Why the name Hunting sequence?
This terminology has logic behind it the switch after Receiving Authentication from AUC and with message of CRI and MSRN /TLDN from HLR and acceptance from other switch to route the call is to decide which CIC (Circuit Identification Code) to be occupied for this call. The switch hence always decides which CIC needs to be assigned to a particular call.
There are multiple ways on which you can make an inter connectivity decide which CIC needs to be selected. This decision is important as the two switches are not aware that what all CICs are available at that point of time and in two way TGs they may end up sending calls on the same CIC resulting in dual siezure.
Types of Hunting Sequence/CIC Selection Method:-
A. Highest to lowest
B. Odd to Even
C. Random Selection and Many more similar
The CIC selection method once implemented makes switch understands that whoever switch has higher point code the Switch will implement the Left Side Method and the lower will implement the other one. CIC selection method Random should be selected only if the TG is oneway as the chances of dual seizure is not present. Also Random CIC selection method is never implemented in case of Both way TG.
CIC selection method or hunting type is very important parameter in addressing the ASR concerns of any route. If someone asks me the priority of these methods:-
1st priority is Odd to Even.
2nd Priority is Highest to lowest
3rd Priority is Random
To portray the CIC Selection method in mind I draw this description:-
Odd to Even
Higher DPC Calls to be routed to CIC 1,3,5,7,9,11….61
Lower DPC Calls to be routed to CIC 0,2,4,6,8,10….62
Highest to Lowest
Higher DPC Calls to be routed to CIC 1,3,5,7,9,11….
Lower DPC Calls to be routed to CIC 0,2,4,6,8,10….
Random
Switch 1 0,1,2,3,4,5,6….
Switch 2 0,1,2,3,4,5,6….
Tele-Columnist!