Nortel Networks NN43001-563 Outgoing calls attempted/completed mismatch

Outgoing calls attempted/completed mismatch 409

The IP trunk card base code performs the following tests:

•ﬂash integrity test

•PGA read/write test

•PC Card controller test (also tests the PCI bus)

•timer and DMA tests

•DSP test

Before communicating with the system, the 8051XA controller downloads

FPGA and performs tests to check correct programming of the FPGA.

Outgoing calls attempted/completed mismatch

The difference between the attempted and completed outgoing call numbers

should never be less than the sum of the QoS Fallback, Address Translation

fallback, and Calls Rejected fallback (totaled as "Outgoing Fallback"). It

may be more. A caller may release a call before the attempt reaches the

far node, butsince the or iginator released beforethe call could complete, it

might not even be recorded as an attempt bythe remote ITG card.

For example, a user dials a validESN AC1 and LOC, but an incorrect

DN (with an incorrect last digit). As soon as the user dials the digit, he or

she realizes the mistake and releases the call. The SETUP message has

already gone to the ITG card, but the call is cleared beforethe H.323 SETUP

message traversed the IP network, so no call reaches the destination. An

outgoing attempt has been made and cleared, so no fallback occurred and

no call attempt is recorded at the destination.

The main reasons for valid completed call mismatches are:

•Time of day that the statistics were last read and cleared may vary.

This is the most common reason for mismatch. For example, although

both ITG cards were read at 10:00, it is important to know if the clocks

are synchronized, and when statistics were last cleared. A one-minute

discrepancy could mean quite a few calls in the difference. Therefore,

the ﬁrst eight calls of one card may havealready been counted for the

other card. The statistics are more reliable when looked at over the day.

•"Messages in ﬂight"

This ranges from trivial to extreme. In the extreme case, if a CONNECT

message is delayed severaltenths of seconds (or even seconds) by

trafﬁc bursts, the snapshot mayoccur while the CONNECT message

is still traversing the network. Therefore, one or more calls is still

unaccounted for. In the trivial case, even in a lightly loaded network, it

Nortel Communication Server 1000

IP TrunkFundamentals

NN43001-563 02.01 Standard

Release 5.5 21December 2007