Bridge priority and sys-id-ext number?

Discussion in 'Cisco' started by BB, Jan 17, 2005.

  1. BB

    BB Guest

    Anyone can help me explain what the "sys-id-ext" parameter in show
    spanning-tree below is?

    Spanning tree mode MST
    Instance 0
    VLANs Mapped: 2-4094
    Designated Root 00-03-6c-aa-14-01
    Designated Root Priority 32770 (root priority: 32768, sys ID ext: 2)
    Designated Root Cost 2000000
    Designated Root Port 4/1

    thanks
    BB, Jan 17, 2005
    #1
    1. Advertising

  2. In article <>, BB <> wrote:
    :Anyone can help me explain what the "sys-id-ext" parameter in show
    :spanning-tree below is?

    :VLANs Mapped: 2-4094
    :Designated Root Priority 32770 (root priority: 32768, sys ID ext: 2)

    http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00800e46f8.html

    The bridge priority is combined with the system ID extension (that
    is, the ID of the VLAN) to create the bridge ID priority for the VLAN.

    Notice the '2' of the sys id matches the '2' of the first vlan number.
    --
    Those were borogoves and the momerathsoutgrabe completely mimsy.
    Walter Roberson, Jan 17, 2005
    #2
    1. Advertising

  3. BB

    BB Guest

    Thank you,


    But What is the Bridge ID priority?
    Bridge priority or Bridge ID priority is used for Spanning Tree Protocol?

    BB

    "Walter Roberson" <-cnrc.gc.ca> wrote in message
    news:csfksh$ivu$...
    > In article <>, BB <>

    wrote:
    > :Anyone can help me explain what the "sys-id-ext" parameter in show
    > :spanning-tree below is?
    >
    > :VLANs Mapped: 2-4094
    > :Designated Root Priority 32770 (root priority: 32768, sys ID ext: 2)
    >
    >

    http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00800e46f8.html
    >
    > The bridge priority is combined with the system ID extension (that
    > is, the ID of the VLAN) to create the bridge ID priority for the VLAN.
    >
    > Notice the '2' of the sys id matches the '2' of the first vlan number.
    > --
    > Those were borogoves and the momerathsoutgrabe completely mimsy.
    BB, Jan 17, 2005
    #3
  4. In article <>, BB <> wrote:
    :Thank you,
    :But What is the Bridge ID priority?
    :Bridge priority or Bridge ID priority is used for Spanning Tree Protocol?

    The Bridge ID Priority is used for Spanning Tree purposes.

    Please have a look at the document I referenced: it goes into
    detail about all the different ways to configure spanning trees.
    In particular, the default priority is dependant on which version
    of the spanning tree you have set up.

    http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00800e46f8.html
    --
    Ceci, ce n'est pas une idée.
    Walter Roberson, Jan 17, 2005
    #4
  5. BB

    BB Guest

    Thanks, I have checked your referenced document, but I still don't know why
    they use Bridge ID priority for STP instead Bridge Priority.

    BB
    "Walter Roberson" <-cnrc.gc.ca> wrote in message
    news:csg9jt$em8$...
    > In article <>, BB <>

    wrote:
    > :Thank you,
    > :But What is the Bridge ID priority?
    > :Bridge priority or Bridge ID priority is used for Spanning Tree Protocol?
    >
    > The Bridge ID Priority is used for Spanning Tree purposes.
    >
    > Please have a look at the document I referenced: it goes into
    > detail about all the different ways to configure spanning trees.
    > In particular, the default priority is dependant on which version
    > of the spanning tree you have set up.
    >
    >

    http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00800e46f8.html
    > --
    > Ceci, ce n'est pas une idée.
    BB, Jan 18, 2005
    #5
  6. BB

    aswath Guest

    Hi,

    In each system the bridgeId for the spanntree must be unique. For that
    in std mstp the instance id is concatenated to get a unique bridgeId
    for each spanning tree. In cisco PVST there is a spanning tree running
    for each vlan. so vlan id is used as the extended id to get a unique
    bridge id for the entire system.

    Regards,
    Aswath.
    aswath, Jan 18, 2005
    #6
  7. BB

    BB Guest

    Thank you,
    allmost clear
    "aswath" <> wrote in message
    news:...
    > Hi,
    >
    > In each system the bridgeId for the spanntree must be unique. For that
    > in std mstp the instance id is concatenated to get a unique bridgeId
    > for each spanning tree. In cisco PVST there is a spanning tree running
    > for each vlan. so vlan id is used as the extended id to get a unique
    > bridge id for the entire system.
    >
    > Regards,
    > Aswath.
    >
    BB, Jan 19, 2005
    #7
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Moon
    Replies:
    2
    Views:
    4,862
  2. John Edwards

    Question about Aperture priority and Shutter Priority

    John Edwards, Jan 4, 2005, in forum: Digital Photography
    Replies:
    8
    Views:
    486
    Owamanga
    Jan 5, 2005
  3. ½ Confused

    Should I use shutter-priority or appurature-priority?

    ½ Confused, Feb 21, 2006, in forum: Digital Photography
    Replies:
    4
    Views:
    490
    Neil Ellwood
    Feb 22, 2006
  4. Replies:
    13
    Views:
    680
    David Ruether
    Sep 14, 2006
  5. Chico
    Replies:
    21
    Views:
    1,820
    ihary
    Jun 23, 2008
Loading...

Share This Page