DSDPlus Different Sites found for same system

[nokoa3116]

I am doing discovery on a really big P25 Phase 2 system which has over 145 sites. I noticed that when DSDPlus finds me the neighbor sites for the currently monitored site some have 1.(site number) and some have 2.(site number). Some of the site numbers also conflict with others, but not all. For example I have one site 1.81, and another 2.81 for the same system, with each being a different frequency.

    Neighbor: BEE00.***-1.1
    Neighbor: BEE00.****-1.11
    Neighbor: BEE00.***-1.34
    Neighbor: BEE00.***-1.52
    Neighbor: BEE00.***-1.53
    Neighbor: BEE00.***-1.59
    Neighbor: BEE00.***-1.84
    Neighbor: BEE00.***-2.81
    Neighbor: BEE00.***-2.85
    Neighbor: BEE00.***-2.89
    Neighbor: BEE00.***-2.120
    Neighbor: BEE00.***-2.121
    Neighbor: BEE00.***-2.133
    Neighbor: BEE00.***-2.144
    Neighbor: BEE00.***-2.145

I hid the system ID in the above, they all have the same system ID.

What does this mean?

 

[RaleighGuy]

The 1 or 2 is the RF subsystem ID number which many P25 systems have, in NC we have 3. That is not a conflict as the subsystem is different.

Look at the data base and you'll see examples of this, I'm sure the wiki will explain more.

 

[u2brent]

Each RFSS has a 150 site limit. So, If more than 150 are required to provide coverage. They add additional RFSS controllers 1.xxx, 2.xxx, 3.xxx,
It's not a conflict, They are treated as different sites, different locations, different frequencies..
You'll find many systems like this..
Here's an example from the RR DB..

United States Department of Defense (14C) Trunking System, Various, Multi-State

United States Department of Defense (14C) Trunking System Profile

www.radioreference.com

and another just bursting for another RFSS in order to expand. (reached the 150 limit)

PA-STARNet: Pennsylvania Statewide Radio Network Trunking System, Statewide, Pennsylvania

PA-STARNet: Pennsylvania Statewide Radio Network Trunking System Profile

www.radioreference.com

 

[nokoa3116]

Ahh so that number is RFSS, makes sense. Thank you!

 

[slicerwizard]

Try looking at the console log some time.

RFSS_STS_BCST SysID=3C2 LRA=0 RFSS=1 Site=5 CC=769.93125 SC=70

 

[maus92]

Each RFSS has a 150 site limit. So, If more than 150 are required to provide coverage. They add additional RFSS controllers 1.xxx, 2.xxx, 3.xxx,
It's not a conflict, They are treated as different sites, different locations, different frequencies..
You'll find many systems like this..
Here's an example from the RR DB..

United States Department of Defense (14C) Trunking System, Various, Multi-State

United States Department of Defense (14C) Trunking System Profile

www.radioreference.com

and another just bursting for another RFSS in order to expand. (reached the 150 limit)

PA-STARNet: Pennsylvania Statewide Radio Network Trunking System, Statewide, Pennsylvania

PA-STARNet: Pennsylvania Statewide Radio Network Trunking System Profile

www.radioreference.com

Another reason to have multiple RFSS is for system resiliency. Maryland has three "zones" (aka RFSS's) in its statewide system, each with it own core and geographically separated redundant / backup core. The largest zone has ~30 sites (with numerous simulcast subsites.). I'm not sure if the 150 site limitation is for logical sites, or physical tower sites.

 

[u2brent]

Logical Sites, a simulcast site can have many towers, but counts as just one of the 150 total.

 

[maus92]

Logical Sites, a simulcast site can have many towers, but counts as one.

Yea, it's all very mysterious - the Cecil site was moved from Zone 1 to Zone 3 to free up resources in Zone 1 - perhaps a hardware or licensing limitation at the Zone 1 Core.