Power over Ethernet on the Cisco Catalyst 4500 E-Series Platform
The Cisco® Catalyst® 4500 E-Series platform offers line cards, power supplies, and accessories (including an AC power shelf) to support 15.4W per port simultaneously on every port in any fully loaded Cisco Catalyst 4500 E-Series switch. Although all references to "Power over Ethernet" (PoE), "inline power," and "voice" power supply and line cards are synonymous, there are only two versions: Cisco prestandard PoE and 802.3af-compliant PoE. Every Cisco Catalyst 4500 Series chassis and PoE power supply supports the IEEE 802.3af standard and the Cisco prestandard power implementation, helping ensure backward compatibility with existing Cisco powered devices.
All Cisco Catalyst 4500 Series PoE line cards can distinguish an IEEE or Cisco prestandard powered device from an unpowered network interface card (NIC) to help ensure that power is applied only when an appropriate device is connected. With a Cisco PoE network, administrators can depend on a robust network that is safe to deploy and simple to maintain.
PoE
PoE provides -48-VDC power over standard Category 5 unshielded twisted-pair (UTP) cable up to 100 meters when an IEEE 802.3 af-compliant or Cisco prestandard powered device is attached to the PoE line-card port. Instead of requiring wall power, attached devices such as IP phones, wireless base stations, video cameras, and other IEEE-compliant appliances can use power provided from the Cisco Catalyst 4500 Series PoE line cards. This capability gives network administrators centralized control over power and eliminates the need to install outlets in ceilings and other out-of-the-way places where a powered device can be installed. When a switch is connected to an uninterruptible-power-supply (UPS) system, network administrators can ensure that power outages will not affect network availability.
Deploying PoE on the Cisco Catalyst 4500 E-Series
When the Cisco Catalyst 4500 E-Series is properly configured, implementing PoE is easy when used with a Cisco powered device that supports Cisco Discovery Protocol. All Cisco Catalyst 4500 Series PoE line cards automatically detect an attached powered device the moment they are installed. Moreover, the Cisco Catalyst 4500 Series returns unused port power to the system power budget for use by other devices because it supports the IEEE802.3af optional power classifications.
The Cisco Catalyst 4500 E-Series offers internal power supplies and external power devices for multiple deployment scenarios, including small and large deployments in AC or DC environments for data-only configurations, and scalability up to 15.4W per port for PoE configurations.
The Cisco Catalyst 4510R-E (10 slot), 4507R-E (7 slot), 4506-E (6 slot), and 4503-E (3 slot) models as well as non-E-Series classic chassis share a common power-supply form factor. Each Cisco Catalyst 4500 Series chassis is designed for 1 + 1 power protection while meeting the needs of PoE demands. In addition to power resiliency, the Cisco Catalyst 4500 Series includes 1 + 1 supervisor-engine redundancy (Cisco Catalyst 4507R and 4510R models only) and software-based fault tolerance. Integrated resiliency in both hardware and software minimizes network downtime, helping ensure workforce productivity, profitability, and customer success.
Table 1 gives an overview of IEEE 802.3af power classifications.
Table 1. Overview of IEEE 802.3af Power Classifications (Measured at the Switch Port)
|
IEEE 802.3af Class |
Power Available at the Switch Port |
|
0 |
15.4W: Default class |
|
1 |
4W |
|
2 |
7W |
|
3 |
15.4W |
|
4 |
Future expansion |
|
Cisco prestandard PoE |
6.3W |
Comparison Between Cisco Prestandard PoE and 802.3af-Compliant PoE
From a power perspective, there are several significant differences between the Cisco prestandard and 802.3af-compliant line cards. The differences are illustrated by comparing the total number of PoE devices supported by the Cisco prestandard inline power line card and the 802.3 af-compliant line cards (Table 2).
Table 2. Number of Powered Devices Supported when Using Power Supplies in a 1 + 1 Mode Using IEEE 802.3af-Compliant Line Cards
Cisco Catalyst 4500 E-Series Power-Supply Options: AC and DC
The Cisco Catalyst 4500 E-Series offers a variety of power supplies and accessories to meet the diverse needs of enterprise and service provider customers. All available Cisco Catalyst 4500 Series power supplies can be used for data-only deployments, which typically require just a few hundred watts. For deployments that dictate support for PoE power, Cisco offers several options.
The Cisco Catalyst 4500 E-Series offers AC power with several internal supplies: 1000W (data only), 1400W (data only), 1300W (data and PoE), 2800W (data and PoE), and 4200W (data and PoE). When 5500W or less are required, the 4200W power supply can provide 5500W while protecting the chassis from a power or power-supply sub-unit failure. When more than 5500W of redundant data and PoE are required for a Cisco Catalyst 4500 Series chassis in an AC-powered environment, Cisco offers an external AC power shelf that houses two 2500-WAC power supplies. When two power shelves are combined, they can produce 7500W -- the remaining 2500W supply can be used for N + 1 protection.
The Cisco Catalyst 4500 E-Series has two DC power options -- one is optimized for data-only deployments in service provider central offices (part number PWR-C45-1400DC), and the other is used for high-power PoE deployments (PWR-C45-1400DC-P).
Cisco Catalyst 4500 E-Series External AC Power Shelf and 1400-WDC Power Supply with Integrated Power Entry Module
The Cisco Catalyst 4500 E-Series external AC power shelf must be used in conjunction with the 1400-WDC-P power supply. In addition to providing power for the chassis, fans, and non-PoE line cards, the 1400-WDC power supply contains a power entry module (PEM). The PEM is used to pass additional power through to the chassis backplane -- power demanded by the PoE line cards. The chassis power trace used for PoE is independent from the one used by the supervisor engine(s), fan tray, and backplane components. The 1400-WDC power supply can accept up to 7500 WDC for data and PoE applications. Up to 1400W can be dedicated for data (supervisor[s], fan tray, etc.), while the remaining power is passed through the PEM and is used for PoE.
When only one external AC power shelf is used (with two 2500-WAC power supplies), it provides the 1400-WDC power supply with 5000W of DC power. When two AC power shelves are strapped together, the Cisco Catalyst 4500 Series can provide up to 7500W of DC power (3 + 1 redundant).
Cisco Catalyst 4500 E-Series Service Provider DC Power Supply
The triple-input 1400-WDC power supply is optimized for service provider central-office deployments. By providing multiple inputs, the service provider DC power supply allows central-office technicians to customize the output power to meet their application needs. Many central-office deployments require only a fraction of the 1400W available in the service provider power supply. With low-current inputs, technicians can connect the supply to smaller fuses and breakers. The service provider power supply makes it possible to deploy a Cisco Catalyst 4503 with a single 15A circuit. Likewise, it is possible to deploy a fully populated Cisco Catalyst 4510R with one 15A and two 20A circuits rather than a single 60A connection, which often requires rack rewiring (Table 3).
Table 3. Triple-Input 1400-WDC Power-Supply Input Modes
Cisco Catalyst 4500 E-Series Dual Input 4200w Power Supply
Combined Mode Power Resiliency is an extension of the traditional combined mode power-supply behavior; it is applicable only to the 4200W power supply. Each 4200W power supply contains two smaller power supplies (called sub-units). In Combined Mode Power Resiliency the system relies only on power from three out of four power-supply sub-units. When using 200 VAC, this feature helps ensure that 5500W of power are available while the switch is protected against a single input power failure or sub-unit component failure. When using four 110 VAC, Combined Mode Power Resiliency provides up to 2728W (Tables 4 and 5).
Table 4. Dual-Input 4200 WAC Power-Supply Input Mode (Single Power Supply)
Table 5. Total Output Power in Combined Mode Power Resiliency
|
PS1-1 |
PS1-2 |
PS2-1 |
PS2-2 |
Total Output Power |
|
110V |
110V |
110V |
110V (hot standby) |
2728W |
|
220V |
220V |
220V |
110V (hot standby) |
5500W |
Cisco Catalyst 4500 E-Series Power Supplies
In any deployment scenario, whether AC or DC, the Cisco Catalyst 4500 Series has the power supplies and external power devices to meet customers' power needs for data, voice, and video applications (Figure 1).
Figure 1. Cisco Catalyst 4500 Series Power Supplies
Features
For information on Catalyst 4500 E-Series power-supply specifications, see Tables 6 through 9.
Table 6. Cisco Catalyst 4500 E-Series Power-Supply Specifications (Data-Only Power Supplies)
Table 7. Cisco Catalyst 4500 E-Series Power-Supply Specifications (Data and Voice)
Table 8. Specifications of Cisco Catalyst 4500 E-Series