Subject: DS1 Channelization

From: "Laurence V. Marks" <[email-masked]>
Date: Tue, 3 Feb 98 21:06:31 EST

Ref:  Your note of Tue, 3 Feb 1998 17:34:10 -0800 (PST) (attached)

> For DS3 to DS1:
> - DS3 to DS1 (M13 channelization)
> - DS3 to DS2 to DS1 (M23 channelization followed by DS1 channelization)
>
To the best of my knowledge, these are the same.  The M13 mux chips
perform both conversions.  This is necessary to delete/insert the
variable number of 'stuff' bits.

Laurence V. Marks

---

From: Gary Hanson <[email-masked]>
Date: Thu, 5 Feb 1998 11:54:38 -0800 (PST)

Laurence,

>From the questions I have recently asked around here, I believe you
are absolutely correct.  In fact, I understand that it would be an
oddity to actually see a DS2 interface presented electrically, and
that it tends only to exist within the M13 mux chips that you refer to.

It kind of makes me wonder about several things then:

- Why did we select (in RFC 1407) the terminology of "dsx3M23(2)"
  for the dsx3LineType instead of "dsx3M13(2)".  I can't tell you
  the number of times people have asked about why no M13 option
  was presented, and I have always responded by saying that the
  two are really the same and the DS3-MIB creators simply chose
  the term they did.  (At the same time while responding this way,
  I have always internally wondered why this choice was made that
  way, nevertheless.)

- Where is the interest in supporting DS2 interfaces coming from?

  I can see the value in having J2 supported by these MIBs (although
  it is not, currently), since it is actually in use in Japan.  (I
  would be happy to propose any necessary ASN.1 modifications to add
  J2 support if there is one or more other vendors interested in it.)

  But who actually presents DS2 interfaces in the physical sense?  If
  they exist only logically, but are always bypassed in the DS3 to DS1
  channelization process, then why are they needed?  Does anybody know
  who originally requested that support for DS2 (and E2 for that matter)
  be added to the DS1-MIB?

  The same question goes for E2, especially since I am unfamiliar with
  the frequency of its use around the world.

Gary