Distributed Link Service Reactivation Fails with Event 77,x0AFF (180935)

SYMPTOMS

Under certain circumstances, when Event 23 outage 0x0A is reported by a Distributed Link Service, the reconnection fails with the following event log error:

Event ID: 77
Source: SNA Server
Description:
Connection <name> failed to activate due to failure at link service.
Error Code = x0AFF

X'0AFF' - Duplicate destination MAC/SAP for link service%n

This problem occurs even when no other connections are configured to use the link service that is running on the central server.

CAUSE

When the LAN session is broken between the remote link service (running in the remote branch) and the central link service (running in the central office), both SNA Server and the centralized link service receive a "lost locality" message. However, in some cases, SNA Server receives a "lost locality" before the centralized link service. This causes SNA Server to reissue a new Open(Link) request while the central link service still believes its current connection is still active, causing the central link to respond with error x0AFF (duplicate destination mac/sap for link service).

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 3.0, 3.0 SP1, 3.0 SP2, and 4.0.

This problem was corrected in the latest SNA Server versions 3.0 and 4.0 U.S. Service Packs. For information on obtaining these Service Packs, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

With the fix applied, the distributed link service retries the Open(Link) request if it receives error 0x0AFF from the central link service. The updated module is: <snaroot>\system\snaremls.dll.

Branch Server      Central Server
DLS         Shared Link             Host

<-- Outage 0x0A --
-- Close(Link) Rq ->
<-- Close(Link) Ok --
   ...      <-- Outage 0xAE -- (on LPI 09160001)
   ...
   ...
-- Open(Link) Rq ->
          -- Open(Link) Rq ->(on LPI 0A160001)
         <-- Open(Link) Error 0x0AFF -- (on LPI 0A160001)
<-- Open(Link) Error 0x0AFF --
         -- Close(Link)Rq ->(on LPI 09160001)