Providing services for 802.11b and 802.11g on the cisco 1200 access points

Discussion in 'Cisco' started by Chris Davies, Jun 14, 2004.

  1. Chris Davies

    Chris Davies Guest

    Hi All,

    I have an issue with the Cisco 1231G wireless access points.

    I have to provide access for clients with 802.11b cards and also
    clients with 802.11g cards.

    The documentation at the following URL's indicate that this is
    possible using the access point that I have mentioned.

    I also find the same information on the linksys site regarding their
    WAP54G wireless G access point.

    I have trolled through the cisco website but I cannot find any
    information on how this can be achieved.

    I rang our suppliers and the engineer I spoke to informed me that this
    is not the case, you CANNOT enable 802.11b client card connections to
    a Cisco 1231G you have to buy the Cisco 1231b.

    I understood that the 802.11g standard allowed for backwards
    compatibility with 802.11b clients ?

    If anyone can help me out here I would be grateful ?

    Cheers ...
    Drop the ZZZ to reply

    Cheers ...
    Chris Davies, Jun 14, 2004
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  2. I use Cisco 1100 WAPs, 802.11g variety. I have 802.11g and 802.11b
    clients connecting to the same WAP at the same time with no problems
    at all.
    Richard Field, Jun 14, 2004
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  3. Chris Davies

    MC Guest

    I have not been able to get caught up on the 802.11g specs not sure if the
    same behaivor of the 802.11b & a.

    I thought that with access points that are able to run both the 802.11b & a
    modes, that if any lower speed device makes a valid attempted connection
    that the entire access point reverts to the lower speed, all higher speed
    cards then connect at a lower speed.

    If operates the same, then even with a 802.11g capable card that also can do
    802.11b and the access point doing the same then they would most likely
    pick the 802.11g mode. However if a 802.11b only device comes along then
    all will reduce their rates down to the 802.11b mode, hence everyone
    operating at the same time.

    Is this the case ?

    MC, Jun 15, 2004
  4. Chris Davies

    Chris Davies Guest

    Hi Richard,

    Any chance you could post an example of the config you use please ?

    Drop the ZZZ to reply

    Cheers ...
    Chris Davies, Jun 15, 2004
  5. Chris Davies

    AnyBody43 Guest

    I thought that with access points that are able to run both the 802.11b & a


    Cisco, and no less others, seem to have a policy of not making
    such clashes clear. The documentation is full of statements that
    a device does this and a device does that however some obvious
    things like, 'it doesn't do this and that' at the same time are

    The words "no" and "not", seem missing from the authors' vocabulary.
    It must be fun at home:)

    Anyway the documents do seem pretty clear(ish):-

    There are two radio modules available:-

    1. IEEE 802.11a
    2. IEEE 802.11b *or* IEEE 802.11g

    HOWEVER the 1200 series can apparently take two radios and if
    you want 802.11a support as well as b/g you need to install both.

    Maybe it can take two b/g radios and you can have a 'b' and a 'g'?

    The problem is that I suspect that 'g' is required to support 'b'
    as well and so Cisco can say that you can have 'b' and 'g' at the
    same time when you are really running on 'b'. It is true but
    maybe not exactly all that we might want to know.
    AnyBody43, Jun 15, 2004
  6. Chris Davies

    Chris Davies Guest

    On 15 Jun 2004 01:53:46 -0700, (AnyBody43)

    I suspect that your last paragraph covers it really.

    It seems that you can have B and G clients connected as long as you
    limit the speed so that you only have the B range enabled.

    This does of course mean that any G clients connecting will only get a
    maximum speed of 11M.

    I have included some of the IOS config ...

    interface Dot11Radio0
    no ip address
    no ip route-cache
    ssid tsunami
    authentication open
    speed basic-1.0 basic-2.0 basic-5.5 basic-11.0
    rts threshold 2312
    station-role root
    bridge-group 1
    bridge-group 1 subscriber-loop-control
    bridge-group 1 block-unknown-source
    no bridge-group 1 source-learning
    no bridge-group 1 unicast-flooding
    bridge-group 1 spanning-disabled

    Now to see if 802.11b cards will support LEAP.
    Drop the ZZZ to reply

    Cheers ...
    Chris Davies, Jun 15, 2004
  7. Chris Davies

    Chris Davies Guest

    It seems I may have a small bug in my IOS software ..

    Quote from cisco site ..

    "On the 802.11g radio, the default option sets data rates 1, 2, 5.5,
    and 11 to basic, and data rates 6, 9, 12, 18, 24, 36, 48, and 54 to
    enabled. These data rate settings allow both 802.11b and 802.11g
    client devices to associate to the access point's 802.11g radio. "

    Although this looked to be set, after manually setting all the G
    speeds to default and the B speeds to basic all seems to be ok.

    One warning to anyone heading down this path .. make sure that any G
    cards you are working with have the latest drivers and that any B
    cards have the latest firmware as well.

    Thank you to everyone who helped out with this problem.

    Drop the ZZZ to reply

    Cheers ...
    Chris Davies, Jun 15, 2004
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