Point to Point Links

I need to link two small LANs with a point to point wireless link.

The two small LANS are just groups of PCs connected to a 10/100mbs
switch with patch cables. One of these small LANs has a broadband
connection that the other LAN wants access to.

If I use two Wireless access points in point to point mode does the
combined LAN now become one TCP\IP network, i.e. will all devices be
within a single 192.168.0.xxx network ?

Can the wireless access points, when in point to point mode act as a
normal access point as well ? i.e. if at either end I want to connect a
wireless equipped laptop do I need an additional wireless access point
at that end ?

If I want to use DHCP do I set this up on one of the wireless bridges,
or both - each with a seperate TCP\IP address range ?


Stevie

(E-Mail Removed) wrote in
news:(E-Mail Removed) oups.com:

> I need to link two small LANs with a point to point wireless link.
>
> The two small LANS are just groups of PCs connected to a 10/100mbs
> switch with patch cables. One of these small LANs has a broadband
> connection that the other LAN wants access to.
What is the distance between the two LANs?

1. If they are some distance apart (say > 30m) you will likely need a
mating pair of multi-mode access point devices, configured in
wireless bridge mode. [The advantage of this configuration is that
with line of sight, some height, and directional antennae you will be
able to bridge several miles]

2. If the distance is < 30m, you may be able to use two multi-mode
access point devices, one configured in access point mode, the other
in wireless client mode.
>
> If I use two Wireless access points in point to point mode does
> the combined LAN now become one TCP\IP network, i.e. will all
> devices be within a single 192.168.0.xxx network ?
Think of the wireless bridge as a long length of Ethernet cable. So
assuming you have a single DHCP server, you will create a single
network and each DHCP client will be handed an address in the same
subnet.

You can of course be more complex and bridge between two routers. You
can then have different network address on each LAN. It depends on
your requirements.

> Can the wireless access points, when in point to point mode act as
> a normal access point as well ? i.e. if at either end I want to
> connect a wireless equipped laptop do I need an additional
> wireless access point at that end ?
If you are using a mating pair of bridges (Option 1. above) then the
devices will not also act as access points [but see below]

If you go for Option 2. above, then you will already have an access
point and the laptop will be able to connect. Again, it depends on
the distance, and also on the environment. It is possible that you
may need additional access point(s) to fill in 'dead spots'.

A number of devices implement WDS (Wireless Distribution System).
Although WDS is described in IEEE 802.11 it is not fully defined, and
implementations betwen different manufacturers (and even between
different products from the same manufacturer!) are likely to be
incompatible. Some WDS devices can act as both wireless client and
access point. I do not have personal experience of a device in bridge
mode also acting as an access point, but some may do so.

> If I want to use DHCP do I set this up on one of the wireless
> bridges, or both - each with a seperate TCP\IP address range ?

[See also above] If you have dfferent network addresses on each side
of the bridge, you will need to route between them. In that case, it
is likely the router(s) will be the DHCP server. The simplest
configuration is however a single network with a single DHCP server.

In my experience, this class of device will only act as a DHCP server
when configured in access point mode, so if you go for the 'mating
pair of bridge' approach (Option 1 above) you will need a separate
DHCP server. If you go for Option 2. you will already have a device
which can act as the DHCP server.

You say "One of these small LANs has a broadband connection".
Assuming this is a broadband router, then this should act as the DHCP
server rather than the access point.

The configuration you talk about is exactly how my network is
configured. It is structured as small workgroup clusters of 2-3 PCs +
print server, connected to a switch. Also connected to each switch is
a wireless client device. A wireless router provides infrastructure
mode wireless comms, together with Internet access to all users.
Laptops can roam freely, although I do have futher access points
(same SSID) in addition to the wireless router ['Workgroup' in this
context means 'group of workers' rather than Windows network
workgroup, of which there is only one]. Works just fine.

Hope this helps

--

Richard Perkin
To email me, change the AT in the address below
richard.perkinATmyrealbox.com

It's is not, it isn't ain't, and it's it's, not its, if you mean it
is. If you don't, it's its. Then too, it's hers. It isn't her's.
It isn't our's either. It's ours, and likewise yours and theirs.
-- Oxford University Press, Edpress News

Thanks for the reply

>2. If the distance is < 30m, you may be able to use two
>multi-mode access point devices, one configured in access
>point mode, the other in wireless client mode

The distance between the LANs, where the access points could be located
is about 20M, in a simple test with a normal access point and a
notebook it worked fine.

I see, so its possible for one of the pairs in the 'bridge' to act as a
normal access point but not the other.

> You say "One of these small LANs has a broadband
> connection". Assuming this is a broadband router, then this
> should act as the DHCP
> server rather than the access point.

A fair point, if the bridge is setup to be one TCP\IP network then the
PCs on the LAN without the broadband router ought to be able to access
the DHCP server on the other side of the bridge.

"Richard Perkin" <(E-Mail Removed)> wrote in message
news:Xns95FA7257490DBfnurdle@130.133.1.4...
> (E-Mail Removed) wrote in
> news:(E-Mail Removed) oups.com:
>
> > I need to link two small LANs with a point to point wireless link.
> >
> > The two small LANS are just groups of PCs connected to a 10/100mbs
> > switch with patch cables. One of these small LANs has a broadband
> > connection that the other LAN wants access to.
> What is the distance between the two LANs?
>
> 1. If they are some distance apart (say > 30m) you will likely need
a
> mating pair of multi-mode access point devices, configured in
> wireless bridge mode. [The advantage of this configuration is that
> with line of sight, some height, and directional antennae you will
be
> able to bridge several miles]
>
> 2. If the distance is < 30m, you may be able to use two multi-mode
> access point devices, one configured in access point mode, the other
> in wireless client mode.
> >
> > If I use two Wireless access points in point to point mode does
> > the combined LAN now become one TCP\IP network, i.e. will all
> > devices be within a single 192.168.0.xxx network ?
> Think of the wireless bridge as a long length of Ethernet cable. So
> assuming you have a single DHCP server, you will create a single
> network and each DHCP client will be handed an address in the same
> subnet.
>
> You can of course be more complex and bridge between two routers.
You
> can then have different network address on each LAN. It depends on
> your requirements.
>
> > Can the wireless access points, when in point to point mode act as
> > a normal access point as well ? i.e. if at either end I want to
> > connect a wireless equipped laptop do I need an additional
> > wireless access point at that end ?
> If you are using a mating pair of bridges (Option 1. above) then the
> devices will not also act as access points [but see below]
>
> If you go for Option 2. above, then you will already have an access
> point and the laptop will be able to connect. Again, it depends on
> the distance, and also on the environment. It is possible that you
> may need additional access point(s) to fill in 'dead spots'.
>
> A number of devices implement WDS (Wireless Distribution System).
> Although WDS is described in IEEE 802.11 it is not fully defined,
and
> implementations betwen different manufacturers (and even between
> different products from the same manufacturer!) are likely to be
> incompatible. Some WDS devices can act as both wireless client and
> access point. I do not have personal experience of a device in
bridge
> mode also acting as an access point, but some may do so.
>
> > If I want to use DHCP do I set this up on one of the wireless
> > bridges, or both - each with a seperate TCP\IP address range ?
>
> [See also above] If you have dfferent network addresses on each side
> of the bridge, you will need to route between them. In that case, it
> is likely the router(s) will be the DHCP server. The simplest
> configuration is however a single network with a single DHCP server.
>
> In my experience, this class of device will only act as a DHCP
server
> when configured in access point mode, so if you go for the 'mating
> pair of bridge' approach (Option 1 above) you will need a separate
> DHCP server. If you go for Option 2. you will already have a device
> which can act as the DHCP server.
>
> You say "One of these small LANs has a broadband connection".
> Assuming this is a broadband router, then this should act as the
DHCP
> server rather than the access point.
>
> The configuration you talk about is exactly how my network is
> configured. It is structured as small workgroup clusters of 2-3 PCs
+
> print server, connected to a switch. Also connected to each switch
is
> a wireless client device. A wireless router provides infrastructure
> mode wireless comms, together with Internet access to all users.
> Laptops can roam freely, although I do have futher access points
> (same SSID) in addition to the wireless router ['Workgroup' in this
> context means 'group of workers' rather than Windows network
> workgroup, of which there is only one]. Works just fine.
>
> Hope this helps
>

It is my understanding (which is not a whole lot) that AP Client mode
wont handle multiple macs by itself.....Correct me on this if its BS.
A workgroup bridge is also an option for the remote end and an AP at
the host side.

(E-Mail Removed) wrote in
news:(E-Mail Removed) ups.com:

>>2. If the distance is < 30m, you may be able to use two
>>multi-mode access point devices, one configured in access
>>point mode, the other in wireless client mode
>
> The distance between the LANs, where the access points could be
> located is about 20M, in a simple test with a normal access point
> and a notebook it worked fine.
A couple of points:
- If you don't have one already and you're looking to save money, you
could buy a wireless router and offset the cost by selling the device
you have already (presumaby without wireless). The new wireless
router would of course be an access point. However, this type of
single-box device does offer less flexibility in terms of
positioning.

- the device I have called a multi-mode access point is, as far as
I'm concerned, a 'normal' access point. Most (all?) models from most
manufacturers support several modes, usually:
access point
wireless bridge
multi-point bridge
wireless client
repeater

> I see, so its possible for one of the pairs in the 'bridge' to act
> as a normal access point but not the other.
Provided it's configured as an access point
[avoiding for the moment any discussion of WDS]
You can have as many access points as you like (avoid overlapping
channels).

>> You say "One of these small LANs has a broadband
>> connection". Assuming this is a broadband router, then this
>> should act as the DHCP
>> server rather than the access point.
>
> A fair point, if the bridge is setup to be one TCP\IP network then
> the PCs on the LAN without the broadband router ought to be able
> to access the DHCP server on the other side of the bridge.
Precisely. Don't make things too complicated

Hope this helps

--

Richard Perkin
To email me, change the AT in the address below
richard.perkinATmyrealbox.com

It's is not, it isn't ain't, and it's it's, not its, if you mean it
is. If you don't, it's its. Then too, it's hers. It isn't her's.
It isn't our's either. It's ours, and likewise yours and theirs.
-- Oxford University Press, Edpress News

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> I need to link two small LANs with a point to point wireless link.
>
> The two small LANS are just groups of PCs connected to a 10/100mbs
> switch with patch cables. One of these small LANs has a broadband
> connection that the other LAN wants access to.
>
> If I use two Wireless access points in point to point mode does the
> combined LAN now become one TCP\IP network, i.e. will all devices be
> within a single 192.168.0.xxx network ?

As others have pointed out, two AP's that are cable of "Bridge Mode" will
bring these two LANs together. Each AP in "Bridge Mode" is half a bridge.
You can either keep two IP networks or merge them together as one.
Whichever you prefer. When I think of a bridge, I think of something that
is connecting two seperate IP networks though.

> Can the wireless access points, when in point to point mode act as a
> normal access point as well ? i.e. if at either end I want to connect a
> wireless equipped laptop do I need an additional wireless access point
> at that end ?

The (WDS capable) DWL-7100APs (802.11a, 802.11g) that I just picked up are
'supposibily' capable of doing such -- operate simultaneously as both a half
bridge and an AP for each band. As I don't need bridge functionality, I
haven't tried it though. Due to firmware problems with these APs, it became
a major headache just to get it operating in "Repeater Mode" for both bands.
(Latest firmware couldn't do it, but after rolling back to a previous
version, I got it working.) During the course of trying to get it working,
I did a lot of google/deja searches -- which led to many others having
similiar problems across many manufacturers (Linksys, D-Link, Netgear, etc).
Seems like many manufacturers still have a ways to go with "WDS". Also came
across many postings stating that specific APs were handling "WDS"
beautifully. *shrug*. I'd probably do a lot of homework if looking for
such APs. Read the reviews, see what others are saying about them, ect. As
for the DWL-7100AP, unfortunetly right now I couldn't recommend this AP for
anything other than use as an AP. Hoping D-Link releases a new firmware
that takes care of it's issues soon.

Cheers 'n beers!

We use these set to ad-hoc and share the connection under network settings.
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7134132437

"Airhead" <(E-Mail Removed)> wrote in message
news:420caf37$0$22516$(E-Mail Removed) m...
>
> "Richard Perkin" <(E-Mail Removed)> wrote in message
> news:Xns95FA7257490DBfnurdle@130.133.1.4...
>> (E-Mail Removed) wrote in
>> news:(E-Mail Removed) oups.com:
>>
>> > I need to link two small LANs with a point to point wireless link.
>> >
>> > The two small LANS are just groups of PCs connected to a 10/100mbs
>> > switch with patch cables. One of these small LANs has a broadband
>> > connection that the other LAN wants access to.
>> What is the distance between the two LANs?
>>
>> 1. If they are some distance apart (say > 30m) you will likely need
> a
>> mating pair of multi-mode access point devices, configured in
>> wireless bridge mode. [The advantage of this configuration is that
>> with line of sight, some height, and directional antennae you will
> be
>> able to bridge several miles]
>>
>> 2. If the distance is < 30m, you may be able to use two multi-mode
>> access point devices, one configured in access point mode, the other
>> in wireless client mode.
>> >
>> > If I use two Wireless access points in point to point mode does
>> > the combined LAN now become one TCP\IP network, i.e. will all
>> > devices be within a single 192.168.0.xxx network ?
>> Think of the wireless bridge as a long length of Ethernet cable. So
>> assuming you have a single DHCP server, you will create a single
>> network and each DHCP client will be handed an address in the same
>> subnet.
>>
>> You can of course be more complex and bridge between two routers.
> You
>> can then have different network address on each LAN. It depends on
>> your requirements.
>>
>> > Can the wireless access points, when in point to point mode act as
>> > a normal access point as well ? i.e. if at either end I want to
>> > connect a wireless equipped laptop do I need an additional
>> > wireless access point at that end ?
>> If you are using a mating pair of bridges (Option 1. above) then the
>> devices will not also act as access points [but see below]
>>
>> If you go for Option 2. above, then you will already have an access
>> point and the laptop will be able to connect. Again, it depends on
>> the distance, and also on the environment. It is possible that you
>> may need additional access point(s) to fill in 'dead spots'.
>>
>> A number of devices implement WDS (Wireless Distribution System).
>> Although WDS is described in IEEE 802.11 it is not fully defined,
> and
>> implementations betwen different manufacturers (and even between
>> different products from the same manufacturer!) are likely to be
>> incompatible. Some WDS devices can act as both wireless client and
>> access point. I do not have personal experience of a device in
> bridge
>> mode also acting as an access point, but some may do so.
>>
>> > If I want to use DHCP do I set this up on one of the wireless
>> > bridges, or both - each with a seperate TCP\IP address range ?
>>
>> [See also above] If you have dfferent network addresses on each side
>> of the bridge, you will need to route between them. In that case, it
>> is likely the router(s) will be the DHCP server. The simplest
>> configuration is however a single network with a single DHCP server.
>>
>> In my experience, this class of device will only act as a DHCP
> server
>> when configured in access point mode, so if you go for the 'mating
>> pair of bridge' approach (Option 1 above) you will need a separate
>> DHCP server. If you go for Option 2. you will already have a device
>> which can act as the DHCP server.
>>
>> You say "One of these small LANs has a broadband connection".
>> Assuming this is a broadband router, then this should act as the
> DHCP
>> server rather than the access point.
>>
>> The configuration you talk about is exactly how my network is
>> configured. It is structured as small workgroup clusters of 2-3 PCs
> +
>> print server, connected to a switch. Also connected to each switch
> is
>> a wireless client device. A wireless router provides infrastructure
>> mode wireless comms, together with Internet access to all users.
>> Laptops can roam freely, although I do have futher access points
>> (same SSID) in addition to the wireless router ['Workgroup' in this
>> context means 'group of workers' rather than Windows network
>> workgroup, of which there is only one]. Works just fine.
>>
>> Hope this helps
>>
>
> It is my understanding (which is not a whole lot) that AP Client mode
> wont handle multiple macs by itself.....Correct me on this if its BS.
> A workgroup bridge is also an option for the remote end and an AP at
> the host side.
>
>

"Airhead" <(E-Mail Removed)> wrote in
news:420caf37$0$22516$(E-Mail Removed) m:

> "Richard Perkin" <(E-Mail Removed)> wrote in message
> news:Xns95FA7257490DBfnurdle@130.133.1.4...
>> (E-Mail Removed) wrote in
>> news:(E-Mail Removed) oups.com:

>> 2. If the distance is < 30m, you may be able to use two
>> multi-mode access point devices, one configured in access point
>> mode, the other in wireless client mode.

> It is my understanding (which is not a whole lot) that AP Client
> mode wont handle multiple macs by itself.....Correct me on this if
> its BS. A workgroup bridge is also an option for the remote end
> and an AP at the host side.

The ability to handle multiple MAC addresses is one of the things
which is never well documented. Most (but not all) devices sold as
'gaming bridges' will do it.

Most multi-mode access points which implement repeater mode will do
it. This is because repeating is an implementation of WDS, so it's
likely that WDS is also used to implement wireless client mode.

MAC frames as defined in IEEE 802.11 uses 4 MAC addresses. These
are:
DA: Destination Address - the final destination
SA: Source Address - the originator
RA: Receiver Address - the immediate recipient
TA: Transmitter Address - the immediate transmitter

Using all four addresses together with the To DS and From DS fields
within the Frame Control field is what allows a WDS implementation
to handle data to/from multiple MAC addresses. If the wireless
client device is programmed to structure its MAC frames correctly
using all four addresses, it will work. If not, it won't.

This can be observed if the traffic is sniffed using Ethereal or
other similar tool. Both the addresses of the wireless client bridge
device and the actual device behind the switch will be seen.

I belive that such consumer-class devices can usually handle a total
of 32 MAC addresses.

--

Richard Perkin
To email me, change the AT in the address below
richard.perkinATmyrealbox.com

It's is not, it isn't ain't, and it's it's, not its, if you mean it
is. If you don't, it's its. Then too, it's hers. It isn't her's.
It isn't our's either. It's ours, and likewise yours and theirs.
-- Oxford University Press, Edpress News

Correct me if im wrong but this is what you have now correct?

Internet<------------Network 1--------] No Connection @20M [--------Network
2

And this is what you want correct?

Internet<-----Router----->Network 1-------->Bridged AP1 (@20M) Bridged
AP2<--------Network 2

The Easiest way is to insert a wired router at your broadband Internet modem
and your Switch in Network 1, purchase 2 wireless AP's and place them in
Bridge mode and let the Router handle the DHCP addressing effectivly making
it one LAN. You will have to goto each client computer and set them to
obtain the IP via DCHP, since I assume they are all set with a static IP
now.


<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
>I need to link two small LANs with a point to point wireless link.
>
> The two small LANS are just groups of PCs connected to a 10/100mbs
> switch with patch cables. One of these small LANs has a broadband
> connection that the other LAN wants access to.
>
> If I use two Wireless access points in point to point mode does the
> combined LAN now become one TCP\IP network, i.e. will all devices be
> within a single 192.168.0.xxx network ?
>
> Can the wireless access points, when in point to point mode act as a
> normal access point as well ? i.e. if at either end I want to connect a
> wireless equipped laptop do I need an additional wireless access point
> at that end ?
>
> If I want to use DHCP do I set this up on one of the wireless bridges,
> or both - each with a seperate TCP\IP address range ?
>
>
> Stevie
>

Thanks for the comment about homework, from what you are saying it
seems that soem of the features that are advertised dont work to well.


Can anyone suggest a decent referance site for background info on the
various wireless modes and how they are supposed to work ?