Cisco CallManager Flow Chart for Single Campuses
Route Pattern
9.@
Route List
Local PSTN
Route Group
Gateway 2
Route Group
Gateway 1
Calling
Party
(A)
Destination
(B)
PSTN
Digit Manipulation PSTN
(Removal of Dialed Access Code)
Digit Manipulation
(Removal of Dialed Access Code)
This Gateway is configured
as the Primary Gateway.
This Gateway is configured
as the Secondary Gateway.
The dial plan is set up to use one route pattern.The 9.@ is the configuration
pattern that signifies the 9 as the access code to connect to the PSTN.The @ is
required to configure the dialing plan as the North American standard (E.164).
The “.” is used by the Cisco CallManager to tell it which digits are considered
after the access code.This needs to be configured to be sure to remove the correct
digits (the digits located on the left of the dot).
The route pattern will also allow the dialing of 911 for emergency services.
The route group is configured to remove the access code (9) from the dialed
string so the call can be properly routed through the PSTN.
You would often see the multiple PSTN setup for redundancy.This way, if
one PSTN becomes unavailable, or the gateway connected to the PSTN does not
function, the Cisco CallManager will route the call through the secondary
gateway.
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Figure 9.4 Cisco CallManager Flow Chart for Single Campuses
Route Pattern
9.@
Route List
Local PSTN
Route Group
Gateway 2
Route Group
Gateway 1
Calling
Party
(A)
Destination
(B)
PSTN
Digit Manipulation PSTN
(Removal of Dialed Access Code)
Digit Manipulation
(Removal of Dialed Access Code)
This Gateway is configured
as the Primary Gateway.
This Gateway is configured
as the Secondary Gateway.
AVVID Dial Plans • Chapter 9 311
When configuring a Cisco IOS H.323 gateway, try to minimize the number
of entries. For the most part, the dial plan configurations should occur at the
Cisco CallManager.This adds to the efficiency of the router.You could also configure
these gateways to use the Skinny Gateway Protocol or MGCP, but you will
more commonly use the H.323-based gateways.
dial-peer voice 1 voip
codec g711ulaw \\This states that the Dial peer for
\\ all incoming calls from PSTN to
\\ Cisco CallManager's IP address must
\\be G.711
dtmf-relay h245-alphanumeric
destination-pattern 9....
session target ipv4:10.1.100.1 \\This is the Cisco CallManager's IP
\\address
!
dial-peer voice 2 pots \\This is the Dial peer for all 7-digit
\\outgoing PSTN numbers
destination-pattern......
port 1/0:1
!
dial-peer voice 3 pots \\This is the Dial peer for all 10-
\\digit outgoing PSTN numbers
destination-pattern 1.......
prefix 1
port 1/0:1
!
dial-peer voice 4 pots \\This is the Dial peer for 911
\\services
destination-pattern 911
prefix 911
port 1/0:1
With this configuration, the Cisco CallManager assumes the 1 + 10 digit dial
string is required to make long distance calls through the PSTN, and that sevendigit
calling would use the PSTN for local calls. Even though the addition of the
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312 Chapter 9 • AVVID Dial Plans
9.@ (as discussed earlier) includes the ability to dial 911 for emergencies, the Cisco
IOS gateway requires an entry for the dial peer.You could also add dial peers for
411 if you want that service to be available (this is also handled by the 9.@).
NOTE
Voice over IP points to layer three (routed) addresses, so it looks like IP
packet-based traffic as it traverses the network. POTS traffic (and VoFR)
is based on layer two, so it is treated as a voice call all the way to
completion.