The BISDN Inter-Carrier Interface

Transcription

1 The BISDN Inter-Carrier Interface Topics Scope Permanent Virtual Connection (PVC) Support Service Independent Functions Services (CRS, CES, FRS and SMDS) Switched Virtual Connection (SVC) Support New Areas of Work Page 1 1

2 Topics Scope Permanent Virtual Connection (PVC) Support Service Independent Functions Services (CRS, CES, FRS and SMDS) Switched Virtual Connection (SVC) Support New Areas of Work The Public Mission Public Define a Public Carrier to Public Carrier Interface to Facilitate End-to-End National and International Service Team The (BISDN Inter-Carrier Interface) Working Group of the Forum Output Version 1.1 (9/94) - PVC-Based Service Version 2.0 (12/95) - SVC-Based Service Version 2.1 (11/96) - Addendum on VBR, NCCI, and AESA Support Page 2 2

3 Characteristics Capable of Supporting UNI Features Capable of Supporting Interworking with Other s Frame Relay SMDS Narrowband Suitable for Public (e.g., Highly Reliable) and other Forum I/Fs User Public User Private or Switch Private or Switch User Private UNI Private NNI Public UNI Public Page 3 3

4 and other (non-) Public I/Fs UNI Carrier A Carrier B FRS UNI Frame Relay FRS NNI Frame Relay SMDS SNI SMDS SMDS ICI SMDS The supports the functionality of multiple service specific interfaces (e.g. SMDS ICI, FR NNI) in a multiservice package. Topics Scope Permanent Virtual Connection (PVC) Support Service Independent Functions Services (CRS, CES, FRS and SMDS) Switched Virtual Connection (SVC) Support New Areas of Work Page 4 4

5 Inter-Carrier CRS CPE CPE User-Specific layers Carrier A Carrier B User-Specific layers UNI UNI Service Attributes Basic, Pure Service; No Interworking UNI 3.1 QoS Classes Service rates up to rates (minus overhead) PVC and SVC Service Inter-Carrier CES CBR User (DS1 or DS3) Carrier A Carrier B CBR User (DS1 or DS3) AAL 1 UNI AAL 1 Inter- Working Functions non- DSn Interface DS1/DS3 DS1 or DS3 CBR User (DS1 or DS3) Carrier A Carrier B CBR User (DS1 or DS3) non- DSn Interface Inter- Working Functions AAL 1 AAL 1 Inter- Working Functions non- DSn Interface DS1 or DS3 DS1/DS3 DS1/DS3 DS1 or DS3 Service Attributes PVC Only AAL 1 Unstructured Data Transfer (UDT), i.e., No Subrate (nxds0 or nxds1) Switching QoS Class 1 as per Forum UNI AAL1// Page 5 5

6 FR/ Interworking Carrier A Carrier B FR-CPE FR I W F I W F FR FR-CPE FR-CPE FR-CPE Upper Layers Upper Layers Q.922 CORE Q.922 CORE FR-SSCS CPCS SAR PVC Only IWF = Interworking Function AAL5 SAR (Segmentation and Reassembly) and CPCS (Common Part Convergence Sublayer) FR - SSCS = Frame Relay Service Specific Convergence Sublayer FR-SSCS CPCS SAR Q.922 CORE Q.922 CORE SMDS/ Interworking SNI SMDS Carrier A IWF Carrier B IWF SMDS SNI MF MF SNI SIP L3 SIP L2 ICIP_CLS AAL 3/4 ICIP_CLS AAL 3/4 SIP L3 SIP L2 SNI SIP L1 SIP L1 Page 6 6

7 Topics Scope Permanent Virtual Connection (PVC) Support Service Independent Functions Services (CRS, CES, FRS and SMDS) Switched Virtual Connection (SVC) Support New Areas of Work Switched Virtual Connections (SVCs) Signaling to Support Switched Virtual Connections (SVCs) added in 2.0 Based on ITU-T BISDN Signaling Supports UNI 3.1 Suitable for Use within a Public as well as between Public s Includes the Following Capabilities Point-to-Point and Point-to-Multipoint Connections Symmetric and Asymmetric Connections CBR and VBR Connections E.164 Addresses and End System Addresses (Only Transport for Non-E.164 AESAs) Page 7 7

8 Signaling Protocol Stack BISUP Broadband ISDN User Part (BISUP) Derived from Narrowband SS7 ISUP MTP Level 3 SAAL Physical Message Transfer Part Level 3 (MTP 3) Subset of Narrowband MTP 3 Signaling AAL (SAAL) Consisting of Service Specific Convergence Function (SSCF) Service Specific Connection Originated Part (SSCOP) Common Part Specific AAL 5 and same as UNI A /P-NNI Differences Purpose Public network use Ancestry Narrowband public network Signaling Protocol SS7-based (BISUP/MTP-3) Routing Statically provisioned Approach to Reliability Signaling link redundancy and MTP- 3 protocol Distinctive Features Public (e.g., usage measurements) P-NNI Private network use Private networks and Internet Q.2931 (like UNI) Dynamic, via routing protocol Dynamic routing protocol and crankback Private (e.g., ABR) Page 8 8

9 Associated and Quasi-Associated Signaling Architectures STP Quasi-Associated Associated Associated = Signaling Follows Transport Path (Switch to Switch) Quasi-Associated - Signaling Goes via Signal Transfer Points (STPs) Signaling Channels Signaling Entity (SPC = x) Signaling Link Set Signaling Entity (SPC = y) Public Switches are Identified by Signaling Point Codes (SPCs) A Signalling Link Set Connects Two SPCs Non-Facility Associate Signalling is Supported - Can Have Multiple Links over Multiple Physical Facilities VCI 5 Is Reserved for Signalling Virtual Paths are Labeled by Virtual Path Connection Identifiers (VPCIs), which are used in Signalling Messages and May Be Different from the VPIs in the Cell Header Page 9 9

10 Call Setup Scenario UNI Signaling BISUP UNI Signaling SETUP CALL PROC Initial Address Msg Initial Address Ack SETUP CALL PROC ALERT CONNect Public Switch Address Complete Msg Answer Msg Public Switch ALERT CONNect CONN ACK CONN ACK RELease RL Complete Carrier A RELease RL Complete Carrier B RELease RL Complete Address Types has adopted two basic types of addresses: End System Addresses (AESAs) - Based on ISO NSAP - Come in multiple varieties, most notably DCC (Data Country Code) ICD (International Code Designator) E.164 (E.164 address contained in AESA) E Same type of address used by telephony - Often called Native E.164 to distinguish from E.164 variety of AESA Page 10 10

11 Native E.164 Addresses N.A Country Code = 1 (ITU Assigned) NPA - Area Code = 202 (Washington D.C.) NXX - Office Code = 224 Subscriber # = 1234 UK Country Code = 44 (ITU Assigned) City Code = 171 (London) Local # = N. Korea x x x y y y y Country Code = 850 (ITU Assigned) City Code = 2 (Pyongyang) Local # = xxx-yyyy AESA Format 20 octets 7 octets AFI IDI HO - DSP ESI SEL Authority and Format Identifier - identifies what scheme is to follow DSP Domain Specific Part - structured by the authority identified by IDI Initial Domain Identifier - identifies the authority responsible for allocating structure of DSP HO-DSP = Higher Order DSP ESI = End System Identifier (MAC address) SEL = Selector (for end system use only) Page 11 11

12 AESA Formats E.164 AESA: A F I 45 IDI E.164 address HO DSP ESI S E L DCC AESA: A F I 39 IDI HO DSP ESI S E L ICD AESA: A F I 47 IDI HO DSP ESI S E L AFI Authority and Format Identifier HO DSP Higher Order DSP IDI Initial Domain Identifier ESI End System Identifier DSP Domain Specific Part SEL Selector E.164 AESA Format Details E.164 AESA: A F I 45 IDI E.164 address HO DSP ESI S E L Right Adj. Last Nibble = 1111 (F) F Embedded E.164 AESA: A F I 45 IDI E.164 address All Zeros Page 12 12

13 Address Support at Different Interfaces (Private ) AESA E.164 or AESA* Public UNI ( SP ) ES AESA PNNI (Private ) AESA AESA Private UNI E.164** BICI ( SP ) E.164 or AESA* Public UNI * Public UNI must support E.164 or AESAs or both. ** BICI has some AESA interworking capability. SP, if using BISUP, has same address support as BICI (E.164 with limited AESA interworking). Note E.164/AESA interworking problem. ES BICI AESA Support CdPN AESA4CdP AESA E.164 AESA AESA Orig UNI BICI Term UNI AESA copied to AESA4CdP parm, and If E.164 AESA, E.164 number extracted from AESA If non-e.164 AESA, Switch supplies E.164 number or fails call AESA is promoted to CdPN Page 13 13

14 SVC Usage Measurements Transit Orig Intermed Switch Intermed Switch Term Orig Switch Term Switch Usage Measurements Specified for Originating, Intermediate, and Terminating Switches in Originating and Terminating s Measurements Include Cell Counts Call Durations Parameter Values (e.g., Calling Party Number, Broadband Bearer Capability, Quality of Service, Cell Rate) This is a Public Carrier Concern Unique to the Document Maintenance Procedures (cont.) Signaling Congestion Control Relies on Message Transfer Part Message Priorities to Throttle Traffic Each BISUP Message Type has a Priority from 0 to 3 (e.g., Initial Address Message=0, Release=1) When Outgoing Signaling Link Buffers Reach Certain Thresholds, the Congested Switch Enters Congestion Level 1, 2, or 3 This Causes the Switch to Only Send Messages of at Least that Priority to that Destination (See Following Table) Output Buffer Level Sig Congestion Level Priorities Sent Below 1st Threshold - 0, 1, 2, 3 (all) 1st Threshold 1 1, 2, 3 2nd Threshold 2 2, 3 3rd Threshold 3 3 Page 14 14