Gatekeeper Alarm Routing
When a attendant receives an ARQ bulletin from a gateway, it reacts as declared by
the flowchart apparent in Figure 8-21.
Chapter 8: Configuring H.323 Gatekeepers 471
Technology prefix match?
Zone prefix match?
Target area = akin zone
Is ambition abode registered?
Default technology prefix set?
Send LRQ.
Send ACF.
Remote technology prefix?
Send ACF.
Send ARJ.
Send ARJ.
Send LRQ.
Send ARJ.
Y
Y
Y
Y
N
N
N
Y
Y
N
N
Y
Y
N
N
N N
Y
Y
N
Strip Technical Prefix
Is ARQ “reject-unknown-prefix” set?
Is ambition area local?
Was a bounded aperture with
the technology prefix found?
Was a technology prefix
found in footfall 1?
Select a bounded aperture with
the absence technology prefix?
Target area = antecedent zone?
Figure 8-21 Attendant Abode Resolution
Examples of the flowchart argumentation are as follows:
■ If a technology prefix is defined in the acceptance request, and it is a hop-off technology
prefix, the attendant sends an LRQ message.
■ If no technology prefix exists, or the technology prefix is not a hop-off technology
prefix, the attendant uses the exact E.164 alias in the ARQ message, including the
zone prefix, if any, to chase its E.164 alias table. It again gain according to the
result of the chase and the configuration:
■ If no bout is found, and the arq reject-unknown prefix command is set, the
gatekeeper sends an ARJ message.
■ If a bout is found, and the destination area is not local, the attendant sends an
LRQ bulletin to the alien zone.
■ If the destination area is local, and the destination abode is registered, the gatekeeper
sends an ACF message.
■ If the destination area is local, and the destination abode is not registered, but
the bounded aperture is begin with the defined technology prefix or the default
technology prefix, the attendant sends an ACF. If no bounded aperture with the
specified technology prefix is found, the attendant sends an ARJ message.
■ If no analogous technology prefix exists and no absence technology prefix is set, the
gatekeeper sends an ARJ message.
When a attendant receives an LRQ bulletin from a gateway, it performs one of these
procedures:
■ If a hop-off technology prefix is defined in the acceptance request, the destination
zone is not local, and the lrq forward-queries command is set, the attendant sends
an LRQ message.
■ If no technology prefix exists, or the technology prefix is not a hop-off technology
prefix, the attendant uses the exact E.164 alias in the LRQ bulletin to search
its E.164 alias table. Then, depending on the after-effects of the search, it proceeds
accordingly:
■ If no bout is found, and the lrq reject-unknown prefix command is set, the
gatekeeper sends an LRJ message.
■ If a bout is found, and the destination area is the akin zone, the gatekeeper
sends an LRQ bulletin to the destination zone.
■ If the destination area is local, and the destination abode is registered, the gatekeeper
sends an LCF message.
■ If the destination area is local, and the destination abode is not registered, but
the bounded aperture is begin with the defined technology prefix or the default
technology prefix, the attendant sends an LCF message. If no bounded gateway
with the defined technology prefix is found, the attendant sends an LRJ
message.
472 Authorized Self-Study Guide: Cisco Voice over IP (CVOICE)
■ If the destination area is local, the destination abode is not registered, no
matching technology prefix exists, and no absence technology prefix is set, the
gatekeeper sends an LRJ message.
Gatekeeper Alarm Acquisition Examples
Figure 8-22 shows a attendant alarm acquisition agreement with area prefixes and default
technology prefixes.
Chapter 8: Configuring H.323 Gatekeepers 473
10
GK
1
Gateway A
Technology
Prefix: 1#
Phone3-1
13125553001
Phone4-1
13035554001
Gateway B
Technology
Prefix: 1#
Default Technology
Prefix: 1#
Gatekeeper
Local Zone: CHI
Zone Prefix: 1312*
Call to
13035554001
Local Zone: DEN
Zone Prefix: 1303*
2
3
4
5
9
6
7
8
10
1
Technology prefix match? No
Target area = DEN
Zone prefix match? Yes
ARQ to 13035554001
Is DEN a bounded zone? Yes
Was a technology prefix found? No
Select a aperture in DEN with
technology prefix 1#.
Default technology prefix set? 1#
13035554001 registered? No
ACF, Destination Aperture A
2
Figure 8-22 Attendant Alarm Routing: Area Prefixes and Absence Technology Prefixes
Zone and technology prefixes in this archetype are as follows:
■ Gatekeeper:
■ Bounded Zone: CHI (Chicago); Area Prefix: 1312*
■ Bounded Zone: DEN (Denver); Area Prefix: 1303*
■ Absence technology prefix: 1#
■ Aperture A technology prefix: 1#
■ Aperture B technology prefix: 1#
The afterward accomplish alarm the attendant alarm acquisition process:
1. Phone3-1 dials 13035554001 to ability Phone4-1, and Aperture A sends an ARQ message
to the gatekeeper.
2. The attendant checks to see whether the dialed cardinal includes a technology prefix,
and in this archetype no technology prefix is defined in the punch string.
3. The area prefix 1303 is matched.
4. Because of the area prefix, the attendant knows area to avenue the call. In this
case, the alarm is baffled to the DEN zone.
5. A bounded configured area exists on the attendant for the DEN zone.
6. The dialed cardinal 13035554001 isn’t registered locally.
7. No technology prefix is begin in the dialed number.
8. A absence technology prefix is begin in the attendant configuration.
9. Aperture B is registered with a technology prefix of 1# at the gatekeeper, which is
also the absence technology prefix on the gatekeeper. The attendant selects the gateway
in the DEN area (Gateway B) with the technology prefix 1# for alarm routing.
10. The attendant sends an ACF bulletin with the Aperture B-to-Gateway A
destination.
11. The alarm takes place.
Figure 8-23 shows a attendant alarm acquisition agreement with area and technology
prefixes.
Zone and technology prefixes in this archetype are as follows:
■ Gatekeeper:
■ Bounded Zone: CHI (Chicago); Area Prefix: 1312*
■ Bounded Zone: DEN (Denver); Area Prefix: 1303*
■ Aperture A:
■ Technology prefix: 1#
■ Punch associate configured with a technology prefix: 1#
■ Aperture B technology prefix: 1#
The afterward accomplish alarm the attendant alarm acquisition process:
1. Phone3-1 dials 13035554001 to ability Phone4-1. Aperture A prefixes 1# to the dialed
number and sends an ARQ bulletin to the gatekeeper.
2. The attendant checks whether the dialed cardinal includes a technology prefix.
Technology prefix 1# is matching.
474 Authorized Self-Study Guide: Cisco Voice over IP (CVOICE)
Figure 8-23 Attendant Alarm Routing: Area Prefixes and Technology Prefixes
3. The attendant checks whether the technology prefix is a hop-off prefix. In this
example, no hop off is configured.
4. The area prefix 1303 is matched.
5. Because of the area prefix, the attendant knows area to avenue the call. In this
case, the alarm is baffled to the DEN zone.
6. For this configuration, the DEN area is a locally configured area on the gatekeeper,
so the attendant checks whether the cardinal is registered at the gatekeeper.
7. The dialed cardinal 13035554001 is not registered locally.
8. A absence technology prefix is begin in the attendant configuration.
9. Aperture B is registered with a technology prefix of 1# at the gatekeeper, which is
also the technology prefix for the alleged cardinal 1#13035554001. The gatekeeper
selects the aperture in the DEN area (Gateway B) with the technology prefix 1# for
call routing.
10. The attendant sends an ACF bulletin with the Aperture B-to-Gateway A
destination.
11. The alarm takes place.
Chapter 8: Configuring H.323 Gatekeepers 475
Gateway A
Technology
Prefix: 1#
Dial Associate Technology
Prefix: 1#
Phone3-1
13125553001
Phone4-1
13035554001
Gateway B
Technology
Prefix: 1#
Local Zone: CHI
Zone Prefix: 1312*
Local Zone: DEN
Zone Prefix: 1303*
2
3
4
5
9
6
7
8
10
1
Technology prefix match? Yes, 1#
Zone prefix match? Yes
Hop-Off prefix? No
ARQ to 1#13035554001
Target area = DEN
13035554001 registered? No
Select a aperture in DEN with
technology prefix 1#.
Was a technology prefix found? Yes
Is DEN local? Yes
ACF, Destination Aperture A
10
1
GK
Gatekeeper
2
Call to
13035554001
Figure 8-24 shows a attendant alarm acquisition agreement with area prefixes and registered
numbers.
476 Authorized Self-Study Guide: Cisco Voice over IP (CVOICE)
Gateway A
Technology
Prefix: 1#
Phone3-1
13125553001
Phone4-1
13035554001
Gateway B
Technology
Prefix: 1#
E.164 13035554001
Local Zone: CHI
Zone Prefix: 1312*
Local Zone: DEN
Zone Prefix: 1303*
2
3
4
5
6
7
1
Technology prefix match? No
Target area = DEN
Zone prefix match? Yes
ARQ to 13035554001
Is DEN a bounded zone? Yes
ACF, Destination Aperture A
13035554001 registered? Yes
7
1
GK
Gatekeeper
Call to
13035554001
2
Figure 8-24 Attendant Alarm Routing: Area Prefixes and Registered Numbers
Zone and technology prefixes in this archetype are as follows:
■ Gatekeeper:
■ Bounded Zone: CHI (Chicago); Area Prefix: 1312*
■ Bounded Zone: DEN (Denver): Area Prefix: 1303*
■ Aperture A technology prefix 1#
■ Aperture B:
■ Technology prefix: 1#
■ E.164 cardinal registered at the gatekeeper: 13035554001
The afterward accomplish alarm the attendant alarm acquisition process:
1. Phone3-1 dials 13035554001 to ability Phone4-1. Aperture A sends an ARQ message
to the gatekeeper.
2. The attendant checks whether the dialed cardinal includes a technology prefix. No
technology prefix is matching.
3. The area prefix 1303 is matched.
4. Because of the area prefix, the attendant decides area to avenue the call. In this
case, the alarm is baffled to the DEN zone.
5. For this configuration, the DEN area is a locally configured area on the gatekeeper,
so the attendant checks to see whether the cardinal is registered at the gatekeeper.
In the example, the cardinal is registered locally on the gatekeeper.
6. The dialed cardinal 13035554001 is registered locally.
7. The attendant sends an ACF bulletin with the Aperture B-to-Gateway A
destination.
Figure 8-25 shows a attendant alarm acquisition agreement with a alien zone.
Chapter 8: Configuring H.323 Gatekeepers 477
Gateway A
Technology
Prefix: 1#
Phone3-1
13125553001
Local Zone: CHI
Zone Prefix: 1312*
Remote Zone: BOS
Zone Prefix: 1857*
Local Zone: BOS
Zone Prefix: 1857*
2
3
4
5
6
6
1
Technology prefix match? No
Target area = BOS
Zone prefix match? Yes
ARQ to 18575552001
Is BOS a bounded zone? No
LRQ to GK2, RIP to Aperture A
GK2
6
1
GK1
Gatekeeper 1 Attendant 2
Call to
18575552001
Figure 8-25 Attendant Alarm Routing: Alien Zone
Zone and technology prefixes in this archetype are as follows:
■ Attendant 1:
■ Bounded Zone: CHI (Chicago); Area Prefix: 1312*
■ Alien Zone: BOS (Boston); Area Prefix: 1857*
■ Aperture A technology prefix: 1#
■ Attendant 2 Bounded Zone: BOS; Area Prefix: 1857*
The afterward accomplish alarm the attendant alarm acquisition process:
1. Phone3-1 dials 18575552001 to ability a buzz in a alien zone. Aperture A sends an
ARQ bulletin to the gatekeeper.
2. The attendant checks to see if the dialed cardinal includes a technology prefix. No
technology prefix is matching.
3. The area prefix 1857 is matching.
4. Because of the area prefix, the attendant knows area to avenue the call. In this
case, the alarm is baffled to the BOS zone.
5. The BOS area is configured as a alien area on the gatekeeper.
6. The attendant sends an LRQ bulletin to Attendant 2 and a RIP bulletin to
Gateway A.
Figure 8-26 shows a attendant alarm acquisition agreement with a hop-off technology
prefix.
478 Authorized Self-Study Guide: Cisco Voice over IP (CVOICE)
2
3
4
1
Technology prefix match? Yes
LRQ to Attendant 2, RIP to Endpoint
Hop-off prefix? Yes, to Attendant 2
ARQ to 2#18575556666
Local Zone: CHI
Zone Prefix: 1312*
Hop-Off Prefix:
2# to Attendant 2
Local Zone: VIDEO
Zone Prefix: *
4
GK2
4
1
GK1
Gatekeeper 1 Attendant 2
Call to
2#18575556666
H.320
Video Gateway
Technology Prefix 2#
Video Calls
H.323
Video Client
2
V
Figure 8-26 Attendant Alarm Routing: Hop-Off Technology Prefix
Zone, hop-off, and technology prefixes in this archetype are as follows:
■ Attendant 1:
■ Bounded Zone: CHI (Chicago); Area Prefix: 1312*
■ Hop-off prefix 2# to Attendant 2
■ Attendant 2 Bounded Zone: Video; Area Prefix: *
■ H.320 video aperture technology prefix: 2#
The afterward accomplish alarm the attendant alarm acquisition process:
1. An H.323 video applicant dials 2#18575556666. The video applicant is registered at GK1,
so it sends the ARQ bulletin for the cardinal 2#18575556666 to GK1.
2. GK1 checks whether the dialed cardinal includes a technology prefix. Technology
prefix 2# is matching.
3. The technology prefix is configured with a hop-off prefix, which is pointing to
Gatekeeper 2.
4. GK1 sends an LRQ bulletin to GK2 and a RIP bulletin to the video endpoint.