Transcript 20080123-contino

Call Detail and Call
Maintenance
Records for
Performance
Measurement
• Call Detail Records - CDR:
info about
the endpoints and control/routing of a
call
• Used for billing
• Call Management Record - CMR: info
about the quality of the streamed audio
of a call
• May have more than one CMR per
CDR
• Both CDR and CMR are needed
• Documented by Cisco
Background and
Motivation
• 1998 Voice over IP with Selsius
• now > 12,000 ethernet VoIP
instruments
• Integrated Backbone Architecture
• ATM moving to routed ethernet
• Star of routers - 2 levels
• 8 routers at UP
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Service Level for
Voice
• Performance SL developed to support
voice
• One way latency < 25ms
• Loss < 0.001% packets
• Jitter < 5ms
SL continued
• Model voice traffic and measure it
• Modeled by UDP streams at 85 kbps
• Measured loss, latency and jitter
• Van Jacobson talk/paper about
pathchar - MSRI
• using iperf 1.7
QoS for Voice
• Implemented Expedited Forwarding
• To protect the voice traffic
• in 6500/7600 Cisco router
• Compared with best effort vs EF for
voice
While at a meeting
• While at a meeting with Cisco about a
separate problem, I stumbled upon the
fact that the Cisco IP Phones track
network statistics
• The phones report loss, latency, jitter,
packets and octets sent and received.
• which can be recorded in CDR/CMR
• CMR
So, the next step
• Establish thresholds
• intra system
• phone-to-phone
• Inter-system
• phone-to-someone-else’s-stuff
• This is still a work in progress
• Questions
• Thank you