WebSphere brand IBM WebSphere Telecom Web Services Server, Version 7.1

Troubleshooting Service Platform components

The Service Platform components are deployed on a WebSphere® Application Server Network Deployment platform to provide common service implementation functions. Use this information, along with your normal service support, to assist in tuning or troubleshooting Service Platform components.

You can also refer to the WebSphere Application Server information center for additional information specific to that product.

Admission Control component Web service

This component keeps track of service usage information and can constrain the rate of requests accepted by the service, both at the server level and cluster level. When used in a cluster, each cluster member maintains a local hierarchy of rate limiting buckets that are used to calculate request admission. Reservations for additional rate capacity are made against each operation as more rate is needed. When additional rate has been reserved, the allocate rate is added to the operation rate limiting bucket and the parent service rate limiting bucket. Limits set at the server level constrain the rate of requests for all operations executed against that service. Limits set at the operation level limit the rate of requests for the particular operation. The rate limit for the service bucket is the sum of the rates of its child operation buckets.

Exceed Operation limit recorded as ServiceAdmissionControlFault

In certain cases, there is no way to determine if a reservation was denied due to a service or operation limit being exceeded. This is because Admission Control component Web service performs the admission against its local view. The following is an example of a local operation reservation request resulting in a ServiceAdmissionControlFault. Token flow rates are expressed in tokens per second.
  1. At the cluster level, the server limit is set at 15 tokens, which means a local service can send a reservation request for up to 15 tokens. The cluster operation limit is set at 5, which means a local operation can send a reservation request for up to 5 tokens (per second). The Cluster service remaining is 15 tokens, because no tokens have yet been reserved. The cluster operation remaining is 5 tokens, because no tokens have yet been reserved. The following table shows the initial token count:
    Table 1. Initial number of tokens at the beginning of the operation.
    Cluster service remaining Cluster operation remaining Local service limit (max 15) Local operation limit (max 5)
    15 5 0 0
  2. At the local view, the operation requests five tokens. The local reserved service limit, which is the sum of the reserved limits for its child operations, is set to five tokens. Note that the operation has requested the maximum number of tokens it can reserve. The cluster still has ten tokens remaining that could be requested by the service, but zero tokens are available for reservation by the operation.
    Table 2. Number of tokens after the initial reservation.
    Cluster service remaining Cluster operation remaining Local service limit (max 15) Local operation limit (max 5)
    10 0 5 5
  3. At the local view, the operation requests an additional five tokens within the same time span (one second) as the first request. It receives a reserve amount of zero from the cluster as each operation is limited to five tokens per second. The operation is rejected and no change is made to the reservation amount.
  4. The Admission Control component Web service returns a ServiceAdmissionControlFault because it cannot determine whether the reservation for tokens was rejected as a result of an operation level limit or a service level limit being exceeded. No change is made to the reservation amount. The node member receiving the rejected reservation request enters a silence period.

Verification of whether a request can be admitted is performed using the local view. A reservation request may be denied at any time due to lack of sufficient rate at the service or operation level. When a node member receives a rejected reservation request, it will enter a silence period. This silence period will suppress additional reservation requests, reducing inter-cluster traffic and allowing the network to settle before attempting additional reservation. In steady state, this will minimize the inter-cluster messaging required.

Address Masking component Web service

If address masking does not work as expected, verify that you configured the masking and shadowing operations correctly. For example, are the right number of digits specified for shadowing? If masking expiry is used, has the specified time interval elapsed?




Terms of use
(C) Copyright IBM Corporation 2009. All Rights Reserved.