Transcript Juniper Networks Presentation Template-US

GSMPv3 applicability to L2CP
draft-wadhwa-gsmp-l2control-configuration-00.txt
L2CP BOF
IETF-65
Sanjay Wadhwa
Juniper Networks
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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
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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).
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Broadband Access Aggregation
Network
Customer
Premises Network
Access Aggregation Network
RG
Regional Broadband Network
BNG
DSLAM
(Access-Node)
Video
Head End or
ASP
ASP
(e.g. IP
Telephony)
Aggregation Network
IP Backbone
ISP
(Internet)
RG
L2CP
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L2CP: Layer2 Control in Access
Networks
 Control Plane required between BNG and Accessnode 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.
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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.
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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.
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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.
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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.
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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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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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GSMPv3 applicability to L2C
• GSMP Connection Establishment
• Access-node (slave) initiates TCP connection
•Ease of provisioning on BNG
•Divergence from base GSMP specification
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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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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.
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Use Case 1: Access Line Discovery
• Change in access-line attributes also reported to the
BNG.
• Access-line reporting uses GSMP “Port-Up” and “PortDown” EVENT messages.
• TLVs defined for “access-line identification” and “accessline attributes”.
• TLVs are carried in “technology specific extension block”
of the EVENT message.
• “Technology Type” field is extended with a new value for
“DSL”.
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8- Business
logic
Access-line Discovery
Radius
7-Sync Rate to
radius in
access-request
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
3-RG Turned On,
Synchronized with
DSLAM
DSLAM
Internet Port
9-Service
VSAs
5-Access Loop
Parameters
Stored
BNG
Video
Head End or
ASP
1-L2CP Session
Established
ASP
(e.g. IP
Telephony)
RG
IPTV Port
2-Access-Line Discovery
Capability Advertised
2-Subscriber logs in
(PPP/DHCP session)
IP Backbone
6-Set Shaping
Rate, Adjust
Shaping Mode
ISP
(Internet)
 Ensures no congestion in the access network
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8- Business
logic
Access-line Attributes Update
Radius
7-Sync Rate to
radius in
access-request
4-PORT_UP MESSAGE
(Updated Line Parameters)
ACI : [xyz-Dslam-1]eth 207/1:350
1-DSL LINE
RESYNCH
Line Attributes : Downstream = B/W 512K
Upstream = B/W 300
Local Loop Type = ATM
9-Service
VSAs
5-Access Loop
Parameters
Updated
BNG
Video
Head End or
ASP
DSLAM
ASP
(e.g. IP
Telephony)
Internet Port
RG
IPTV Port
IP Backbone
6-Set Shaping
Rate, Adjust
Shaping Mode
ISP
(Internet)
 QOS and Service control updated
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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.
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Use Case 2: Line Configuration
• BSR “managed” access and QOS control enforced by the accessnode.
• 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”
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8- Business
logic
Line Configuration
Radius
7-Sync Rate to
radius in
access-request
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
3-RG Turned On,
Synchronized with
DSLAM
BNG
DSLAM
Internet Port
RG
IPTV Port
9-Service
VSAs
Video
Head End or
ASP
1-L2C Session
Established
ASP
(e.g. IP
Telephony)
2-Access-Line Discovery &
Line Config Capability
Advertised
2-Subscriber logs in
(PPP/DHCP session)
IP Backbone
6-Set Shaping
Rate, Adjust
Shaping Mode
ISP
(Internet)
Enterprise
VPNs
10- PORT_MANAGEMENT MESSAGE
ACI : [TCOM-DSLAM-1] eth 207/1:350
Service-Profile : Gold
IGMP-Profile : Premium-Package
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2- Business
logic
Line Configuration Update
Web Portal/OSS etc
Radius/AAA
Policy
3-Change of
Authorization
BNG
DSLAM
Video
Head End or
ASP
1-Subscriber logs in
(PPP/DHCP session)
ASP
(e.g. IP
Telephony)
Internet Port
RG
IPTV Port
IP Backbone
ISP
(Internet)
10- PORT_MANAGEMENT MESSAGE
ACI : [TCOM-DSLAM-1] eth 207/1:350
Service-Profile : Gold
IGMP-Profile : Premium-Package
Enterprise
VPNs
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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
Aggregation
Network
L2C: Port Management
Remote LB for ACI
L2-specific
L2C: Port Management
loop-back
LB Report for ACI – Success/Fail
procedure
Code: 0x500 : Specified access line does not exist.
• AN can trigger:
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 training
0x507 : DSL line integrity error
0x508 : DSLAM resource not available
0x509 : invalid test parameters
• F5 loopback cells for
ATM based local loop
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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.
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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 accesslines)
 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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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-ooghel2c-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-l2controlconfiguration-00.txt
 Field trials of these implementations underway.
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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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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.
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Thank You
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