also to add to this in PAgP
Network devices are classified as PAgP physical learners or aggregate-port
learners. A device is a physical learner if it learns addresses by physical
ports and directs transmissions based on that knowledge. A device is an
aggregate-port learner if it learns addresses by aggregate (logical) ports.
The learn method must be configured the same at both ends of the link.
but then there is a *NOTE* which confuses me:
The switch supports address learning only on aggregate ports even though the
*physical-port* keyword is provided in the CLI. The *pagp
learn-method*command and the
*pagp port-priority* command have no effect on the switch hardware, but they
are required for PAgP interoperability with devices that only support
address learning by physical ports.
I haven't had a chance to test this, yet...
later..
garry..
-- Garry L. Baker "There is no 'patch' for stupidity." - www.sqlsecurity.com On Mon, Sep 27, 2010 at 12:15 PM, Paul Cocker <paul.cocker_at_gmx.com> wrote: > Should have attached the below, as you see, the frame wasn't seen coming > from port 13, 14 or 15, it was seen coming from the port-channel. > > SW2#sh mac-address-table > Mac Address Table > ------------------------------------------- > > Vlan Mac Address Type Ports > ---- ----------- -------- ----- > > 1 000e.83cd.a88e DYNAMIC Po10 > > > SW2#sh etherchannel summary > Flags: D - down P - in port-channel > I - stand-alone s - suspended > H - Hot-standby (LACP only) > R - Layer3 S - Layer2 > U - in use f - failed to allocate aggregator > u - unsuitable for bundling > w - waiting to be aggregated > d - default port > > > Number of channel-groups in use: 1 > Number of aggregators: 1 > > > Group Port-channel Protocol Ports > > ------+-------------+-----------+----------------------------------------------- > 10 Po10(SU) - Fa0/13(P) Fa0/14(P) Fa0/15(P) > > > > > > On 27/09/2010 18:06, Paul Cocker wrote: > >> If a switch doesn't have an entry in its mac-address-table for a >> particular destination, it forwards the frame out of all ports >> (including port channels) EXCEPT the port it was received on. When there >> are loops in the topology, this can cause a storm, as it can keep coming >> back around. >> >> Are we agreed so far? >> >> In your case, the frame is received on a port-channel. So, if the switch >> doesn't know the destination mac, it will be forwarded out all ports in >> that vlan (including other port channels), except the port-channel that >> it was received on. >> >> Hey presto, no switching loop. >> >> Regards, >> Paul >> >> >> On 27/09/2010 17:47, HEMANTH RAJ wrote: >> >>> yeah Hammer u right ,But my question is how that LACP/PagP protocols >>> handle >>> and sends the traffic to the destination without any formation of loop >>> >>> In reality if there are two ports which is forwarding and there will be a >>> formation of loop,MAC table instability which results in a broadcast >>> storm >>> how does it is not happening? >>> >>> >>> >>> On Mon, Sep 27, 2010 at 10:12 PM, --Hammer--<bhmccie_at_gmail.com> wrote: >>> >>> That's the trick. Both ports are NOT forwarding. The port-channel IS. >>>> The >>>> port-channel is what STP monitors and places in a forwarding state. >>>> It is >>>> unaware of the individual ports. On the other side of the cables, the >>>> receiving switch is receiving STP on the port-channel. Not on an >>>> individual >>>> port associated with it. So the STP merely hands instructions to the >>>> port-channel interface to send out BPDUs. It doesn't care how they get >>>> there. The Port-channel interface (and associated PAGP/LACP protocol) >>>> are >>>> responsible for getting the BPDU across the wire. STP does not see both >>>> ports in a forwarding state. >>>> >>>> --Hammer-- >>>> >>>> >>>> On 9/27/2010 11:36 AM, HEMANTH RAJ wrote: >>>> >>>> hey Hameer i m asking about loop avoiding mechanism .If both the >>>> ports are >>>> forwarding and STP is not aware of the both the ports,then thee will >>>> be a >>>> chance of loop forming on that particular channel >>>> >>>> On Mon, Sep 27, 2010 at 10:01 PM, --Hammer--<bhmccie_at_gmail.com> wrote: >>>> >>>> Someone step in if I mis-quote something. >>>>> >>>>> You're statement is a bit off. STP is not forwarding on both ports. >>>>> STP is >>>>> forwarding on the port-channel. STP is no longer aware of the >>>>> individual >>>>> ports. How the channel handles STP traffic is a different matter. I >>>>> don't >>>>> think STP sends traffic on both ports in a LACP or PAGP channel. I >>>>> think the >>>>> L2 protos (STP, CDP, DTP, etc) are just passed on the primary link. >>>>> I'm not >>>>> where I can google this to confirm it. Anyone? >>>>> >>>>> --Hammer-- >>>>> >>>>> >>>>> On 9/27/2010 11:25 AM, HEMANTH RAJ wrote: >>>>> >>>>> 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 >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> _______________________________________________________________________ >>>>>>> >>>>>>> >>>>>>> Subscription information may be found at: >>>>>>>> >>>>>>>>> http://www.groupstudy.com/list/CCIELab.html >>>>>>>>> >>>>>>>>> >>>>>>>>> Blogs and organic groups at http://www.ccie.net >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________________________________ >>>>>>>> >>>>>>>> >>>>>>> Subscription information may be found at: >>>>>>>> http://www.groupstudy.com/list/CCIELab.html >>>>>>>> >>>>>>>> >>>>>>> >>>>>> Blogs and organic groups at http://www.ccie.net >>>>>> >>>>>> >>>>>> _______________________________________________________________________ >>>>>> >>>>>> Subscription information may be found at: >>>>>> http://www.groupstudy.com/list/CCIELab.html >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> -- >>>>> Problems arise Bcoz we talk,prblms r not solve bcoz we dont talk So >>>>> gud r >>>>> bad talk to ur affectionate one's freely >>>>> >>>>> Urs Friendly, >>>>> HP HEMANTH RAJ >>>>> >>>>> >>>>> >>>> >>>> -- >>>> Problems arise Bcoz we talk,prblms r not solve bcoz we dont talk So >>>> gud r >>>> bad talk to ur affectionate one's freely >>>> >>>> Urs Friendly, >>>> HP HEMANTH RAJ >>>> >>> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html >> > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Mon Sep 27 2010 - 12:45:11 ART
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