Subject: Megaco MIB questions

From: Dan Elbert <[email-masked]>
Date: Thu, 12 Jul 2001 15:44:27 -0500

Hi
We are currently reviewing the Internet draft for the Megaco MIB
(draft-ietf-megaco-mib-02.txt, dated May 2001).
We have several questions:
1. In general, we don't understand what the term Link Id (also referred to
as signaling link) means.  What does this correspond to in the megaco
protocol, an mId, a socket, a pair of communicating mIds, or something else?
2.  We are equally confused about Media Gateway Id.  Is the sole purpose of
the Media Gateway ID to distinguish multiple Media Gateways residing on a
single IP node (single IP address) or does this have some other
correspondence with the Megaco protocol itself?
3. In the "Controller table", the controller entries contain fields for IP,
port, and operational status.  In order to configure a connection from an MG
to and MGC, the MG needs to know the encoding  scheme (text, or binary) and
the transport type (UDP, TCP, SCTP, ...).  Is there plans to add these to
the controller entry?
4. By the documents title it appears that the MIB is for Megaco, yet there
is a MIB variable in the configration table entry for a "Gateway Protocol".
Can someone explain the purpose of this field or why the title reflects
Megaco, but the MIB supports other protocols? 
5. The title and text also implies that the MIB supports both MG and MGC
entities, and yet we can't find any tables for the Media Gateway Controller
entity. Can someone clarify this?
6. When is the next meeting scheduled for this working group?
I apologize up front if some or all of this has already been discussed
previously, but we are just now getting involved in the Network Management
topic.
 Thanks
 
Dan Elbert
RADVISION

---

From: Thomas Stone <[email-masked]>
Date: Tue, 17 Jul 2001 12:29:47 -0700

-----Original Message-----
From: Dan Elbert [mailto:[email-masked]]
Sent: Thursday, July 12, 2001 4:44 PM
To: [email-masked]'
Subject: Megaco MIB questions

Hi

*It corresponds most closely to a socket.  In the Config table, it is the
socket that the MGC uses to communicate with the MG.  In the Controller
table, each entry corresponds to a valid controller.  An incoming message is
verified as coming from a valid controller by checking against the entries
in this table.

*The Media Gateway Id allows a physical gateway to be treated as multiple
virtual media gateways (VMGs).  Having a separate gateway id allows for
separate name spaces on things like termination names. The physical gateway
has a single mib that is addressed using a single IP address but each VMG
could have a different MG side IP address that may or may not reside on a
common physical interface.

*Good point!  One question is whether this should be flexible per controller
or whether the gateway should be set for one type of controller.  If the
latter, then this information should go in the gateway table, otherwise the
controller table.

*This was in the initial strawman MIB published about 1.5 yrs ago.  Looks
like it was just never removed.

*What tables would be needed?

*Yours is the first posting I've seen regarding this MIB submission.  Have
they been coming through without the word MIB in the subject line?

*Tom Stone
*Jetstream Communications

 Thanks
 
Dan Elbert
RADVISION

---

From: Dan Elbert <[email-masked]>
Date: Wed, 18 Jul 2001 13:38:49 -0500

My comments below 

-----Original Message-----
From: Thomas Stone [mailto:[email-masked]]
Sent: Tuesday, July 17, 2001 3:30 PM
To: 'Dan Elbert'; [email-masked]'
Subject: RE: Megaco MIB questions

-----Original Message-----
From: Dan Elbert [mailto:[email-masked]]
Sent: Thursday, July 12, 2001 4:44 PM
To: [email-masked]'
Subject: Megaco MIB questions

>It corresponds most closely to a socket.  In the Config table, it is the

Are you assuming a connection oriented transport?  I'm not sure how this
makes sense for transport over UDP.  In that case one socket could be
associated with a number of entities.  For an MG running over UDP it will
have only a single link ID.  Actually, in most normal cases only one link ID
will be present even with TCP, since an MG deals only with a single MGC at a
time....

>The Media Gateway Id allows a physical gateway to be treated as multiple

We understand the concept of VMG and that is what we had thought the MIB
referred to, but wanted to be sure.

>Good point!  One question is whether this should be flexible per controller

As a data point, we provide the flexibility to specify the transport and
encoding on a per controller basis.

>This was in the initial strawman MIB published about 1.5 yrs ago.  Looks

So it sounds like this MIB is still not close to being locked down. I know
the MIB is long over due.  Whats the timeline now?

>What tables would be needed?

Here are a few ideas:
a. A stats table would be useful on the MGC as well.  It might even be
useful to
have the stats on a per MG (medGwyGatewayId) basis. 

b. Configuration:
        Oper. status (r) - Up, shutting down, down
        Admin Status (r/w) - Up, (graceful) down, (force) down, redirect
        Redirect IP (r/w)
        Redirect port (r/w)

Note: That having the concept of an medGwyControllerId (like the
medGwyGatewayId) would allow multiple MGC's to run on a single IP address.
This would of course mean that configuration would be a table indexed by
medGwyControllerId and the stats would be indexed either by both
medGwyControllerId and medGwyGatewayId or just medGwyControllerId (depending
on whether stats are kept per MG or not).

>Yours is the first posting I've seen regarding this MIB submission.  Have

We have not seen many emails on this topic, but we haven't been
concentrating on this either.

>Tom Stone
>Jetstream Communications

>>RADVISION

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