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GSMPv3 applicability to L2CP draft-wadhwa-gsmp-l2control-configuration-00.txt L2CP BOF IETF-65. Sanjay Wadhwa Juniper Networks. Agenda. Layer2 Control in Access Networks (L2CP) GSMPv3 applicability to L2CP GSMPv3 extensions for L2CP Adjacency Protocol Access-Line discovery - PowerPoint PPT Presentation
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Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 1
GSMPv3 applicability to L2CPdraft-wadhwa-gsmp-l2control-configuration-00.txt
L2CP BOFIETF-65
Sanjay Wadhwa
Juniper Networks
2Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 2
Agenda Layer2 Control in Access Networks (L2CP)
GSMPv3 applicability to L2CP
GSMPv3 extensions for L2CP
• Adjacency Protocol
• Access-Line discovery
• Line Configuration
• Remote connectivity check
• “Transactional” Multicast
Current Status
3Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 3
L2CP : Layer2 Control Protocol in DSL Access Networks
BNG (Broadband Network Gateway)• Aggregation point for subscriber traffic.
• Serves as injection point for policy and IP QOS management in access/regional network.
Acess-Node• Terminates the “local-loop”.
• First point in the network where traffic is aggregated from multiple “local-loops” on to a single network (e.g. DSLAM in DSL access networks).
4Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 4
Broadband Access Aggregation Network
IP Backbone
BNGRG
VideoHead End or
ASP
DSLAM (Access-Node)
ASP(e.g. IP
Telephony)
ISP(Internet)
RG
Aggregation Network
Customer Premises Network Access Aggregation Network Regional Broadband Network
L2CP
5Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 5
L2CP: Layer2 Control in Access Networks
Control Plane required between BNG and Access-node for dynamic “QOS-related”, “service-related” and “subscriber-related” operations.
Dynamic control protocol eliminates dependency on integration with a complex OSS system spanning multiple entities.
6Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 6
L2C: Layer2 Control in Access Networks
Desired control plane attributes:• Simple
• Ease of implementation
• Time to market
• Light-weight
– Allow implementation on AN with limited control plane resources (CPU/memory)
• Extensible
• Possible to extend the protocol for use-cases relevant to access technologies other than DSL (e.g PON).
• Supports addition of new capabilities in a downward compatible manner.
7Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 7
L2C: Layer2 Control in Access Networks
• Flexible
• Independent of underlying access/aggregation network (e.g. ATM or Ethernet).
• Supports transactional exchange
• Request/response model for BNG to communicate control decisions or request information from AN.
• Supports “asynchronous” notifications from AN to BNG.
8Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 8
L2C: Layer2 Control in Access Networks
• Minimize configuration overhead and maximize automation of operation.
• OPEX reduction
• Supports configurable keep-alive
• Detection for loss of connectivity and failure of peer node.
• Support efficient resynchronization after loss of peering.
• Supports graceful shutdown notification.
9Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 9
L2C: Layer2 Control in Access Networks
• Scalable• Number of adjacencies
• Number of transactions
• Does not require any soft state.• Supports Incremental update of
information.• Ease of supporting non-disruptive “on
demand” state refresh capability.• Ease of supporting Graceful Restart and
High availability.
10Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 10
GSMPv3 applicability to L2C Leverage subset of GSMPv3 as the base
control protocol to build upon.
Subset of GSMPv3 relevant to L2C identified in draft-wadhwa-gsmp-l2control-configuration-00.txt.
• Contains DSL specific modifications and extensions to GSMPv3 for few currently envisaged use-cases of L2C.
• Based on draft-ietf-gsmp-v3-base-spec-07.txt
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IETF 65 (L2C BOF) 11
GSMPv3 applicability to L2C
Master (Controller) - BNG (Broadband Network Gateway)
Slave (Switch) - Access Node (e.g. DSLAM in DSL access)
GSMP over TCP encaps
Separate “logical connection” for L2C.
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IETF 65 (L2C BOF) 12
GSMPv3 applicability to L2C
• GSMP Connection Establishment
• Access-node (slave) initiates TCP connection
• Ease of provisioning on BNG
• Divergence from base GSMP specification
13Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 13
Adjacency Protocol : Extension
• Base GSMP adjacency protocol is extended:
• Adjacency messages extended to carry Capability TLVs.
• Negotiation procedure for “Least Common Denominator” capability set defined.
• Capability mis-match prevents adjacency to be formed.
• Capabilities defined for current use-cases.
• Configurable adjacency keepalive (ACK) interval.
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IETF 65 (L2C BOF) 14
Use Case 1: Access Line Discovery• Access-node asynchronously informs BNG of access-line
state and attributes (e.g. sync rate) when line comes up.
• BNG can adjust QOS for the local-loop based on the sync rate (aka “remote link scheduling”).
• BNG can inform the access-line attributes to a policy server.
• Embedded “business logic” in the policy server can factor in the access-line attributes.
• Policy server can then trigger the BNG to turn on/off services or modify service attributes for the subscriber on the local loop.
15Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 15
Use Case 1: Access Line Discovery• Change in access-line attributes also reported
to the BNG.
• Access-line reporting uses GSMP “Port-Up” and “Port-Down” EVENT messages.
• TLVs defined for “access-line identification” and “access-line attributes”.
• TLVs are carried in “technology specific extension block” of the EVENT message.
• “Technology Type” field is extended with a new value for “DSL”.
16Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 16
Access-line Discovery
Ensures no congestion in the access network
IP Backbone
BNG
Internet Port
IPTV Port
RG
VideoHead End or
ASPDSLAM
ASP(e.g. IP
Telephony)
ISP(Internet)
1-L2CP Session Established
3-RG Turned On, Synchronized with
DSLAM
4-PORT_UP MESSAGE ACI : [TCOM-Dslam-1]eth 207/1:350 Line Attributes : Downstream = B/W 768 Upstream = B/W 300
Local Loop Type = ATM
5-Access Loop Parameters
Stored
6-Set Shaping Rate, Adjust
Shaping Mode
2-Access-Line Discovery Capability Advertised
7-Sync Rate to radius in
access-request
9-Service VSAs
8- Business logic
Radius
2-Subscriber logs in (PPP/DHCP session)
17Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 17
Access-line Attributes Update
QOS and Service control updated
IP Backbone
BNG
Internet Port
IPTV Port
RG
VideoHead End or
ASPDSLAM
ASP(e.g. IP
Telephony)
ISP(Internet)
1-DSL LINE RESYNCH
4-PORT_UP MESSAGE (Updated Line Parameters)ACI : [xyz-Dslam-1]eth 207/1:350 Line Attributes : Downstream = B/W 512K Upstream = B/W 300
Local Loop Type = ATM
5-Access Loop Parameters
Updated
6-Set Shaping Rate, Adjust
Shaping Mode
7-Sync Rate to radius in
access-request
9-Service VSAs
8- Business logic
Radius
18Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 18
Access Line Discovery Best-practice recommendations:
• Desirable to dampen Access-line state changes by the Access-Node.
• Desirable to use use “BULK” transaction message for access-line reporting on startup.
19Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 19
Use Case 2: Line Configuration• BSR “managed” access and QOS control enforced by the
access-node.
• Provides for centralized “service management”.
• BSR can download service profiles/parameters to the access-node (e.g. “IGMP Filter Lists”) via L2C.
• “Line Config” uses GSMP “Port Management” message to convey “service attributes” from the BNG to the Access-node.
• “Function” field carried in the message has been extended with a new value to support “line configuration”.
• TLVs defined for “access-line identification” and “service attributes”.
• TLVs are carried in “technology extension block” of the PORT_MANAGEMENT message.
• “Technology type” is extended with a new value for “DSL”
20Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 20
Line Configuration
IP Backbone
BNG
Internet Port
IPTV Port
RG
VideoHead End or
ASPDSLAM
ASP(e.g. IP
Telephony)
ISP(Internet)
EnterpriseVPNs
1-L2C Session Established
3-RG Turned On, Synchronized with
DSLAM
4- EVENT (PORT_UP) MESSAGE ACI : [TCOM-Dslam-1]eth 207/1:350 Line Attributes : Downstream = B/W 768 Upstream = B/W 300
Local Loop Type = ATM
5-Access Loop Parameters
Stored
6-Set Shaping Rate, Adjust
Shaping Mode
2-Access-Line Discovery & Line Config Capability
Advertised
7-Sync Rate to radius in
access-request
9-Service VSAs
8- Business logic
Radius
2-Subscriber logs in (PPP/DHCP session)
10- PORT_MANAGEMENT MESSAGE ACI : [TCOM-DSLAM-1] eth 207/1:350 Service-Profile : Gold IGMP-Profile : Premium-Package
21Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 21
Line Configuration Update
IP Backbone
BNG
Internet Port
IPTV Port
RG
VideoHead End or
ASPDSLAM
ASP(e.g. IP
Telephony)
ISP(Internet)
EnterpriseVPNs
3-Change of Authorization
2- Business logic
Web Portal/OSS etcRadius/AAA
Policy
1-Subscriber logs in (PPP/DHCP session)
10- PORT_MANAGEMENT MESSAGE ACI : [TCOM-DSLAM-1] eth 207/1:350 Service-Profile : Gold IGMP-Profile : Premium-Package
1-Service on Demand
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IETF 65 (L2C BOF) 22
Use Case 3: Remote Connectivity Check
BNG triggered “local loop” test capability.
Provides fault detection and to some extent fault isolation.
L2 Network Independent
Verify the integrity of a local loop
• Request AN Initiate Loop-specific LB Procedure
• LB Results returned to BNG via L2C
• AN can trigger:
• F5 loopback cells for ATM based local loop
• 8023.ah procedures for EFM.
AggregationNetwork
L2-specific
loop-back
procedure
L2C: Port ManagementRemote LB for ACI
L2C: Port ManagementLB Report for ACI – Success/FailCode: 0x500 : Specified access line does not
exist. 0x501 : Loopback test timed out. 0x502 : Reserved 0x503 : DSL line status showtime. 0x504 : DSL line status idle. 0x505 : DSL line integrity silent. 0x506 : DSL line status training0x507 : DSL line integrity error0x508 : DSLAM resource not available0x509 : invalid test parameters
23Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 23
Remote Connectivity Check PORT_MANAGEMENT message is used for OAM request and
response.
“Function” field in the message extended with a new “remote loopback” value.
PORT_MANAGEMENT message carrying the loopback test response has a valid “result” field (Success/Failure)
“Code” field in PORT_MANAGEMENT message extended to carry detailed OAM loopback test response.
24Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 24
Use Case 4 : Transactional Multicast
Typically, BNG terminates user requests for receiving multicast channels via IGMP.
BNG performs “authorization” , “access-control” (checks subscription rights for the subscriber) and does admission control.
Ideal for BNG to send a single copy of “multicast stream” to a given access-node (as opposed to a separate copy for each subscriber behind the access-node).
BNG can set “replication state” in the access node using L2C (e.g. P2MP PVC cross-connect OR mapping of “multicast MAC” to access-lines)
Access node can replicate based on native L2 mechanisms (e.g. ATM p2mp cell replication or ethernet data-link bridging).
GSMP extensions for this use-case : TBD.
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IETF 65 (L2C BOF) 25
Current Status Some work to define L2C use-cases is happening in DSL forum
(Working Text 147)
Desirable to undertake framework/requirement, and protocol specification work for L2C in IETF.
L2C framework/requirements and GSMPv3 extensions for L2C are defined in draft-wadhwa-gsmp-l2control-configuration-00.txt.
Framework/requirements also defined in a later ID draft-ooghe-l2c-framework-00.txt. The two drafts should be combined to yield a single requirements draft.
Initial inter-operable implementations from different vendors (3 BNG and 4 DSLAM) exist based on draft-wadhwa-gsmp-l2control-configuration-00.txt
Field trials of these implementations underway.
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IETF 65 (L2C BOF) 26
Potential Protocol Work Mechanism for “Graceful Restart”.
Mechanisms/Extensions to scale to a large number of L2C adjacencies.
Support for “subtended DSL topologies” (large number of remote Access-nodes controlled by a central BNG).
Mechanism on BNG for non-disruptive, “on-demand” retrieval of all state on the Access node.
Definition of MIBs.
Support for redundant controllers (BNGs) for a single AN (or a single partition on an AN)
Applicability to other broadband access technologies (e.g. PON, WIMAX etc).
If needed, support for appropriate security mechanisms (to ensure authentication of message initiator and integrity of messages).
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IETF 65 (L2C BOF) 27
Recommendations An IETF WG be formed to undetake L2C framework,
requirements and protocol specification work.
“GSMPv3 extensions for L2C” draft be considered as a WG item.
28Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IETF 65 (L2C BOF) 28
Thank You