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Community Member

Some concept of cisco wireless product

Hi All,

I am new to wireless. I had read some information of the cisco wireless product. But something I am confused. Here is my questions, I hope some body can give me the answer:

1. I saw the information about aironet have some terms like "aironet 350 access point" and "aironet 350 bridge" ? are they different products? The meaning of the information is the "access point" is used indoor and the distance between the access point and the client can not longer than 1 mile while "bridge" is used outdoor and the distance between the client and the bridge can be 25 miles. But I don't know why???

2. I saw a case in this forum:

SiteA need to connect to SiteB but the distance between SiteA and SiteB is longer than 25 miles (not consider the LOS first) so I need to add a bridge between SiteA and SiteB. the topology is like the following:

SiteA----NewBridge----SiteB

My question is how should I config the role of the bridge. To my knowledge the 1 wireless domain can have just 1 root bridge and the non-root bridge just can connect to client and root bridge. so in this case the NewBridge must set to root bridge and the bridges in SiteA and SiteB must be non-root bridge. But if so, and if the distance between SIteA and SiteB is longer than 50 miles and in this case two NewBridges need to be added and can not set the role.

Another question is in that case the link between NewBridge and SiteA and the link between NewBridge and SiteB should use different channel, am I right or wrong?

Hope somebody can answer my question or provide the links in web site about the information. Thank You very much!!

Best Regards

Teru Lei

3 REPLIES
Cisco Employee

Re: Some concept of cisco wireless product

Hi Teru Lei,

1. I saw the information about aironet have some terms like "aironet 350 access point" and "aironet 350 bridge" ? are they different products? The meaning of the information is the "access point" is used indoor and the distance between the access point and the client can not longer than 1 mile while "bridge" is used outdoor and the distance between the client and the bridge can be 25 miles. But I don't know why???

They are different devices. Part numbers AIR-AP352 for the access point and AIR-BR350 for the bridge. The main difference being that with a pair of Bridges you can go from 10baseT ethernet over a wireless link to another 10baseT ethernet link

----|-- Ethernet--- BR350 -------radio link------BR350----|--Ethernet

You can not do this with access points. The only way that you can make one access point associate to another access point is to have one of them configured in repeater mode which will disable your ethernet port of the AP in repeater mode

You can get the longer range from a bridge as you can adjust the receive window size, it take more time for a radio wave to travel a longer distance and as such the receiver has to listen for longer. You can not adjust this on the AP

2. I saw a case in this forum:

SiteA need to connect to SiteB but the distance between SiteA and SiteB is longer than 25 miles (not consider the LOS first) so I need to add a bridge between SiteA and SiteB. the topology is like the following:

SiteA----NewBridge----SiteB

My question is how should I config the role of the bridge. To my knowledge the 1 wireless domain can have just 1 root bridge and the non-root bridge just can connect to client and root bridge. so in this case the NewBridge must set to root bridge and the bridges in SiteA and SiteB must be non-root bridge. But if so, and if the distance between SIteA and SiteB is longer than 50 miles and in this case two NewBridges need to be added and can not set the role.

Another question is in that case the link between NewBridge and SiteA and the link between NewBridge and SiteB should use different channel, am I right or wrong?

The new bridge should be Repeater or non root with clients. This set up will half your throughput as each radio frame will be recieved then re transmitted (repeater function)

In this case they will all be on the same channel.

The better solution although more expensive is to use 4 bridges

----|--- ethernet ---BR350 root----------Ch1radio link ----BR350 Non Root without clients ----|--ethernet--- BR350 Root ch 6 radio link---- BR350 non root without clients--|------ethernet

This will mean that you are not having the retransmision of the same data on the same radio link and as such you do not reduce your the thoughput by half.

Hope this clears up your questions

David

Community Member

Re: Some concept of cisco wireless product

Hi David,

Thank you for your reply. But I still have a question in the scenario. I remember in some information it said that the non-root bridge just can communicate to the root bridge, but in the manual of 350 bridge, the manual said that non-root bridge can also communicate to another non-root bridge. So in the scenario, can I just use 3 bridges like following:

----|--- ethernet ---BR350 root----------Ch1radio link ----BR350 Non Root without clients ---- ch 6 radio link---- BR350 non root without clients--|------ethernet

Can I do this without lower the throughout like using repeater? Thank You!!

Best Regards

Teru Lei

Cisco Employee

Re: Some concept of cisco wireless product

The radio can only use 1 radio channel so you can use the above toplogy but it will be ch1 for the whole network You will also have to make the middle bridge non root with clients if you want the 3rd bridge to associate to it

It is the Root bridge that will decide the radio channel.

In the above topology you will see the reduction in throughput of a repeater

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