enhancing ims to support content-oriented networking · 2011-09-26 · content-oriented networking...
TRANSCRIPT
Enhancing IMS to Support
September 2011
© 2011 InterDigital, Inc. All rights reserved.
Enhancing IMS to Support Content-Oriented Networking
Hang Liu
Joint work with Xavier De Foy, Osama Lotfallah, Robert Gazda, and Serhad DokenInterDigital Communications [email protected]
ETSI Future Network Technologies Workshop 26 September 2011 Sophia Antipolis, France
What about content?
• Multimedia traffic is significant and continuously growing – This is well
know.
• Content is stored at multiple locations
– Traditional CDN and transparent web caching
– Distributed in-network caching at routers, base stations, relay nodes
• Advances in storage capacity and processing power enable networking elements
© 2011 InterDigital, Inc. All rights reserved.
• Advances in storage capacity and processing power enable networking elements
to cache large contents.
– Mobile network and telecom operators are deploying their own CDNs
and interconnecting them.
• A multimedia content object, e.g. a video clip, can have many
representations: coding format, resolution
2
Client-Server Model of Today’s Networks
• But today’s mobile networks and Internet were built to interconnect
computing nodes and devices (terminals, servers, etc.), not well suited
for content retrieval
–Packet transporting based on the host’s IP address
–As a result, users identify and access multimedia content based on
“where is it stored”,
• However…as a user, I care about the content itself, not where it is
© 2011 InterDigital, Inc. All rights reserved.
• However…as a user, I care about the content itself, not where it is
stored.
–desire that the content delivered to me:
• matches my device’s operating conditions
• with proper format/resolution
• at the best available quality
3
Content-Oriented Networking
• Locate, route, and deliver content based on the content itself,
not on its storage location => Content-Oriented Routing
–decouple contents from hosts at the networking level and retrieve the
content by its name or ID
–a clean-slate redesign of the Internet architecture
• Enable scalable and efficient content access => higher QoE
© 2011 InterDigital, Inc. All rights reserved.
• Enable scalable and efficient content access => higher QoE
– In-network caching to optimize bandwidth
–Content delivery from the best location(s)
–Free application and service developers from reinventing application-
specific delivery mechanisms
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IP Multimedia Subsystem (IMS)
• Developed by 3GPP and TISPAN
• Standardized framework for delivering IP multimedia
services.
• Enables end users to access a wide range of services
and applications via a common control plane
regardless of network access technology
© 2011 InterDigital, Inc. All rights reserved.
regardless of network access technology
• Allows the network to control the services,
• Creates a form of fixed-mobile convergence for next
generation networks (NGNs)
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IMS Architecture
• client-server model
• device centric
• no adequate mechanisms to
support content-oriented
functionality
• Horizontal control layer : a good foundation that can be
enhanced to support “content-oriented networking”
– Flexibility to negotiate data plane protocols and content format
– Potentially achieve the same scalability, security, and
performance as the clean-slate architecture.
Application Plane
Application Servers
• P-CSCF: Proxy Call Session Control
Function
• S-CSCF: Serving-CSCF
• I-CSCF: Interrogating-CSCF
• HSS: Home Subscriber Server
• PDF: Policy Decision Function
© 2011 InterDigital, Inc. All rights reserved.66
MRFP
P-CSCF I-CSCF
Control Plane
Device with IMS User Agent
HSS
A-BGF/A-GW Data Plane
I-BGF
IBCF/SBC
S-CSCF
PDF PDFMRFC
To other networks
To other networks
DNS/ENUM
• PDF: Policy Decision Function
• A-BGF: Access Border Gateway Function
• IBCF: Interconnect Border Controller
Function
• SBC: Session Border Controller
• I-BGF: Interconnect Border Gateway
Function
• A-GW: Access Gateway
• P-GW: Packet Gateway
• MRFC: Media Resource Function Controller
• MRFP: Media Resource Function
Processor
• ENUM: Telephone Number Mapping
• DNS: Domain Name System
P-GW
Content-Aware IMS
• Content Name Resolution Handler (CNRH): Map content object name or ID (OID) to
location (URL or host IP address)
Application Plane
eP-CSCF eI-CSCF
Control PlaneHSS
Application Servers
eIBCF/eSBC
eS-CSCF
To other
DNS/ENUM
CNRH
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• CNRH Implementation Choices: • Co-located or integrated with enhanced S-CSCF• Implemented as application server• Enhance DNS/Electronic Number Mapping System (ENUM) with CNRH functions
eMRFP
Device with IMS User Agent
A-BGF/A-GW Data Plane
I-BGF
PDF PDFeMRFC
To other networks
To other networks
P-GW
Enhancement of IMS
• Each content object is assigned a unique ID – decouple the content identity from its network locations
– facilitate automatic content location resolution
– enable interconnection or peering of content service networks to reach more contents, more types/formats of a content object, and more resources
• User agents and IMS network control entities interact for locating and
accessing a content object by its OID instead of URL or host IP address– CNRH maps the requested content OID to URL/host IP address or more general delivery
directive
© 2011 InterDigital, Inc. All rights reserved.
– Initiate, negotiate and control content retrieval session
– route the control messages within and across network domains.
• Network elements (base stations, eNodeB, gateways, routers) cache and
publish the cached/hosted content objects via enhanced IMS SIP signaling and
CNRH– Enable more efficient and scalable content delivery (caching to optimize bandwidth, deliver
content from the best location(s) along the best path(s), load balancing, improved latency and QoE)
8
Content Naming
• Flat OID– Hash of a public key + label or hash of the content data
– Self-certifying, persistent, unique
– Need mapping between human-readable name and flat OID, Difficult to aggregate
• Hierarchical OID– Similar to encoded URL
– Prefix-based aggregation: aggregate hierarchical OIDs with the common prefix for scalability• The effectiveness of aggregation reduces as content objects are replicated at multiple locations
© 2011 InterDigital, Inc. All rights reserved.
• “suffix hole”: a host may not have all the content objects for a given prefix.
– Name may become misleading if the location domain changes
• Type-Length-Value (TLV) encoded OID– consist of a set of variable-size information elements (IE)
– each IE encoded as a TLV
– hierarchical or peer relationships
– location independent and flexible
– E.g. organizationTLV-authorTLV-categoryTLV-titleTLV-formatTLV-segmentationTLV
9
Content Registration
• A content server/cache publishes its content objects
–Using enhanced SIP messages
© 2011 InterDigital, Inc. All rights reserved.10
Content Retrieval
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• User agent (UA) initiates content retrieval
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Network Services Enabling
• Networks can insert middle boxes to provide services and control content access– Session control function (SCF) controls enhanced media resource function (eMRF) to manipulate content data,
e.g. stream mixing, advertisement insertion, transcoding, etc.
© 2011 InterDigital, Inc. All rights reserved.12
• SIP messages between SCF, CRNH, content cache/server go through the IMS CN subsystem even if
not indicated on the sequences.
Network Services Enabling (Cont.)
• SCF queries CNRH
© 2011 InterDigital, Inc. All rights reserved.13
• SIP messages between SCF, CRNH, content cache/server go through the IMS CN subsystem even if not
indicated on the sequences.
Multiple CNRHs
• Multiple CNRHs form a DHT ring
–Map content object IDs to CNRH node ID in hash space
CNRH
219
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© 2011 InterDigital, Inc. All rights reserved.14
CNRH
CNRH
CNRH 810
15
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Cross-Domain Content Peering
Peering
eP-CSCF eI-CSCFeIBCF/eSBC
eS-CSCF
CNRH
eI-CSCF eP-CSCFeIBCF/eSBC
eS-CSCF
CNRH
© 2011 InterDigital, Inc. All rights reserved.15
Device with IMS User Agent
A-BGF/A-GW
I-BGF
PDF PDF
A-BGF/A-GW
I-BGF
PDF PDF
ContentCache/Server
Content Data
P-GWP-GW
Inter-Domain Content Routing Example
• CNRHs form hierarchical tree with peered links or hierarchical DHT
– maps to the Internet hierarchy
CNRH
CNRH
CNRHCNRHCNRH
CNRHContent Publish
Inter-domain SIP
messages between
CNRHs go through
eIBCF/eSBC to
enforce security and
inter-domain policies.
© 2011 InterDigital, Inc. All rights reserved.16
CNRHCNRHCNRHCNRH CNRH
PeeringPeering
• Content PUBLISH propagates up along the hierarchy and among peers
• Each CNRH maintains the location information of all the content objects published in its
descendants and peers
• Mapping of OID to next-hop CNRH/address and distance/cost to the host of this content copy
• Content request/INVITE is routed to the closest copy
•
Standardization
• Standardization Aspects
–Content Naming
– IMS architecture enhancement for content awareness
–CNRH
–SIP signaling enhancement
– Interconnection of networks
© 2011 InterDigital, Inc. All rights reserved.
– Interconnection of networks
• Standardization Bodies
–ETSI TISPAN, 3GPP, IETF
• InterDigital will continue developing new technologies
and contributing to the standards.
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© 2011 InterDigital, Inc. All rights reserved.
Thank You!