceplates, front covers, and rear covers are in place.

Warning The customer 48 volt power system must provide reinforced insulation between the primary AC power and the 48 VDC output.

Safety Guidelines

To reduce the risk of bodily injury, electrical shock, fire, and damage to the equipment, observe the following precautions.

General Precautions

Observe the following general precautions for using and working with your system:

Observe and follow service markings. Do not service any Cisco product except as explained in your system documentation. Opening or removing covers that are marked with the triangular symbol with a lightning bolt may expose you to electrical shock. Components inside these compartments should be serviced only by an authorized service technician.
If any of the following conditions occur, unplug the product from the electrical outlet and replace the part or contact your authorized service provider:
- The power cable, extension cord, or plug is damaged.
- An object has fallen into the product.
- The product has been exposed to water.
- The product has been dropped or damaged.
- The product does not operate correctly when you follow the operating instructions.
Keep your system components away from radiators and heat sources. Also, do not block cooling vents.
Do not spill food or liquids on your system components, and never operate the product in a wet environment. If the unit gets wet, see the appropriate chapter in your troubleshooting guide or contact your service representative.
Do not push any objects into the openings of your system components. Doing so can cause fire or electric shock by shorting out interior components.
Use the product only with other Cisco-approved equipment.
Allow the product to cool before removing covers or touching internal components.
Use the correct external power source. Operate the product only from the type of power source indicated on the electrical ratings label. If you are not sure of the type of power source required, consult your service representative or local power company.
Use only approved power cables. If you have not been provided with a power cable for your Content Router or storage system or for any AC-powered option intended for your system, purchase a power cable that is approved for use in your country. The power cable must be rated for the product and for the voltage and current marked on the product's electrical ratings label. The voltage and current rating of the cable should be greater than the ratings marked on the product.
To help prevent electric shock, plug the system components and peripheral power cables into properly grounded electrical outlets. These cables are equipped with three-prong plugs to help ensure proper grounding. Do not use adapter plugs or remove the grounding prong from a cable. If you must use an extension cord, use a three-wire cord with properly grounded plugs.
Observe extension cord and power strip ratings. Make sure that the total ampere rating of all products plugged into the extension cord or power strip does not exceed 80 percent of the extension cord or power strip ampere ratings limit.
Do not use appliance or voltage converters or kits sold for appliances with your product.
To help protect your system components from sudden, transient increases and decreases in electrical power, use a surge suppressor, line conditioner, or uninterruptible power supply (UPS).
Position cables and power cords carefully; route cables and the power cord and plug so that they cannot be stepped on or tripped over. Be sure that nothing rests on your system components' cables or power cord.
Do not modify power cables or plugs. Consult a licensed electrician or your power company for site modifications. Always follow your local or national wiring rules.

Protecting Against Electrostatic Discharge

Static electricity can harm delicate components inside your system. To prevent static damage, discharge static electricity from your body before you touch any of your system's electronic components. You can do so by touching an unpainted metal surface on the chassis.

You can also take the following steps to prevent damage from electrostatic discharge (ESD):

When unpacking a static-sensitive component from its shipping carton, do not remove the component from the antistatic packing material until you are ready to install the component in your system. Just before unwrapping the antistatic packaging, be sure to discharge static electricity from your body.
When transporting a sensitive component, first place it in an antistatic container or packaging.
Handle all sensitive components in a static-safe area. If possible, use antistatic floor pads and workbench pads.

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