Call Processing Overview - TANDBERG Gatekeeper User Manual

4.8.

Call Processing Overview

Figure 6 illustrates the process the Gatekeeper performs when receiving call requests.



On local
Yes
network?

IPAddress
Direct
mode?
LRQ all Alternates
with hopcount = 1

Received
Yes


Figure 6: Location decision flow diagram
Receive Request
from Endpoint
(ARQ) or other
gatekeeper (LRQ)
Apply Transforms
Locally
registered
Yes
endpoint?
No
Locally
registered
Yes
service?
No
IP address
literal?
Yes

No

No
Off
Indirect
Alternates
configured?
Yes
No
LCF?
No

Received LRQ as
a GK and
Yes
Forwarding is
Off?
No
LRQ all alive strong-
matching Neighbour
and Traversal Zones
that match the Alias
Received
Yes
LCF?
No
LRQ all weak-
Received
matching non-
Traversal Zones



Yes

Found
No
address(es)?

Attempt to locate Call
Signaling port using
DNS A/AAAA
No
Received
Call signaling
Yes
port located? LCF?
Attempt to locate Call
LRQ foreign
Signaling port using
gatekeeper
DNS SRV
No
Foreign
gatekeeper
Yes
located?
Attempt to locate
foreign gatekeeper
using DNS SRV
Yes
Does alias
DNS Resolution
resemble E.164
No No
mode on?
address?
Yes

LRQ from Known
No GK received by
this GK?

Received
Yes
LCF?
LRQ all weak-
No matching Traversal
LCF?
 Zones
Yes
TANDBERG Gatekeeper User Guide
Search Algorithm
Success: return LCF or ACF
Failure: return LRJ or ARJ
Yes

No
Feed URIs back in
priority order to
Location Search
algorithm
No

Empty candidate
Yes
set of URIs?
Perform E.164-URI
resolution using
ENUM algorithm
Yes
Yes
ARQ from
registered EP
No and alias does
not contain local
domain?
No
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