Oracle Communications EAGLE (Hardware)
 

PLA-Support>Sun Systems>CommsGBU>Global Signaling Solutions>SN-SND: Tekelec Eagle 5
 

In this Document

Symptoms

Cause

Solution

Created from <SR 3-12526076768>

Applies to:

Symptoms

2 x associations have excessive acknowledgement delays : UAM 0217

Cause

There is too much latency in the customer IP network
 
Service Event Timestamp
  In Service 16-04-10 17:14:19.290
  T7 Timeout 16-04-10 17:14:20.500
  In Service 16-04-10 17:14:22.390
  T7 Timeout 16-04-10 17:14:23.595
  In Service 16-04-10 17:14:25.445
  T7 Timeout 16-04-10 17:14:26.650
  In Service 16-04-10 17:14:28.595
  T7 Timeout 16-04-10 17:14:29.805

Also the Round trip-time values are greater than the Minimum RTO, which indicates a latency issue on the network :

> pass:loc=1307:cmd="assocrtt assoc2"

  eaglestp 16-04-10 10:39:21 EST EAGLE5 46.0.3-65.26.29
  ASSOCRTT: Association round-trip time report (in milliseconds)
  Retransmission Configuration
  Retransmission Mode : LIN
  Minimum RTO : 120
  Maximum RTO : 800
  Normal Traffic Round-Trip Times
  Minimum round-trip time : 160
  Maximum round-trip time : 255
  Weighted Average round-trip time : 193
  Last recorded round-trip time : 180

And here the Maximum round-trip reached 587 ms which is high :
> pass:loc=1215:cmd="assocrtt assoc1"

  eaglestp 16-04-10 10:39:43 EST EAGLE5 46.0.3-65.26.29
  ASSOCRTT: Association round-trip time report (in milliseconds)
  Retransmission Configuration
  Retransmission Mode : LIN
  Minimum RTO : 120
  Maximum RTO : 800
  Normal Traffic Round-Trip Times

  Minimum round-trip time : 97
  Maximum round-trip time : 587
  Weighted Average round-trip time : 127
  Last recorded round-trip time : 137

We see in the sctp command a transmission quality issue on you network :

> pass:loc=1215:cmd="sctp -a assoc1"

  eaglestp 16-04-11 08:58:23 EST EAGLE5 46.0.3-65.26.29
  dup tsns rcvd = 9
  gap ack blocks rcvd = 268
  retransmit data chunks sent = 2781
  retransmit timer count = 1094
  RTO between RMIN and RMAX inclusive = 214322
  fast retransmit count = 37
 

Solution

1. Provide the COMP-SCTPASOC measurements for the day of the 11/04/2016

2. Run the below commands to check if the network can handle IP packets with an MTU of 1500 bytes :
> pass:loc=1215:cmd=”ping –f –n 1480 194.150.199.29”
> pass:loc=1307:cmd=”ping –f –n 1480 194.150.198.29”

3. Check that the routers in the network are configured with the highest priority given to the SCTP traffic.
The preferred way of eliminating the retransmissions is to activate IP quality of service in the network and give SCTP the highest priority.

4. The issue is not on the Eagle side, check also the SCTP configuration on the far end and see if it is coherent with the Eagle.
You can increase the RMIN value from 120 to 250 for instance and see if it helps, but this is not what we recommend as we guarantee the RSVDSLKTPS for RMIN=120 ms.
 

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