© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Cisco IP Communications PSTN and PBX Integrations Introducing PSTN and PBX Trunks

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Introduction to Trunks Connection to the CO switch or a PBX Analog or digital interfaces Various signaling protocols In-band or out-of-band signaling Protocol-dependant features

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v PSTN Rome E1 CCS Trunk Chicago E&M Trunk London T1 CAS Trunk T1 QSIG Trunk E1 R2 Trunk San Jose Denver T1 PRI T1 QSIG Trunk Introduction to Trunks (Cont.)

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Hardware Requirements VIC or VWIC slots for trunk interfaces: –Available via various network modules –Integrated VWIC slots on ISR platforms Cisco Communication Media Module (CMM) or Cisco Catalyst 6608 T1/E1 blade for Cisco Catalyst 6500 Series Digital Signal Processors (DSPs) required to terminate voice calls: –Required configuration depends on hardware platform Most Cisco voice platforms, including ISRs and High- Density Voice Network Modules (NM-HDVs), can be equipped with a variable number of DSP resources. Cisco CMM, Catalyst 6608, and NM-HD modules have fixed DSP resources onboard.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Examples of Hardware Platforms Integrated Service Routers (ISR) Network Module Communication Media Module (CMM)

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DSP Types and Codec Complexity Number of concurrent voice calls depends on DSP type: –Old DSP: C549, common on PVDM –New DSP: C5510, common on PVDM2 C549 supports low, medium, and high complexity codecs C5510 supports flex, medium, and high complexity codecs –Flex mode greatly increases call capacity

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DSP Types and Codec Complexity (Cont.) Medium complexity mode Available on all DSP platforms Higher number of voice calls than high complexity mode Supports these codes and features: –G.711 (a-law or mu-law) –Fax modem pass-through –Clear channel –G.726 (32K, 24K, or 16K) –GSM-FR –Fax relay –G.729a –G.729a Annex B

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DSP Types and Codec Complexity (Cont.) High complexity mode Available on all DSP platforms Lower number of voice calls than medium complexity mode Supports these codecs and features: –All supported features and codecs of medium complexity –G.729 and G.729b –G.728 –G (32K, 24K, or 16K), G.723.1a (5.3K or 6.3K) –GSM-EFR –Modem relay

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DSP Types and Codec Complexity (Cont.) Flex complexity mode Available on C5510 chipset-based DSP hardware Complexity-dependant codecs and features Complexity defined in MIPS MIPS subtracted dynamically depending on the type of call New calls established as long as enough MIPS are available

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DSP Types and Codec Complexity (Cont.) 15 MIPS –G.711 (a-law or mu-law) –Fax modem pass-through –Clear channel 30 MIPS –G.726 (32K, 24K, or 16K) –GSM-FR –Fax relay –G.729 –G.729 (a, b, or ab) 40 MIPS –G.728 –G (32K, 24K, or 16K) –G.723.1a (5.3K or 6.3K) –GSM-EFR –Modem relay

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Calculating DSP Resources PSTN Phone Phone San Jose Router 1 Model Number: 2801 IOS Release: 12.4 Lines required: 20 Codec: G.711 VWIC Module: VWIC-1MFT-T1

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Calculating DSP Resources (Cont.) Step 1: Select router model and IOS version.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Calculating DSP Resources (Cont.) Step 2: Select the voice card and channel usage.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Calculating DSP Resources (Cont.) Step 3: Evaluate the results.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Analog Trunks E&M Interface E&M Port Trunk Side of PBX FXO Interface FXO Port Station Port CO FXS Interface FXS Port PSTN DID Interface DID Port CO PSTN

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Analog Trunks (Cont.) TypeCircuit OptionComments AnalogSubscriber Loop: FXS/DIDRJ11 connector Connects to end devices Supplies ring, voltage, and dial tone Direct Inward Dial (DID) Subscriber Loop: FXORJ11 connector Connects to central office (CO) or Foreign Exchange Station Port (FXS) Centralized Automatic Message Accounting (CAMA) E&MRJ48 connector Connects to PBX trunk ports Signaling technique for 2-wire and 4-wire trunk interfaces

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Analog Trunks (Cont.) Analog Extension Station ID Number Station ID Name John Smith Call 1 Call 2 Ext Service Provider Database Number Name ACME Enterprises Caller ID Display Number Name John Smith Caller ID Display Number Name ACME Enterprises PSTN Inbound and Outbound Caller ID with FXO and FXS:

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Analog CAMA Trunk Support: Analog Trunks (Cont.) Phone Phone Chicago Router3 PSTN T1 PRI for standard calls PSAP CAMA trunk for emergency calls

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Digital Trunks TypeCircuit OptionComments DigitalT1/E1 CAS E1 R2 Analog signaling over digital T1/E1 Can provide Automatic Number Identification (ANI) ISDNT1 PRI E1 PRI More services than channel associated signaling (CAS) Separate data channel (D channel) Common on modern PBXs PRI NFASMultiple ISDN PRI interfaces controlled by a single D channel Backup D channel can be configured BRIMostly for Europe, Middle East, and Africa QSIGCreated for interoperation of PBXs from different vendors Rich in supplementary services

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Digital Trunks (Cont.) 24 B channels (voice) T1 CAS 30 B channels (voice) E1 R2 No D Channel required Analog signaling No D Channel required Analog signaling

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Digital Trunks (Cont.) D channel 16 kbps (signaling) 2 B channels (voice) ISDN BRI D channel 64 kbps (signaling) 30 B channels (voice) ISDN E1 PRI NET5 D channel 64 kbps (signaling) 23 B channels (voice) ISDN T1 PRI NFAS 24 B channels (voice)

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Clocking for Digital Interfaces Used to synchronize sending and receiving devices Drives router backplane and digital voice ports Improper clocking results: –CRC errors –Decreased voice quality –Failed faxes –Failed data calls Separate clocking domains for each network module and the router motherboard

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Clocking for Digital Interfaces (Cont.) Clock of Router AClock of Router B Router BRouter A Clock of Router AClock of Router B Clocking is in sync. The information of one time slot send fills up one time slot at the receiving router. Time slot Router A Time slot Router B Time slot Router A Time slot Router B Clocking out of sync. The information of one time slot send fills up two time slots at the receiving router. 1 2

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Standard Carrier Clocking for Digital Interfaces (Cont.) Long Distance Carrier Clock 1 Clock 2 Use motherboard DSPs and VWICs for long distance carrier Use network module DSPS and VWICs for standard carrier T1 0/0/0T1 1/0/0

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v PSTN Trunks When planning PSTN trunks, consider these things: Number of required channels Type of interface Signaling protocol Clock source Valid DIDs on the trunk Incoming number format

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v DNIS and ANI Phone Phone User dials San Jose xxxx Router1 (MGCP) PSTN New York xxxx Phone Phone DNIS ANI T1 CASFXO

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v PBX Trunks When planning PBX, trunks consider these things: Number of required channels Type of interface Signaling protocol Feature transparency: –Name display –Callback –Message waiting indicator Clock source Incoming and outgoing number formats

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Voice Mail PBX Trunks (Cont.) T1 QSIG BobAlice Alice dials Incoming call: Alice Message Waiting Indicator Alice leaves a voice mail message for extension Clock Source

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Summary Trunk interfaces can be installed in Network Modules, CMMs, and directly into ISRs. Trunk interfaces need DSP resources to decode and encode voice signals. Depending on the DSP chip set, various codec complexity modes are available. The online Cisco DSP Calculator tool can be used to calculate the correct number of DSP modules. Analog trunks can be built using FXS, FXO, or E&M interfaces. Digital trunks can be built using T1, E1, or BRI interfaces using various signaling protocols.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v Summary (Cont.) Clocking is required for all types of digital trunks. PSTN trunks offer the same set of features as PSTN telephones. DNIS is the called party number. ANI is the calling party number. PBX trunks offer additional features if QSIG is used.

© 2006 Cisco Systems, Inc. All rights reserved.GWGK v