Cisco Sg3008 Manual

							Smartport
Built-in Smartport Macros
186 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version) 
11
ap
[ap]
#macro description ap
#macro keywords $native_vlan $voice_vlan
#
#macro key description:  $native_vlan: The untag VLAN which will be 
configured on the port 
						

							12
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  187
 
Port Management: PoE 
The Power over Ethernet (PoE) feature is only available on PoE-based devices. For 
a list of PoE-based devices, refer to the Device Models section.
This section describes how to use the PoE feature.
It covers the following topics: 
•PoE on the Device
•Configuring PoE Properties
•Configuring PoE Settings
PoE on the Device
A PoE device is PSE (Power Sourcing Equipment) that delivers electrical power to 
connected PD (Powered Devices) over existing copper cables without interfering 
with the network traffic, updating the physical network or modifying the network 
infrastructure.
See Device Models for information concerning PoE support on various models.
PoE Features
PoE provides the following features:
•Eliminates the need to run 110/220 V AC power to all devices on a wired 
LAN. 
•Removes the necessity for placing all network devices next to power 
sources.
•Eliminates the need to deploy double cabling systems in an enterprise 
significantly decreasing installation costs. 
						

							Port Management: PoE
PoE on the Device
188 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version) 
12
Power over Ethernet can be used in any enterprise network that deploys relatively 
low-powered devices connected to the Ethernet LAN, such as:
•IP phones
•Wireless access points
•IP gateways
•Audio and video remote monitoring devices
PoE Operation
PoE implements in the following stages: 
•Detection—Sends special pulses on the copper cable. When a PoE device 
is located at the other end, that device responds to these pulses. 
•Classification—Negotiation between the Power Sourcing Equipment (PSE) 
and the Powered Device (PD) commences after the Detection stage. During 
negotiation, the PD specifies its class, which is the amount of maximum 
power that the PD consumes. 
•Power Consumption—After the classification stage completes, the PSE 
provides power to the PD. If the PD supports PoE, but without classification, 
it is assumed to be class 0 (the maximum). If a PD tries to consume more 
power than permitted by the standard, the PSE stops supplying power to 
the port.
PoE supports two modes: 
•Port Limit—The maximum power the device agrees to supply is limited to 
the value the system administrator configures, regardless of the 
Classification result. 
•Class Power Limit—The maximum power the device agrees to supply is 
determined by the results of the Classification stage. This means that it is 
set as per the Clients request.
PoE Configuration Considerations
There are two factors to consider in the PoE feature:
•The amount of power that the PSE can supply
•The amount of power that the PD is actually attempting to consume 
						

							Port Management: PoE
PoE on the Device
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  189
12
 
You can decide the following: 
•Maximum power a PSE is allowed to supply to a PD
•During device operation, to change the mode from Class Power Limit to 
Port Limit and vice versa. The power values per port that were configured 
for the Port Limit mode are retained.
NOTEChanging the mode from Class Limit to Port limit and vice versa when 
the device is operational forces the Powered Device to reboot.
•Maximum port limit allowed as a per-port numerical limit in mW (Port Limit 
mode).
•To generate a trap when a PD tries to consume too much and at what 
percent of the maximum power this trap is generated.
The PoE-specific hardware automatically detects the PD class and its power limit 
according to the class of the device connected to each specific port (Class Limit 
mode).
If at any time during the connectivity an attached PD requires more power from the 
device than the configured allocation allows (no matter if the device is in Class 
Limit or Port Limit mode), the device does the following:
•Maintains the up/down status of the PoE port link
•Turns off power delivery to the PoE port
•Logs the reason for turning off power
•Generates an SNMP trap
!
CAUTIONConsider the following when connecting switches capable of supplying PoE:
The PoE models of the Sx200, Sx300, and SF500 series switches are PSE (Power 
Sourcing Equipment) that are capable of supplying DC power to attaching PD 
(Powered Devices). These devices include VoIP phones, IP cameras, and wireless 
access points. The PoE switches can detect and supply power to pre-standard 
legacy PoE Powered Devices. Due to the support of legacy PoE, it is possible that 
a PoE device acting as a PSE may mistakenly detect and supply power to an 
attaching PSE, including other PoE switches, as a legacy PD. 
Even though Sx200/300/500 PoE switches are PSE, and as such should be 
powered by AC, they could be powered up as a legacy PD by another PSE due to 
false detection. When this happens, the PoE device may not operate properly and  
						

							Port Management: PoE
Configuring PoE Properties
190 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version) 
12
may not be able to properly supply power to its attaching PDs. 
To prevent false detection, you should disable PoE on the ports on the PoE switches 
that are used to connect to PSEs.   You should also first power up a PSE device 
before connecting it to a PoE device. When a device is being falsely detected as a 
PD, you should disconnect the device from the PoE port and power recycle the 
device with AC power before reconnecting its PoE ports.
Configuring PoE Properties
The PoE Properties page enables selecting either the Port Limit or Class Limit PoE 
mode and specifying the PoE traps to be generated. 
These settings are entered in advance. When the PD actually connects and is 
consuming power, it might consume much less than the maximum power allowed. 
Output power is disabled during power-on reboot, initialization, and system 
configuration to ensure that PDs are not damaged. 
To configure PoE on the device and monitor current power usage:
STEP 1Click Port Management > PoE > Properties.
STEP  2Enter the values for the following fields:
•Power Mode—Select one of the following options:
-
Por t Limit—The maximum power limit per each port is configured by the 
user.
-
Class Limit—The maximum power limit per port is determined by the 
class of the device, which results from the Classification stage. 
NOTEWhen you change from Port Limit to Class Limit or vice versa, you 
must disable PoE ports, and enable them after changing the power 
configuration.
•Tr a p s—Enable or disable traps. If traps are enabled, you must also enable 
SNMP and configure at least one SNMP Notification Recipient.
•Power Trap Threshold—Enter the usage threshold that is a percentage of 
the power limit. An alarm is initiated if the power exceeds this value. 
						

							Port Management: PoE
Configuring PoE Settings
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  191
12
 
The following counters are displayed:
•Nominal Power—The total amount of power the device can supply to all the 
connected PDs.
•Consumed Power—Amount of power currently being consumed by the PoE 
ports.
•Available Power—Nominal power minus the amount of consumed power.
STEP  3Click Apply to save the PoE properties.
Configuring PoE Settings
The PoE Settings page displays system PoE information for enabling PoE on the 
interfaces and monitoring the current power usage and maximum power limit per 
port.
NOTEPoE can be configured on the device for a specific period. This feature enables you 
to define, per port, the days in the week and the hours that PoE is enabled. When 
the time range is not active, PoE is disabled. To use this feature, a time range must 
first be defined in the Time Range page.
Click Port Management > PoE > Settings.
This page limits the power per port in two ways depending on the Power Mode: 
•Por t Limit: Power is limited to a specified wattage. For these settings to be 
active, the system must be in PoE Port Limit mode. That mode is configured 
in the PoE Properties page.
When the power consumed on the port exceeds the port limit, the port 
power is turned off.
•Class Limit: Power is limited based on the class of the connected PD. For 
these settings to be active, the system must be in PoE Class Limit mode. That 
mode is configured in the PoE Properties page.
When the power consumed on the port exceeds the class limit, the port 
power is turned off.
PoE priority example:
Given: A 48 port device is supplying a total of 375 watts. 
						

							Port Management: PoE
Configuring PoE Settings
192 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version) 
12
The administrator configures all ports to allocate up to 30 watts. This results in 48 
times 30 ports equaling 1440 watts, which is too much. The device cannot provide 
enough power to each port, so it provides power according to the priority.
The administrator sets the priority for each port, allocating how much power it can 
be given.
These priorities are entered in the PoE Settings page.
See Device Models for a description of the device models that support PoE and 
the maximum power that can be allocated to PoE ports.
To configure PoE port settings:
STEP 1Click Port Management > PoE > Settings.The list of fields below is for Port Limit 
Power Mode. The fields are slightly different if the Power Mode is Class Limit.
STEP  2Select a port and click Edit. The list of fields below is for Port Limit Power Mode. 
The fields are slightly different if the Power Mode is Class Limit.
STEP  3Enter the value for the following field:
•Interface—Select the port to configure.
•PoE Administrative Status—Enable or disable PoE on the port. 
•Ti m e  R a n g e—Select to enabled PoE on the port.
•Time Range Name—If Time Range has been enabled, select the time range 
to be used. Time ranges are defined in the Time Range page.
•Power Priority Level—Select the port priority: low, high, or critical, for use 
when the power supply is low. For example, if the power supply is running at 
99% usage and port 1 is prioritized as high, but port 3 is prioritized as low, 
port 1 receives power and port 3 might be denied power. 
•Administrative Power Allocation—This field appears only if the Power Mode 
s e t  i n  t h e  P o E  P r o p e r t i e s  p a g e  i s  P o r t  L i m i t .  I f  t h e  Po w e r  m o d e  i s  Po w e r  L i m i t ,  
enter the power in milliwatts allocated to the port. 
•Max Power Allocation—This field appears only if the Power Mode set in the 
PoE Properties page is Power Limit. Displays the maximum amount of power 
permitted on this port.  
						

							Port Management: PoE
Configuring PoE Settings
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  193
12
 
•Class—This field appears only if the Power Mode set in the PoE Properties 
page is Class Limit. The class determines the power level:
•Power Consumption—Displays the amount of power in milliwatts assigned 
to the powered device connected to the selected interface. 
•Overload Counter—Displays the total number of power overload 
occurrences. 
•Short Counter—Displays the total number of power shortage occurrences. 
•Denied Counter—Displays number of times the powered device was 
denied power.
•Absent Counter—Displays the number of times that power was stopped to 
the powered device, because the powered device was no longer detected. 
•Invalid Signature Counter—Displays the times an invalid signature was 
received. Signatures are the means by which the powered device identifies 
itself to the PSE. Signatures are generated during powered device 
detection, classification, or maintenance.
STEP  4Click Apply. The PoE settings for the port are written to the Running Configuration 
file.
Class Maximum Power Delivered by Device Port
0 15.4 watt
14.0 watt
27.0 watt
3 15.4 watt
430.0 watt 
						

							Port Management: PoE
Configuring PoE Settings
194 Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version) 
12 
						

							13
Cisco Small Business 200, 300 and 500 Series Managed Switch Administration Guide (Internal Version)  195
 
VLAN Management
This section covers the following topics:
•VLANs
•Configuring Default VLAN Settings
•Creating VLANs
•Configuring VLAN Interface Settings
•Defining VLAN Membership
•GVRP Settings
•VLAN Groups
•Voic e VL AN
•Access Port Multicast T V VLAN
•Customer Port Multicast T V VLAN
VLANs
A VLAN is a logical group of ports that enables devices associated with it to 
communicate with each other over the Ethernet MAC layer, regardless of the 
physical LAN segment of the bridged network to which they are connected.