Subject: RFC 2558: Using the Circuit Identifier as Path Trace

From: Wexler Mishael <[email-masked]>
Date: Thu, 4 Nov 1999 11:21:27 +0200

Hello,

I wanted to know if we can use the Circuit Identifier mentioned at the
rfc2558 document as Path Trace massage (J1 byte in the SONET/SDH).

Thank you,

MISHAEL

Mishael Wexler
System Engineering 
Transport Networks 
ECI Telecom Ltd.
Tel: +972-3-926-2502
Fax: +972-3-926-3460
Martin Gehl St. 16
49104 Petah-Tikva
ISRAEL

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From: "C. M. Heard/VVNET, Inc." <[email-masked]>
Date: Thu, 4 Nov 1999 11:23:11 -0800 (PST)

> rfc2558 document as Path Trace massage (J1 byte in the SONET/SDH).

If the path trace message is provisioned in accordance with G.707, then
the 15-character string which follows the header byte meets all the
requirements for a circuit identifier, namely that it is assigned by
the circuit vendor and uniquely identifies the circuit.  Under those
circumstances it seems quite reasonable to return that string as the
value of ifPhysAddress for those ifTable entries that correspond to
SDH paths.

Presumable one could use the section trace message as the ifPhysAddress
for those ifTable entries that correspond to SDH sections (note that the
same ifTable entry is used for the regenerator and multiplex section
layers).

Mike
--
C. M. Heard/VVNET, Inc.
[email-masked]

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From: Keith McCloghrie <[email-masked]>
Date: Thu, 4 Nov 1999 12:11:29 -0800 (PST)

> value of ifPhysAddress for those ifTable entries that correspond to

Despite the statements on use of ifPhysAddress in RFCs 2495/2496/2558,
I think a circuit identifier is a "name" rather than an "address", and
thus, is more suited to be the value of ifAlias (see RFC 2233).  But
maybe it's too late to fix this now.

Keith.

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From: "C. M. Heard/VVNET, Inc." <[email-masked]>
Date: Thu, 4 Nov 1999 15:18:37 -0800 (PST)

> maybe it's too late to fix this now.

The same though occurred to me when I was re-reading RFC 2558 to answer
Mishael's question.   I think the reason why RFC 2558 has the circuit
identifier into ifPhysAddress rather than ifAlias is historical:  the
text describing how to use the ifTable was carried over more-or-less
unchanged from RFC 1595, and when RFC 1595 was written ifAlias did not
yet exist -- it's not in RFC 1573, at any rate.

Kaj, can you confirm or deny this?

I suppose that a vendor always has the option to return a zero-length
octet string for ifPhysAddress and then allow the customer to provision
whatever circuit identifier is deemed appropriate into ifAlias.  Under
both SONET and SDH the stuff in a path trace message is plain text
(assuming that the SDH header byte is stripped off) and is 64 characters
at most, and so conforms to the SYNTAX of ifAlias.

Mike
--
C. M. Heard/VVNET, Inc.
[email-masked]

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From: Kaj Tesink <[email-masked]>
Date: Thu, 04 Nov 1999 18:59:58 -0500

>maybe it's too late to fix this now.

i suspect that this is an holdover all the way back to the early days
of the trunk mibs. i agree with your observation, even more so since
there is also sonetMediumCircuitIdentifier (...). but it seems difficult
to change all this history/implementations and revise 3 rfcs in sync for 
this, no?

kaj

> > same ifTable entry is used for the regenerator and multiplex section

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Kaj Tesink
Telcordia Technologies (formerly Bellcore)
Email  [email-masked]
Tel    732.758.5254
Fax    732.758.2269
Postal 331 Newman Springs Rd
        Red Bank, NJ 07701
        USA

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