Power Requirements for DC-Powered SRX3400 Services Gateways
 | Note: If you plan to operate a maximally configured DC-powered services gateway, we recommend that you provision 30 A @ -48 VDC for the system. |
If you do not plan to provision 30 A @ -48 VDC for the system, you can use the information in Table 1 and Table 2 to calculate the power consumption @ -48 VDC, and thermal output for various hardware configurations.
Table 1 lists the power requirements for base DC-powered devices operating under typical voltage conditions.
Table 1: DC-Powered Base System Requirements
DC Power Supply Configuration | Power Requirement, (Watts) |
|---|---|
Nonredundant configuration includes DC power supply, midplane, SFB, Routing Engine, and fan tray. | 288 W (approximate) |
Redundant configuration includes two DC power supplies, midplane, SFB, Routing Engine, and fan tray. | 310 W (approximate) |
| Note: The power requirement values shown in Table 1 are for a lightly loaded system. For a heavily loaded system, the contribution of the base system to the overall system power requirement is lower, because the power supply efficiency improves as the load increases. For a heavily loaded system, both the redundant and nonredundant base systems contribute approximately 288 W to the overall system power requirement. |
Table 2 lists the power requirements for various hardware components when the services gateway is operating under typical voltage conditions.
Table 2: Component DC Power Requirements
Component | Power Requirement (Watts) | 48V Input Power Requirement at 80% Power Supply Efficiency |
|---|---|---|
Routing Engine | 53 W | 66 W |
SPC | 118 W | 148 W |
NPC | 64 W | 80 W |
SCM | 35 W | 44 W |
IOC (max) | 40 W | 50 W |
IOC (min) | 52 W | 65 W |
Use the information in Table 1 and Table 2 to calculate power consumption for various hardware configurations, input current from a different source voltage, and thermal output, as shown in the following examples. These examples use maximum values per IOC.
- Minimum DC-powered configuration:Base device (nonredundant) + 1 SPC + 1 NPC =288 W + 148 W + 80W = 516 W @ -48 VDC = 10.7 A
- Maximum DC-powered configuration:Base device (redundant) + 4 SPCs + 1 NPC + 1 SCM =288 W + 4(148) W + 80 W + 44 W = 288 W + 592 W + 80 W + 44 W = 1004 W @ -48 VDC = 20.9 A
- Input current from a DC source other than -48 VDC
(based on maximum configuration; applies to DC power supply only):(–54 VDC input) * (input current X) = (-48 VDC input) * (input current Y)54 * X = 48 * 20.9 AX = (48 * 20.9)/54 = 18.6 A
- Thermal output for maximally configured DC-powered services
gateway:Watts DC * 3.41 = BTU/hr1004 * 3.41 = 3424 BTU/hr
