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IETF BoF Session Layer 2 Control between Access Node and BNG. Version 1.0. Layer 2 Control Mechanism Co-authors. Layer 2 Control Mechanism Content. Problem Statement – Overall Reference Architecture Problem Statement – Use Cases Use Case 1 - Access Line Discovery - PowerPoint PPT Presentation
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65. IETF Meeting BoF , March 2006Haag, Thomas, T-Systems ENPS PCT15thSeite 1, 22nd of March 2006
- vertraulich / confidential -
IETF BoF SessionLayer 2 Control
between Access Node and BNG
Version 1.0
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 2, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism Co-authors
Thomas Haag, Deutsche Telekom [email protected]
Sanjay Wadhwa, Juniper Networks [email protected]
Sven Ooghe, Alcatel [email protected]
Peter Arberg, Redback Networks [email protected]
Norbert Voigt, Siemens [email protected]
Ole Anderson Helleberg, Ericsson [email protected]
Michel Platnic, ECI Telecom [email protected]
Wojciech Dec, Cisco [email protected]
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 3, 22nd of March 2006
- vertraulich / confidential -
Problem Statement – Overall
Reference Architecture
Problem Statement – Use Cases
Use Case 1 - Access Line Discovery
Use Case 2 - OAM in ATM/Ethernet
Use Case 3 - Multicast
Use Case 4 - Line Configuration
Best Practice - Plugfest Access Line Discovery
Protocol Requirements
Layer 2 Control Mechanism Content
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 4, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control MechanismProblem Statement - Overall
Several sources like ITU-T H.610, DSLForum TR-059 describe the DSL architecture for delivery of voice, video and data services:
The approaches require a static configured data link on layer 2 The models define beside the data link the EMS architecture. Each network element is usually controlled by one element manager.
The service node usually has no knowledge about actual DSL link characteristics - problem of “non synchronized” EMS
Service oriented user entitlement control for Multicast unsolved
End to End OAM in ATM/Ethernet based access networks unsolved
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 5, 22nd of March 2006
- vertraulich / confidential -
PC
RG/CPERG/CPE
GigE
1 (10) GigE GigE GigE
VDSL2/ADSL2+
Fast Ethernet
DSLAM BNG IP Edge Router-
MC-Server
GigE
GigE
STB
PPPoE
L2CP (Link Rate Discovery))
MC-Switch
Hierarchical Scheduler
PPPoE/IPoE session carries all traffic between BNG and DSLAM BNG is Multicast-Replication point.BNG receives information about DSL bit rate from the DSLAM via the principles of a Layer 2 Control Protocol. The BNG performs the QoS handling in downstream. QoS mapping works according hierarchical scheduling.
Layer 2 Control MechanismReference Architecture
Layer 2 Aggregation
Layer 2 Aggregation
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 6, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control MechanismProblem Statement – Use Cases1. Use Case Access Line Discovery (former Link Rate Discovery): Reporting the characteristics of the access links of an access
device to a device that uses the information for e.g. queuing/scheduling purposes;
Enforcement of service parameters on selected access links including physical layer (e.g. DSL sync. rate) or network layer service parameters (e.g. 802.1p scheduling configuration on the access link);
2. Use Case OAM Triggering a point-to-point OAM mechanism on selected access
links. Mechanism include ATM OAM in case of ATM-Ethernet inter
working and Ethernet OAM in case of E2E Ethernet network.
3. Use Case Multicast Communicating multicast information between a subscriber
management device and an access device in order to allow, for example, centralized policy control.
4. Use Case Line Configuration Triggered by subscriber request or Policy Server request the
BNG may send line configuration information to the DSLAM.
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 7, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control MechanismUse Case 1: Access Line Discovery - Problem Statement
Running Rate Adaptive Mode on DSL the data link between CPE and service node no bandwidth guarantee because of different shaper adjustment
to prevent packet loss same shaper settings between DSL and service node needed
alternative solution beside DHCP and PPPoE intermediate agent is not applicable because of having this information only if the customer is in session.
InternetData
BRAS
DSLAM
ATM/EthernetSwitch
RTPolicy Server
Report RequestReport Request
Report ResponseReport Response
InternetData
InternetData
BRAS
DSLAM
ATM/EthernetSwitch
RTPolicy Server
Report RequestReport Request
Report ResponseReport Response
BNG
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 8, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism Use Case 1: Access Line Discovery – The Way out
To close the gap of different non congruent bandwidth settings in the DSLAM and BNG the DSLAM must report to the service node to inform this element of the actual bandwidth to adapt it’s shaper for downstream traffic to the actual DSL line rate.
For transmitting the messages a layer 2 control communication channel between DSLAM and service node should be used
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 9, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work) Use Case 2: OAM – Problem Statement ADSL2plus/ATM
replacing ATM with Ethernet at the V-interface
U-interface will keep ATM for the time being
domain related management systems per access domain, regional domain and service domain - problem of “non synchronized” EMS
Inter working between ATM and Ethernet to preserve existing operational functionality is essential
End to end OAM visibility on L2 between BNG and CPE within layer 2 for addressing customer connection (default ID)
ADSL2plus, ATM DSLAM, L2 Control
CPE
V* A10VS
DSLAM Ethernet- Switch BRAS
U
CPE Domain Access Domain Regional Domain Service Domain
IWF translates port ID to PVC/PVP, ATM ete LB with
default LB ID at CPE
= Loss of ete OAM connectivity
IWF
* = VLAN optional
IWF
Port Status request
Port Status response
ATM F5eteLBIWFCTP
ADSL2plus, ATM DSLAM, L2 Control
CPE
V* A10VS
DSLAM Ethernet- Switch BRAS
U
CPE Domain Access Domain Regional Domain Service Domain
IWF translates port ID to PVC/PVP, ATM ete LB with
default LB ID at CPE
= Loss of ete OAM connectivity
IWF
* = VLAN optional
IWF
Port Status request
Port Status response
ATM F5eteLBIWFCTP
BNG
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 10, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work) Use Case 2: OAM – The Way Out
A solution for inter working between ATM based technologies at the U-interface and Ethernet based aggregation network needs to be worked out
The solution must be applicable to ADSL2plus, and VDSL2
BNG triggers DSLAM for OAM operation using Layer 2 Control Mechanism
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 11, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work)Use Case 3:Multicast - Problem Statement
Multicast services getting increasingly important IPTV services, resource efficient, moving to Ethernet
ATM architecture: “transactional multicast” older DSL Forum work (PD-021)avoid IGMP processing in access/aggregation nodes
Ethernet architecture: IGMP snooping / IGMP proxyEthernet access/aggregation nodes control multicast content replication draft-ietf-magma-snoop-12.txt, draft-ietf-magma-igmp-proxy-06.txt DSL Forum TR-101
(e.g. VLAN L2Control per DSLAM, no PPPoE)
Internet Data
BNG
IGMP
(1:1 VLAN per subscriber, Internet/Traffic PPPoE)
N:1 Multicast VLAN (all channels; data+IGMP)
IGMP/IP Multicast Replication DSLAM
per Subscriber
Control Channel
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 12, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work) Use Case 3: Multicast – The Way Out
For running multicast it may be useful to communicate multicast related information between BNG and an Access Node to allow e.g. centralized policy control
Installing/removing per-user multicast access rights (“user entitlement”) on selected access ports on an Access Node
Synchronization between the IGMP router in the BNG and the IGMP snooper/proxy in the Access Node (e.g. for accounting purposes)
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 13, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work)Use Case 4: Line Configuration - Problem Statement
The Access Node is not session and/or user aware
Statically configured service/subscriber DSL parameter require reconfiguration by operator implying b2b transaction between ISP and Access Provider This system does not enable an automated operation/delivery process
InternetData
BRAS
RTPolicy Server
Report RequestReport Request
Report ResponseReport Response
Subscriber RequestSubscriber Request
Subscriber ResponseSubscriber Response
InternetData
InternetData
BRAS
RTPolicy Server
Report RequestReport Request
Report ResponseReport Response
Report RequestReport Request
Report ResponseReport Response
Subscriber RequestSubscriber Request
Subscriber ResponseSubscriber ResponseBNG
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 14, 22nd of March 2006
- vertraulich / confidential -
Layer 2 Control Mechanism (Future Work)Use Case 4: Line Configuration – The Way Out
Triggered by subscriber request the BNG may send line configuration information to the DSLAM using Report messages.
The BNG should get such line configuration data from a policy server (e.g. RADIUS). The BNG may update the line configuration due to a subscriber service level change (e.g. triggered by the policy server).
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 15, 22nd of March 2006
- vertraulich / confidential -
Target Plug fest November 2005 :
multi-vendor inter-operable implementations of Use Case Link Rate Discovery are based on "Layer2 control protocol extensions to GSMP" outlined in draft-wadhwa-gsmp-l2control-configuration-00.txt
Upcoming Plugfest for Use Case OAM Line
Configuration and Multicast: Verification of Use Case:
OAM
Multicast
Line Configuration
Appreciate to continue future work based on frame workusing an IETF standardized communication protocol
Layer 2 Control Mechanism Best Practice - Plugfest & Interop Testing
65. IETF Meeting BoF Layer 2 ControlHaag,Thomas, ENPS PCT15thSeite 16, 22nd of March 2006
- vertraulich / confidential -
“shutdown” sequence allowing
graceful shut down
ProtocolRequiremen
ts
“keep-alive” mechanism to
auto detect loss of connectivity
“request/response” transaction-oriented
model. If the response is negative, state of the Access Node must be
unchanged.
“report” model for the Access Node
to spontaneousl
y communicate
to the BNG changes of
states
the protocol should be
mapped on top of the IP
network layer (possibly via a
transport layer). allowing to convey long messages
“boot” sequence for
control capabilities (common subset)
between two peers
Layer 2 Control Mechanism Protocol Requirements