Ether-channel cross switches

Discussion in 'Cisco' started by Bjarke Andersen, Sep 20, 2006.

  1. Got 2 Catalyst 4006 with Supervisor Engine III in redundant spanning-tree
    setup.

    Now my systemsadministrator needs a ether-channel but to keep his servers
    redundant he would like to have the interfaces in each Catalyst but as same
    ether-channel.

    Is this possible?

    --
    Bjarke Andersen
    Wanna reply by email? Remove the spammer in address
     
    Bjarke Andersen, Sep 20, 2006
    #1
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  2. Bjarke Andersen

    Brian V Guest

    "Bjarke Andersen" <usenet@*spammer*bjoeg.dk> wrote in message
    news:Xns98448B148D7B9bjoegdk@130.225.247.90...
    > Got 2 Catalyst 4006 with Supervisor Engine III in redundant spanning-tree
    > setup.
    >
    > Now my systemsadministrator needs a ether-channel but to keep his servers
    > redundant he would like to have the interfaces in each Catalyst but as
    > same
    > ether-channel.
    >
    > Is this possible?
    >
    > --
    > Bjarke Andersen
    > Wanna reply by email? Remove the spammer in address



    Nope, channels need to be on the same switch.
     
    Brian V, Sep 20, 2006
    #2
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  3. "Brian V" <die_spammer@no_spam.com> crashed Echelon writing
    news::

    > Nope, channels need to be on the same switch.


    And when saying that you mean ether-channel in general og just this model
    of switch?

    --
    Bjarke Andersen
    Wanna reply by email? Remove the spammer in address
     
    Bjarke Andersen, Sep 20, 2006
    #3
  4. Bjarke Andersen wrote:

    >>Nope, channels need to be on the same switch.

    >
    > And when saying that you mean ether-channel in general og just this model
    > of switch?


    Etherchannel in general. The only 'cross-switch' Etherchannel possible
    is to different members of a 3750-series switch stack.

    Regards,

    Marco.
     
    M.C. van den Bovenkamp, Sep 20, 2006
    #4
  5. Bjarke Andersen

    Guest

    M.C. van den Bovenkamp wrote:
    > Bjarke Andersen wrote:
    >
    > >>Nope, channels need to be on the same switch.

    > >
    > > And when saying that you mean ether-channel in general og just this model
    > > of switch?

    >
    > Etherchannel in general. The only 'cross-switch' Etherchannel possible
    > is to different members of a 3750-series switch stack.


    Hi,

    I believe that some end stations use "Etherchannel" to achieve
    resilient
    network connections in the case where there are two connections,
    one to each of two different switches.

    No bundling actually occurs and the station uses only one
    link unless it has failed in which case it uses the other one.

    The station configuration is identical to "Bundling" and the
    switches get no special configuration at all.

    Very nice I say.

    IIRC it was HP servers with Windows.

    I have no idea what happens if you were to use
    say 4 connections, two to each switch.

    http://www.brianmadden.com/content/content.asp?id=584
    Switch Assisted Load Balancing (SLB)

    Seems to describe it.

    The article tantalisingly says:
    "If automatic port trunking is required, 802.3ad Dynamic team
    type should be used with an IEEE 802.3ad Dynamic capable switch."

    But does not describe the behaviour.
     
    , Sep 21, 2006
    #5
  6. Bjarke Andersen

    stephen Guest

    <> wrote in message
    news:...
    >
    > M.C. van den Bovenkamp wrote:
    > > Bjarke Andersen wrote:
    > >
    > > >>Nope, channels need to be on the same switch.
    > > >
    > > > And when saying that you mean ether-channel in general og just this

    model
    > > > of switch?

    > >
    > > Etherchannel in general. The only 'cross-switch' Etherchannel possible
    > > is to different members of a 3750-series switch stack.

    >
    > Hi,
    >
    > I believe that some end stations use "Etherchannel" to achieve
    > resilient
    > network connections in the case where there are two connections,
    > one to each of two different switches.


    Etherchannel is explicitly defined to be a link between 2 devices, with 2 or
    more links in the bundle.
    >
    > No bundling actually occurs and the station uses only one
    > link unless it has failed in which case it uses the other one.


    This may happen if the device can run Etherchannel, but isnt operating the
    active protocol. If the switch end is not hard configred to use EC on the
    same switch, or the switch doesnt allow the selected ports to be part of the
    same bundle, then the bundle will not come up, and you have 2 or more
    separate links.
    >
    > The station configuration is identical to "Bundling" and the
    > switches get no special configuration at all.


    EC in "desirable"? mode is default AFAIR
    >
    > Very nice I say.
    >
    > IIRC it was HP servers with Windows.
    >
    > I have no idea what happens if you were to use
    > say 4 connections, two to each switch.
    >
    > http://www.brianmadden.com/content/content.asp?id=584
    > Switch Assisted Load Balancing (SLB)


    There may be other ways to do this
    - EC is there to allow the device to use the same MAC on each port and
    distribute the load - you can "team" with different MAC addresses per port
    at least for outbound traffic (which is all you need on many server setups).
    - some of the microsoft teaming schemes can use a source multicast MAC
    address, and if you can force your switch(es) to work with that it sort of
    can be made to work, although you have to be careful about background
    traffic.
    - not many servers can keep a GigE port busy - so a lot of the time the
    load balancing aspects are irrelevant......
    >
    > Seems to describe it.
    >
    > The article tantalisingly says:
    > "If automatic port trunking is required, 802.3ad Dynamic team
    > type should be used with an IEEE 802.3ad Dynamic capable switch."


    Again 802.1ad is defined to have 1 device at each end of the link set. the
    LACP protocol is part of teh standard to control the protocol and bring up
    the group.

    The only kit i know of that can run a 802.1ad group split across 2 devices
    is some of the Nortel switches - main one i worked on was the passport 8600.
    >
    > But does not describe the behaviour.
    >

    --
    Regards

    - replace xyz with ntl
     
    stephen, Sep 23, 2006
    #6
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