Explanation
VTAM® issues
this message as part of a group of messages in response to a DISPLAY
TOPO,LIST=TDUINFO,SCOPE=RECENT command. Possible message groups follow:
- This message group is issued if you allow the FORMAT command to
default or you specify FORMAT=SHORT:
IST350I DISPLAY TYPE = TDU INFORMATION
IST1776I TOPOLOGY RESOURCES WITH MOST RECENT TDU ACTIVITY
IST2275I TDU INFORMATION SINCE LAST RESET ON date AT time
IST2290I TDUDIAG START OPTION = tdudiag_value
[IST2276I NO CORRUPTION OF TOPOLOGY CONTROL VECTORS DETECTED]
[IST924I -------------------------------------------------------------]
[IST2277I POSSIBLE CORRUPTION OF TOPOLOGY CONTROL VECTORS DETECTED]
[IST2278I SINCE VTAM START ON start_date AT start_time]
[IST2284I FOR THE FOLLOWING NODES AND TGS]
[IST2279I CP NAME DESTINATION CP TGN TIME DETECTED]
[IST2280I cp_name destination_cp tgn date_detected time_detected]
⋮
[IST2301I num OF total TOPOLOGY RESOURCES DISPLAYED]
IST924I -------------------------------------------------------------
[IST2359I NO TDU INFORMATION EXISTS]
[IST1779I TDUS RECEIVED BETWEEN first_tdu_date first_tdu_time - last_tdu_date last_tdu_time]
[IST1777I CP NAME RSN DESTINATION CP TGN ACC REJ]
[IST1778I cp_name rsn destination_cp tgn count1 count2]
⋮
[IST2301I num OF total TOPOLOGY RESOURCES DISPLAYED]
[IST924I -------------------------------------------------------------]
[IST2285I TDUS SENT BETWEEN first_tdu_date first_tdu_time - last_tdu_date last_tdu_time]
[IST2288I CP NAME RSN DESTINATION CP TGN SENT REC]
[IST1778I cp_name rsn destination_cp tgn count1 count2]
⋮
[IST2301I num OF total TOPOLOGY RESOURCES DISPLAYED]
IST314I END
- If you specify FORMAT=LONG on the DISPLAY TOPO command, the display
sections for TDUs received and TDUs sent are replaced with the following:
[IST924I -------------------------------------------------------------]
[IST2359I NO TDU INFORMATION EXISTS]
[IST1779I TDUS RECEIVED BETWEEN first_tdu_date first_tdu_time - last_tdu_date last_tdu_time]
[IST2357I CP NAME RSN DESTINATION CP TGN]
[IST2358I cp_name rsn destination_cp tgn]
[IST2353I ACCEPTED = accepted REJECTED = rejected]
⋮
[IST2301I num OF total TOPOLOGY RESOURCES DISPLAYED]
[IST924I -------------------------------------------------------------]
[IST2285I TDUS SENT BETWEEN first_tdu_date first_tdu_time - last_tdu_date last_tdu_time]
[IST2357I CP NAME RSN DESTINATION CP TGN]
[IST2358I cp_name rsn destination_cp tgn]
[IST2352I SENT = sent RECEIVED = received]
⋮
[IST2301I num OF total TOPOLOGY RESOURCES DISPLAYED]
IST314I END
IST350I - This message identifies the type of information in the display
and is always TDU INFORMATION for this message group.
IST1776I - This is a header message for the most recent topology database
updates (TDUs) and possible control vector corruption.
IST1777I - This is a header message for the information about topology resources
in the TDUs that were received most recently that is displayed in
the IST1778I messages that follow. These messages are displayed when
FORMAT=SHORT is specified or the default FORMAT value is taken.
- ACC is the abbreviation for ACCEPTED.
- REJ is the abbreviation for REJECTED.
IST1778I - One IST1778I is issued for each topology resource displayed in
a subgroup when the FORMAT=SHORT operand is specified or the default
FORMAT value is taken.
- The NUM operand can be specified on the DISPLAY command to limit
the number of topology resources that are displayed. The default
value is 10 and the maximum value is 50. If the number of topology
resources on the list since the last TDU count reset is smaller than
the number requested on the display command, the number of IST1778I
messages that are displayed in the subgroup will be smaller than the
NUM value that was specified.
- cp_name is the network-qualified CP name of
the node if the resource that is displayed is a node. If the resource
that is displayed is a TG, cp_name is the network-qualified
CP name of the TG origin node.
- rsn is the resource sequence number (RSN) expressed
in decimal.
- destination_cp is the network-qualified CP
name of the TG's destination node if the resource that is displayed
is a TG. ***NA*** is displayed if the resource is a node.
- tgn is the transmission group number associated
with the TG that is displayed. NA is displayed if the resource is
a node.
- If the subgroup displays the information about topology resources
in the TDUs that were received most recently:
- count1 is the total number of inbound TDUs
that were accepted for this resource at the time the displayed TDU
was received. Inbound TDUs are accepted when they contain new information
that causes the resource record to be updated.
- count2 is the total number of inbound TDUs
that were rejected for this resource at the time the displayed TDU
was received. Inbound TDUs are rejected when they contain inconsistent
information that causes outbound TDUs to be sent as corrections.
- If the subgroup displays the information about topology resources
in the TDUs that were sent most recently:
- count1 is the total number of outbound TDUs
that were sent for this resource at the time the displayed TDU was
sent.
- count2 is the total number of inbound TDUs
that were received for this resource at the time the displayed TDU
was sent.
Tip: A rsn value of ******** or
TDU counter values of ***** indicates that the values are greater
than the available space for those values to be displayed in message
IST1778I. You can enter the command with the FORMAT=LONG operand
to display these values in a format that includes two lines of output
for each resource.
IST1779I - This is a header message for message subgroups that display information
about topology resources in the TDUs that were received most recently.
- The date and time values
indicate the date and time for the first topology resource and the
last topology resource that are displayed in the subgroup. When there
are no topology resources on the list, the first_tdu_date and first_tdu_time values
display the date and time of the last reset of TDU information and
TDU counters and the last_tdu_date and last_tdu_time values
display the current date and time. See DATE and TIME formats for information about the date
and time values.
- The first topology resource that is displayed in the subgroup
is from the TDU that was received most recently. The last topology
resource that is displayed in the subgroup is from the TDU that was
received least recently.
IST2275I - This message displays the date and time when all the TDU information
and TDU counters were reset. All TDU information and TDU counters
are reset every 24 hours when garbage collection runs, or when a DISPLAY
NET,TOPO,LIST=TDUINFO,CLEAR=YES or a DISPLAY NET,TOPO,LIST=TDUDIAG,CLEAR=YES
command is entered. See DATE and TIME formats for
information about the date and time values.
IST2276I - This message indicates that no corruption of topology control
vectors was detected since VTAM was
started.
IST2277I - This is a header message for a message subgroup that displays
information about topology resources that have control vectors in
the topology database that have possibly been corrupted.
- Because the topology control vectors contain the resource sequence
number (RSN) for a node or TG, which determines how the TDU is processed,
it is possible that control vector corruption could cause a TDU war.
The most probable cause of control vector corruption is a storage
overlay.
IST2278I - This message displays the date and time that VTAM was started. See DATE and TIME formats for information about the date and time values.
- Unlike the lists of topology resources in the TDUs that were
received or sent most recently, the list of topology resources with
possible topology control vector corruption is never cleared and includes
any possible corruption detection since the start of VTAM.
IST2279I - This is a header message for the information about topology resources
with possible topology control vector corruption that is displayed
in the IST2280I messages that follow.
IST2280I - One IST2280I message is displayed for each topology resource
that has control vectors that have possibly been corrupted.
- Information about possible corrupted control vectors is maintained
from the start of VTAM and
is not deleted when TDU information is reset. All topology resources
that have possible corrupted control vectors are displayed in this
subgroup, regardless of the reset of TDU information.
- The NUM operand can be specified on the DISPLAY command to limit
the number of topology resources that are displayed. The default
value is 10 and the maximum value is 50. If the number of topology
resources on the list since the start of VTAM is smaller than the number requested on
the display command, the number of IST2280I messages that are displayed
in the subgroup will be smaller than the NUM value that was specified.
- cp_name is the network-qualified CP name of
the node, if the resource that is displayed is a node. If the resource
that is displayed is a TG, cp_name is the network-qualified
CP name of the TG origin node.
- destination_cp is the network-qualified CP
name of the TG's destination node, if the resource that is displayed
is a TG. If the resource is a node, then ***NA*** is displayed.
- tgn is the transmission group number that
is associated with the TG that is displayed. If the resource is a
node, NA is displayed .
- time_detected and date_detected are
the date and time that possible corruption of control vectors for
the topology resource was detected. See DATE and TIME formats for information about date and
time values.
IST2284I - This message indicates that possible topology control vector
corruption was detected for a node or TG.
IST2285I - This is a header message for message subgroups that display information
about topology resources in the TDUs that were sent most recently.
- IST2285I displays the date and time for the first topology resource
and the last topology resource that are displayed in the subgroup.
When there are no topology resources on the list, the first_tdu_date and first_tdu_time values
display the date and time of the last reset of TDU information and
TDU counters. The last_tdu_date and last_tdu_time
display the current date and time. See DATE and TIME formats for information about date and
time values.
- The first topology resource that is displayed in the subgroup
is from the TDU that was sent most recently. The last topology resource
that is displayed in the subgroup is from the TDU sent least recently.
IST2288I - This is a header message for the information about topology resources
in the TDUs that were sent most recently that is displayed in the
IST1778I messages that follow. These messages are displayed when
FORMAT=SHORT is specified or the default FORMAT value is taken.
- REC is the abbreviation for RECEIVED.
IST2290I - tdudiag_value is the user-defined TDUDIAG
start option value, specified on the START command or in the start
list. The tdudiag_value value specifies when TDU
diagnostic information is included with node or TG control vectors
within a TDU. See the TDUDIAG start option information
in z/OS Communications Server: SNA Resource Definition
Reference. Possible values can be one of the following:
- A decimal value in the range of 1-65535
- This is a threshold number of times that this network node has
updated the resource sequence number (RSN) for a topology resource
since the last time that TDU information was reset. When this threshold
value is reached for a node or TG, TDU diagnostic information is included
in the outbound TDU if the RSN is updated.
- ALWAYS
- TDU diagnostic information is always appended with the topology
control vectors included in a TDU for a topology resource when the
RSN for that resource is updated by this network node.
- NEVER
- TDU diagnostic information is never appended with the topology
control vectors included in a TDU.
IST2301I - This message displays the number of topology resources that are
displayed in a message subgroup.
- num is the total number of topology resources
that are displayed in a message subgroup.
- total is the total number of topology resource
records that currently exist on the displayed list.
IST2352I - This message follows message IST2358I and this message pair displays
the information about topology resources in the TDUs that were sent
most recently, when the FORMAT=LONG operand is specified.
- sent is the total number of TDUs that were
sent for this resource at the time that the displayed TDU was sent.
- received is the total number of TDUs that
were received for this resource at the time that the displayed TDU
was sent.
IST2353I - This message follows message IST2358I and this message pair displays
the information about topology resources in the TDUs that were received
most recently, when the FORMAT=LONG operand is specified.
- accepted is the total number of inbound TDUs
that were accepted for this resource at the time that the displayed
TDU was received. Inbound TDUs are accepted when they contain new
information that causes the resource record to be updated.
- rejected is the total number of inbound TDUs
that were rejected for this resource at the time that the displayed
TDU was received. Inbound TDUs are rejected when they contain backlevel
information that causes outbound TDUs to be sent as corrections.
IST2357I - This is a header message for the information about topology resources
in the TDUs that were received most recently or sent most recently.
The information about each topology resource is displayed in a message
pair when FORMAT=LONG is specified.
IST2358I - This is the first of two messages that display the information
about a topology resource when the FORMAT=LONG operand is specified.
- The NUM operand can be specified on the DISPLAY command to limit
the number of topology resources that are displayed. The default
value is 10 topology resources, or message pairs, and the maximum
value is 50. If the number of topology resources on the list since
the last TDU count reset is smaller than the number requested on the
display command, the number of topology resources that are displayed
in the subgroup will be smaller than the NUM value that was specified.
- cp_name is the network-qualified CP name of
the node if the resource that is displayed is a node. If the resource
that is displayed is a TG, cp_name is the network-qualified
CP name of the TG origin node.
- rsn is the resource sequence number (RSN)
expressed in decimal.
- destination_cp is the network-qualified CP
name of the TG's destination node if the resource that is displayed
is a TG. If the resource that is displayed is a node, ***NA*** is
displayed.
- tgn is the transmission group number that
is associated with the TG that is displayed. If the resource is a
node, NA is displayed.
IST2359I - This message is displayed when there are no topology resources
that have been received or sent since the TDU information and TDU
counters were last reset. Message IST2275I displays the last reset
date and time.
System action
Operator response
If you are displaying TDU information because
of performance degradation of the APPN network, use the information
about display TDU information in z/OS Communications Server: SNA Diagnosis Vol
1, Techniques and Procedures, and do the following:
- Repeat the display several times to see if there is a pattern
of excessive TDU activity for a topology resource.
- Enter the DISPLAY NET,TOPO,LIST=TDUINFO,SCOPE=ACTIVITY command
to see the topology resources with the most frequent TDU activity.
- If a node or TG is identified with excessive TDU activity, the
following displays might provide information about the network nodes
that are causing the performance degragation (TDU war):
- DISPLAY NET,TOPO,LIST=TDUDIAG provides a summary of nodes and
TGs with saved TDU diagnostic information.
- DISPLAY NET,TOPO,LIST=TDUDIAG,ID=cp_name provides details about
saved TDU diagnostic information for a node.
- DISPLAY NET,TOPO,LIST=TDUDIAG,ORIG=orig_CP,DEST=dest_CP,TGN=tng
provides details about saved TDU diagnostic information for a TG.
- If you can identify the network nodes that are involved in the
TDU war, bring down the CP-CP sessions from one of the network nodes
involved to all other network nodes in the network or subnetwork.
- If you cannot stop the TDU war, save the system log and request
a dump for problem determination. Contact the system programmer.
Tip: On the DISPLAY TOPO,LIST=TDUINFO command output,
A RSN value of ******** or TDU counter values of ***** indicates that
the value is greater than the available space for the value to be
displayed in message IST1778I or IST2293I. You can use the CLEAR=YES
operand specified on either the DISPLAY TOPO,LIST=TDUINFO command
or the DISPLAY TOPO,LIST=TDUDIAG summary command to clear the TDU
counters, but not the RSN value. Alternately, you can enter the command
with the FORMAT=LONG operand to display these values in a format
that includes two lines of output for each resource.
System programmer response
Take the following actions:
- If the operator provides output from the DISPLAY TOPO,LIST=TDUINFO
or DISPLAY TOPO,LIST=TDUDIAG commands, use the display
TDU information in z/OS Communications Server: SNA Diagnosis Vol
1, Techniques and Procedures to analyze the TDU activity. If possible,
identify the topology resource that is in contention and the network
nodes that are involved in the TDU war.
- If you have access to IBMLink, search for known problems in this
area. If no applicable matches are found, report the problem to IBM® by using the Electronic Technical
Report (ETR) option on IBMLink.
- If you do not have access to IBMLink, report the problem to the IBM software support center.
User response
Module
Routing code
Descriptor code
Automation
Example
The following
is an example of the display output from a DISPLAY TOPO,LIST=TDUINFO,SCOPE=RECENT,NUM=2,FORMAT=LONG
command:
IST350I DISPLAY TYPE = TDU INFORMATION
IST1776I TOPOLOGY RESOURCES WITH MOST RECENT TDU ACTIVITY
IST2275I TDU INFORMATION SINCE LAST RESET ON 01/29/10 AT 11:43:05
IST2290I TDUDIAG START OPTION = 1000
IST2276I NO CORRUPTION OF TOPOLOGY CONTROL VECTORS DETECTED
IST924I ------------------------------------------------------------
IST1779I TDUS RECEIVED BETWEEN 01/29/10 11:43:47 - 01/29/10 11:43:55
IST2357I CP NAME RSN DESTINATION CP TGN
IST2358I NETA.SSCP2A 24369982 NETA.SSCP1A 21
IST2353I ACCEPTED = 1435981 REJECTED = 2537561
IST2358I NETA.SSCP2A 24369980 NETA.SSCP1A 21
IST2353I ACCEPTED = 1435981 REJECTED = 2537560
IST2301I 2 OF 50 TOPOLOGY RESOURCES DISPLAYED
IST924I ------------------------------------------------------------
IST2285I TDUS SENT BETWEEN 01/29/10 11:43:47 - 01/29/10 11:43:55
IST2357I CP NAME RSN DESTINATION CP TGN
IST2358I NETA.SSCP2A 24369984 NETA.SSCP1A 21
IST2352I SENT = 4296828 RECEIVED = 65097324
IST2358I NETA.SSCP2A 24369982 NETA.SSCP1A 21
IST2352I SENT = 4296827 RECEIVED = 65097323
IST2301I 2 OF 50 TOPOLOGY RESOURCES DISPLAYED
IST314I END