Subject: [ANCP] RE: Link bonding

From: "Sanjay Wadhwa" <[email-masked]>
Date: Sun, 28 Oct 2007 23:04:16 -0400

Hi Thomas
  Thanks for the feedback. You are correct in that there is no explicit dependency in ANCP on DHCP opt-82 or PPPoE tags inserted by the intermediate agent. However, the BNG has to correlate ACI present in ANCP to the subscriber (e.g. to adjust its QoS to the learnt DSL sync rate). The ACI could be statically configured on the BNG for the subscriber, or could be learnt from DHCP opt-82 or PPPoE tag inserted by the AN (intermediate agent). In either case, BNG transparently does an "exact match" with the ACI received in ANCP, for subscriber correlation (without the need for interpreting it). This should be true for bonded or un-bonded links. 
The mention in my original mail below was simply to emphasize the need for AN to use "logical addressing" (for ACI) in case of bonded links, both in ANCP and in DHCP opt-82 or PPPoE tag. 
As mentioned in the last IETF meeting, I intend to add a sub-section on link bonding in the next rev of the draft (based on my original mail in this thread below). Other than your feedback, I haven't received any other comments, and assume we are ok with it.

Regards
-Sanjay

>-----Original Message-----
>From: Haag, T [mailto:[email-masked]]
>Sent: Thursday, September 20, 2007 6:46 AM
>To: [email-masked]
>Cc: [email-masked]; Sanjay Wadhwa
>Subject: AW: Link bonding
>
>
>All,
>
>considering link bonding (ITU-T G.998.2 (EFM bonding) and ANCP 
>is very welcome but I would like to recommend not combine DHCP 
>Option 82 or PPPoE intermediate function issues with that use case. 
>
>I think these are two separate issues which may be combined 
>but not necessarily needed to be combined. From an operator's 
>standpoint ANCP protocol issues should be considered stand 
>alone for link bonding without PPPoE or DHCP because for 
>products using bonded links PPP or DHCP is not mandatory. 
>
>Regards
>
>Thomas
>
>-----Ursprüngliche Nachricht-----
>Von: Sanjay Wadhwa [mailto:[email-masked]] 
>Gesendet: Mittwoch, 19. September 2007 20:53
>An: [email-masked]
>Cc: Haag, Thomas; [email-masked]
>Betreff: Link bonding
>
>All  
>   I would like to get some feedback on requirements for ANCP 
>to support link bonding e.g.as defined in ITU-T G.998.2 (EFM 
>bonding). At a high level it seems the AN should report the 
>aggregate rate for the bonded links to the BNG. If an existing 
>link in the bundle goes down or a new link in the bundle is 
>added, the AN should report this to the BNG as a change in the 
>downstream and upstream rate. In case of regular un-bonded 
>link, the ACI that is used for addressing a local-loop has a 
>default syntax that carries 
>AN-name/slot/port/vpi.vci or vlan. In case of link bonding, I 
>suppose the AN should use "logical addressing" for the bonded 
>link when constructing the ACI (inserted in DHCP opt82/pppoe 
>IA tags, and ANCP). BNG would transparently correlate the rate 
>received in ANCP messages to subscriber's interface based on 
>ACI and adjust its traffic-shaping accordingly. The overhead 
>due to (variable sized) fragmentation on the bonded link 
>somehow needs to be accounted for on the BNG to calculate the 
>effective rate of the local-loop. This is dependent on the 
>packet sizes, and the framgentation scheme used on the AN. A 
>very simplistic solution could be for the AN to report a fixed 
>overhead to the BNG for fragmentation.
>
>Do we see other implications of bonding on the 
>topology-discovery/adaptive-rate use case ?
>
>Thanks
>-Sanjay
>  
>

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