[c-nsp] OTV on-a-stick

Tue May 15 13:27:41 EDT 2012

If using a single OTV VDC to connect two 'client' (DCI) VDCs over the core,
I would connect the OTV VDC to the core, not back to one of the 'client'
VDCs, again because it creates a dependency between the 'client' VDCs. (If
VDC 1 is down, and VDC 1 does L3 and/or site VLAN for OTV, then VDC 2 DCI
will be down as well).

(The OTV VDC can only have a single join interface).

-A

-----Original Message-----
From: Antonio Soares [mailto:amsoares at netcabo.pt] 
Sent: 15. maj 2012 18:32
To: 'Asbjorn Hojmark - Lists'
Cc: cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] OTV on-a-stick

Thanks for the feedback, in fact we won't deploy this in any production
network without having Cisco saying it works and it's supported :)

The idea is to extend the concept. We have this:

VDC1===Layer 2 (VLANs 100,101,...)===OTV===Layer 3===VDC1--->Layer 3 to
remote DC

And we want to add this:

VDC2===Layer 2 (VLANs 200,201,...)===OTV

In the case we have overlapping Vlans, the option would be the creation of a
second OTV VDC:

VDC1===Layer 2 (VLANs 100,101,...)===OTV 1===Layer 3===VDC1--->Layer 3 to
remote DC

VDC2===Layer 2 (VLANs 100,101,...)===OTV 2=== ???

Above I don't know if we can configure the Join interface to the same VDC1
or if we need to do it to VDC2. Then since VDC1 is the VDC that connects to
the other DC, we would need a L3 connection between VDC2 and VDC1.

I've come across these 4 scenarios:

http://ccie18473.net/otv-on-a-stick-3.jpg

Scenario 1 is what I want. Scenario 3 is for situations with overlapping
Vlans.

Scenarios 2 and 4, I thought initially that the Internal and Join interfaces
should connect to the same VDC, maybe this is not necessary at all.

Regards,

Antonio Soares, CCIE #18473 (R&S/SP)
amsoares at netcabo.pt
http://www.ccie18473.net

-----Original Message-----
From: Asbjorn Hojmark - Lists [mailto:lists at hojmark.org]
Sent: terça-feira, 15 de Maio de 2012 15:59
To: 'Antonio Soares'
Cc: cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] OTV on-a-stick

You might be able to make that work in the lab, at least with 'switch trunk
allow' so that you don't bridge between the internal interfaces, and if you
make sure that you didn't have overlapping VLAN numbers to extend.

But I wouldn't consider it best practice.

The OTV VDC needs a site VLAN, which would exist on one of the L2
interfaces, but not both, thus making OTV functionality for one 'client' VDC
dependent on the life of the other. Not really where I'd want to go.

If you used a separate physical interface for the site VLAN, it would make
slightly more sense, but you'd still want to be careful with which
interfaces were allowed on the insite, and not to overlap them in the
overlay... and it's not likely to be solution tested and supported from
Cisco, I would think, which means that you should do a lot more testing
yourself.

-A

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Antonio Soares
Sent: 14. maj 2012 12:15
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] OTV on-a-stick

Guys, any comments to this OTV on-a-stick question ?

Thanks.

Regards,

Antonio Soares, CCIE #18473 (R&S/SP)
amsoares at netcabo.pt
http://www.ccie18473.net

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Antonio Soares
Sent: quinta-feira, 10 de Maio de 2012 19:09
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] OTV on-a-stick

Hello group,

Anyone knows if having more than one Routing VDC is a supported deployment ?

Basically I want OTV on-a-stick like we have bellow but I want another VDC
to make use of the OTV VDC:

http://www.cisco.com/en/US/docs/solutions/Enterprise/Data_Center/DCI/whitepa
per/DCI_1.html#wp1215970

So I would need to create a second Internal Interface connected to the new
Routing VDC and use the existing Join Interface connected to the already in
place Routing VDC. Does it work ?

In terms of configuration, it should be something like this:

interface Overlay0
  otv join-interface ethernet1/1

interface Ethernet1/1
  description Layer-3-to-Routing-VDC-1 (join interface)

interface Ethernet1/2
  description Layer2-to-Routing-VDC-1 (internal interface)
  switchport

interface Ethernet1/3
  description Layer2-to-Routing-VDC-2 (internal interface)
  switchport

Thanks.

Regards,

Antonio Soares, CCIE #18473 (R&S/SP)
amsoares at netcabo.pt
http://www.ccie18473.net

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