H323 Digital Failures

H.323 digital failures

Rich Byrne and Baktha Muralidharan
BXB-MS

1

Part I ISDN configuration

Part II Call Routing

Agenda

 Thanks!
 Why are we doing this?
 Scope
 ISDN Config on H.323 Gateways
 Call Routing with digital interfaces on H.323 gateways
 References

Presentation_ID © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3

Thanks!

• Tony for supporting, encouraging us and making sure we had the time to
complete this project.
• David, Andy, Kamal, Adel, Mohammed, Ratin, Kevin for taking all those
extra cases!
• DK, David for their review comments
• RTP and RCH for their support
• Targeted Training Team for the opportunity!


Why are we doing this?

 TSIRT data
• Sample of over 300 cases that had low bingos or transactional survey scores in the
quarter FY Q2-
•Call routing, dial-peers -- 42
•ISDN config -- 18
•Telco issues misc -- 17
•Voice translation -- 11

 Most issues found in two areas-
• Call Routing
• ISDN Configuration

 Indicates a need for training in the above specific topics


Scope

 Digital interfaces
•ISDN T1 PRI
•ISDN E1 PRI
•ISDN BRI
•ISDN NFAS
•T1 CAS
•E1 R2

 H.323 gateway
Call Routing


Scope - contd
What is not covered
 Call Manager
 Review of H.323 protocols other than H.225 and H.245
 Qsig, DPNSS
 In general, any topic that is not specific to digital interfaces and H.323
gateway
 Country-custom variations of E1 R2 CAS
 Call routing in SRST mode


Part I ISDN Configuration
on H.323 Gateways

Rich Byrne

Introduction

 Overview
 ISDN features
 ISDN switch types
 Q921/Q931
 T1 PRI
 E1 PRI
 NFAS
 T1/E1 Clocking
 Troubleshooting/Lab


ISDN Primary Rate Interface (PRI) and Basic Rate
Interface (BRI) Overview

23B or 64 Kbps x 23 OR
64 Kbps x 31 1.544 Mbps (T1)
30B
PRI or
2.048 Mbps (E1)
D 64 Kbps

B channels are for data, D channel is for signaling

64 Kbps
2B { 64 Kbps

BRI
BRI 144 Kbps
D 16 Kbps


ISDN Features

ISDN: Provides End-to-End Digital Communication

Switch Switch
ISDN BRI Telco ISDN PRI

 Uses ITU Q.921 (layer2) and Q.931(layer 3) signaling
 Integration of digital switching and transmission
 Integration of voice and data on the same links
 Switched (packet and circuit) and non-switched applications
 Separate channel for signaling and data
 out-of-band signaling


Q921

Switch WAN Switch
ISDN BRI ISDN PRI

Q.921 Q.921

• Q.921 protocol is used between the TE and the local ISDN switch (not end-to-end)
• The ISDN network does not impose the use of any data link layer protocol for the B
channels
• Full duplex protocol
• Responsible for sending/receiving error-free data
• Reference ITU-T Q921:

http://wwwin-eng.cisco.com/Standards/WWW/ITU/pdf-files/q/q-921.pdf


Q931

Switch WAN Switch
ISDN BRI ISDN PRI

Q.931 Q.931

• Q.931 protocol is used between the TE and the local ISDN switch (not end-to-end)
• The ISDN network does not impose the use of any network layer protocol for the B channels
• Full duplex protocol
• Message based protocol responsible for call setup and call teardown
• Q.931 signaling is encapsulated in Q.921 frames
• Reference ITU-T Q931
http://wwwin-eng.cisco.com/Standards/WWW/ITU/pdf-files/q/q931.pdf

Q931 – contd
Messages
Call Establishment messages Call clearing messages
• SETUP • DISCONNECT
• SETUP ACKNOWLEDGE • RELEASE
• CALL PROCEEDING • RELEASE COMPLETE
• PROGRESS • RESTART
• ALERTING • RESTART ACKNOWLEDGE
• CONNECT
• CONNECT ACKNOWLEDGE
Miscellaneous messages
Call information phase messages • INFORMATION
• RESUME • NOTIFY
• RESUME ACKNOWLEDGE • SERVICE/SERVICE ACK
• RESUME REJECT • STATUS
• SUSPEND • STATUS ENQUIRY
• SUSPEND ACKNOWLEDGE
• SUSPEND REJECT


Q931 - contd
Common Information Elements (IEs)
• Bearer Capability • Calling Party Number
• Cause • Calling Party Subaddress
• Connected Number • Called Party Number
• Call State • Called Party Subaddress
• Channel Identification • Facility
• Progress Indicator • Display


Q931 - contd
Example from Q.931 SETUP IEs
Protocol discriminator M
Call reference M
Message type M
Bearer capability M
Channel identification O M - inclusion is mandatory
Progress indicator O O – includion is Optional
Display O
Calling party number O
Calling party subaddress O
Called party number O
Called party subaddress O
Redirecting number O


ISDN E1 PRI
European Telecommunications Standards Institute
 primary-net5
•European ETSI
•Cisco routers support network and user sides.
•Supports En bloc or Overlap modes
•Configuring Overlap receiving on the D-channel changes the way routers behave
when receiving ISDN calls.
The router responds to the setup message with a SETUP ACK. This informs the network that it is ready
to receive further information messages containing additional call routing elements.
• Good example can be seen here:
http://www.cisco.com/en/US/tech/tk801/tk133/technologies_tech_note09186a00800b48cb.shtml


Non Facility Associated Signaling

• Standard T1 ISDN PRI consists of 24 channels—where a single signaling channel (D-
channel) controls the remaining 23 bearer channels (B-channels) on the interface. In
system terms, this means ports 1 through 23 on the ISDN span (B-channels) are
controlled by port 24 (D-channel). The NFAS option extends D-channel control to B-
channels not resident on the same interface. This allows a single D-channel to control up
to 10 PRI interfaces (a maximum of (10x24 – 1) = 239 B-channels, or a maximum of
(10x24-2) = 238 with one B-channel as a backup).
• NFAS supports D-channel redundancy.
If a backup D-channel is defined for the group, all stable calls are maintained when
control is passed to the standby D-channel.
• NFAS is supported by: 4ess, DMS250, DMS100, National ISDN switch type. It is not
supported on primary 5-ess
• Saves on cost of D channels


ISDN PRI Configuration
Ext. 2000
Digital T1 1/0/0
PBX
ISDN PRI

Ext. 1000

isdn switch-type primary-4ess
!
controller T1 1/0 voice-port 1/0:23
framing esf !
linecode b8zs dial-peer voice 1 pots
pri-group timeslots 1-24 description TO-PBX
clock source line direct-inward-dial
destination-pattern 2…
! incoming called-number .
interface Serial1/0:23 prefix 2
no ip address port 1/0:23
isdn switch-type primary-4ess
isdn incoming-voice voice
no cdp enable dial-peer voice 2 voip
! destination-pattern 1000
port 1/0/0


CUCM H323 Gateway Configuration (1 of 3)


CUCM H323 Gateway Configuration Notes:
Notes:
 Be aware that the h323 gateway will not register to CUCM.
•Registration of ―Unknown‖ is to be expected

 Media Termination Point Required
•Needed for Outbound FastStart

 Wait for Far End H.245 Terminal Capability Set
•CUCM needs to receive the far-end TCS before it sends TCS

 Inbound Calls - Enable Inbound FastStart
• Should match what the GW is doing (faststart by default)

 Outbound Calls
•Numbering Plan and Type


ISDN Number Plan and Type (1 of 2)
Can be set in CUCM or Gateway (CUCM)
 Called party IE number type : Cisco CallManager; Unknown; National;
International; Subscriber.
 Calling party IE number type: Cisco CallManager; Unknown; National;
International; Subscriber.
 Called Numbering Plan: Cisco CallManager; ISDN; National Standard;
Private; Unknown.
 Calling Numbering Plan: Cisco CallManager; ISDN; National Standard;
Private; Unknown.


ISDN Number Plan and Type (2 of 2)
2 ways on Gateway where the ISDN Number Plan and Type can changed
 Voice Translation Rules
•voice translation-rule 8
rule 1 /^2(...$)/ /017793451/ type unknown national plan unknown isdn
This rule matches any four-digit number that starts with "2". The rule removes the "2",
adds the number "01779345" as a prefix, and sets the plan to "isdn" and the type to
"national".
http://www.cisco.com/en/US/tech/tk652/tk90/technologies_tech_note09186a0080325e8e.shtml

 ISDN Map Address
• Configured under the PRI Serial Interface (D-Channel)


ISDN Number Plan and Type Examples: (1 of 3)
*Apr 26 22:42:22.795: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x009A
Bearer Capability i = 0x8090A2
Standard = CCITT
Transfer Capability = Speech
Transfer Mode = Circuit
Transfer Rate = 64 kbit/s
Channel ID i = 0xA98397
Exclusive, Channel 23
Calling Party Number i = 0x0081, '1900'
Plan:Unknown, Type:Unknown
Called Party Number i = 0x80, '1111'



bxb-ms-3845-1(config-if)#isdn map address 1111 plan isdn type national

*Apr 26 22:46:12.791: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x009B
Standard = CCITT
Called Party Number i = 0xA1, '1111'
Plan:ISDN, Type:National



bxb-ms-3845-1(cfg-translation-rule)#rule 1 /1111/ /1111/ type any national plan any isdn

bxb-ms-3845-1#test voice translation-rule 1 1111 type unknown plan unknown
Matched with rule 1
Original number: 1111 Translated number: 1111
Original number type: unknown Translated number type: national
Original number plan: unknown Translated number plan: isdn


ISDN Switch Type
bxb-ms-3845-1(config-if)#isdn switch-type ?

primary-4ess Lucent 4ESS switch type for the U.S.
primary-5ess Lucent 5ESS switch type for the U.S.
primary-dms100 Northern primary-net5
NET5 switch type for UK, Europe, Asia and Australia
primary-ni National ISDN Switch type for the U.S.
primary-ni2c The Cisco NAS-SC switchtype based on NI2C.
primary-ntt NTT switch type for Japan
primary-qsig QSIG switch type
primary-ts014 TS014 switch type for Australia (obsolete)Telecom DMS-100 switch type for the U.S.

Most common are the ―custom‖ switch types 4ess, 5ess, dms100, and ―standards‖ ni (National ISDN-2) .
Most TDM switches/PBX’s can emulate different switch types, so important to find out how the PRI
configured, not the physical switch type.


T1/E1 Clocking
Symptoms
 One-way audio or no audio in either direction, on plain old telephone
service (POTS)-to-VoIP calls or POTS-to-POTS calls.
 Modems that do not train up
 Faxes are incomplete or have missing lines
 Fax connections that fail
 Echo and poor voice quality on VoIP calls
 Static noise heard during phone calls


T1/E1 Clocking - contd
Configuration
 ISR Gateways
network-clock-participate wic slot
where slot is the WAN interface card (WIC) slot number in which the E1 or T1 multiflex trunk module
(MFT) is installed.
network-clock-select priority {E1 | T1} slot
Where slot is the card or slot of the interface.

 AS5350, AS5400, 7200VXR, 2600, 3700, and 1760, have different implementations of a
TDM-based architecture and allow clocking to be propagated across the backplane of
the router and between different interface ports. All of the previously mentioned
platforms use different command-line interface (CLI) commands to configure the
clocking modes.

http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a008031a072.shtml


bxb-ms-3845-1#show network-clocks
Network Clock Configuration
---------------------------
Priority Clock Source Clock State Clock Type
11 Backplane GOOD PLL
Current Primary Clock Source
---------------------------
bxb-ms-3845-1#show controller t1
T1 0/1/1 is up.
Applique type is Channelized T1
Cablelength is long 0db
No alarms detected.
AIS State:Clear LOS State:Clear LOF State:Clear
Framing is ESF, Line Code is B8ZS, Clock Source is Line.
Total Data (last 24 hours)
0 Line Code Violations, 0 Path Code Violations,
23 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
23 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsA


bxb-ms-3845-1(config)#network-clock-select 1 t1 0/1/1
bxb-ms-3845-1#show network-clocks
Network Clock Configuration
1 T1 0/1/1 GOOD T1
Current Primary Clock Source
1 T1 0/1/1 GOOD T1

bxb-ms-3845-1#show controller t1
T1 0/1/1 is up.
Applique type is Channelized T1
Cablelength is long 0db
No alarms detected.
AIS State:Clear LOS State:Clear LOF State:Clear
Framing is ESF, Line Code is B8ZS, Clock Source is Line.
Data in current interval (306 seconds elapsed):
0 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs


Troubleshooting ISDN Layer 2
TEI and SAPI belong to the Address field of the datalink Q.921 frame.

TEI: Terminal Endpoint Identifier : Identifies a terminal
ISDN Layer 2 establishment: TEI = 0-63 are used for fixed TEIs
TEI = 64 to 126 are reserved for assignment at activation
TEI = 127 is reserved for broadcasting
vnt-3745-32a#debug isdn q921
SAPI: Service Access Point Identifier : Defines the message type
debug isdn q921 is ON. SAPI = 0 is used for Q931 signaling information
SAPI = 16 is used for X.25 on the D-channel

vnt-3745-32a#
Feb 6 22:03:42.049: ISDN Se1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0
Feb 6 22:03:43.048: ISDN Se1/0:23 Q921: User TX -> SABMEp sapi=0 tei=0
Feb 6 22:03:43.056: ISDN Se1/0:23 Q921: User RX <- UAf sapi=0 tei=0
Feb 6 22:03:53.042: ISDN Se1/0:23 Q921: User RX <- RRp sapi=0 tei=0 nr=0
Feb 6 22:03:53.042: ISDN Se1/0:23 Q921: User TX -> RRf sapi=0 tei=0 nr=0
Feb 6 22:04:03.035: ISDN Se1/0:23 Q921: User RX <- RRp sapi=0 tei=0 nr=0
Feb 6 22:04:03.039: ISDN Se1/0:23 Q921: User TX -> RRf sapi=0 tei=0 nr=0


Troubleshooting ISDN
vnt-3660-33a#show isdn status
Global ISDN Switchtype = primary-ni
ISDN Serial2/0:23 interface
dsl 0, interface ISDN Switchtype = primary-ni
Layer 1 Status:
ACTIVE ― ACTIVE‖ indicates that the physical wiring looks good
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status: Indicates the ISDN interface and Telco switch are have
1 Active Layer 3 Call(s) successfully negotiated Q.921 (ISDN L2) parameters
CCB:callid=1F, sapi=0, ces=0, B-chan=23, calltype=VOICE
Active dsl 0 CCBs = 1
The Free Channel Mask: 0x803FFFFF
Number of L2 Discards = 0, L2 Session ID = 3
Total Allocated ISDN CCBs = 1


Troubleshooting No Ring Back

 Ring Back can be played In-Band or by the Gateway
 Debugs:
•debug ISDN Q931
•debug voip ccapi inout
•debug voip hpi inout

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a0080094c33.shtml


Incoming PRI h323 to CUCM - GW plays Ring Back

dial-peer voice 1 voip
destination-pattern 1900
session target ipv4:10.86.176.140
incoming called-number 111.
codec g711ulaw
no vad

004460: *Apr 26 17:19:55.584: ISDN Se0/1/1:23 Q931: TX -> ALERTING pd = 8 callref = 0x800B

005242: *Apr 26 17:29:54.224: //155/293FD4A98028/CCAPI/ccCallAlert:
Progress Indication=NULL(0), Signal Indication=SIGNAL RINGBACK(1)
005259: *Apr 26 17:29:54.224: //155/293FD4A98028/HPI/[0/1:1]/hpi_inband_tone_on:
CPTone ON
Tone ID=1, Num of frequencies=2, Frequency(hz)=440/480, Power(dBm0)=7354/7354, Direction=1
Cadence(ms)=2000/4000 0/0


Incoming PRI h323 to CUCM – Ring Back Played In-Band

progress_ind alert enable 8
codec g711ulaw
no vad

005364: *Apr 26 17:35:56.532: ISDN Se0/1/1:23 Q931: TX -> ALERTING pd = 8 callref = 0x8016
Progress Ind i = 0x8188 - In-band info or appropriate now available

005348: *Apr 26 17:35:56.528: //157/01326ABB8029/CCAPI/ccCallAlert:
Progress Indication=INBAND(8), Signal Indication=SIGNAL RINGBACK(1)


Why Did This Call Fail?? (what is missing)
*Apr 26 18:30:49.976: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x0098
Standard = CCITT
*Apr 26 18:30:50.108: ISDN Se0/1/1:23 Q931: RX <- CALL_PROC pd = 8 callref = 0x8098
Progress Ind i = 0x8188 - In-band info or appropriate now available
*Apr 26 18:30:50.108: ISDN Se0/1/1:23 Q931: TX -> STATUS pd = 8 callref = 0x0098
Cause i = 0x80E018 - Mandatory information element missing
Call State i = 0x01
*Apr 26 18:30:50.108: ISDN Se0/1/1:23 Q931: RX <- ALERTING pd = 8 callref = 0x8098
*Apr 26 18:30:50.112: ISDN Se0/1/1:23 Q931: TX -> STATUS pd = 8 callref = 0x0098
Call State i = 0x01
*Apr 26 18:30:50.132: ISDN Se0/1/1:23 Q931: TX -> RELEASE pd = 8 callref = 0x0098
*Apr 26 18:30:50.148: ISDN Se0/1/1:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x8098


Answer:
Channel ID IE is Missing
 From ITU Q.931
 TABLE 3-3/Q.931
 CALL PROCEEDING message content
 Mandatory in the network-to-user direction if this message is the first message
in response to a SETUP message. It is mandatory in the user-to-network
direction if this message is the first message in response to a SETUP message,
unless the user accepts the B-channel indicated in the SETUP message.
 Reference: ITU Q.931
 Link to Q931: ISDN user-network interface layer 3 specification for basic call control
 http://wwwin-eng.cisco.com/Standards/WWW/ITU/pdf-files/q/q931.pdf


Why did this call fail?
*May 4 21:51:16.110: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x00AA
Standard = CCITT
Display i = 'Targeted Training'
*May 4 21:51:16.242: ISDN Se0/1/1:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x80AA
Cause i = 0x80AC - Requested circuit/channel not available
*May 4 21:51:16.950: ISDN Se0/1/1:23 Q931: TX -> RELEASE pd = 8 callref = 0x00A9
Cause i = 0x8290 - Normal call clearing
*May 4 21:51:16.966: ISDN Se0/1/1:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x80A9


RX Cause i = 0x80AC - Requested circuit/channel
not available
Other side has this Bearer Channel either in use or busied out.

The ―fix‖ has to be to clear this channel on the ISDN Switch side.
Reasons it may have got into this state:
• ISDN Switch Type mismatch?
• Bad hardware
• Protocol does not support Q931 Service Messages.


How can we work around this problem?

*May 4 21:51:16.110: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x00AA
Standard = CCITT
*May 4 21:51:16.242: ISDN Se0/1/1:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x80AA
Cause i = 0x80AC - Requested circuit/channel not available
*May 4 21:51:16.950: ISDN Se0/1/1:23 Q931: TX -> RELEASE pd = 8 callref = 0x00A9
Cause i = 0x8290 - Normal call clearing
*May 4 21:51:16.966: ISDN Se0/1/1:23 Q931: RX <- RELEASE_COMP pd = 8 callref = 0x80A9

Answers (2 ways) One:
bxb-ms-3845-1(config-if)#isdn service b_channel 1 state 2

*May 4 21:51:52.542: ISDN Se0/1/1:23 Q931: TX -> SERVICE pd = 67 callref = 0x00
Change Status i = 0xC2 - out-of-service
*May 4 21:51:52.570: ISDN Se0/1/1:23 Q931: RX <- SERVICE ACKNOWLEDGE pd = 67 callref = 0x80
May 4 21:52:00.786: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x00AB
<edited>
<edited>
*May 4 21:52:00.914: ISDN Se0/1/1:23 Q931: RX <- CALL_PROC pd = 8 callref = 0x80AB
*May 4 21:52:00.914: ISDN Se0/1/1:23 Q931: RX <- ALERTING pd = 8 callref = 0x80AB
*May 4 21:52:07.426: ISDN Se0/1/1:23 Q931: RX <- CONNECT pd = 8 callref = 0x80AB

ISDN Channel/Service State
bxb-ms-3845-1#show isdn service
PRI Channel Statistics:
ISDN Se0/1/1:23, Channel [1-24]
Configured Isdn Interface (dsl) 2
Channel State (0=Idle 1=Proposed 2=Busy 3=Reserved 4=Restart 5=Maint_Pend)
Channel : 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
State : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3
Service State (0=Inservice 1=Maint 2=Outofservice 8=MaintPend 9=OOSPend)
Channel : 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
State : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2


ISDN Channel/Service State
bxb-ms-3845-1#
*May 13 22:50:35.169: ISDN Se0/1/1:23 Q931: RX <- SERVICE pd = 3 callref = 0x0000
*May 13 22:50:35.169: ISDN Se0/1/1:23 Q931: TX -> SERVICE ACKNOWLEDGE pd = 3 callref = 0x8000
bxb-ms-3845-1#show isdn service
PRI Channel Statistics:
ISDN Se0/1/1:23, Channel [1-24]
Configured Isdn Interface (dsl) 2
Channel State (0=Idle 1=Proposed 2=Busy 3=Reserved 4=Restart 5=Maint_Pend)
Channel : 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
State : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3
Service State (0=Inservice 1=Maint 2=Outofservice 8=MaintPend 9=OOSPend)
Channel : 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
State : 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2

Second way:
bxb-ms-3845-1(config-if)#isdn negotiate-bchan

*May 4 21:53:00.938: ISDN Se0/1/1:23 Q931: TX -> SETUP pd = 8 callref = 0x00AD
Standard = CCITT
Channel ID i = 0xA18381 Notice Channel 1 still requested (Preferred)
Preferred, Channel 1
*May 4 21:53:01.086: ISDN Se0/1/1:23 Q931: RX <- CALL_PROC pd = 8 callref = 0x80AD
Channel ID i = 0xA98382 ISDN Switch replies with Channel 2 and the call completes
*May 4 21:53:01.086: ISDN Se0/1/1:23 Q931: RX <- ALERTING pd = 8 callref = 0x80AD
*May 4 21:53:05.110: ISDN Se0/1/1:23 Q931: RX <- CONNECT pd = 8 callref = 0x80AD

What causes this?…..What can we do to fix this?

bxb-ms-3845-1(config-controller)#
*May 5 20:36:17.001: %CONTROLLER-5-UPDOWN: Controller T1 0/1/1, changed state to up
*May 5 20:36:19.001: %LINK-3-UPDOWN: Interface Serial0/1/1:23, changed state to up
*May 5 20:36:21.001: ISDN Se0/1/1:23 Q931: Ux_DLRelInd: DL_REL_IND received from L2BAD
FRAME()BAD FRAME()
*May 5 20:36:30.001: ISDN Se0/1/1:23 Q931: Ux_DLRelInd: DL_REL_IND received from L2BAD
FRAME()BAD FRAME()BAD FRAME()BAD FRAME()BAD FRAME()BAD FRAME()BAD FRAME()BAD FRAME()


Answer:
ISDN PRI is a ―network‖ / ―user‖ Protocol
 One side must be the ―Network‖ the other side must be the ―User‖
 2 Reasons why you could see L2BAD FRAME()BAD FRAME()
• (1) T1 line has a loopback on it. (What is sent on TX is being received on RX)
o Fix by removing loopback
• (2) Both ISDN sides are trying to do same network/user protocol.
(both side configured as User or both sides are configured as Network)
o Fix by bxb-ms-3845-1(config)#interface serial 0/1/1:23
bxb-ms-3845-1(config-if)#isdn protocol-emulate ?
network ISDN protocol emulation network side
user ISDN protocol emulation user side (default)
obxb-ms-3845-1(config-if)#isdn protocol-emulate network


Binding H.323 traffic to interface
Inbound call failure
 Sets the source address of packets carrying H.323 signaling messages to
the interface.
 Configure h323-gateway voip bind srcaddr x.x.x.x under the source
interface, where x.x.x.x is the IP address of the interface.
 x.x.x.x must be the same IP address that is configured in
CallManager, for the H.323 gateway.


Binding H.323 traffic to interface
Example if h323 Bind is not there
*Apr 28 21:49:26.030: ISDN Se0/1/1:23 Q931: RX <- SETUP pd = 8 callref = 0x002E
Standard = CCITT
*Apr 28 21:49:26.030: ISDN Se0/1/1:23 Q931: Received SETUP callref = 0x802E callID = 0x0002 switch = primary-ni
interface = User
*Apr 28 21:49:26.038: ISDN Se0/1/1:23 Q931: TX -> CALL_PROC pd = 8 callref = 0x802E
*Apr 28 21:49:26.046: ISDN Se0/1/1:23 Q931: TX -> DISCONNECT pd = 8 callref = 0x802E
Cause i = 0x80A6 - Network out of order


Part II Call Routing with
Digital Interfaces on H.323
Gateways

Baktha Muralidharan

Intro
Topics
 H.323
 Digital interfaces
 Reference topologies
 Dial plans
 Call routing
 Digit manipulations
 Calling name display
 Fax
 Troubleshooting
 Call flow
 Common problem symptoms


H.323
Intro
 H.323 is an ITU standard
 4 is the current version
 Can handle video and data, in addition to audio
 Default protocol on Cisco gateways (―show gateway‖)
 Specifications: h.225, h.245, h.450, h.261, h.263 h.320, T.120
 Components: gateways, gatekeepers, endpoints, MCU, proxy servers


H.323 - contd
Call flow
 The gateway exchanges signaling messages with the TDM switch. E.g. if it is an
ISDN switch, Q.931 messages are exchanged.
 Validates the endpoint information received from the switch and determines the
H.323 peer entity corresponding to the endpoint.
 The H.323 gateway exchanges H.225 call setup messages, using TCP port
1720. One of those, the Connect message, contains the control channel
address to use for H.245 signals.
 The gateway then exchanges several H.245 capabilities negotiation messages.
When the negotiation is successful, the gateway exchanges the calling endpoint
IP address and RTP port numbers, and the called endpoint IP address with RTP
port numbers, in OpenLogicalChannel messages.
 The call is successful, and RTP media stream is sent.


H.323 - contd
Connect options
 Fast start
•one of the setup messages includes a FastStart element, which contains a list of
capabilities and supported coder/decoder (codec) options
• H245 tunneling
• Tunnels H.245 traffic inside H.225 messages; saves on TCP connections

 Slow start
•H.245 exchange follows successful completion of h.225 exchange

• We won’t be discussing these further, as they pertain to media
negotiations


H.323 - contd
Pros
 H.323 provides caller ID from Foreign Exchange Office (FXO) and T1
channel-associated signaling (CAS) ports, whereas MGCP does not.
 H.323 supports the use of a fractional PRI.
 H.323 is widely used and interoperates well with applications and devices
from multiple vendors. Because all H.323 devices must support the core
protocols, a gateway and CallManager have no version dependence
 H.323 allows a great amount of control over the treatment of calls to and
from the gateway, such as for digit manipulation, load balancing, and call
rerouting. You can use Toolkit Command Language (Tcl) and voice
extensible markup language (VXML) applications.


H.323 - contd
Pros
 Can integrate legacy systems based on POTS or ISDN lines into your H.323
network. H.323 supports more types of TDM interfaces and signaling than
MGCP.
 Multimedia support— You can use H.323 for both voice calls and video
conferencing. H.323 also allows data transfer.
 Non-Facility Associated Signaling (NFAS) support— H.323 supports NFAS,
which allows you to control multiple ISDN PRI lines with just one D channel,
thus giving you more usable channels.
 H.323 gatekeepers— Gateways can point to a gatekeeper for call control and
address resolution.
 PRI call preservation— Because the gateway terminates both Q.921 and Q.931
signaling, the loss of its CallManager does not require dropping calls using the
PRI line.
 Advanced Fax support – e.g. T.37


H.323 - contd
Cons
 Configuration
 Lack of centralized dial-plan
 Call survivability – by default, calls dropped on loss of connection to UCM
 Qsig facility IE support


Digital Interfaces
Intro
 Basically T1/E1
 Typically offer much greater capacity, quality, and reliability
 Midsize and larger businesses use to connect to PSTN.
 Provide DNIS and ANI
 Theory covered extensively in first half as well as in VoIP bootcamp etc.


Digital Interfaces - contd
Signaling types
 CAS – Channel Associated Signaling. Signaling takes place within the
voice channel (inband). Also known as ABCD signaling and Robbed bit
signaling.
 CCS – Common Channel Signaling. Signaling messages is sent in a
dedicated (out of band) channel (DS0)


Digital interfaces - contd
Common Interface types
 T1 CAS
 E1 R2
 ISDN
•T1 PRI
•E1 PRI
•BRI
•PRI NFAS
•Fractional PRI


Signaling protocols
 CAS
•―Analog signaling‖ on a digital circuit
•Most common forms
•Loop start
•Ground start
•E&M variants
•Note: ABCD signaling without robbed bit (e.g. E1 R2)

 CCS
•Q.931
•SS7
•Other, proprietary protocol


Digital interfaces - contd
T1 PRI
 23 B channels
 1 D channel (channel # 23)

controller T1 0/1/0
pri-group 0 timeslots 1-24

dial-peer voice 1 pots
direct-inward-dial
port 0/1/0:23


E1 PRI
 30 B channels
 1 D channel (channel #15)

controller E1 0/2/0

direct-inward-dial
port 0/2/0:15


BRI
 2 B channels
 1 D channel (16kbps)
 Common in Europe

interface BRI0/0/0
isdn switch-type ntt
isdn tei-negotiation first-call
isdn incoming-voice voice

direct-inward-dial
port 0/0/0


Fractional PRI
 H.323 gateways supports fractional T1 PRIs
 For example, can configure 12 B-channels. The D-channel is always
required. D channel automatically added, i.e. even if you do not include
the D-channel in the timeslot range.

controller T1 0/1/0

direct-inward-dial
port 0/1/0:23


NFAS
 Allows single D channel to serve as signaling channel for multiple PRIs
 Frees up a channel in the PRIs to carry voice
 Backup D channel can be configured
 Dial peer config for each NFAS controller should contain the primary of the NFAS group
controller T1 1/0
pri-group timeslots 1-24 nfas_d primary nfas_interface 0 nfas_group 1

controller T1 1/1
pri-group timeslots 1-24 nfas_d backup nfas_interface 1 nfas_group 1

incoming called-number .
destination-pattern 35...
direct-inward-dial
port 1/0:23
http://www.cisco.com/en/US/partner/docs/ios/12_3/vvf_c/cisco_ios_isdn_voice_configuration_guide/isdn06.html

T1 CAS
 LSB [of every DS0] on every sixth frame;
 ESF has 24 frames; A in 6th, B in 12th, C in 18th and D in 24th frames
 E&M signaling most widely used

http://www.cisco.com/en/US/partner/tech/tk652/tk653/technologies_tech_note09186a00800e2560.s
html


T1 CAS
 FGB supports ANI collection, but only on AS5xx platforms
 FGD - can only receive ANI
 FGD-EANA - can only send ANI

controller T1 0/1/0
ds0-group 0 timeslots 1-12 type e&m-fgd
ds0-group 1 timeslots 13-24 type fgd-eana
!
destionation-patter 9T
port 0/1/0


E1 R2
 It is CAS for E1
 Signaling is not completely in-band. Supervisory is Out-of-band.
 Defines two types of signaling
Line signaling
Inter-register signaling

 Similar ―Supervisory‖ and ―addressing‖
 Signaling exists in several country versions or variants

http://www-tac.cisco.com/Training/voice_bootcamp/lecture_ppt/revised-02/day3_e1r2.pdf


E1 R2
 Line signaling; Used for call setup and teardown. R2 supports three
methods of line signaling:
•R2-Digital (more common)
•Line Signaling carried in timeslot 16 of the E1 frame.
•Only the A and B bits are used by R2
•In the on-hook state, the A bit is set to 1 and the B bit is set to 0.
•These bits have different meanings depending on which side is initiating the call.
•forward - bits coming from the calling party
•backward - bits coming from the called party.

•R2-Analog
•Only A bit is used
•R2-Pulse


E1 R2
 Inter-register signaling; Cisco VGs support-
•R2-Compelled— Forward tones stay on until the remote end responds. The tones
are compelled to stay on until you turn them off.
•R2-Noncompelled— Forward tones are sent as pulses. Group-B responses are also
sent as pulses. Noncompelled inter-register signaling has no Group-A signals.
•R2-Semi-Compelled— Forward tones are sent as compelled. Responses are sent
as pulses. Semi-compelled is the same as compelled, except that the backward
signals are pulsed instead of continuous.
•DTMF— In-band DTMF tones are used for address signaling.

• Register signaling carried in-band, in each time slot.


Reference network topologies

SCCP VoIP, VoFR,
VoATM

RTP PSTN
V


Reference network topologies - contd
Toll bypass

VoIP, VoFR,
PSTN VoATM & RTP PSTN
V V


Dial plan

 Central part of any telephony solution.
 Has to be done regardless of the VoIP protocol, interfaces etc.
•Specific dialing patterns
•Access codes
•Area codes
•Specialized codes
•Combinations of number of digits dialed

 However, unlike MGCP, with H.323, dial plan configuration has to happen
on gateways as well


Dial plan - contd
Components
 Endpoint addressing
 Call routing and path selection
 Digit manipulation
 Calling privileges
 Call coverage


Call routing

 Route the call depending on the dialed number
 Select the appropriate path
 Handled by dial peers


Call routing - contd
Dial-peers
 Dial-peers are like static routes that define where the phone numbers are
located in the VOIP network. Dial-peers define both locally connected
phone numbers (e.g. FXS ports) as well as remote phone numbers on
other VOIP Gateways.
 Big topic! Covered extensively in VoIP bootcamp. In this presentation, we
will focus on-
•Aspects of dial-peer that are peculiar to digital interfaces


Call legs


Importance of inbound dial-peers
 Common misunderstanding- dial-peers only configured for outbound
functionality, that is, to map a dial string to a remote network device.
 Inbound dial peers determine some important call parameters
 Also needed in scenarios where non−default services, applications,
and/or capabilities are present.
 On inbound POTS call legs received at the originating router/gateway,
some non−default services and applications of incoming calls include:
•Direct−inward−dial (DID)
•TCL-based Applications-
•Interactive Voice Response (IVR)
•On−Ramp Faxing


Direct-inward-dial
 Direct Inward Dialing (DID) is a service offered by telephone companies that enables
callers to dial directly to an extension on a PBX without operator assistance.
 If direct-inward-dial is configured on the selected inbound POTS dial peer, the entire
called number is used to match outbound dial peers. This is referred to as one-stage
dialing.
 If the direct-inward-dial command is not configured on the selected inbound POTS dial
peer, digit-by-digit analysis is performed. This is called two-stage dialing. In this case,
the gateway will play secondary dial-tone.
 The only case in which the called number is not used to match the destination pattern is
when overlap-receiving is configured on an ISDN interface. With overlap-receiving,
switch sends additional digits after the initial setup message. Digit-by-digit matching is
used.
 DNIS is en-bloc on ISDN interfaces.
 On T1 CAS, en-bloc if ―dtmf dnis‖ is configured; Digit-by-digit, otherwise


Incoming Interface POTS?
y n
Inbound dial-peer matching
digit-by-digit?
y
 Dial-peers searched based on extract DNIS
type (of incoming call interface)
Match incoming y Select dial-
 Different processing for en-bloc called-number? peer!

versus digit-by-digit
 Having destination-pattern in the Loop y Select dial-
through Mach answer-
config allows for same dial-peer All POTS address? peer!
to be used as inbound as well as dial-peers
outbound
Match y
 Answer-address destination- Select dial-
pattern? peer!
•―Calling Party‖ from ISDN (Q.931)
•ANI from T1 CAS fgd
y Select dial-
Match port?
peer!
dial-peer 0 

Outbound call matching
 Both POTS and VoIP dial peers are considered
 ―destination-pattern <called-number pattern>‖ is used to find the
dial-peer
 On POTS dial peers, the port command is then used to forward the call.
 On VoIP dial peers, the session target command is then used to
forward the call.


Outbound call matching, with variable length dial-plan
 DNIS received one digit at a time
• best shortest complete matching dial-peer is selected, unless digit ―T‖ is not used.
• This could result in premature/incorrect call routing
• Longest match followed if all destination-patterns have digit ―T‖.

 If DNIS received en-bloc, then longest match used.


Call Routing - contd
Overlap receiving
Digits are sent after the initial Setup message. Because the entire digit
string might not be received when the inbound dial peer is matched, digit-
by-digit matching is used.

interface Serial3/0:15
no ip address
no logging event link-status
isdn switch-type primary-qsig
isdn overlap-receiving
isdn incoming-voice
isdn send-alerting


Overlap receiving – incorrect configuration
no ip address
isdn overlap-receiving
isdn incoming-voice
isdn send-alerting



Overlap-receiving – incorrect configuration
# An incoming call with the first digit of called number 5.
*Mar 2 01:47:05.705: ISDN Se3/0:15: RX <- SETUP pd = 8 callref = 0 001A
*Mar 2 01:47:05.705: Bearer Capability i = 0 8090A3
*Mar 2 01:47:05.709: Channel ID i = 0xA9839B
*Mar 2 01:47:05.713: Calling Party Number i = 0 00, 0 83, ‘5000′, Plan:Unknown, Type:Unknown
*Mar 2 01:47:05.717: Called Party Number i = 0 80, ‘5′, Plan:Unknown, Type:Unknown
*Mar 2 01:47:05.717: High Layer Compat i = 0 9181
# An information message with the next digit 5.
*Mar 2 01:47:05.729: ISDN Se3/0:15: TX -> SETUP_ACK pd = 8 callref = 0 801A
*Mar 2 01:47:05.729: Channel ID i = 0xA9839B
*Mar 2 01:47:06.385: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0 001A
# The router matches received digits 55 with dial peer 1.
*Mar 2 01:47:06.393: ccCallSetupRequest numbering_type 0 80
*Mar 2 01:47:06.393: ccCallSetupRequest encapType 2 clid_restrict_disable 1
null_orig_clg 0 clid_transparent 0 callingNumber 5000
*Mar 2 01:47:06.393: dest pattern 5, called 55, digit_strip 0
*Mar 2 01:47:06.393: callingNumber=5000, calledNumber=55, redirectNumber= display_info=
calling_oct3a=83


Overlap-receiving – correct configuration

no ip address
isdn overlap-receiving t302 10000
isdn incoming-voice
isdn send-alerting

destination-pattern 5T

The "T" terminator causes the router to wait for the T302 timer to expire after each digit's reception,
allowing the full number to be collected before placing the call.


# An incoming call with the first digit of called number 5. (called number: 5678)
*Mar 2 21:36:10.132: ISDN Se3/0:15: RX <- SETUP pd = 8 callref = 0 0024
*Mar 2 21:36:10.136: Bearer Capability i = 0 8090A3
*Mar 2 21:36:10.136: Channel ID i = 0xA98386
*Mar 2 21:36:10.140: Calling Party Number i = 0 00, 0 83, ‘5000′, Plan:Unknown,
Type:Unknown
*Mar 2 21:36:10.144: High Layer Compat i = 0 9181
*Mar 2 21:36:10.164: ISDN Se3/0:15: TX -> SETUP_ACK pd = 8 callref = 0 8024
*Mar 2 21:36:10.164: Channel ID i = 0xA98386
*Mar 2 21:36:10.360: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0 0024
# The router matches received digits 5678 with dial peer 1.
*Mar 2 21:36:20.168: ccCallSetupRequest encapType 2 clid_restrict_disable 1
null_orig_clg 0 clid_transparent 0 callingNumber 5000

Incoming call with no calling number
 Ends up selecting dial-peer based on using port dial-peer voice 1 pots
matching direct-inward-dial
 Matches a dial peer that is configured with any
port 1/0:23
destination pattern
 Gateway uses the value of the destination pattern
as the calling number on the outgoing call

 Prevent by configuring a POTS dial peer with dial-peer voice 2 pots
just ―incoming called-number‖. ―incoming called-
direct-inward-dial
number‖ has higher priority than destination
pattern for inbound POTS matching.


Miscellaneous
In Europe, BRI interfaces sometimes get
deactivated (by layer 1) on call inactivity. no dial-peer outbound status-check pots
To get around this-

service ani_filter
Service ani-filter flash:ani_filter.tcl
group-name ani_filter
! new_dest should be something
unreachable so that the caller
gets number of out service
message from telco
param new_dest 5555
param clid1 626xxxxxxx

Trunks and trunk groups
 Used to group multiple voice ports or ISDN channels into a single logical
target for an outbound dial peer
 Reduce the no. of peers required in scenarios with multiple PRIs.
 Can dedicate some channels of an ISDN circuit to particular dial peers.
See example below
 Trunk groups apply only to outbound calls. The gateway cannot control
channel assignment of incoming calls.

Gateway(config)#controller t1 2/0
Gateway(config-controller)#pri-group timeslots 1-24
Gateway(config-controller)#trunk-group Emergency timeslots 1-2
Gateway(config-controller)#trunk-group Standard timeslots 3-23


Call Routing – contd
Call Manager Interface
 With H.323, CallManager sees the gateway only as a peer call routing
entity-
•Cannot specify which port /route the call should use
•Does not even know that multiple ports exist on the gateway.
•In the reverse direction, an H.323 gateway decides how to route calls.

 In MGCP, didn’t have to configure gateway and CallManager separately
for dialing.
 Need to make sure that CallManager sends the appropriate digits as well
as prefix digits (e.g. 9) for proper call routing.
 Inbound CSS of gateway should allow incoming calls to reach IP phones.
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps556/products_tech_note09186a0080094636.sht


Call routing
Call parameters
ISDN PRI ISDN BRI T1 CAS fgd T1 CAS T1 CAS E1 R2
Winkstart Winkstart
dtmf dnis
DID? yes yes yes no Yes no
Enbloc? enbloc enbloc Enbloc Digit-by-digit enbloc Digit-by-
digit
Inbound algorithm algorithm algorithm port Algorithm port
dial-peer
matching
DNIS Yes yes Yes yes yes yes
ANI Yes Yes yes No no yes
ANI format N/A N/A MF N/A N/A MF


Digit manipulations

 Refers to adding, subtracting and changing the following information-
•Calling numbers Inbound voice port translation Match outbound dial-peer
•Called numbers Numexp
Match inbound dial-peer
Dial-peer voice translation
profile
•Redirecting numbers Dial-peer translation profile

 on these calls Incoming Call
•Inbound calls Global voice translation profile Match outbound dial peer
Numexp Dial-peer voice translation
•Outbound calls Or Match inbound dial-peer Digit strip
Dial-peer voice translation Prefix
•Globally to all calls profile forward

• Since this is not specific to digital interface and has been dealt with
extensively in VoIP bootcamp, we won’t be discussing this further.


Calling name display

 CallManager interprets calling name information only in the Display IE of the
H.323 Setup and Notify messages. Name display information delivered in an
H.323 Facility message is not interpreted by CallManager.
 Two ways to fix this..


Calling Name display - contd

When a Q.931 Setup msg with a "name-to-
voice service voip
follow" indication is received from an ISDN
switch, an H.323 Setup msg with no name
h323
information is sent to CUCM. When the h225 display-ie ccm-compatible
subsequent Q.931 Facility msg is received
with calling name information, it is mapped to
an H.323 Notify Display IE.

Gatewat receives abd buffers Setup msg until
the subsequent Facility msg with calling name
information is received. The name info from
voice service voip
the Q.931 Facility msg is then placed into the h323
H.323 Setup msg Display IE and sent to h225 timeout ntf <50-5000>
CUCM. If the buffer timer expires before the isdn supp-service name calling
Facility msg is received, an H.323 Setup is
sent with no name information; if it
subsequently arrives, the information is sent
on using an H.323 Notify message.

Fax
T.37 OnRamp
 Tcl application
 Invoked by ―application setting‖ under inbound pots dial-peer

call application voice onramp
flash:app_libretto_onramp.2.0.1.1.tcl
…
application onramp
incoming called-number 891314[4-5]
direct-inward-dial port 0/0/0:23

http://cae-wiki.cisco.com/index.php/Cisco_Fax_Wiki#T.37_Store-and-Forward_Fax


troubleshooting

show voice call sta debug isdn q931 Call manager traces
show call active voice debug h225 asn1
show dialplan number debug h245 asn1
debug vpm signaling
debug voip ccapi inout


Tools

 “csim start”
http://www.ccievoicestudy.com/Cisco/VoIP/csim_start:_Using_and_Understanding/
 “show dialplan number”
 PCM capture
http://tac-wiki/Image:Pcm-tool.pdf#filelinks
 EEM
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6555/ps6815/config_g
uide_eem_configuration_for_cisco_integrated_services_router_platforms.html
http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_eem_policy_cl
i.html#wp1065918
 “test voice translation-rule”


Common problem symptoms

 In general, any failures, issues with call connecting tend to be P1/P2. ―If
you can’t connect, you have a ―service outage!‖
 Connects and then drops? Might not be call routing, might be
media/codec issue!
 Outbound call troubleshooting- Are calls even getting the correct
gateway?
 Inbound calls fail? Locate and check the incoming dial-peer for digit
manipulation, that might result in call being unroutable
 Firewall– check if port 1720 is blocked
 Dial-peer with ―incoming called-number .‖ not matched ? DNIS being
received digit by digit ?


Common problem symptoms

 Sometimes, both pots and voip dial-peers have same destination-pattern– bad
design! Change pots dial-peer to use more specific destination pattern
 ―Your call cannot be completed as dialed‖– on outbound calls? Look at CUCM
route patterns
 ―Your call cannot be completed as dialed‖ on inbound calls? Check if digit-by-
digit is happening
 High cpu– dial-peer looping? Only two calls in progress. Show commands show
lot more call legs!
 With H.323, no registration is required. So, ip routing/connectivity issues
between CUCM and VG won’t show until calls are attempted.
 T1 CAS- fast busy? Make sure ANI/DNIS is passed in (by telco) with correct
delimiters


Direct-inward-dial
DID not configured
incoming called-number 1900

*Apr 27 15:05:25.983: //-1/xxxxxxxxxxxx/CCAPI/cc_setupind_match_search:
Try with the demoted called number 1900
*Apr 27 15:05:25.983: //80/25012D5C8071/CCAPI/ccCallSetContext:
Context=0xC0AC53C8
*Apr 27 15:05:25.983: //80/25012D5C8071/CCAPI/cc_process_call_setup_ind:
>>>>CCAPI handed cid 80 with tag 2 to app "_ManagedAppProcess_Default"
*Apr 27 15:05:25.983: //80/25012D5C8071/CCAPI/ccCallSetupAck:
Call Id=80
*Apr 27 15:05:25.983: //80/25012D5C8071/CCAPI/cc_api_set_transfer_info:
Transfer Number=, Transfer Reason=0x0
*Apr 27 15:05:25.983: //80/25012D5C8071/CCAPI/ccGenerateToneInfo:
Stop Tone On Digit=TRUE, Tone=Dial Tone,
Tone Direction=Network, Params=0x0, Call Id=80


Direct-inward-dial
DID configured
incoming called-number 1900
direct-inward-dial

*Apr 27 15:49:36.203: //-1/xxxxxxxxxxxx/CCAPI/cc_setupind_match_search:
Try with the demoted called number 1900
*Apr 27 15:49:36.203: //82/50A8A2958078/CCAPI/ccCallSetContext:
Context=0xC0AAFD38
*Apr 27 15:49:36.203: //82/50A8A2958078/CCAPI/cc_process_call_setup_ind:
*Apr 27 15:49:36.203: //82/50A8A2958078/CCAPI/ccCallProceeding:
Progress Indication=NULL(0)
*Apr 27 15:49:36.207: //82/50A8A2958078/CCAPI/ccCallSetupRequest:
Destination=, Calling IE Present=FALSE, Mode=0,
Outgoing Dial-peer=1, Params=0xC0AB36A0, Progress Indication=ORIGINATING SIDE IS NON
ISDN(3)
*Apr 27 15:49:36.207: //82/50A8A2958078/CCAPI/ccCheckClipClir


“Your call cannot be completed as dialed”
*May 10 18:14:52.388: //-1/C347AE408153/CCAPI/cc_api_display_ie_subfields:
cc_api_call_setup_ind_common:
cisco-username= controller T1 0/1/0
----- ccCallInfo IE subfields -----
cisco-ani= cablelength long 0db
cisco-anitype=0
cisco-aniplan=0
ds0-group 0 timeslots 1-24 type e&m-wink-start
cisco-anipi=0
cisco-anisi=0
dest=
cisco-desttype=0 incoming called-number 1900 (# Don’t Ca
cisco-destplan=0
cisco-rdie=FFFFFFFF port 0/1/0:0
cisco-rdn=
cisco-lastrdn=
!
cisco-rdntype=0 dial-peer voice 1 voip
cisco-rdnplan=0
cisco-rdnpi=0 destination-pattern 190
cisco-rdnsi=0
cisco-redirectreason=0 fwd_final_type =0 delay transport-address
final_redirectNumber =
hunt_group_timeout =0
*May 10 18:14:52.388: //-1/C347AE408153/CCAPI/cc_api_call_setup_ind_common:
Interface=0x670F51EC, Call Info( codec g711ulaw
Calling Number=,(Calling Name=)(TON=Unknown, NPI=Unknown, Screening=Not Screened,
Presentation=Allowed),
no vad
Called Number=(TON=Unknown, NPI=Unknown),
Calling Translated=FALSE, Subscriber Type Str=RegularLine, FinalDestinationFlag=FALSE,
Incoming Dial-peer=2, Progress Indication=ORIGINATING SIDE IS NON ISDN(3), Calling IE
Present=FALSE,
Source Trkgrp Route Label=, Target Trkgrp Route Label=, CLID Transparent=FALSE), Call Id=-1


Why did this call fail - contd
…
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/cc_process_call_setup_ind:
Event=0x66CF82C8
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/ccCallSetContext:
Context=0x663EFE4C
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/cc_process_call_setup_ind:
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/ccCallSetupAck:
Call Id=171
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/cc_api_set_transfer_info:
Transfer Number=, Transfer Reason=0x0
*May 10 18:14:52.388: //171/C347AE408153/CCAPI/ccGenerateToneInfo:
Stop Tone On Digit=TRUE, Tone=Dial Tone,


Why did this call fail – contd
*May 10 18:14:53.024: //171/C347AE408153/CCAPI/cc_api_call_digit_begin:
Destination Interface=0x0, Destination Mask=0x1, Destination Call Id=-1,
Source Call Id=171, Digit=1, DigitBeginFlags=0x1,
Rtp Timestamp=0x6023A47D, Rtp Expiration=0x0
*May 10 18:14:53.084: //171/C347AE408153/CCAPI/cc_api_call_digit_end:
1
Source Call Id=171, Digit=1, Duration=92,
Xrule Calling Tag=0, Xrule Called Tag=0, Digit Tone Mode=DTMF
Call Entry(Handoff Depth=0)
Rtp Timestamp=0x6023A885, Rtp Expiration=0x0
*May 10 18:14:53.200: //171/C347AE408153/CCAPI/cc_api_call_digit_end: 9
Rtp Timestamp=0x6023AC48, Rtp Expiration=0x0
0
*May 10 18:14:53.320: //171/xxxxxxxxxxxx/CCAPI/ccCallReportDigits:
(callID=0xAB, digit_event=0x0, enable=FALSE, consume=FALSE)
*May 10 18:14:53.320: //171/C347AE408153/CCAPI/ccCallReportDigits:
Enabled=TRUE, Call Id=171
*May 10 18:14:53.320: //171/xxxxxxxxxxxx/CCAPI/cc_api_call_report_digits_done:
(vdbPtr=0x670F51EC, callID=0xAB, disp=0, digit_event=0x0, enable=FALSE, consume=FALSE)


*May 10 18:14:53.320: //171/C347AE408153/CCAPI/ccCallReportDigits:
Enabled=TRUE, Call Id=171
*May 10 18:14:53.320: //171/xxxxxxxxxxxx/CCAPI/cc_api_call_report_digits_done:
(vdbPtr=0x670F51EC, callID=0xAB, disp=0, digit_event=0x0, enable=FALSE, consume=FALSE)
*May 10 18:14:53.320: //171/C347AE408153/CCAPI/cc_api_call_report_digits_done:
Enabled=TRUE, Disposition=0x0, Interface=0x670F51EC, Call Id=171
*May 10 18:14:53.320: //171/C347AE408153/CCAPI/cc_api_call_report_digits_done:
Call Entry(Initial Digit Timeout=15000(ms), Inter Digit Timeout=10000(ms))
*May 10 18:14:53.320: //171/C347AE408153/CCAPI/ccCallProceeding:
Progress Indication=NULL(0)
*May 10 18:14:53.324: //171/C347AE408153/CCAPI/ccCallSetupRequest:
Destination=, Calling IE Present=FALSE, Mode=0,
Outgoing Dial-peer=1, Params=0x663EEB94, Progress Indication=ORIGINATING SIDE IS NON ISDN(3)
*May 10 18:14:53.324: //171/C347AE408153/CCAPI/ccCheckClipClir:
In: Calling Number=(TON=Unknown, NPI=Unknown, Screening=Not Screened, Presentation=Allowed)
*May 10 18:14:53.324: //171/C347AE408153/CCAPI/ccCheckClipClir:
Out: Calling Number=(TON=Unknown, NPI=Unknown, Screening=Not Screened, Presentation=Allowed)
Destination Pattern=190, Called Number=190, Digit Strip=FALSE


Answer
incoming called-number 1900 (# Don’t Care)
port 0/1/0:0
!
destination-pattern 190T
delay transport-address
codec g711ulaw
no vad


H.323 Call processing
VoIP, VoFR,
VoATM PSTN

Call Manager <-> IPphone

Note: slow start

Call Accepted

h.323 Call processing - contd
Inbound ISDN call •If en-bloc, follow •Use DNIS, preference to
inbound matching resolve outbound dial-
•Receive Setup algorithm peer
•Msg valid per Q.931 FSM? Else use port to •Apply outbound voice
determine inbound dial- translation
peer •Determine codec and
other parameters

•Validate msg params
•Apply translation from Voice port
•Overlap receiving? •Num-exp
•Inbound dial-peer based on •Inbound Voice-port
port translation
•Setup_Ack •Inbound Dial-peer
•Start t302 Translation profile
•Wait and rcv INFO messages
•If t302 expires, proceed to
Presentation_ID process
© 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 112

H.323 call processing - contd
Inbound call •Receive response msg
•Stop timer
•Send ISDN alerting
•Generate Ringtone?

•H.245 exchange

•Determine target
•open TCP connection •Receive Connect msg
•Build Setup msg •Stop timer
•Add faststart element •Send ISDN Connect
•Send Setup •Note down IP/port of
•If fast start, done
•Start H.323 timers endpoint
•If slow start, set up
•Wait for response another TCP Connection
•If ―voice rtp send-recv‖,
cut audio path

References
Books, training courses
 Voip bootcamp
 Cisco Voice Gateways and Gatekeepers, David Mallory, Ken Salhoff,
Denise Donohue, ciscopress.com
 Fax, modem, and Text for IP Telephony, David Hanes and Gonzalo
Salgueiro


References
Reference links
 Link to Q931: ISDN user-network interface layer 3 specification for basic call control
http://wwwin-eng.cisco.com/Standards/WWW/ITU/pdf-files/q/q931.pdf
 Link to Q850: Usage of cause and location in the Digital Subscriber Signalling System No. 1
http://wwwin-eng.cisco.com/Standards/WWW/ITU/pdf-files/q/q-850.pdf
 q931 IE decoder
http://www-tac.cisco.com/wan/isdn/tools/q931frame.html
 Configuring NFAS with Four T1s
http://www.cisco.com/en/US/tech/tk801/tk379/technologies_configuration_example09186a00800a6bf2.shtml

 Understanding debug isdn q931 Disconnect Cause Codes
http://www.cisco.com/en/US/tech/tk801/tk379/technologies_tech_note09186a008012e95f.shtml


References
Reference links - contd
 ITU Q-Series Recommendation
http://wwwin-eng.cisco.com/Standards/ITU/q-series.html
 Digital Signaling
http://www-tac.cisco.com/Teams/AVVID/rtp/Debugging/digital_signaling.html
 Integrating PBXs into VoIP Networks Using the TDM Cross Connect Feature
http://www.cisco.com/en/US/tech/tk652/tk653/technologies_configuration_example09186a008010f05d.shtml

 Troubleshooting No Busy Tone and No Announcement Messages on ISDN-VoIP (H.323) Calls
http://www.cisco.com/en/US/partner/tech/tk652/tk653/technologies_tech_note09186a0080111b58.shtml

 Configuring ISDN PRI
 http://www.cisco.com/en/US/partner/docs/ios/12_2/dial/configuration/guide/dafchant.html


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