B-16
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 Prior to Maintenance Release 1.1
KA Attempts Unsuccessful, MGW Unreachable, and Stable Call Is Present
If no ACK is received during any KA attempt, and no MGCP messages have been exchanged between
the BTS 10200 and the MGW for a specified time interval (see the time interval description in the
drawing), the system performs a specified number of KA retries before declaring the MGW to be
unreachable. This condition is shown in
for the case with stable call(s) present.
Figure B-11
KA Attempts Unsuccessful, MGW Unreachable, and Stable Call Is Present
Notes for
•
The keepalive attempts labeled KA 1-2, KA 1-3, and KA 1-4 represent retries of the original
keepalive attempt KA 1-1. The number of retries is provisioned as
mgcp-keepalive-retries
.
•
The keepalive attempts labeled KA 2-1, KA 3-1, and further, represent new attempts spaced
according to the provisioned value of
mgcp-keepalive-interval
.
•
Each keepalive attempt, KA 1-1, KA 1-2, ... KA 2-1, KA 3-1, and further, has a unique MGCP
transaction ID.
Note
For detailed examples of successful KA attempts, see
The system takes the following actions in the scenario shown in
•
If a KA attempt is successful, and stable calls exist: The system implements the KA pattern shown
in Scenario 1. (See
•
For RGWs with 16 or fewer endpoints—If a KA attempt is successful, and no stable calls exist: The
system implements the KA pattern shown in Scenario 2. (See
Scenario 2 (Special Case)—Reachable
RGW with 16 or Fewer Endpoints and No Stable Calls In Progress
KA 1-1
KA 1-2
KA 1-
3
KA 1-4
KA 2-1
KA
3
-1
KA 4-1
allowed to exceed 60 seconds (not provisionable).
Interval between KA attempts:
S
tarts at 10
seconds and increases as shown, but is not
10 seconds 20 seconds 40 seconds
Time interval with no MGCP
messages, when ther are
stable calls as in
S
cenario 1:
mgcp-keepalive-interval
(default = 60 seconds).
Initial KA attempt,
unsuccessful
KA attempt failure – Gateway unreachable.
Occurs if no ACK is received at
any time during this AUEP transaction.
mgcp-keepalive-interval
(default = 60 seconds)
2*mgcp-t-hist
mgcp-keepalive-retries
(default =
3
)
2500
3
0
Time
Unsuccessful KA
S
uccessful KA
Legend
ACK
mgcp-t-max 2*mgcp-t-hist
