Task 2.3 Layer 2 Tunneling

Hi,

Just a quick heads up for the Tech Edit team :

1) Strangely enough, I didn't need to add the no switchport config to the f0/16 on SW3 and SW4. Maybe newer IOS versions automatically add it when a L3-specific is set on the port?

2) The SG for this tasks contains a typo in the interface numbers.

 

Eric

Comments

  • Update from 2011,

     Tech Edit Team, the typo are still there can you please.

    What would be the implications of adding the "switchport mode dot1q-tunnel" on these interfaces instead of just  "l2protocol-tunnel cdp" as in SG?

  • Since i'm doing this task righ tnow, i figured i'd chime in.  I think if you configured the interfaces fa0/16 and fa0/19 as switchport mode dot1q-tunnel then you'd be adding a second dot1q tag to the traffic.  In doing so you would need to increase your mtu size.  Being that ports 16 and 19 are just used as transport for the L3 traffic going between SW3 and SW4 and they arent' actually trunking, I think its best to just do as SG suggests and simply L2-tunnel protocol CDP traffic for SW3 and SW4 through Sw2.

    If anyone else has a different opinion please chime in, thank you.

     

    Wil

  • Works perfectly with the below config,

     

    RSRack8SW2#show run int fa1/0/16

    Building configuration...

     

    Current configuration : 74 bytes

    !

    interface FastEthernet1/0/16

     l2protocol-tunnel cdp

     no cdp enable

    end

     

    RSRack8SW2#show run int fa1/0/19

    Building configuration...

     

    Current configuration : 74 bytes

    !

    interface FastEthernet1/0/19

     l2protocol-tunnel cdp

     no cdp enable

    end

     

    As SW3 and 4 are not trunking, SW2 will associate their MAC addresses with VLAN1 and simply switch their traffic as normal.

     

    RSRack8SW2#show mac address-table interface fa1/0/16

              Mac Address Table

    -------------------------------------------

     

    Vlan    Mac Address       Type        Ports

    ----    -----------       --------    -----

       1    0013.1a06.dd00    DYNAMIC     Fa1/0/16

    Total Mac Addresses for this criterion: 1

    RSRack8SW2#show mac address-table interface fa1/0/19

              Mac Address Table

    -------------------------------------------

     

    Vlan    Mac Address       Type        Ports

    ----    -----------       --------    -----

       1    000b.4636.6800    DYNAMIC     Fa1/0/19

    Total Mac Addresses for this criterion: 1

    RSRack8SW2#

     

    RSRack8SW4#

    RSRack8SW4#show cdp neigh

    Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

                      S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

     

    Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID

    RSRack8SW2       Fas 0/17           158          S I      WS-C3750-4Fas 1/0/20

    RSRack8SW3       Fas 0/16           173          S I      WS-C3550-2Fas 0/16

    RSRack8R4        Fas 0/4            175         R S I     Cisco 1841Fas 0/1

    RSRack8SW4#ping 128.8.109.9   

     

    Type escape sequence to abort.

    Sending 5, 100-byte ICMP Echos to 128.8.109.9, timeout is 2 seconds:

    !!!!!

    Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

    RSRack8SW4#

     

    Marc

  • switchport mode dot1q-tunnel and system mtu 1504 is needed on the switch 2

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