M2UA PeerPeer Adaptation Layer SIGTRAN Working Group March 29, 2000 - PowerPoint PPT Presentation

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M2UA PeerPeer Adaptation Layer SIGTRAN Working Group March 29, 2000

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Drivers for M2UA Peer-Peer (Case 2) Support MTP3 transport over SCTP ... Dissimilar functions makes it hard on the reader ! Page 7. March 29, 2000 - W. Davis ... – PowerPoint PPT presentation

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Title: M2UA PeerPeer Adaptation Layer SIGTRAN Working Group March 29, 2000


1
M2UA Peer-Peer Adaptation LayerSIGTRAN Working
GroupMarch 29, 2000
2
M2UA Peer-Peer Adaptation
  • Background
  • First incorporated into M2UA draft-ietf-sigtran-m2
    ua-01
  • Case 1 M2UA Backhaul
  • Case 2 M2UA Peer-Peer (M2Peer)
  • Ram Dantu presentation, IETF-46 November 1999
  • Drivers for M2UA Peer-Peer (Case 2)
  • Support MTP3 transport over SCTP (RFC 2719)
  • Seamless intermix of SS7 Links and IP Links
  • Maintain added MTP3 End-End Reliability Functions
  • Changeover / Changeback / MSU Retrieval
  • Link Alignment / Proving
  • Congestion Detection / Notification
  • SLS Loadsharing

3
M2UA Case 1 (Backhaul) Architecture
SS7
IP
SEP
SG
MGC
SS7 Appl
SS7 Appl
MTP2 Primitives
Backhaul
MTP3
MTP3
NIF
IP Network
SEP - SS7 Signaling Endpoint NIF -
Nodal Interworking Function SG - Signaling
Gateway SCTP - Simple Control Transmission
Protcol
4
M2UA Case 2 (Peer-Peer) Architecture
SS7
IP
SEP
SG
MGC
SS7 Appl
SS7 Appl
MTP3
MTP3
MTP3
Peer-to-Peer
Link Protocol
IP Network
SEP - SS7 Signaling Endpoint SG -
Signaling Gateway SCTP - Simple Control
Transmission Protcol
5
Contrasting M2UA Case 1 and Case 2
  • Case 2 M2UA Peer-Peer
  • Protocol Characteristics
  • Symmetric
  • SP Peer SP Peer
  • Protocol DataUnits
  • Data
  • Status - Out Of Alignment
  • Status - Normal Alignment
  • Status - Emergency Alignment
  • Status - Out Of Service
  • Status Processor Outage
  • Status Busy
  • Case 1 M2UA Backhaul
  • Protocol Characteristics
  • Asymmetric
  • MGC Client SG Server
  • Protocol DataUnits
  • Data
  • Establish Request
  • Establish Confirm
  • Release Request
  • Release Confirm
  • Release Indication
  • State Request
  • State Confirm
  • State Indication
  • Data Retrieval Request
  • Data Retrieval Confirm
  • Data Retrieval Indication
  • Data Retrieval Complete Indication

6
Contrasting M2UA Case 1 and Case 2
  • Case 2 M2UA Peer-Peer
  • Application Server Messages
  • Not applicable covered by alignment /
    changeover procedures)
  • State Control
  • Link Out-Of-Service
  • Link Alignment
  • Link In-Service
  • Link Congestion Onset
  • Link Congestion Abatement
  • Link Remote Processor Outage
  • Case 1 M2UA Backhaul
  • Application Server Messages
  • ASP Up
  • ASP Down
  • ASP Active
  • ASP Inactive
  • State Control
  • ASP-Active
  • ASP-Active-Old
  • ASP-Active-New
  • ASP-Up
  • ASP-Down
  • Dissimilar functions makes it hard on the reader
    !

7
M2UA Peer-Peer Adaptation
  • Proposal Split out Backhaul and Peer-Peer Cases
  • M2UA Backhaul
  • draft-ietf-sigtran-m2ua-03
  • M2UA Peer-Peer
  • draft-george-sigtran-m2peer-00
  • Requested Action
  • Add M2UA Peer-Peer as SIGTRAN work item
  • Unique Port and SCTP Protocol Ids
  • Mail List Issues For Resolution
  • Multiple Streams per Link (SLS basis)
  • Proving Period Functionality (Optional)
  • SCTP Peer-Peer Association Setup (Collision
    Resolution)

8
Backup Slides
9
Layered Communications - OSI Model
Layer N1
Layer N1
.response
.indication
.request
.confirm
Layer N Primitives
Layer N SAP (Service Access Point)
Layer N Protocol (Protocol DataUnits)
Layer N Connection Endpoints
Layer N Connections
Bearer Functions
Management Functions
Bearer Functions
Management Functions
Layer N
Layer N
Layer N-1 SAP
Layer N-1
Layer N-1
10
Standard SS7 MTP3 Layer
Peer User Layers
MTP3 User Layers
MTP3 Primitives
Unitdata (DPC, SLS, Priority) .request,
.indication
MTP Pause / Resume (DPC) .indication
MTP Status (DPC, Congestion Level) .indication
MTP Restart Begin / End ( ) .indication
MTP3 Protocol DataUnits
Message (MSU) Transfer
User Part Unavailable
Transfer Prohibited / Restricted / Allowed
(No Connections Defined)
Peer MTP3 Layer
Transfer Controlled / RouteSet Congestion Test
MTP3 (Network) Layer
Changeover / Changeback
M2UA / SCTP / IP
MTP2
SAAL
Peer Link Layers
MTP Link Layers
11
Standard SS7 MTP2 Layer
Peer User Layer
MTP2 User Layer (MTP3)
MTP2 Primitives
Data (Length) .request, .indication
Link Start / Stop .request, .indication
Link Status (State) .indication
Data Retrieval (SN) .request, .indication
MTP2 Protocol DataUnits
MessageSignal Unit (MSU)
Link Status Signal Unit (LSSU)
Fill In Signal Unit (FISU)
Peer MTP2 Layer
MTP2 Datalink Layer
MTP2 Connection (Datalink)
T1E1 Chan
DS0A
V.35
Peer MTP1 Link Layers
MTP1 Link Layers
12
MTP2 Adaptation Layer Variants
Peer MTP3 Layer
MTP3 Layer (MTP2 User)
MTP2 Primitives
AS
Data (Length) .request, .indication
Link Start / Stop .request, .indication
STP/SCP
( Backhaul )
Link Status (State) .indication
Data Retrieval (SN) .request, .indication
SG
MTP2 Protocol DataUnits
MessageSignal Unit (MSU)
Link Status Signal Unit (LSSU)
Peer MTP2 Layer
MTP2 Connection (Datalink)
MTP2 Datalink Layer
IP Network
T1E1 Chan
DS0A
V.35
Peer MTP1 Link Layers
( Peer-Peer )
MTP1 Link Layers
13
Standard SS7 Layer Summary
Signalling System
  • TCAP Application
  • Remote Operation Invocation, Parameter Encoding
  • Application Transaction Control
  • Example Application LNP Ported Number
    Translation
  • SCCP Layer
  • Network Application Subsystem Addressing
  • Global Title Translation (TN Digits -gt Subsystem
    Address)
  • Remote Subsystem Status Management
  • MTP3 Layer
  • Network PointCode Addressing
  • PointCode Relay Routing, Re-routing, Multi-Link
    Loadsharing
  • Link, LinkSet, RouteSet Status Management
  • MTP2 Layer
  • Link alignment, proving, error-rate monitoring
  • MSU Seq / CRC generation / checking
  • MSU queuing / dequeuing, retrieval, congestion
    monitoring
  • MSU delineation, zero insertion, transmit /
    receive, re-transmit
  • Physical Layer
  • Physical connectivity (e.g. V.35)

TCAP Application
SCCP
MTP3
MTP2
PHY
14
MTP2 User Adaptation Layer Case 2Ram
DantuSIGTRAN Working GroupNovember 9, 1999
15
MTP2 User Adaptation Layer Case2
Ram.Dantu - 1999-11-09
16
Overview
  • Background SS7-IP Interface Adaptation Options
  • Problem Definition (Case1 and Case2)
  • Case 1 One application of M2UA
  • SSCOPMCE based solution for Case 2
  • Case2 SCTP based solution for STP-IPSCP
    Interface
  • Overview of Solution
  • Link Changeover
  • Link Proving
  • Congestion Detection
  • Emergency Alignment
  • Conclusions

Ram.Dantu - 1999-11-09
17
Background SS7-IP Adaptation Layer Options
ISUP/SCCP
SS7
MTP3
ISUP/SCCP
Q.923
MTP3
Q.2140
MTP2UA
MTP3UA
Q.921UA
ITU
SSCOPMCE
SCTP
SCTP
SCTP
IETF Sigtran
UDP
UDP
UDP
UDP
SAAL
ATM/IP
IP
IP
IP
IP
ATM
E-Net/DS1/DS3/OC3
E-Net/DS1/DS3/OC3
E-Net/DS1/DS3/OC3
E-Net/DS1/DS3/OC3
Ram.Dantu - 1999-11-09
18
Problem Definition
  • A protocol M2UA (MTP2 User Adaptation Layer) is
    being defined by IETF Sigtran Group. The users of
    this layer are MTP3 and a MTP2-backhauling layer
    (Case1). One application is the inter working of
    MTP3 layer and IP networks seamlessly similar
    to MTP3 layer and MTP2 layer in SS7 network
    (Case2). In particular, this interface is useful
    between STP and IP enabled SCPs (IPSCP). To this
    end, several primitives and procedures are
    defined for MTP2 User Adaptation Layer.

Ram.Dantu - 1999-11-09
19
Case1
MTP3 MTP2UA SCTP UDP IP
Signaling Transfer OR Media Gateway
MTP2UA SCTP UDP IP
Media Gateway Controller
MTP3 MTP2
Signaling Gateway
IP Network
MTP2
Ram.Dantu - 1999-11-09
20
Case1
  • Backhauling signaling traffic at layer 2 to the
    Media Gateway Controller.
  • Using MTP2 user adaptations layer as an extension
    of MT2 link layer
  • SGW has no point code and not visible in SS7
    network

Ram.Dantu - 1999-11-09
21
SSCOPMCE Solution for High Speed Link
STP
SCP
MTP3 Q.2140 SSCOPMCE ATM
MTP3 Q.2140 SSCOPMCE ATM
ATM Link
Ram.Dantu - 1999-11-09
22
SSCOPMCE Solution
  • A Solution for high speed interface between two
    STPs or between STP and SCP.
  • SSCOPMCE is a similar transport protocol like
    SCTP
  • SSCOPMCE solution is primarily meant for ATM but
    Interface between SSCOPMCE and IP requires
    considerable work (under progress)
  • SCTP has several additional features.

Ram.Dantu - 1999-11-09
23
Case2 STP-IPSCP Interface
Ram.Dantu - 1999-11-09
24
MTP2 and MTP3 Functions
  • MTP2 Functions
  • Signal unit deliminations
  • Signal unit alignment
  • Signal unit detections
  • Signal unit error corrections
  • Signaling link initial alignment
  • Signaling link error monitoring
  • Flow control
  • Sequence numbering
  • Cyclic Redundancy Check
  • Preventive Cyclic Retransmission
  • Data Retrieval
  • Congestion Management
  • MTP3 Functions
  • Link activation
  • Link restoration
  • Link deactivation
  • Change over
  • Change back
  • Emergency change over
  • MTP restart
  • Transfer prohibited
  • Transfer allowed
  • Transfer restricted
  • Transfer controlled
  • Signaling-route-set-test
  • Signaling-route-set-congestion-test
  • Transfer cluster prohibited
  • Transfer cluster allowed
  • Transfer cluster restricted
  • Cluster-route-set-test

Ram.Dantu - 1999-11-09
25
M2UA Case2
  • High speed IP link between SEP/STP and STP/SCP
  • New functions are added to M2UA. In particular,
    M2UA supporting SS7 link management features.
  • Enhancements
  • Mapping of sequence numbers between SS7 Network
    and IP Network
  • Additional primitives Data Retrieval during
    link change over
  • Additional primitives for Link proving
  • Additional primitives for Congestion Detection
  • Additional primitives for Emergency alignment
  • Procedures for Data Retrieval during link change
    over
  • Procedures for Link proving
  • Procedures for Congestion Detection
  • Procedures for Emergence Alignment

Ram.Dantu - 1999-11-09
26
MTP3-M2UA Primitives
MTP3
M2UA
Received Message
Link Congested
Primitives
Link Congestion Ceased
Emergency
Emergency Ceased
STOP Communicating To Peer
START Communicating To Peer
Link Available
Link Out Of Service
Flush Buffers
Continue
Retrieve_BSNT
BSNT Confirm
Retrieval_Reqest_And FSNC
Retrieved Messages
Retrieved Complete
BSNT Delivery of BSTN Value
BSNT_Not_Retrievable
Ram.Dantu - 1999-11-09
27
M2UA-SCTP Primitives
INITIALISE
ASSOCIATE
UDP
SCTP
UDP Port
Terminate
SEND (associates ID, buffer address
Byte count (mode flags) (context) (stream D)
RECEIVE (buffer address, byte count)
(association ID) (max size of data to be released)
STATUS (association ID)
Status date (receive windows size, send window
size, connecting state, number of buffers
awaiting acknowledgment, number of buffers
pending transmit, Round trip time on all active
interfaces
Ram.Dantu - 1999-11-09
28
M2UA SCTP Primitives
Data Arrive
SEND FAILURE
SCTP
NETWORK STATUS CHANGE
Communication up
Communication Lost
Ram.Dantu - 1999-11-09
29
Link Changeover
STP/SCP
SEP/SCP
SS7 network
Internal IP Transport
Leased IP Network
1. If there is a link fail, link can change over
2. If link is congested then also there can be
change over 3. Change over for links of unequal
bandwidth for further study
Ram.Dantu - 1999-11-09
30
Link Changeover
MTP2UA
SCTP
SCTP
MTP2UA
MTP3
MTP3
Communication lost
Link out of service
TX Find gaps in the received msgs (numbered
before first gap)
Retrieve BSN
Indicate BSN
COO (BSN)
Relieve BSN
Indicate BSN
COA (BSN)
Go through the transmit queue and find unack and
unsent msg.
Retrieve FSN
15 7
0
0000000
FSN Not
Retrievable
Last 7 bits are used for FSN/BSN
Retrieval Msg
- Extending to 24 bits for further study
Retrieval Complete
Ram.Dantu - 1999-11-09
31
Link Proving
MTP2UA
SCTP
SCTP
MTP2UA
MTP3
MTP3
1. During proving, only unordered service is
considered. This means message is delivered
immediately. 2. Proving time is configurable. 3.
Estimated - parameters are compared with
performance requirements of the application
that opened the stream. 4. Link Proving is done
on both sides.
Communication
Emergency Ceased Emergency
Up
Status (or heartbeat
No. of messages for n sec
RTT
RTT
Status
n Sec Estimate - average delay - packet loss -
etc.,
Link In Service
Communications link up
Link is same
RTT
Ram.Dantu - 1999-11-09
32
Congestion Detection
MTP2UA
SCTP
SCTP
MTP2UA
MTP3
MTP3
Send failure
Send failure
3 consecutive failures (implemen- tation
dependent)
Send failure
Congestion
Detected
Terminate
Terminate Successful
Communication Lost
Link Out of Service (Link Change Over Procedures
are Started)
Link brought back to service after proving
Ram.Dantu - 1999-11-09
33
Emergency Alignment
MTP2UA
SCTP
MTP3
Emergency
Disable proving
Emergency Ceased
Enable proving
Ram.Dantu - 1999-11-09
34
Conclusions
  • With wireless and other new configurations, SCPs
    require high bandwidth links. A high speed link
    based on SCTP/IP is defined between STPs as well
    as STP and SEP/SCPs. M2UA seems to be a good fit
    for interface between SS7 and IP networks.
  • SCP applications require reliable, available,
    and proved links. To this end, new
    primitives/procedures are defined in M2UA.
  • Minor enhancements are made to SCTP for
    supporting this feature. M2UA document will be
    modified to clearly distinguish the Case1 and
    Case2 solutions.

Ram.Dantu - 1999-11-09
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