John, This is from one my 6509's with an MSFC router module, which is similar to your 4006...we do use the trunk allow to put our trunks in the native vlan and the vlans for data/voice...we also use portfast bpdu-guard on the access ports in the floor switches..it stops the potential of loops in the floor/main switches...
I am not sure about the flap error, since its between two uplinks going to two different places.. interface GigabitEthernet3/1 description to sjc5-fxs-sw1 no ip address udld enable mls qos trust cos switchport switchport trunk encapsulation dot1q switchport trunk allowed vlan 1,159,1002-1005 switchport mode trunk switchport nonegotiate ! interface GigabitEthernet3/2 description to sjc5-11-sw1 no ip address udld enable mls qos trust cos switchport switchport trunk encapsulation dot1q switchport trunk allowed vlan 1,151,154,200,1002-1005 switchport mode trunk switchport nonegotiate Larry Letterman Network Engineer Cisco Systems > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of > John Brandis > Sent: Wednesday, April 02, 2003 7:05 PM > To: [EMAIL PROTECTED] > Subject: VLAN Trunk Question and spanning tree [7:66730] > > > hi All, > > Please tell me if I am wrong and best practices > > A trunk link, by default, is a member of all VLANS > > Would it be best practice, to place your trunk ports in a particualr VLAN, > then define what you want pruned/not pruned ? > > Reason I ask is that I am getting the hostflapping error every > now and then, > which first made me believe I had a developer plugging in hubs around the > place. However, now I think its a question of my design/config. Here is an > example of the error on my cat-4006 gig ports which trunk to my floor > switchs. > > Host 00:06:29:F9:75:A2 in vlan 23 is flapping between port Gi2/12 and port > Gi2/11 > > NOTE: 2/12 go's to sw2 and 2/11 go's to sw1, which are connected to one > another as you can see below > > I checked it out, there are no hubs any where that could do this, > and I have > spanning tree in place to stop the redundant links on my floor switch;s > coming back into the core. Here is the config of my trunk ports > on the floor > switch > > SW1 > interface GigabitEthernet0/1 > description link to core > switchport mode trunk > no ip address > ! > interface GigabitEthernet0/2 > description link to sw2 floor switch > switchport mode trunk > no ip address > > SW2 > interface GigabitEthernet0/1 > description link to core > switchport mode trunk > no ip address > ! > interface GigabitEthernet0/2 > description link to sw1 floor switch > switchport mode trunk > no ip address > > If any one can suggest anything, I would appreciate it > (I am interested in the use of the bpdu-port guard, would this > help here ?) > > Thanks > John > Sydney Australia > > > ********************************************************************** > > This email message (and attachments) may contain information that is > confidential to Solution 6. If you are not the intended recipient > you cannot > use, distribute or copy the message or attachments. In such a > case, please > notify the sender by return email immediately and erase all copies of the > message and attachments. Opinions, conclusions and other information in > this message and attachments that do not relate to the official > business of > Solution 6 are neither given nor endorsed by it. > > ********************************************************************* Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66735&t=66730 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
