Subject: MGC Handoff and Failover

From: Jennifer Liu <[email-masked]>
Date: Thu, 16 Sep 1999 15:36:50 -0500

Brian,

I have two more questions related to MGC handoff/failover, and would
appreciate if you can provide some insight:

1. MGC handoff

     The standard states that after handoff, "commands in progress
     continue, transaction replies are sent to the new MGC", this
     would require ServiceChange command  have higher priority than
     other commands to allow it to be processed first to reflect
     the MGC handoff, right?   The standard might need to
     explicitly state it if this is the case.

2.  MGC failover

     In this case,  after MGC establish new connections with backup
     MGC, If there are still outstanding commands from old MGC,
     should  MG continue processing them and send response to
     new_MGC, or simply discard them?

Thanks,

Jennifer

---

From: Brian Rosen <[email-masked]>
Date: Thu, 16 Sep 1999 16:54:52 -0400

1. MGC handoff 

The standard states that after handoff, "commands in progress continue,
transaction replies are sent to the new MGC", this would require
ServiceChange command  have higher priority than other commands to allow it
to be processed first to reflect the MGC handoff, right?   The standard
might need to explicitly state it if this is the case. 
 
Actually, this is important simply because there is no order dependence
between transactions, and the MG is free to start any number of transactions
it gets "simultaneously" and report results when it is done with them in
any order.  perhaps we need words to that effect 

2.  MGC failover 

In this case,  after MGC establish new connections with backup MGC, If there
are still outstanding commands from old MGC, should  MG continue processing
them and send response to new_MGC, or simply discard them?  
In failover, I would say discard is acceptable.

Thanks, 

Jennifer