IP Phones and Network Management

Terry Slattery
Principal Architect

I’ve found that IP Phone vendors have done a poor job of instrumenting their phones to be remotely monitored and managed.  There are several things that need to be made more visible.  One is detecting operational call problems.  Having the phones send data to their respective call controller is acceptable, but the call controller needs to send that data on to a management station, probably in an asynchronous message like syslog as well as be available via SNMP polling.

For example, Cisco’s phones allow you to see the delay, jitter, and packet loss stats by pressing buttons on the phone.  This data is only for the average across the duration of the call.  So any call that has a 30 second burst of high jitter over a much longer call will make the burst virtually invisible.

Avaya allows the phone to export the RTCP (RealTime Control Protocol) to a management station, providing better granularity to call performance parameters.  Their problem is that there can be only one destination and Avaya’s product for receiving the RTCP stream doesn’t have a way to forward the stream to other management systems that need it.

Another nit is providing visibility into use of the phone’s auxiliary data port.  There doesn’t seem to be a way to find out if the port is being used, the MAC address of the device that is connected to it, and the speed, duplex, performance counters, and error counters on the port.  A vendor independent mechanism would be really nice, perhaps via a standard MIB in the phone, or in data returned to the call controller.  This data will make it much easier to track down a specific user on the network and where that person’s phone and workstation are located and to identify if there are problems with the workstation’s connection.

My recommendation is that the vendors work towards making their VoIP infrastructure more easily monitored and managed.  It will reduce their support costs and make their products favorable over other vendor products.  Ultimately, a common set of solutions would be preferable over vendor-specific solutions.



Re-posted with Permission 

NetCraftsmen would like to acknowledge Infoblox for their permission to re-post this article which originally appeared in the Applied Infrastructure blog under http://www.infoblox.com/en/communities/blogs.html


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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.


Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.


John Cavanaugh

CCIE #1066, CCDE #20070002, CCAr
Chief Technology Officer, Practice Lead Security Services, NetCraftsmen

John is our CTO and the practice lead for a talented team of consultants focused on designing and delivering scalable and secure infrastructure solutions to customers across multiple industry verticals and technologies. Previously he has held several positions including Executive Director/Chief Architect for Global Network Services at JPMorgan Chase. In that capacity, he led a team managing network architecture and services.  Prior to his role at JPMorgan Chase, John was a Distinguished Engineer at Cisco working across a number of verticals including Higher Education, Finance, Retail, Government, and Health Care.

He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.