Cisco Cisco TelePresence MX700 Manual De Manutenção
Automatic Quality of Service
Quality of Service is essential for a well-performing
Quality of Service is essential for a well-performing
network, providing preferential service to latency, jitter or
loss sensitive applications like voice and video; deferential
service to misbehaving applications such as viruses and other
undesirable network traffic; and fair treatment to routine,
non-time sensitive traffic such as e-mail or web browsing.
However, QoS can be complex to configure and manage, and
the administrator needs to be assured that the traffic entering
the network is marked with the correct QoS values. For user-
facing devices such as PCs, IP-based telephones and video
terminals, the administrator must establish a demarcation
point where QoS markings coming in from
these devices are either not trusted—and
instead overwritten to an administratively
configured value—or trusted to set their
own QoS values and the Ethernet switch
will honor those values. This demarcation
point, or trust boundary, ensures that
if the user accidently, or intentionally,
tampers with the QoS values assigned
to these devices, those QoS values will
be remarked by the administrator as they
ingress the network.
CDP provides a method of automatically
extending this trust boundary (at the
administrators’ discretion) so that the
phone or video terminal can mark its
packets with the desired QoS values, and
the switch will trust the phones packets
(because the administrator knows that
the specific model of phone in question
can be trusted to behave properly and
cannot be tampered with) and forwards
those packets on into the network. This
functionality is known as AutoQoS on the
Cisco Catalyst line of Ethernet switches.
Figures 3 and 4 illustrate the concept of
AutoQoS.
Further information about AutoQoS can be
found at the following reference:
• Medianet Campus QoS Design guide:
• Medianet Campus QoS Design guide:
Power over Ethernet (PoE) negotiation
The 802.3af standard provides for Power over Ethernet to
The 802.3af standard provides for Power over Ethernet to
devices such as IP-based telephones and video terminals.
CDP provides additional benefit by allowing the endpoint to
indicate to the Ethernet switch how much power it requires—
and for the switch to advertise to the endpoint how much
power is available—thereby allowing more granular level
of negotiation between the switch and the endpoint, and
allowing the Ethernet switch to more closely track its available
power budget. Note that PoE is currently not used by the
Cisco TelePresence endpoints, but is mentioned here as
informational benefit to the reader since PoE is widely used
by many other models of Cisco Unified IP Phones, Wireless
Access Points, surveillance cameras, and myriad other
devices.
Location awareness
With the introduction of IP-based telephones, a new level of
With the introduction of IP-based telephones, a new level of
mobility was afforded in that an IP endpoints could be plugged
in anywhere in the network, obtain an IP address, and start
making calls, reducing the costs associated with physically
patching telephone cables when moving an employee from
one office to another. However, certain management functions
and emergency services rely on knowing the precise
location of a telephone. CDP allows for network management
applications to identify the physical location of a phone (by
detecting what Ethernet port that phone is attached to, and
hence, where it physically is located). This information is
then leveraged by applications such as Cisco Emergency
Responder to direct telephone calls made to emergency
services personnel to the correct dispatch office. There are
many other real and potential uses for location information.
Ethernet speed / duplex mismatch detection
Ethernet devices use the 802.3 auto negotiation procedure
Ethernet devices use the 802.3 auto negotiation procedure
to automatically negotiate their speed and duplex settings.
However, a very common problem is that one side or the
other is accidently configured for the wrong settings, resulting
in packet loss. For example, the network administrator has
configured all the Gigabit Ethernet ports on the switch for auto
negotiation, but the user accidently sets the port on his or her
PC, IP phone or video terminal to a manually configured value,
such as 100 Mbps / Full duplex. This can result in a mismatch
Fig. 3: Without
CDP / AutoQoS
Fig. 4: With
CDP / AutoQoS
Cisco TelePresence Endpoints running TC5 and Cisco Unified Communications Manager 8.6
Quick Reference Guide
D14878.06 Administering TC5 Endpoints on CUCM 8.6, January 2013.
www.cisco.com — Copyright © 2013 Cisco Systems, Inc. All rights reserved.
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Contents
Introduction
Endpoint configuration
CUCM configuration
Setting passwords
Appendices
Appendices