thought for the week no question is a bad question!
TRANSCRIPT
Thought For The Week
No Question Is A Bad Question!
In Telephone Circuits, Signals Can Be Sent In Two Different Ways:
In-Band
Out-of-Band
Signals Include:
Digits That You Dial
Dial Tone
Ringing
Disconnect Signals
etc.
In-Band Signaling
In-Band Signaling Signaling Made Up Of Tones Which Pass Within The Voice Frequency Band And Are Carried Along The Same Circuit As The Talk Path.
Out-of-Band Signaling Signaling That Is Separated From The Channel That Is Carrying The Information, e.g. Voice.
Local Loop
Class 5 Office
Local Loop
For Example
Lucent 5ESS Nortel DMS
If Endpoints In Same CO95% Of Local Loop Circuits Are In-Band Signaling
Local Loop
Class 5 Office
Local Loop
For Example
Lucent 4ESS
If Endpoints Connect To Different CO’s (One-Hop)Interoffice Signaling Via In-Band Signaling
Class 5 Office
Class 4 Office(W/ Tandem Switch)
Out-Of-Band-Band Signaling
Common Channel Signaling Is The Most Prominent Out- of-Band Signaling System.
Common Channel Interoffice Signaling A Way Of Transmitting All Signaling Information For A Group Of Trunks In A Separate Channel.
Class 5 CO Class 5 COVoice Path
Separate Signaling Network
Common Channel Signaling System No. 7 (i.e. SS7)
A Global Standard For Telecommunications Defined By The International Telecommunication Union (ITU) Telecommunication Standards Sector (ITU-T).
The ITU Definition Of SS7 Allows For National Variants Such As The American National Standards Institute (ANSI) Standards Used In North America And The European Telecommunications Standards Institute (ETSI) Standard Used In Europe.
The SS7 Network And Protocol Are Used For:
Basic Call Setup, Management, And Tear Down.
Wireless Services Such As Personal Communications Services (PCS), Wireless Roaming, And Mobile Subscriber Authentication.
Local Number Portability (LNP).
Toll-free (800/888) And Toll (900) Wireline Services.
Enhanced Call Features Such As Call Forwarding, Calling Party Name/Number Display, And Three-way Calling
Efficient And Secure Worldwide Telecommunications.
PBX
SCP SCP
STP
STP
SSP
PRI BRIResidential
PBX
PRI BRIResidential
STP
STP
SSPVoice Path
There Are Three Kinds Of Elements In The SS7
Network.
SSP - A Service Switching Point (Class 5 CO Switch).
SSPs Are Switches That Originate, Terminate, Or Tandem Calls.
An SSP Sends Signaling Messages To Other SSPs To Setup, Manage, And Release Voice Circuits Required To Complete A Call.
An SSP May Also Send A Query Message To A Centralized Database (An SCP) To Determine How To Route A Call (E.G., A Toll-free 1-800/888 Call In North America).
SCP – Service Control Point, Various Data Bases.
An SCP Sends A Response To The Originating SSP Containing The Routing Number(s) Associated With The Dialed Number.
An Alternate Routing Number May Be Used By The SSP If The Primary Number Is Busy Or The Call Is Unanswered Within A Specified Time.
Actual Call Features Vary From Network To Network And From Service To Service.
The SSP Is The Local Exchange To The Subscriber And The Subscribers Interface To The Network.
The SSP Creates SS7 Signaling Units At The Sending SSP And Translates Them At The Receiving SSP.
The SSP Supports Database Access Queries For 800/900 Numbers.
The STP Is A Router For The SS7 Network.
It Relays Messages Through The Network, But Does Not And Translates Them At The Receiving Originate Them.
STPs Are Installed As
A national STP.
An International STP.
A Gateway STP.
SS7 Is An International Standard, Nevertheless, There Are “Some” Differences Between The Way That Countries Implement SS7.
In The United States, SS7 Is Implemented To ANSI Standards.
In Many Other Countries SS7 Is Implemented To ITU-T Standards.
In The United States, STPs Provides Conversions Between ANSI SS7 And ITU-T SS7.
Collect And Store Traffic And Usage Statistics For OAM.
Collects Billing Information.
Acts As The Interface Into The Telephone Company Databases.
Business Services Database (BSDB)
Depends On RBOC and Subscriber
Call Management Services Database(CMSDB)
Routing Information, Some Billing Information
Reaction To Congestion
SCP
Acts As The Interface Into The Telephone Company Databases.
SCP
Line Information Database (LIDB)
Calling Card, Billing, Third Party Billing.
PINs, Custom Calling Features.
Home Location Register (HLR)
Used In Cellular Networks.
Visitor Location Register (VLR)
Used In Cellular Networks.
A Link Is Another Name For A Communications Channel Or Circuit.
A Link Known Also As Access Links. Used To Connect SSPs And SCPs To STPs.
B Link Known Also As Bridge Links. Used To Connect Mated STP Pairs To Other Mated STP Pairs.
C Link Known Also As Cross Links. Used To Connect STPs Together To Form Mated Pairs.
STPs Are Deployed As Mated Pairs.
Uses A Fully Meshed Topology Which Provides 100 Percent Redundancy.
Any Single Point Of Failure Does Not Bring Down The System.
C Link Known Also As Cross Links. Used To Connect STPs Together To Form Mated Pairs.
The Telephone User Should Not Have To Worry About SS7 Addresses.
A Customer Should Only have To Enter A Called Party Telephone Number – Even Non-Conventional Telephone Numbers Such As 911, A Mobile Phone Number, Or An 800/900 Number.
SS7 Accepts These Logical Addresses And Translates Them To Routable Numbers.
C Link Known Also As Cross Links. Used To Connect STPs Together To Form Mated Pairs.
Signaling Is The Exchange Of Information Between The Components Of A Telephony For The Purposes Of Establishing, Monitoring, Or Releasing Phone Circuits.
The Four Main Functions Of Switch Signaling Are:
Alerting
Transmitting Address Information
Supervising
Transmitting Information.
Common Channel Signaling Was Developed By AT&T In The 1970s After They Had Lost Significant Revenue To Fraudulent Use Of In-Band Signaling.
Signaling System No.7 (SS7) Is A Particular Type Of CCS Employed By Modern Telephone Networks.
SS7 Is A Standard Developed And Published By The ITU.
In SS7, Any Central Office Or Other Telecommunications Switching Facility Is Called A Service Switching Point (SSP).
SCPs Supply Customer Information To STPs.
STPs Act As Intermediaries For Signals Moving Between SCPs And SSPs.
Class 5Local Office
(Wausau, WI)
Analog Local Loop
Analog Local Loop
Analog Line Card
ResidenceOffice
Digital T1 Local Loop
Digital T1 Local Loop
Digital Line Card
Class 5Local Office
(Raeford, NC)
Analog Local Loop
Analog Local Loop
Analog Line Card
ResidenceOffice
Digital T1 Local Loop
Digital T1 Local Loop
Digital Line Card
Class 4Toll Center
WaUsau, WI
Class 3Primary Center
Stevens Point, WI
Class 2Section CenterEau Claire, WI
Class 1Regional Center
Norway, IL
Class 4Toll Center
Fayetteville, NC
Class 3Primary CenterFayetteville, NC
Class 2Section Center
Greensboro, NC
Class 1Regional CenterRockdale, GA
Intra-Office Call
Toll Call Using AT&Ts Five-Level Network