ITEM: AM9923L
AIXSNA LS timers on activation
ENV: SNA Server, Token ring
Desc: Start linkstation times out in 60 seconds; however, it may
take up to 90 seconds for other box to respond. So how
do you change liskstation timeout to be 90 seconds?
Response:
Act: Based on test results below, told customer to set the
response time-out parameter in SNA token ring DLC profile
to 12 (16 test frames 6 seconds apart = 96 seconds). Then
at the 60 second mark to ignore the sna command message
"request timed out; system is busy or in error; try you
request later". The linkstation really is still trying to
start.
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Testing reveals that start linkstation returns at least
2 messages indicating potential failure to connect:
1. The request timed out. The system is busy or in error; try
your request later.
2. 0105-2900 start linkstation cannot find specified remote
station
.You get message \#1 if the start linkstation (as regulated by
the response time-out parameter) takes longer than 60 seconds.
.You get message \#2 if the start linkstation fails in less than 60
seconds.
.However, in the case of message \#1, the start linkstation process
(sending out TEST frames) actually continues for the duration of
the response time-out interval and TEST frame count (16).
For example, if response time-out =40 and number test frames sent
is 16, the linkstation is trying to start for 5 minutes 20 seconds.
--------------------------------------------------------------------
...
The inactivity timeout field is not covered in the above comments.
These comments apply only when no frames are received by the RS/6000
adapter in response to frames sent.
.DLC will send Retransmit_count x2 TEST frames and Retransmit_count x3
null XID frames and then timeout. The Response time-out timer pops
every 0.5 seconds, thus the time between frames sent will be between
(0.5 x response_timeout_value) and (0.5 x (response_timeout_value + 1)).
When the link times out on XID's you will see a LAN8004 POLL COUNT
EXHAUSTED event in the system log. This event is not logged if the
timeout is on TEST frames.
.Inactivity procedures are covered in Chapter 7 of
SC31-7014 AIX SNA Server/6000: Configuration Reference
Each of the inactivity fields have detailed usage help under smit
contextual help (F1) for that field. These help items include the
relationship among the various inactivity fields. Each field is also
documented in Chapter 16 Token Ring Installation of the Configuration
Reference.
...
Token Ring SNA DLC Profile
.Retransmit count
This field specifies the number of unsuccessful polls the local
station must make to a remote station before the local station
can declare the remote to be down.
.
Polling occurs on all unnumbered and supervisory commands and
is also started whenever an inactivity time-out has occurred.
Each poll command is transmitted to the remote at an interval
specified in the "Response time-out" field. If the remote
station does not respond within the number of polls specified
in this field, the local station starts inactivity procedures.
.
The appropriate value for this field depends on the remote
station's ability to respond in a timely manner. If the value
is too low, the local station may declare that a busy (but
operating) remote station is down. If the value is too high,
the local station wastes time polling a nonfunctioning remote.
Adjust the value of this field and the values in the
"Inactivity time-out" and "Response time-out" fields to find a
combination that works well on your network.
.Inactivity time-out
This field determines the number of seconds to wait for a valid
receive packet from the remote station. Once this time-out
expires, the remote station is polled with an appropriate
command at the rate specified in the "Response time-out" field.
If the remote station does not respond to the polls after the
number of polls specified in the "Retransmit count" field is
completed, the local station starts inactivity procedures.
.Response time-out
This field specifies the number of seconds that the station
should wait for a required response from the remote station.
After waiting for the specified period with no response from
the remote station, the local station retransmits the command
up to the number of retries specified in the "Retransmit count"
...
The following message is returned by the sna command.
The request timed out.
The system is busy or in error; try your request later.
The link station activation procedure is not affected by this
message. The sna command process waits 60 seconds for a response
from any process it has started. If no return is received in 60
seconds the sna command process prints the "request timed out"
message and ends. Any process started by the sna command such as
link activation will continue.
.The following message
0105-2900 start linkstation cannot find specified remote station
is returned by the link activation process and is an indication that
link activation failed.
.Details of link activation flows can be reviewed in a LS trace started
from the link station profile.
Current state of all link stations can be displayed by
\# sna -d l
or
\# sna -d l -o l
.There are also LS restart parameters available on the LS profile.
...
Support Line: AIXSNA LS timers on activation ITEM: AM9923L
Dated: April 1996 Category: N/A
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