Browse Prior Art Database

Managing Topology Changes in a Message Broker Environment

IP.com Disclosure Number: IPCOM000123669D
Original Publication Date: 1999-Mar-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Bolam, S: AUTHOR [+5]

Abstract

When one or more brokers are added to or removed from a hierarchic broker topology where brokers exchange subscriptions and only deliver publications where necessary then it is difficult to predict when a publisher can reliably publish and expect all relevant subscribers in the network to receive the publication.

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This is the abbreviated version, containing approximately 82% of the total text.

Managing Topology Changes in a Message Broker Environment

   When one or more brokers are added to or removed from a
hierarchic broker topology where brokers exchange subscriptions and
only deliver publications where necessary then it is difficult to
predict when a publisher can reliably publish and expect all
relevant subscribers in the network to receive the publication.

   For example, the network may be as shown in Figure 1,
having three brokers 1, 2, 3, a publisher 4 and a subscriber 5.
Details of the subscriber have been propagated from Broker1 to
Broker2 to Broker3.  If a publisher publishes at Broker3, the
publication will be delivered to the subscriber at Broker1.

   Referring to Figure 2, as the brokers are arranged in a
strict hierarchy then Broker3 can only have a single parent.  The
relationship with Broker2 must be broken before a new parent
(Broker1) can be established.  If the publisher should publish at
the instance when Broker3 has no parent then the subscriber would be
unknown to Broker3 and the publication would not be sent to the
subscriber.

   As shown in Figure 3, Broker3 becomes known to Broker1 then
these two brokers will exchange subscriptions.  If the publisher
should publish before this subscription exchange has completed then
the publication will not be delivered to the subscriber.

   The solution described here addresses this problem by
providing a mode of starting the broker where subscriptions are
exchanged but publication messag...