P2MP design

Unanswered Question
Apr 15th, 2008
User Badges:

I am in the process of designing a Wireless solution to connect 2 separate buildings that are hard to wire. In the design, I have a central building that will home all of the networking devices including, wireless bridge, and the gateway. This is the building where I will put the central bridge and a directional antanna. My question is, how should I connect the other 2 buildings to this central building?

Would it be with one cental bridge and antanaa to connect the other 2 buildings (P2MP)? Would this allow full-duplex for each connection?

Would it be with 2 cental bridges and 2 directional antannas to connect to the 2 separate buildings (P-to-P) to allow full-duplex for each connection?

Thanks for the prompt response,


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
bcolvin Tue, 04/15/2008 - 11:37
User Badges:
  • Bronze, 100 points or more

First whether you have two roots with separate links to each building or or one root for both non-roots will be determined by the bandwidth required over the links. The other consideration is will both non-root AP's be covered by a single directional antenna.

Second the Cisco 1200, 1300 and 1400 AP radios all operate in half-duplex mode.

Hope this helps


skhirbash Tue, 04/15/2008 - 12:28
User Badges:

So, which one of the following scenarios provides best preformance considering that VoIP will be implemented?

- 1 root bridge with one directional antenna(Central bldg) connecting 2 non-root bridges(2 directional antennas).

- 1 root bridge with 2 directional antennas (Central bldg)connecting 2 non-root bridges(2 directional antennas).

- or 1 root bridge, 1 non-root bridge with 2 directional antennas (Central bldg) connecting 2 non-root bridges(2 directional antennas)

In all scenarios, all duplex mode will operate in half-duplex?

bcolvin Tue, 04/15/2008 - 12:58
User Badges:
  • Bronze, 100 points or more


now some info to work with

best configuration, 2 root bridges each with unique SSID and a single directional antenna. one non-root in each remote location with a directional antenna.

a second antenna is not needed as multipath is not an issue with bridges.

In all scenarios the radios operate in half-duplex. the radio cannot transmit and recieve simultaneously.

the bridges will require clear line of sight, also the distance between root and non-root is a factor to consider in you design. check these links for details.



There is much more information available just follow the links in the abpve documents.

Good luck with your project


skhirbash Tue, 04/15/2008 - 13:11
User Badges:

Are there any bridges/antennas that would operate in full-duplex? Half-duplex will present issues for VoIP implementation.



bcolvin Tue, 04/15/2008 - 13:23
User Badges:
  • Bronze, 100 points or more

Yes there are Proxim.com has several models that will probably meet your requirements. there are also other manufactures of theis equipment a web search should find them. just remember these products are ususlly much more expensive than the Cisco 2.4 and 5.8 products but they do offer 100mbit full duplex.




This Discussion



Trending Topics: Other Wireless Mobility

client could not be authenticated
Network Analysis Module (NAM) Products
Cisco 6500 nam
reason 440 driver failure
Cisco password cracker
Cisco Wireless mode