Configuring SCTP Retransmission Control for a M2PA Association

This procedure is used to gather the information required to configure the retransmission parameters for M2PA associations assigned to cards running either the IPLIM or IPLIMI applications. Perform the Configuring an IPSG Association for SCTP Retransmission Control procedure to configure the retransmission parameters for M2PA associations assigned to IPSG cards. If any assistance is needed to configure the retransmission parameters for associations, contact My Oracle Support (MOS).

The retransmission parameters are configured using the rmode, rmin, rmax, rtimes, and cwmin parameters of the chg-assoc command.

:rmode – The retransmission mode used when packet loss is detected. The values are rfc or lin.

rfc – Standard RFC 2960 algorithm in the retransmission delay doubles after each retransmission. The RFC 2960 standard for congestion control is also used.
lin – Oracle's linear retransmission mode where each retransmission timeout value is the same as the initial transmission timeout and only the slow start algorithm is used for congestion control.

:rmin – The minimum value of the calculated retransmission timeout in milliseconds.

:rmax – The maximum value of the calculated retransmission timeout in milliseconds.

Note:

The rmin and rmax parameter values form a range of retransmission values. The value of the rmin parameter must be less than or equal to the rmax parameter value.

:rtimes – The number of times a data retransmission occurs before closing the association.

:cwmin – The minimum size in bytes of the association's congestion window and the initial size in bytes of the congestion window.

The Changing the Attributes of an M2PA Association procedure is used to change the values of these parameters. In addition to using the Changing the Attributes of an M2PA Association procedure, these pass commands are also used in this procedure.

ping – tests for the presence of hosts on the network.
assocrtt – displays the SCTP round trip times for a specified association. Minimum, maximum, and average times are kept for each open association. The Retransmission Mode (RFC or LIN) and the configured Minimum and Maximum Retransmission Timeout limits are also displayed.
sctp – provides a summary list of all SCTP instances.
sctp -a <association name> – displays the measurements and information for a specific association.

Note:
The values for the minimum and maximum retransmission times in the output from this command are shown in microseconds.

For more information on the pass commands, see Commands User's Guide.

The chg-assoc command contains other optional parameters that can be used to configure an association. These parameters are not shown here because they are not necessary for configuring the SCTP retransmission parameters. These parameters are explained in more detail in the Changing the Attributes of an M2PA Association procedure, or in the and chg-assoc command description in Commands User's Guide.

Canceling the RTRV-ASSOC Command

Because the rtrv-assoc command used in this procedure can output information for a long period of time, the rtrv-assoc command can be canceled and the output to the terminal stopped. There are three ways that the rtrv-assoc command can be canceled.

Press the F9 function key on the keyboard at the terminal where the rtrv-assoc command was entered.
Enter the canc-cmd without the trm parameter at the terminal where the rtrv-assoc command was entered.
Enter the canc-cmd:trm=<xx>, where <xx> is the terminal where the rtrv-assoc command was entered, from another terminal other that the terminal where the rtrv-assoc command was entered. To enter the canc-cmd:trm=<xx> command, the terminal must allow Security Administration commands to be entered from it and the user must be allowed to enter Security Administration commands. The terminal’s permissions can be verified with the rtrv-secu-trm command. The user’s permissions can be verified with the rtrv-user or rtrv-secu-user commands.

For more information about the canc-cmd command, go to Commands User's Guide.

Display the associations in the database using the rtrv-assoc command.

This is an example of possible output.


rlghncxa03w 06-10-28 09:12:36 GMT EAGLE5 36.0.0

                CARD IPLNK
ANAME           LOC  PORT  LINK ADAPTER LPORT RPORT OPEN ALW
swbel32         1201 A     A    M3UA    1030  2345  YES  YES
a2              1305 A     A    SUA     1030  2345  YES  YES
a3              1307 A     A    SUA     1030  2346  YES  YES
assoc1          1201 A     A    M2PA    2000  1030  YES  YES

Enter the rtrv-card command with the location of the card that is hosting the M2PA association that will be changed in this procedure. For this example, enter this command.
rtrv-card:loc=1201

This is an example of possible output.
```
rlghncxa03w 08-03-06 15:17:20 EST EAGLE5 38.0.0
CARD   TYPE      APPL     LSET NAME   LINK SLC LSET NAME   LINK SLC
1201   DCM       IPLIM    lsn1        A    0
```
If the application assigned to the card is IPLIM or IPLIMI, shown in the APPL column, continue the procedure with 3.

If the application assigned to the card is IPSG, perform the Configuring an IPSG Association for SCTP Retransmission Control procedure.

Display the association that will be changed by entering the rtrv-assoc command with the name of the association. For this example, enter this command.

rtrv-assoc:aname=assoc1

This is an example of the possible output.


rlghncxa03w 10-07-28 21:14:37 GMT EAGLE5 42.0.0
 ANAME assoc1
       LOC      1201          IPLNK PORT  A          LINK  A
       ADAPTER  M2PA          VER         M2PA RFC
       LHOST    IPNODE2-1205
       ALHOST   ---
       RHOST    gw100.nc-tekelec.com
       ARHOST   ---
       LPORT    2000          RPORT       1030
       ISTRMS   2             OSTRMS      2           BUFSIZE  400
       RMODE    LIN           RMIN        120         RMAX     800
       RTIMES   10            CWMIN       3000        UAPS     10
       OPEN     YES           ALW         NO          RTXTHR   2000
       RHOSTVAL MATCH         M2PATSET    1

IP Appl Sock/Assoc table is (8 of 4000) 1% full
Assoc Buffer Space Used (1600 KB of 1600 KB) on LOC = 1201

Enter the ping pass command specifying the card location of the local host, shown in 3 , and the name of the remote host assigned to the association being changed, shown in 3 .

This command is entered several times to obtain the average round trip time. For this example, enter this command.

pass:loc=1201:cmd=”ping gw100.nc.tekelec.com”

The following is an example of the possible output


rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0
PASS: Command sent to card

rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0
PING command in progress

rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0
PING GW100. NC. TEKELEC. COM (192.1.1.30): 56 data bytes
64 bytes from tekral.nc.tekelec.com (192.1.1.30): icmp_seq=0. time=5. ms
64 bytes from tekral.nc.tekelec.com (192.1.1.30): icmp_seq=1. time=9. ms
64 bytes from tekral.nc.tekelec.com (192.1.1.30): icmp_seq=2. time=14. ms
----tekral PING Statistics----
3 packets transmitted, 3 packets received, 0% packet loss
round-trip (ms)  min/avg/max = 5/9/14

PING command complete

If the SCTP retransmission parameters do not need to be changed, do not perform 5 through 8. This procedure is finished.

Perform the Changing the Attributes of an M2PA Association procedure to change the retransmission parameters of the association based on the results of pinging the remote host.

Enter the assocrtt pass command to display the round trip time data collected after an association is established when an SCTP INIT message is sent and an acknowledgment is received.

The assocrtt command is entered with the card location from 4 (the card location assigned to the association being changed), and the name of the association being changed. This association must contain the host name used in 4. For this example, enter this command.

pass:loc=1201:cmd=”assocrtt assoc1”

The following is an example of the possible output


rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0
PASS: Command sent to card

rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0

ASSOCRTT: Association round-trip time report (in milliseconds)

Retransmission Configuration
    Retransmission Mode              : LIN
    Minimum RTO: 120
    Maximum RTO: 800

Traffic Round-Trip Times

    Minimum round-trip time          : 5
    Maximum round-trip time          : 120
    Weighted Average round-trip time : 10
    Last recorded round-trip time    : 10

Measured Congested Traffic Round-Trip Times

    Minimum round-trip time          : 0
    Maximum round-trip time          : 0
    Weighted Average round-trip time : 0
    Last recorded round-trip time    : 0
;
rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0
ASSOCRTT command complete

Enter the sctp -a <association name> pass command to determine if retransmissions have occurred.

The association name is the association name specified in 6. Specify the card location used in 6. For this example, enter this command.

pass:loc=1201:cmd=”sctp -a assoc1"

The following is an example of the possible output


    rlghncxa03w 10-12-28 21:15:37 GMT EAGLE5 43.0.0

    Aname            Local           Local  Remote          Remote
                     IP Address      Port   Address         Port
    Assoc1           192.168.110.12  2222   192.168.112.4   5555
                     192.168.112.12  

             Configuration                         State
        Retransmission Mode = LIN        State = OPEN
Min. Retransmission Timeout = 10000      ULP association id = 18
Max. Retransmission Timeout = 800000     Number of nets = 2
     Max. Number of Retries = 10         Inbound Streams = 1
    Min. Congestion Window = 3000        Outbound Streams = 2
            Inbound Streams = 2
           Outbound Streams = 2
         Checksum Algorithm = crc32c
       Send/Rcv Buffer Size = 204800

                              Nets Data

         IP Address    192.168.112.4      State     Reachable
               Port     7777             Primary     YES
                MTU     1500                cwnd     16384
           ssthresh     16384                RTO     120

         IP Address     192.168.113.5      State     Reachable
               Port     7777             Primary     NO
                MTU     1500                cwnd     16384
           ssthresh     16384                RTO     120

                    Last Net Sent To = 192.168.112.4
                  Last Net Rcvd From = 192.168.112.4
                 Over All Eror Count = 0
                          Peers Rwnd = 13880
                             My Rwnd = 16384
                          Max Window = 16384
                  Initial Seq Number = 24130
             Next Sending Seq Number = 124686
               Last Acked Seq Number = 124669
         Maximum Outbound Char Count = 16384
         Current Outbound Char Count = 2112
            Number Unsent Char Count = 0
           Outbound Data Chunk Count = 16
                       Number Unsent = 0
                Number To Retransmit = 0
  
                  ip datagrams rcvd = 155402
 ip datagrams with data chunks rcvd = 120844
                   data chunks rcvd = 367908
                   data chunks read = 367900
                      dup tsns rcvd = 8
                         sacks rcvd = 38734
                gap ack blocks rcvd = 3
            heartbeat requests rcvd = 135
                heartbeat acks rcvd = 52
            heartbeat requests sent = 52
                  ip datagrams sent = 129254
 ip datagrams with data chunks sent = 73084
                   data chunks sent = 396330
        retransmit data chunks sent = 135
                         sacks sent = 64872
                        send failed = 0
             retransmit timer count = 0
    consecutive retransmit timeouts = 0
RTT between RMIN and RMAX inclusive = 6
              RTT greater than RMAX = 0
              fast retransmit count = 135
                   recv timer count = 0
              heartbeat timer count = 244
                   none left tosend = 0
                none left rwnd gate = 5
                none left cwnd gate = 8

;

    rlghncxa03w 10-12-28 21:15:37 GMT EAGLE5 43.0.0

    SCTP command complete


    rlghncxa03w 06-10-28 21:15:37 GMT EAGLE5 36.0.0

    Aname            Local           Local  Remote          Remote
                     IP Address      Port   Address         Port
    Assoc1           192.168.110.12  2222   192.168.112.4   5555
                     192.168.112.12  

             Configuration                         State
        Retransmission Mode = LIN        State = OPEN
Min. Retransmission Timeout = 10         ULP association id = 18
Max. Retransmission Timeout = 800        Number of nets = 2
     Max. Number of Retries = 10         Inbound Streams = 1
    Min. Congestion Window = 3000        Outbound Streams = 2
            Inbound Streams = 2
           Outbound Streams = 2

                              Nets Data

         IP Address    192.168.112.4      State     Reachable
               Port     7777             Primary     YES
                MTU     1500                cwnd     16384
           ssthresh     16384                RTO     120

         IP Address     192.168.113.5      State     Reachable
               Port     7777             Primary     NO
                MTU     1500                cwnd     16384
           ssthresh     16384                RTO     120

                    Last Net Sent To = 192.168.112.4
                  Last Net Rcvd From = 192.168.112.4
                 Over All Eror Count = 0
                          Peers Rwnd = 13880
                             My Rwnd = 16384
                          Max Window = 16384
                  Initial Seq Number = 24130
             Next Sending Seq Number = 124686
               Last Acked Seq Number = 124669
         Maximum Outbound Char Count = 16384
         Current Outbound Char Count = 2112
            Number Unsent Char Count = 0
           Outbound Data Chunk Count = 16
                       Number Unsent = 0
                Number To Retransmit = 0
  
                  ip datagrams rcvd = 155402
 ip datagrams with data chunks rcvd = 120844
                   data chunks rcvd = 367908
                   data chunks read = 367900
                      dup tsns rcvd = 8
                         sacks rcvd = 38734
                gap ack blocks rcvd = 3
            heartbeat requests rcvd = 135
                heartbeat acks rcvd = 52
            heartbeat requests sent = 52
                  ip datagrams sent = 129254
 ip datagrams with data chunks sent = 73084
                   data chunks sent = 396330
        retransmit data chunks sent = 135
                         sacks sent = 64872
                        send failed = 0
             retransmit timer count = 0
    consecutive retransmit timeouts = 0
RTT between RMIN and RMAX inclusive = 6
              RTT greater than RMAX = 0
              fast retransmit count = 135
                   recv timer count = 0
              heartbeat timer count = 244
                   none left tosend = 0
                none left rwnd gate = 5
                none left cwnd gate = 8

    SCTP command complete

Perform the Changing the Attributes of an M2PA Association procedure to change the retransmission parameters of the association based on the results of the outputs of 6 and 7.

The Weighted Average round-trip time shown in the assocrtt pass command output in 6, and the data retransmission counts shown in the sctp -a pass command output in 7 are used as a guide to determine the appropriate values for the rmode, rmin, rmax, and rtimes parameters. If the retransmission parameters do not have to be adjusted, do not perform this step. This procedure is finished.

Figure 3-21 Configuring the SCTP Retransmission Control for a M2PA Association