0535 - IP Connection Restricted

Although an IP connection has failed, some traffic is still flowing through an alternate SIGTRAN (SS7-over-IP) link.

The following two scenarios exist:

• The SCTP association is established and the SCTP far-end is multi-homed and the Eagle determines one or more far-end IP destinations for the association are unreachable.

• The SCTP association is established and the SCTP far-end is uni-homed and the SCTP near_end has an LHOST and an ALHOST configured.

Note:

IP Connection UAMs 0086 (Congested), 0535 (Restricted), and 0536 (Excess Retransmits) conditions can occur simultaneously. However, only one alarm per device can be displayed at a time. If two or more are present, the display of these alarms is prioritized as follows:

1. 0086 - IP Connection Congested (MSUs are being dropped)
2. 0536 - IP Connection Excess Retransmits (MSUs may be dropped. The EAGLE 5 ISS sustains a certain rate of dropped MSUs without triggering this alarm, then issues UIM 0536 when that rate is exceeded.)
3. 0535 - IP Connection Restricted (MSUs are being transmitted at reduced rate. A path of a multi-homed association has failed. )

Example

RLGHNCXA21W 00-12-07 12:01:43 EST  EAGLE 31.3.0
*   0014.0535  *  IP7 assoc1        IP Connection Restricted

Alarm Level: Minor

Recovery

1. Issue a pass command to determine which scenario is occurring. For example, for the association name (ANAME) ipl1301a at location 1301, enter the command: pass:loc=1301:cmd="sctp -a ipl1301a"
   Refer to the resulting output to troubleshoot the problem.

   eagle10212 01-05-27 08:09:42 EST  UNKNOWN ??.?.?-63.18.0
       Aname             Local              Local   Remote             Remote
                         Address            Port    Address            Port
       ipl1301a          10.254.110.9       1301    10.254.110.2       1301
   
                  Configuration                            State
               Retransmission Mode = LIN         State = OPEN
       Min. Retransmission Timeout = 120000      ULP association id = 0
       Max. Retransmission Timeout = 800000      Number of nets = 1
            Max. Number of Retries = 10          Inbound Streams = 2
            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     10.254.110.2            State   Reachable
                  Port     1301                  Primary   YES
                   MTU     1500                     cwnd   3000
              ssthresh     204800                    RTO   120
                           Last Net Sent To = 10.254.110.2
                         Last Net Rcvd From = 10.254.110.2
                        Over All Eror Count = 0
                                 Peers Rwnd = 204800
                                    My Rwnd = 204800
                                 Max Window = 204800
                         Initial Seq Number = 11209
                    Next Sending Seq Number = 11728
                      Last Acked Seq Number = 11727
                Maximum Outbound Char Count = 204800
                Current Outbound Char Count = 0
                   Number Unsent Char Count = 0
                  Outbound Data Chunk Count = 0
                              Number Unsent = 0
                       Number To Retransmit = 0
   
                          ip datagrams rcvd = 10
         ip datagrams with data chunks rcvd = 10
                           data chunks rcvd = 10
                           data chunks read = 10
                              dup tsns rcvd = 0
                                 sacks rcvd = 58
                        gap ack blocks rcvd = 0
                    heartbeat requests rcvd = 1392
                        heartbeat acks rcvd = 1412
                    heartbeat requests sent = 1412
                          ip datagrams sent = 2921
         ip datagrams with data chunks sent = 110
                           data chunks sent = 519
                retransmit data chunks sent = 1
                                 sacks sent = 10
                                send failed = 0
                     retransmit timer count = 1
            consecutive retransmit timeouts = 0
        RTT between RMIN and RMAX inclusive = 0
                      RTT greater than RMAX = 0
                      fast retransmit count = 0
                           recv timer count = 4
                      heartbeat timer count = 1415
                           none left tosend = 0
                        none left rwnd gate = 0
                        none left cwnd gate = 0
                                    UNKNOWN = 1

2. Determine why the other end is unreachable (for example, is a cable pulled?).
   All connections at the far end need to be reachable. After they are reachable, the alarm will clear – IP Connection Available.

   Refer to the SIGTRAN User Guide for additional troubleshooting information for SS7-over-IP connections.

3. Reconfigure the association to be either both ends uni-homed or both ends multi-homed and make sure all connections are reachable.
4. Errors (collisions, etc.) on the network interface?

   netstat -d 0/1t

5. Far end reachable?

   ping

   traceroute

6. Near end and far end use same SCTP CRC?

   netstat –p sctp

   rtrv-sg-opts