Cvoice 6.0 S03 L01

Implementing H.323 Gateways

Implementing VoIP Gateways

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-1

H.323 Gateway H.323 gateways perform these services:  Translation between audio, video, and data formats  Conversion between call setup signals and procedures  Conversion between communication control signals and procedures

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-2

Recommendation H.323 Elements System Control and User Interface

Video I/O Equipment

Audio I/O Equipment

User Data Applications T.120

System Control H.245 Control Signaling H.225 Call Signaling

Video Codec H.261 H.263

Audio Codec G.711, G.722, G.723, G.723.1, G.728, G.729

Session Layer and Above

Receive Path Delay

RAS Control H.225 H.225 Layer LAN Stack

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-3

H.323 Adapted to IP Video I/O Equipment

Video Codec H.261, H.263

RTP Audio I/O Equipment User Data Applications T.120

UDP

Audio Codec G.711, G.722, G.723, G.723.1, G.728, G.729

System Control H.245 Control Signaling

RTCP

H.225 Layer

IP

TCP

H.225 Call Signaling

System Control and User Interface © 2008 Cisco Systems, Inc. All rights reserved.

RAS Control H.225

UDP

CVOICE v6.0—3-4

Why H.323? Advantages of H.323 gateways:  Dial plans can be configured directly on the gateway.  Translations can be defined per gateway.  Regional conditions can be met within multisite deployments.  Call routing configuration can be more specific than on Cisco Communications Manager.  There is no need for extra Cisco Unified SRST call routing configuration.  There is no dependency on the Cisco Unified Communications Manager version.  More voice interface types are supported.  ISDN NFAS is supported.  Fax support is advanced.  Call preservation was enhanced for PRI calls since Cisco IOS Release 12.4(9)T. © 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-5

Regional Requirements Example Calling party: 43917216111 Type: international

1 Calling Berni in the United States.

Translate calling number and route to destination.

3

U.S. Gateway

I have an external call. To call back, I need to dial 901143917216111.

© 2008 Cisco Systems, Inc. All rights reserved.

Madrid

5 6

4 Berni

2

Calling Bill in Germany.

Germany Gateway

Translate calling number and route to destination.

7 I have an external call. To call back, I need to dial 00043917216111.

Bill

CVOICE v6.0—3-6

H.323 Network Components H.323 Terminal

H.323 Terminal

Gatekeeper

Multipoint Control Unit

Gateways

H.320 Terminal (ISDN)

IP

Cisco UBE Intranet

Internet

PBX

PSTN

H.324 Terminal (POTS)

ITSP

Gateway H.323 Terminal

© 2008 Cisco Systems, Inc. All rights reserved.

Speech Only (Telephones)

CVOICE v6.0—3-7

H.323 Gateways H.323 Gateway

H.323 endpoint

H.323 Terminal

© 2008 Cisco Systems, Inc. All rights reserved.

Protocol translation and media transcoding

Non-H.323 endpoint

Telephone

CVOICE v6.0—3-8

Cisco Unified Border Element (Cisco UBE) 12.10.10.11 DGK*

Via GK*

Public Network 10.10.x.x 10.10.10.5

Public Network 12.10.x.x Cisco UBE 12.10.10.10

12.10.10.12 PSTN

DGK

Public Network 192.168.x.x

192.168.10.5

DGK = directory gatekeeper GK = gatekeeper © 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-9

H.323 Gatekeepers H.323 Terminal

H.323 Terminal

Gatekeeper

Multipoint Control Unit

Address translation and access control

H.320 Terminal (ISDN)

Intranet

Internet

PSTN H.324 Terminal (POTS)

H.323 Terminal

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-10

Multipoint Control Unit H.323 Terminal

H.323 Terminal

Multipoint Control Unit

Gatekeeper

Multimedia conferencing mixing audio, video, and data

Gateway

Intranet

Internet

H.320 Terminal (ISDN)

PSTN H.320 Terminal (POTS)

H.323 Terminal

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-11

Component Relationships for Call Establishment and Management  Endpoint (gateway) to endpoint (gateway)  Endpoint (gateway) to gatekeeper  Gatekeeper to gatekeeper

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-12

H.323 Basic Call Setup PSTN/ Private Voice

H.323 Gateway

H.323 Gateway IP QoS Network

PSTN/ Private Voice

Setup

H.225 (TCP)

POTS/PSTN Call Setup: Ringing, Answer… Connect

Q.931-Derived Call Setup

Capabilities Exchange

H.245 (TCP)

Open Logical Channel

Capabilities Negotiation

Signaling

Open Logical Channel Acknowledge Bearer or Media

© 2008 Cisco Systems, Inc. All rights reserved.

RTP Stream RTP Stream RTCP Stream

Media (UDP)

CVOICE v6.0—3-13

H.323 Fast Connect Call Setup H.323 Gateway PSTN

H.323 Gateway IP

1.1.1.1

1.1.1.2 Setup

Signaling

POTS/PSTN Call Setup: Ringing, Progress, Answer…

Connect Bearer or Media

© 2008 Cisco Systems, Inc. All rights reserved.

PSTN

RTP Stream RTP Stream RTCP Stream

H.2250/H.245 (TCP) Q.931-Derived Call Setup H.245 Open Logical Channel Information Contained in Fast Connect Element

Media (UDP)

CVOICE v6.0—3-14

Multipoint Conferences A

B

C

F

MCU

Centralized Multipoint

E

A

D

B

C

D

E MCU

F

Decentralized Multipoint

A

Video Audio © 2008 Cisco Systems, Inc. All rights reserved.

F

B

MCU

E

C

Ad Hoc

D

MCU = Multipoint Control Unit CVOICE v6.0—3-15

Configuring Standalone H.323 Gateways Required  Enable VoIP Services  Configure VoIP Dial Peers – Dial peers default to H.323 protocol

Optional  Configure Codecs  Tune H.323 Timers – H.225 settings  Configure DTMF and fax relay  Others

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-16

H.323 Configuration Example

PSTN or Private Network

Lo0: 10.10.1. 1 IP Network

PSTN or Private Network

router(config)# voice service voip router(conf-voi-serv)# h323 router(conf-voi-serv)# no shutdown router(config)# interface loopback 0 router(config-if)# ip address 10.10.1.1 255.255.255.0 router(config-if)# h323-gateway voip interface router(config-if)# h323-gateway voip h323-id gw1 router(config-if)# h323-gateway voip bind srcaddr 10.10.1.1

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-17

Codec Configuration

PSTN or Private Network

PSTN or Private Network

IP Network

router(config)# voice class codec 100 router(config-class)# codec preference 1 g711alaw router(config-class)# codec preference 2 g729br8 router(config)# dial-peer voice 500 voip router(config-dial-peer)# voice-class codec 100 Or router(config-dial-peer)# codec g711alaw

For multiple codec negotiation

To specify a single codec © 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-18

Tuning H.323 Parameters

PSTN or Private Network

IP Network

PSTN or Private Network

router(config)# voice class h323 600 router(config-class)# h225 timeout tcp establish 10 router(config-class)# h225 timeout setup 10 router(config)# dial-peer voice 500 voip router(config-dial-peer)# voice-class h323 600 router(config)# voice service voip router(conf-voi-serv)# h323 router(conf-serv-h323)# h225 timeout tcp call-idle never

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-19

Configuring H.323 Fax Pass-Through San Jose

H.323 Gateway

H.323 Gateway

Austin

IP Network 10.1.1.50

Router(config)# dial-peer Router(config-dial-peer)# Router(config-dial-peer)# Router(config-dial-peer)# Router(config-dial-peer)#

© 2008 Cisco Systems, Inc. All rights reserved.

Ext. 550

voice 550 voip destination-pattern 550 session target ipv4:10.1.1.50 fax protocol pass-through g711ulaw fax rate 14400

CVOICE v6.0—3-20

Configuring H.323 Fax Relay Austin

San Jose Voice Gateway

Voice Gateway

DNIS:15125551750

WAN 10.1.1.50 DNIS:15125551760

Router(config)# voice service voip Router(conf-voi-serv)# fax protocol t38 Router(conf-voi-serv)# exit Router(config)# dial-peer voice 14151 voip Router(config-dial-peer)# destination-pattern 15125551750 Router(config-dial-peer)# session target ipv4:10.1.1.50 Router(config-dial-peer)# fax-relay ecm disable Router(config-dial-peer)# fax-relay sg3-to-g3 Router(config-dial-peer)# fax rate 14400 Router(config-dial-peer)# exit Router(config)# dial-peer voice 14152 voip Router(config-dial-peer)# destination-pattern 15125551760 Router(config-dial-peer)# session target ipv4:10.1.1.50 Router(config-dial-peer)# fax protocol cisco © 2008 Cisco Systems, Inc. All rights reserved.

Uses fax protocol configuration from voice service VoIP

Cisco fax relay used for the other dial peer CVOICE v6.0—3-21

DTMF Relay

PSTN or Private Network

PSTN or Private Network

IP Network Non-H.323 Gateway

router(config)# dial-peer voice 500 voip router(config-dial-peer)# dtmf-relay h245-alphanumeric

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-22

Verifying H.323 Gateways

Router# show gateway H.323 ITU-T Version: 4.0

H323 Stack Version: 0.1

H.323 service is up This gateway is not registered to any gatekeeper Alias list (CLI configured) is empty Alias list (last RCF) is empty

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-23

Verifying H.323 Gateways (Cont.) Router# show gateway Gateway gateway1 is registered to Gatekeeper gk1 Gateway alias list H323-ID gateway1 H323 resource thresholding is Enabled and Active H323 resource threshold values: DSP: Low threshold 60, High threshold 70 DS0: Low threshold 60, High threshold 70

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-24

Summary  ITU-T Recommendation H.323 describes an infrastructure of terminals, common control components, services, and protocols that are used for multimedia communications.  There are at least ten advantages to using H.323 gateways as voice gateways.  Functional components of H.323 include terminals, gateways, gatekeepers, Cisco UBEs, and multipoint control units.  Calls can be established between endpoints, endpoints to gatekeepers, or gatekeepers to gatekeepers.  H.323 calls may occur with or without the use of a gatekeeper.  H.323 defines three types of multipoint conferences.

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-25

Summary (Cont.)  Many options are available when setting up an H.323 gateway.  When configuring codecs, you can specify one codec or set up codec negotiation.  You may want to adjust some of the H.323 timers to meet network requirements.  There are several commands used to configure fax features on H.323 gateways.  DTMF relay solves the problem of DTMF distortion.  Use the show gateway command to verify H.323 gateway status.

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-26

© 2008 Cisco Systems, Inc. All rights reserved.

CVOICE v6.0—3-27