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RE: AW: [ANCP] Layer 2 Parameters in the Protocol document

Hi Michel
  One of the main requirements on the BNG is to be able to correlate L2C messages pertaining to a given access loop with subscriber sessions over that access-loop. This is done via matching ACIs received in L2C messages with what is received in DHCP opt 82 or PPPoE IA tag.  Ideally the BNG should not have to interpret these values and should be able to to transparently do an exact match. Keeping the formats in L2C and DHCP/PPPoE identical allows this.
The IETF draft mentions the syntax that you refer below as "typical" syntax. However, it clearly states that the format of the ACI should be identical to what is inserted by the DSLAM (signalling relay) in subscriber signalling messages (as defined in TR-101, cited as a reference in the IETF draft). TR-101 specifies a default syntax for the ACI which includes VPI/VCI. However, it allows the default syntax to be overriden by "flexible" syntax, which I believe lets you specify just the slot/port.
The intent in the IETF draft it to only require that the ACI sent in L2C and DHCP/PPP messages by the DSLAM should match (and the format should be transparent to the BNG).
 
To your other point about encaps for multiple VCs per access-loop, it doesn't have to be a seperate message. It could be a single message containing a set of {ACI, DSL line attributes}. Other then encaps, rest of the attributes would be identical in each set.
 
Regards
-Sanjay
 
 
 
-----Original Message-----
From: Michel.Platnic at ecitele.com [mailto:Michel.Platnic at ecitele.com]
Sent: Wednesday, September 27, 2006 12:18 PM
To: Haag, T
Cc: ancp at ietf.org
Subject: Re: AW: [ANCP] Layer 2 Parameters in the Protocol document


Hi Thomas and All,

Layer 2 parameters transmitted within the Access-Loop-Circuit-ID are indeed a MUST for several use cases,
so, as explained in your email, this layer 2 information should not be removed.

The Access-Loop-Circuit-ID is defined within 'draft-wadhwa-gsmp-l2control-configuration-01.txt' as follows:
 “Access-Node-Identifier atm slot/port:vpi.vci”   (when ATM/DSL is used)

 “Access-Node-Identifier eth slot/port[:vlan-id]” (when Ethernet/DSL is used)

This means that for ATM interfaces at UI, vpi.vci MUST always be transmitted.


This brings us to at least 3 scenarios for the topology discovery use case (when ATM/DSL is used):
1- no layer 2 information needed, only layer 1 information required to be transmitted
2- single VC and layer 2 encapsulation required to be transmitted
3- multi-VC and layer 2 encapsulation required to be transmitted

Comments:
Scenario1: vci.vpi is actually not required to be transmitted within Access-Loop-Circuit-ID
Scenario2: vci.vpi needed
Scenario3: if encapsulation is needed for each (n) vci.vpi, it means that n topology discovery messages must be transmitted.



Proposal:
If we replace  “Access-Node-Identifier atm slot/port:vpi.vci”   (when ATM/DSL is used)
by  “Access-Node-Identifier atm slot/port:[vpi.vci]”   (when ATM/DSL is used)
then vpi.vci becomes optional and we are fine with case 1.

Question:
Are we fine with the fact that in case of multiple VC (multiple VLAN as well) we must transmit multiple messages?


Regards,
Michel.



"Haag, T" <Thomas.Haag at t-systems.com>

26/09/2006 23:38

To
<Menachem.Dodge at ecitele.com>
cc
ancp at ietf.org
Subject
AW: [ANCP] Layer 2 Parameters in the Protocol document





Menachem,
 
The usage of a VPI/VCI is really dependent on the use case you are considering.
Regarding the use case access line topology it is optional because there is no strong relation to a layer 2 parameter if we report the net data rate.
 
But considering the use cases OAM (F5 LB for ADSL2/2plus) or line configuration the layer 2 parameter such as VPI/VCI or VLAN is essential. So I would recommend keeping these layer 2 parameters in the format of the “Access-Loop-Circuit-ID”.
 
Regards
 
Thomas
 


Von: Menachem.Dodge at ecitele.com [mailto:Menachem.Dodge at ecitele.com]
Gesendet: Montag, 28. August 2006 15:57
An: ancp at ietf.org; swadhwa at juniper.net; jmoisand at juniper.net; ssubramanian at juniper.net; Haag, Thomas; norbert.voigt at siemens.com
Betreff: [ANCP] Layer 2 Parameters in the Protocol document
 

Hi,

       I have a question regarding the "Access-Loop-Circuit-ID" as defined in the document "draft-wadhwa-gsmp-l2control-configuration-01.txt".

       In the case of an Ethernet based local loop the format is defined as:

       "Access-Node-Identifier eth slot/port[:vlan-id]" meaning that the vlan-id is optional.

       In the case of an ATM based local loop the format is defined as:

       "Access-Node-Identifier atm slot/port:vpi.vci"  meaning that the vpi.vci is mandatory.

       I would like this changed to "Access-Node-Identifier atm slot/port[:vpi.vci]" meaning that the vpi.vci is optional.

       This would allow for multiple vpi/vci(s) on the same port as a message could be sent  without the vpi.vci field.


===========================================================================

I have a similar question regarding the "Access-Aggregation-Circuit-ID-ASCII" as defined in the document "draft-wadhwa-gsmp-l2control-configuration-01.txt".

       In the case of an Ethernet based local loop the format is defined as:

       "Access-Node-Identifier eth slot/port[:inner-vlan-id][:outer-vlan-id]" meaning that the vlan-ids are optional.

       In the case of an ATM based local loop the format is defined as:

       "Access-Node-Identifier atm slot/port:vpi.vci"  meaning that the vpi.vci is mandatory.

       I would like this changed to "Access-Node-Identifier atm slot/port[:vpi.vci]" meaning that the vpi.vci is optional.

       
Thank you kindly.

Best Regards,
Menachem _______________________________________________
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