Re: Redundant Dot1Q Tunnels

Hi Antonio,

How about using different VLAN IDs for the Metro Tag as suggested by Brian?

Regards,
Alexander Lim

On 26 Feb, 2013, at 6:57 PM, "Antonio Soares" <amsoares_at_netcabo.pt> wrote:

> VLAN100 is the MetroTag that I want to transport across the SP network to
> the remote site.
>
> Do you see a solution to the problem ?
>
> Regards,
>
> Antonio Soares, CCIE #18473 (R&S/SP)
> amsoares_at_netcabo.pt
> http://www.ccie18473.net
>
>
> -----Original Message-----
> From: Brian Dennis [mailto:bdennis_at_ine.com]
> Sent: terga-feira, 26 de Fevereiro de 2013 03:18
> To: Antonio Soares; 'Cisco certification'
> Subject: Re: Redundant Dot1Q Tunnels
>
> Is there a reason the same VLAN 100 is used on the PE switch's interfaces to
> the CE switch?
>
> --
> Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice) bdennis_at_ine.com
>
> INE, Inc.
> http://www.INE.com
>
>
>
> On 2/25/13 7:06 PM, "Antonio Soares" <amsoares_at_netcabo.pt> wrote:
>
>> Hello group,
>>
>> I have requirement that needs redundant Dot1Q Tunnels between switches:
>>
>> SW1===FastEthernet===SW2
>> SW1===GigabitEthernet===SW2
>>
>> SW1 is configured with normal dot1q trunks. SW2 is configured with
>> dot1q tunnel.
>>
>> I made a test in the lab and this setup creates a spanning-tree loop.
>> This is because SW2 has bpdu filtering enabled. And this is internal,
>> the command "spanning-tree bpdufilter disable" doesn't have any effect.
>>
>> In the lab I made the test with FastEthernet interfaces only:
>>
>> SW1===F0/13===F0/13===SW2
>> SW1===F0/14===F0/14===SW2
>>
>> +++++++++++++++++
>> SW1 the CE switch
>> +++++++++++++++++
>> SW1#sh run int f0/13
>> Building configuration...
>>
>> Current configuration : 150 bytes
>> !
>> interface FastEthernet0/13
>> switchport trunk encapsulation dot1q
>> switchport trunk allowed vlan 10,20
>> switchport mode trunk
>> load-interval 30
>> end
>>
>> SW1#sh run int f0/14
>> Building configuration...
>>
>> Current configuration : 150 bytes
>> !
>> interface FastEthernet0/14
>> switchport trunk encapsulation dot1q
>> switchport trunk allowed vlan 10,20
>> switchport mode trunk
>> load-interval 30
>> end
>>
>> SW1#
>>
>> +++++++++++++++++
>> SW2 the PE switch
>> +++++++++++++++++
>> SW2#sh run int f0/13
>> Building configuration...
>>
>> Current configuration : 140 bytes
>> !
>> interface FastEthernet0/13
>> switchport access vlan 100
>> switchport mode dot1q-tunnel
>> no cdp enable
>> spanning-tree bpdufilter enable
>> end
>>
>> SW2#
>> SW2#sh run int f0/14
>> Building configuration...
>>
>> Current configuration : 141 bytes
>> !
>> interface FastEthernet0/14
>> switchport access vlan 100
>> switchport mode dot1q-tunnel
>> no cdp enable
>> spanning-tree bpdufilter disable
>> end
>>
>> SW2#
>>
>> +++++++++++++++++
>> bpdufilter disable has no effect
>> +++++++++++++++++
>> SW2#sh spanning-tree int f0/13 detail
>> Port 15 (FastEthernet0/13) of VLAN0100 is designated forwarding
>> Port path cost 19, Port priority 128, Port Identifier 128.15.
>> Designated root has priority 32868, address 000f.f76d.ac80
>> Designated bridge has priority 32868, address 001f.2711.d580
>> Designated port id is 128.15, designated path cost 19
>> 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 filter is enabled internally <-----------------------------
>> BPDU: sent 0, received 0
>> SW2#
>> SW2#sh spanning-tree int f0/14 detail
>> Port 16 (FastEthernet0/14) of VLAN0100 is designated forwarding
>> Port path cost 19, Port priority 128, Port Identifier 128.16.
>> Designated root has priority 32868, address 000f.f76d.ac80
>> Designated bridge has priority 32868, address 001f.2711.d580
>> Designated port id is 128.16, designated path cost 19
>> 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 filter is enabled internally <-----------------------------
>> BPDU: sent 0, received 0
>> SW2#
>>
>> This creates a loop, both SW1 and SW2 are forwarding on both links for
>> all vlans involved (10 and 20 on the CE side and 100 on the PE side).
>>
>> This is the kind of messages we never want to see in our lives but it
>> happens :)
>>
>> *Mar 1 01:26:53.402: %SW_MATM-4-MACFLAP_NOTIF: Host 0011.21c4.5d00 in
>> vlan
>> 10 is flapping between port Fa0/13 and port Fa0/14 *Mar 1
>> 01:26:53.947: %SW_MATM-4-MACFLAP_NOTIF: Host 0011.21c4.5d00 in vlan
>> 20 is flapping between port Fa0/13 and port Fa0/14
>>
>>
>> In the real scenario, I have a 1Gbps link between the switches and a
>> 200Mbps port-channel as well. The objective is to have the 200M backup
>> if the 1G fails.
>>
>> If I'm not wrong, this is impossible to achieve. Or am I missing
>> something ?
>>
>>
>> Thanks.
>>
>> Regards,
>>
>> Antonio Soares, CCIE #18473 (R&S/SP)
>> amsoares_at_netcabo.pt
>> http://www.ccie18473.net
>>
>>
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Received on Tue Feb 26 2013 - 21:10:47 ART