From: Bit Gossip (bit.gossip@chello.nl)
Date: Mon Aug 27 2007 - 13:02:03 ART
For PAgP, LACP and ULD to work it is mandatory that the intermediate switch
emulates point-to-point connections which means 2 different VLANs
"PAgP, LACP, and UDLD protocol tunneling is only intended to emulate a
point-to-point topology. An erroneous configuration that sends tunneled
packets to many ports could lead to a network failure. "
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12225see/scg/swtunnel.htm
Thanks,
Bit.
----- Original Message -----
From: "Joseph Brunner" <joe@affirmedsystems.com>
To: "'CCIE 19999'" <ccie@iprimus.com.au>; "'Gregory Gombas'"
<ggombas@gmail.com>; "'Cisco certification'" <ccielab@groupstudy.com>
Sent: Monday, August 27, 2007 2:35 AM
Subject: RE: IE Lab9 Task 1.7 L2 Tunnel
>I tried to get it going as the task hinted, with 1 vlan only. The channel's
> kept bouncing and pings were not successful. I realized how etherchannel
> is
> a POINT TO POINT technology. Using 1 vlan for "both dot1q tunnels" would
> break that point to point technology, and make it running etherchannel via
> hub (of sorts)...
>
> I did it with 2 vlans, and it worked, so I verified, add the points and
> kept
> going.
>
> LOL
>
> -Joe
>
> -----Original Message-----
> From: CCIE 19999 [mailto:ccie@iprimus.com.au]
> Sent: Sunday, August 26, 2007 7:32 PM
> To: 'Joseph Brunner'; 'Gregory Gombas'; 'Cisco certification'
> Subject: RE: IE Lab9 Task 1.7 L2 Tunnel
>
> Joe,
>
> When you apply the command L2protocol-tunnel cdp, the end ports would see
> each other directly connected. Isn't it? Also, the task says, IF YOU NEED
> ANY ADDITIONAL VLANS, then use 100. And you are using 100 and 101. Is that
> a
> correct approach?
>
> So in my opinion, of you can get this working without using any additional
> vlans, the solutions must be correct.
>
> Any addional thoughts welcome.
>
> Regards,
> Shine
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Joseph Brunner
> Sent: Monday, 27 August 2007 8:36 AM
> To: 'Gregory Gombas'; 'Cisco certification'
> Subject: RE: IE Lab9 Task 1.7 L2 Tunnel
>
> Because they are asking you to make the logical topology do one thing,
> (two DIRECT links between Sw3 & Sw4 using the stated ports), when in the
> physical topology those ports are indeed going to SW1.
>
> So SW1 must be INVISIBLE between SW3 & 4 on this L3 ether-channel link.
>
>>I was able to get this working simply with the l2protocol tunnel
>>command on the middle switch with the ports in access mode.
>
> Read the task again, Look at where they say "if an additional VLAN is
> needed
> use VLAN 100"... This should give you the hint you need to approach this
> task - Dot1q-tunnel mode on SW1, the intermediary...
>
> Look at the solution where they use VLAN 100 + VLAN 101 as each
> "link" between SW3 and SW4 needs an intermediary vlan to tunnel the
> etherchannel on. I tried this task without making two vlans and the
> channel
> didn't work properly. Originally, I just tried to use VLAN 100 on all 4
> ports of SW1. I realized the channeling was getting confused and it was
> looping traffic. I created a second vlan (like they did, 101) and the
> channel did come up fine.
>
> With your solution, what was your verification you had completed the task?
> Did you verify on SW3 & SW4 "show etherchannel summary" ?
> Did you verify on SW1 "show interface switch | beg 0/17 ?
> Did you verify on SW1 "show interface switch | beg 0/18 ?
> Did you verify on SW1 "show interface switch | beg 0/20 ?
> Did you verify on SW1 "show interface switch | beg 0/21 ?
>
>
> -Joe
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Gregory Gombas
> Sent: Sunday, August 26, 2007 5:38 PM
> To: Cisco certification
> Subject: IE Lab9 Task 1.7 L2 Tunnel
>
> The task requires you to connect two switches via a layer 3
> etherchannel by tunneling through another switch in the middle.
>
> The solution states to use this config on the middle switch:
> switchport mode dot1q-tunnel
> l2protocol tunnel cdp
>
> My question is why are they using a dot1q-tunnel when the end switches
> are not even using dot1q encapsulation (they are layer 3 ports)?
> I was able to get this working simply with the l2protocol tunnel
> command on the middle switch with the ports in access mode.
>
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