Subject: [Sigtran] [M3UA] Heartbeat procedures

From: ksrinivas <[email-masked]>
Date: Wed, 22 Jan 2003 10:10:57 +0530

Brian,

In Section, 4.3.4.6 Heartbeat Procedures of M3UA RFC, the following is
mentioned.

[...Either M3UA peer may optionally send Heartbeat messages
periodically, subject to a provisionable timer T(beat).  Upon receiving
a Heartbeat message, the M3UA peer MUST respond with a Heartbeat Ack
message...]

The following are understood from the above para:

1. Heartbeat messages are periodically sent subject to a provisionable
timer T(beat).

Once in every T(beat) interval, a Heartbeat message is sent.

2. Upon receiving a Heartbeat message, the M3UA peer MUST respond with a
Heartbeat Ack message.

Since Heartbeat message is sent Once in every T(beat) interval, the
Heartbeat Ack message should also be received Once in every T(beat)
interval if everything is proper.

Is my understanding proper?.

[...If no Heartbeat Ack message (or any other M3UA message) is received
from the M3UA peer within 2*T(beat), the remote M3UA peer is considered
unavailable.  Transmission of Heartbeat messages is stopped and the
signalling process SHOULD attempt to re-establish communication if it is
configured as the client for the disconnected M3UA peer...]

Can you please clarify my following doubts from the above para:

1. In response to Heartbeat message sent, should the M3UA expect either
the Heartbeat Ack message or any other M3UA message?

2. What should happen if the Heartbeat Ack message is not received
within the first T(beat) interval.?
    Should we wait for one more T(beat) interval for the Heartbeat Ack
message?.

--Srini

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From: "Brian F. G. Bidulock" <[email-masked]>
Date: Wed, 22 Jan 2003 07:14:49 -0700

Srini,

An M3UA peer must respond to a BEAT with a BEAT ACK.  If it doesn't
the M3UA sending the DEAT can assume that the peer is dead.  Its
that simple.

--brian

ksrinivas wrote:                               (Wed, 22 Jan 2003 10:10:57)

-- 
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

---

From: ksrinivas <[email-masked]>
Date: Thu, 23 Jan 2003 10:52:34 +0530

Brian,

    In Section, 4.3.4.6 Heartbeat Procedures of M3UA RFC, Why are the
following things mentioned?.

 [...If no Heartbeat Ack message (or any other M3UA message) is received from
the M3UA peer within 2*T(beat), the remote M3UA peer is considered
unavailable...]

  1. Why "or any other M3UA message" is mentioned?.
  2. What is 2*T(beat)?. Does it mean that we have to send Heartbeat message
once in every 2*T(beat) interval?.

--Srini

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From: "Brian F. G. Bidulock" <[email-masked]>
Date: Wed, 22 Jan 2003 22:35:50 -0700

ksrinivas,

ksrinivas wrote:                                                                 (Thu, 23 Jan 2003 10:52:34)
>     [...If  no  Heartbeat  Ack  message  (or  any  other M3UA message) is
>    received  from the M3UA peer within 2*T(beat), the remote M3UA peer is
>    considered unavailable...]
> 

The M3UA peer is hardly "dead" if it is sending messages.

>       2.  What is 2*T(beat)?. Does it mean that we have to send Heartbeat
>    message once in every 2*T(beat) interval?.

Sounds like a reasonable time to wait, doesn't it?

--brian

>      [1]http://www.openss7.org/
> 
> References
> 
>    1. http://www.openss7.org/