Subject: [PWE3] CAS over CESoPSN (5086)

From: Javi <[email-masked]>
Date: Fri, 27 Nov 2009 14:00:06 +0100

What is the difference between?

5.3.  Extending Basic NxDS0 Services with CE Application Signaling: CE 
maintains a separate application
   state per DS0 channel (e.g., CAS for the telephony applications)

5.4.  Trunk-Specific NxDS0 Services with CAS

A TDM multiframe E1/DS1 with CAS signaling can be carried by both, 
right?. So what gives to each other?

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From: Javi <[email-masked]>
Date: Sun, 29 Nov 2009 14:21:29 +0100

Under these RFCs, I understand that:

+ A PW CESoPSN or TDMoIP AAL1 can only carry TDM channels from a single 
TDM trunk (if a cross-connect is used to mix channels from different TDM 
trunks, this would not be visible to the TDMPW)

+ A PW TDMoIP AAL2 is able to carry channels from different TDM trunks 
(identified by their CID). May these trunks be of different type (E1 and 
some other DS1, for example)?

If a TDMPW could transport channels from different TDM trunks, how does 
they carry error indicators (AIS, RDI) of theml?. Control word (CW) 
allows only transporting from a trunk.

Javi

Javi escribió:
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From: Javi <[email-masked]>
Date: Sun, 29 Nov 2009 18:22:20 +0100

I detail my question.

According to RFC 5086, the mechanism:

+ "5.3.  Extending Basic NxDS0 Services with CE Application Signaling": 
it may transport the state signalling of CEs, e.g., CAS for the 
telephony applications.

+ "5.4.  Trunk-Specific NxDS0 Services with CAS": it transport CAS 
signalling for the telephony applications.

In principle, both represent two distinct possibilities. However:

a) Apart from CAS for the telephony applications, what other real 
example of CE Application Signaling may be proposed?

b) If the mechanism 5.3 necessary, why is not covered by the RFC 5087 
(TDMoIP) for AAL.1?

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From: Javi <[email-masked]>
Date: Sun, 29 Nov 2009 18:25:33 +0100

If a TDMPW could transport channels from different TDM trunks, how may a 
single TDMPW carry error indicators (AIS, RDI) of all TDM trunks?. 
Control Word (CW) may only carry error indicators from a trunk.

Javi

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From: "STUART VENTERS" <[email-masked]>
Date: Mon, 30 Nov 2009 10:11:15 -0600

Javi,

I've wondered that too.
   It appears to be two ways to do essentially the same thing.

It might be a case of two views of the world.
  Sending CAS in with the timeslots is more friendly to DS0 cross connect hardware.
  Sending CAS on change in separate packets is more friendly to S/W DS0 termination.

Depending on if the CAS bits are changing or not, one might be more bandwidth friendly.

Does putting the CAS bits in separate packets allow signaling AIS and RDI on a per-DS0 basis?
  If not, then the trunk specific stuff might be a red herring.

Regards,

Stuart

Maybe engineers just like to invent things.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Javi
Sent: Friday, November 27, 2009 7:00 AM
To: [email-masked]
Subject: [PWE3] CAS over CESoPSN (5086)