B-24
Cisco BTS 10200 Softswitch Troubleshooting Guide, Release 5.0.x
OL-8723-19
Appendix B System Usage of MGW Keepalive Parameters, Release 5.0
Keepalive for Release 5.0 Maintenance Release 1.1 and Later
MGCP-MAX2-RETRIES and MGCP-T-MAX
The BTS 10200 limits retransmissions of the AUEP message to
mgcp-max2-retries
or a total duration
of
mgcp-t-max
(default = 20 seconds), whichever occurs first. If the system has not received an ACK
at this point, it takes the following actions:
•
It stops all retransmissions and abandons the transaction.
•
If keepalive functionality is
enabled
on the system (
mgw-monitoring-enabled=Y
and
keepalive-method=AUEP
as described in the
“Provisionable Parameters” section on page B-19
the system expedites the KA process (as described in the
“Keepalive Process” section on page B-25
)
without immediately declaring the termination to be unreachable. However, if the KA process also
fails, the system declares the MGW and all associated terminations to be unreachable. The
operational status of each of the terminations is marked as TERM_UNREACH.
•
If keepalive functionality is
disabled
on the system, the system marks the operational status of each
of the terminations as UNKNOWN.
shows how the system handles AUEP retransmissions and takes action if no ACK is
received. In this example, mgcp-max2-keepalive attempts are completed before the expiration of
mgcp-t-max. In general, the system stops retransmissions when mgcp-max2-keepalive attempts are
completed or at the expiration of mgcp-t-max, whichever occurs first.
Figure B-17
Timeout Limitations When No ACK Is Received
mgcp-t-max (default = 20 seconds)
Maximum time allowed for retransmissions.
(No additional
retransmissions sent)
mgcp-max1-retries (default = 2)
Maximum number of AUEP
retransmissions sent to each
IP address of the MGW.
mgcp-max2-retries (default =
3
)
Maximum number of AUEP
retransmissions sent to the
last IP address of the MGW.
25014
8
Time
mgcp-t-tran
2*mgcp-t-tran
4*mgcp-t-tran
8
*mgcp-t-tran
KA attempt
(AUEP transaction)
AUEP,
initial
transmission
AUEP,
2nd transmission
(1st retransmission)
AUEP,
3
rd transmission
(2nd retransmission)
AUEP,
4th transmission
(
3
rd retransmission)
16*mgcp-t-tran