Re: Ether Channel Query!!

Hey If STP has forwarding both ports, then there will be chance of loop
formation
wat is the actual mechanism
how does it prevent loops at the same time it makes all the ports forwarding

can anyone explain me?

On Mon, Sep 27, 2010 at 8:39 PM, --Hammer-- <bhmccie_at_gmail.com> wrote:

> Thanks Saulat for the quick lab up....
>
> --Hammer--
>
>
>
> On 9/27/2010 9:51 AM, Saulat Ali wrote:
>
>> The bundled ports wont show up in the sh spantree command unless you
>> type in sh span int<physical port> which will show them in forwarding
>> state. As mentioned by Hammer as soon as you put the physical port into
>> an ether channel spanning tree process only shows the logical port in
>> the sh span tree.
>>
>> See below e.g .. port 1/0/52 and 2/0/52 wont show up in the span tree
>> process but you can view their status by entering sh span<vlan> int gig
>> 1/0/52<detail> command,
>>
>> #sh etherchannel summ
>>
>> Group Port-channel Protocol Ports
>> ------+-------------+-----------+---------------------------------------
>> --------
>> 1 Po1(SU) LACP Gi1/0/52(P) Gi2/0/52(P)
>>
>> #sh run int gig 1/0/52
>> Building configuration...
>>
>> Current configuration : 181 bytes
>> !
>> interface GigabitEthernet1/0/52
>> switchport trunk encapsulation dot1q
>> switchport mode trunk
>> switchport nonegotiate
>> channel-group 1 mode active
>> end
>>
>> #sh run int gig 2/0/52
>> Building configuration...
>>
>> Current configuration : 181 bytes
>> !
>> interface GigabitEthernet2/0/52
>> switchport trunk encapsulation dot1q
>> switchport mode trunk
>> switchport nonegotiate
>> channel-group 1 mode active
>> end
>>
>> #sh run int po1
>> Building configuration...
>>
>> Current configuration : 144 bytes
>> !
>> interface Port-channel1
>> switchport trunk encapsulation dot1q
>> switchport mode trunk
>> switchport nonegotiate
>> end
>>
>>
>> #sh span vlan 2
>> VLAN0002
>> Spanning tree enabled protocol rstp
>> Root ID Priority 24578
>> Address 0022.be9f.ab80
>> This bridge is the root
>> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>>
>> Bridge ID Priority 24578 (priority 24576 sys-id-ext 2)
>> Address 0022.be9f.ab80
>> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>> Aging Time 300
>>
>> Interface Role Sts Cost Prio.Nbr Type
>> ---------------- ---- --- --------- --------
>> --------------------------------
>> Po1 Desg FWD 3 128.616 P2p
>>
>>
>> #sh spanning-tree vlan 2 int gi2/0/52 de
>> Port 616 (Port-channel1) of VLAN0002 is designated forwarding
>> Port path cost 3, Port priority 128, Port Identifier 128.616.
>> Designated root has priority 24578, address 0022.be9f.ab80
>> Designated bridge has priority 24578, address 0022.be9f.ab80
>> Designated port id is 128.616, designated path cost 0
>> Timers: message age 0, forward delay 0, hold 0
>> Number of transitions to forwarding state: 1
>> Link type is point-to-point by default
>> BPDU: sent 25045070, received 73
>>
>> #sh spanning-tree vlan 2 int gig1/0/52 de
>> Port 616 (Port-channel1) of VLAN0002 is designated forwarding
>> Port path cost 3, Port priority 128, Port Identifier 128.616.
>> Designated root has priority 24578, address 0022.be9f.ab80
>> Designated bridge has priority 24578, address 0022.be9f.ab80
>> Designated port id is 128.616, designated path cost 0
>> Timers: message age 0, forward delay 0, hold 0
>> Number of transitions to forwarding state: 1
>> Link type is point-to-point by default
>> BPDU: sent 25045075, received 73
>>
>> #sh spanning-tree vlan 2 int po1 de
>> Port 616 (Port-channel1) of VLAN0002 is designated forwarding
>> Port path cost 3, Port priority 128, Port Identifier 128.616.
>> Designated root has priority 24578, address 0022.be9f.ab80
>> Designated bridge has priority 24578, address 0022.be9f.ab80
>> Designated port id is 128.616, designated path cost 0
>> Timers: message age 0, forward delay 0, hold 0
>> Number of transitions to forwarding state: 1
>> Link type is point-to-point by default
>> BPDU: sent 25045080, received 73
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> CCIE KID
>> Sent: 27 September 2010 15:29
>> To: --Hammer--
>> Cc: ccielab_at_groupstudy.com
>> Subject: Re: Ether Channel Query!!
>>
>> Hey can u explain me the process and what r the packets exchanged so
>> that
>> how does STP come to know that that the particular port is bundled
>>
>> What will be in the sh spanning-tree detail for that particular port
>> which
>> is been blocking
>> Whether it will be of forwarding state
>>
>> That bundled link will be in which state in forwarding state in STP ah??
>> pls brief me about that??
>>
>> On Mon, Sep 27, 2010 at 7:51 PM, --Hammer--<bhmccie_at_gmail.com> wrote:
>>
>> CCIE KID,
>>> When you "bond" the two physical interfaces into a logical port
>>>
>> channel,
>>
>>> you will pass traffic over both Fa0/1 and Fa0/2. STP treats the entire
>>> collection of physical interfaces as a single logical port. This is
>>>
>> all
>>
>>> negotiated between the endpoints. Does that help?
>>>
>>> --Hammer--
>>>
>>>
>>>
>>> On 9/27/2010 9:17 AM, CCIE KID wrote:
>>>
>>> I have a doubt in ether Channel
>>>>
>>>> This is my scenario
>>>>
>>>> SW1 fa0/1-------------------------------------------fa 0/1 SW2
>>>> fa0/2-------------------------------------------fa 0/2
>>>>
>>>> In STP SW1 is the root bridge and SW2 is the non root bridge , In SW2
>>>>
>>> fa
>>
>>> 0/1
>>>> is in forwarding state and fa 0/2 is in blocking state .
>>>> So in Ether channel, if we bundle fa0/1 and fa 0/2 ,traffic cannot be
>>>> passed
>>>> through fa 0/2 .
>>>> How Ether Channel informs STP about the bundling and makes the fa 0/2
>>>>
>>> into
>>
>>> forwarding
>>>> Can anyone explain me the process
>>>> I am expecting the experts to explain
>>>>
>>>>
>>>>
>>>> With Warmest Regards,
>>>>
>>>> CCIE KID
>>>> IN PURSUIT OF CCIE
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net
>>>>
>>>>
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