Call Flows in CUC Systems Flashcards
By default, which does CUCM use to define servers to phones in configuration files: DNS names or IP addresses?
DNS names
Where do calls placed from a remote site in a centralized call model go to access the PSTN?
They can be routed out either the branch gateway or from the main location gateway.
Name two items that must be configured on CUCM for SRST to work as expected.
- Extensions supported by SRST should have CFUR set up to reach them when their branch is down.
- The call-routing table should include a PSTN gateway and digit manipulation to support the CFUR numbers.
How many remote locations are supported in a CUCM cluster?
1,000
How many H.323 or MGCP gateways are supported in a CUCM cluster?
1,100
What is the maximum number of phones supported in SRST on a branch router (3945E)?
1,500
Name the two methods of providing CAC.
CUCM location-based CAC and RSVP.
Name two protocols that CUCM can use to control Cisco voice gateways.
MGCP and SCCP
Which calling model is simpler: centralized multi-site or distributed multi-site?
Centralized multi-site
Name three protocols used for signaling between CUCM clusters in a distributed multi-site model.
SIP, H.323, ICT (Inter-Cluster Trunk).
What device type allows scalability of distribute multi-site architectures to thousands of facilities?
Gatekeepers
What configuration option is needed to implement AAR? How does it help?
AAR groups are needed to manipulate dialed digits for routing over the PSTN.
What does AAR stand for?
Automated Alternate Routing
What are HEHO and TEHO?
Head-end hop-off and tail-end hop-off refer to PSTN access at the local and remote locations for a call.
An end-to-end call between IP phones attached to separate CME routers requires how many dial peer statements?
Four
What type of CME dial peer is used for connections via an FXO/FXS port?
POTS
Give the CME commands that configure dial peer #1 for extension 7777 on the FXS interface at location 0/0/1.
(config)# dial-peer voice 1 pots
(config-dial-peer)# destination-pattern 7777
(config-dial-peer)# port 0/0/1
Give the command that shows what voice ports are installed on a router.
show voice port summary
Name the three areas of configuration on FXS ports.
Signaling
Call progress tones
Caller ID information
What are the two signaling options for FXS ports?
Loop start and ground start
Give the commands that tell a router to use loop start signaling for FXS port 0/0/0.
(config)# voice-port 0/0/0
(config-voiceport)# signal loopStart
Give the commands that tell a router to use USA call progress tones on FXS port 0/0/0.
(config)# voice-port 0/0/0
(config-voice-port)# cptone US
Give the commands that tell a router to use the number 555-1000 for the Caller ID number on FXS port 0/0/0.
(config)# voice-port 0/0/0
(config-voice-port)# station-id number 5551000
What two configuration options are available on FXO ports that are not on FXS ports? Give the options, associated commands, and defaults.
Dial type specifies DTMF or pulse. The command is dial-type with a default of dtmf.
Ring number specifies the number of rings before the router answers the call. The command is ring number with a default of 1.
Give the command that configures all the timeslots on a T1 CAS interface for FXO loop start signaling.
(config-controller)# ds0-group 1 timeslots 1-24 type fxo-loop-start
Give the command that configures a full CCS T1 for PRI signaling.
(config-controller)# pri-group timeslots 1-24
What must be configured before a router will accept a CCS T1 configuration for PRI?
The ISDN switch type
You’ve entered the configuration command that sets all the channels in a CCS T1 for PRI, but forgot that you don’t have enough DSPs to support a full T1. How will the router respond?
It returns an error message that includes the number of timeslots you can use.
Give the command that provides a list of all dial peers configured on the router.
show dial-peer voice summary
Give the command that tells the router to display ongoing dial peer matching.
debug voip dialpeer
How does a router differ in its treatment of VoIP and POTS dial peers? How can this be changed?
By default, the router strips all non-wildcard digits from matched POTS dial peers. To keep them, use the command no digit-strip.
Give the commands that tell a router to create dial peer #2000 to match all extensions from 2000-2999. Calls to those extensions should go to 10.1.1.2 via G.711 mu-law.
(config)# dial-peer voice 2000 voip
(config-dial-peer)# destination-pattern 2…
(config-dial-peer)# session target ipv4:10.1.12
(config-dial-peer)# codec g711ulaw
What is the default CME codec for VoIP dial peers?
G.729
Use a wildcard to give a router destination pattern that matches 5523, 55523, and 555523.
5+23
Give the destination pattern wildcard that matches any number up to 32 digits.
T
What is the default T.302 interdigit timeout for a CME router?
10 seconds
You’ve created a POTS dial peer on a router for x11 calls using the destination pattern 9[469]11. What command should be added to the dial peer configuration for this to work?
(config-dial-peer)# forward-digits 3
You’ve created a POTS dial peer for international calls using the destination pattern 9011T. What additional dial peer configuration command should be added for this to work?
(config-dial-peer)# prefix 011
What command configures a voice port to automatically call extension 1102 when the phone is picked up?
(config-voiceport)# connection plar 1102
Name the two primary rules for dial peer matching in CME.
- The most specific destination pattern always wins.
2. When a match is found, the router immediately processes the call.
Other than setting up a hotline, when would one want to configure PLAR on an FXO/FXS port? Why?
When all incoming calls on an FXO port should be routed to a certain extension. POTS lines don’t provide the called number, without PLAR, the router won’t know where to send the call and will wait for caller input.
Give the command that tells a router to display the dial peer for a given dialed number.
show dialplan number
Name three types of devices a router’s VoIP dial peer statements could point to.
- IP phones
- CUCM/CME
- Gatekeepers
What does DNIS stand for and what does it indicate?
Dialed Number Identification Service. It’s the dialed number.
What does ANI stand for? What does it indicate?
Automatic Number Identification. It’s the caller ID.
In CME, inbound POTS dial peers are associated with the incoming POTS call legs of the __________ router or gateway. Inbound VoIP dial peers are associated with the incoming VoIP call legs of the __________ router or gateway.
originating; terminating
Name the five steps CME goes through to find a dial peer match for incoming calls. Include any dial peer configuration commands.
- Match the DNIS using the dial peer configuration command incoming called-number,
- Match the ANI using the dial peer configuration command answer-address.
- Match the ANI using the dial peer configuration command destination-pattern.
- Match an incoming POTS dial peer using the dial peer configuration command port.
- Use dial peer 0.