Cisco Cisco StadiumVision Director Manuale Di Manutenzione
© 2012 Cisco Systems, Inc. All rights reserved.
Page 93 of 103
DMP PoE Issue
With early versions of the Cisco DMP 4310G, there is an issue with the negotiation
of the correct Power over Ethernet (PoE) wattage. The root cause is believed to be
that the switch and the Cisco DMP 4310G fail to consistently negotiate the correct
power class during the (optional) power class negotiation. In some cases, the switch
believes that the DMP can operate at a lower power class then the DMP actually
requires, resulting in the DMP failing to complete boot up.
of the correct Power over Ethernet (PoE) wattage. The root cause is believed to be
that the switch and the Cisco DMP 4310G fail to consistently negotiate the correct
power class during the (optional) power class negotiation. In some cases, the switch
believes that the DMP can operate at a lower power class then the DMP actually
requires, resulting in the DMP failing to complete boot up.
Correction of this problem required a hardware change. Cisco DMP 4310Gs with
serial numbers USI
serial numbers USI
1434
xxxx or greater have this change and should not be subject
to this issue. DMP 4310Gs with serial numbers less than USI
1434
xxxx may be
subject to this issue, and should follow the suggested workaround.
The serial number is located on the back and can be verified through visual
inspection. The serial number is also remotely accessible as a MIB parameter, and
can be located in the management dashboard under MIB Variables in the Status
tab. Affected DMP’s can also be identified using the dashboard search option
“Power over Ethernet DMP does not support PoE”.
inspection. The serial number is also remotely accessible as a MIB parameter, and
can be located in the management dashboard under MIB Variables in the Status
tab. Affected DMP’s can also be identified using the dashboard search option
“Power over Ethernet DMP does not support PoE”.
Workaround
The correct workaround depends on whether the Cisco switch platform that the
DMP is connected to is enhanced Power over Ethernet (ePoE) capable.
DMP is connected to is enhanced Power over Ethernet (ePoE) capable.
• ePoE Capable Platforms - If there is ample PoE power available in the switch’s
power budget, apply the power inline static max 15401 interface-level
command to each access switch port connected to a DMP-4310.
command to each access switch port connected to a DMP-4310.
The use of “power inline static max 15401” command requires “power inline port
max 15401” be configured first.
max 15401” be configured first.
On an ePoE-capable switch platform, specifying a maximum power level greater
than the 802.3af maximum of 15.4W has a side effect of causing the switch port
to bypass the optional power class negotiation phase.
than the 802.3af maximum of 15.4W has a side effect of causing the switch port
to bypass the optional power class negotiation phase.
The use of the static keyword is suggested in order to reserve the required
power from the switch’s power budget at configuration time. If for some reason
the switch’s remaining power budget cannot accommodate the port’s configured
power requirement, the port is placed into error disable state at point of
configuration, rather than point of need.
power from the switch’s power budget at configuration time. If for some reason
the switch’s remaining power budget cannot accommodate the port’s configured
power requirement, the port is placed into error disable state at point of
configuration, rather than point of need.
• Non-ePoE Capable Platforms – Because non-ePoE capable switch platforms
cannot be configured to deliver more than the 802.3af maximum of 15.4W/port,
the suggested workaround is to insert a PoE splitter between the switch port and
the DMP 4310G. Generally, a PoE splitter is used to strip the PoE power from a
PoE-capable switch port and provide it to a non-PoE capable device in lieu of its
usual “power brick”. In this case, the PoE splitter is used to circumvent the DMP
4310G PoE class negotiation issue, since the PoE splitter does not attempt to
the suggested workaround is to insert a PoE splitter between the switch port and
the DMP 4310G. Generally, a PoE splitter is used to strip the PoE power from a
PoE-capable switch port and provide it to a non-PoE capable device in lieu of its
usual “power brick”. In this case, the PoE splitter is used to circumvent the DMP
4310G PoE class negotiation issue, since the PoE splitter does not attempt to