Cisco Cisco TelePresence MX700 Folheto

Automatic Quality of Service
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:  

Power over Ethernet (PoE) negotiation
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 

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 

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 TC6 and Cisco Unified Communications Manager 9.0 

Quick Reference Guide

D14996.01 Administering TC6 Endpoints on CUCM 9.0, 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