Cisco Systems 30 VIP

Cisco IP Telephony Troubleshooting Guide for Cisco CallManager Release 3.0(1)

Field Definitions

numberOctetsReceived The number of octets (bytes) of data received during this

call

The total number of payload octets (that is, not including

header or padding) received in RTP data packets by the

device since starting reception on this connection. The count

includes packets received from different sources, if this is a

multicast call. The value is zero if the connection was set in

“send only” mode.

numberPacketsLost Lost RTP packets during this connection

The total number of RTP data packets that have been lost

since the beginning of reception. This number is defined as

the number of packets expected less the number of packets

actually received, where the number of packets received

includes any that are late or duplicates. Thus, packets that

arrive late are not counted as lost, and the loss may be

negative if there are duplicates. The number of packets

expected is defined to be the extended last sequence number

received, as defined next, less the initial sequence number

received. The value is zero if the connection was set in “send

only” mode. (For details, see RFC 1889)

jitter The interarrival jitter during this connection

An estimate of the statistical variance of the RTP data packet

interarrival time, measured in milliseconds and expressed as

an unsigned integer. The interarrival jitter J is defined to be

the mean deviation (smoothed absolute value) of the

difference D in packet spacing at the receiver compared to

the sender for a pair of packets. Detailed computation

algorithms are found in RFC 1889. The value is zero if the

connection was set in “send only” mode.

latency The latency experienced during this connection

The value is an estimate of the network latency, expressed in

milliseconds. This is the average value of the difference

between the NTP timestamp indicated by the senders of the

RTCP messages and the NTP timestamp of the receivers,

measured when these messages are received. The average

is obtained by summing all the estimates, then dividing by the

number of RTCP messages that have been received. (For

details see RFC 1889)

Call Records Logged By Call Type

Each normal call between two parties logs one CDR End Call record. Each End Call record

contains all fields identified above, but some fields may not be used. If a field is not used, it will

be blank if it is an ASCII string field, or “0” if it is a numeric field. When supplementary

services are involved in a call, more End Call records may be written.

In addition to the CDR End Call record, there may be up to one CMR record per endpoint

involved in a call. In a normal call between two parties each using a Cisco IP Phone, there will

be two CMR records written: one for the originator, and one for the destination of the call.

This section describes the records written for different call types in the system.