[c-nsp] how to connect vss-setup via mpls core

[Arie Vayner (avayner)]

Arne,

In this case you would have a local VSS pair in each local site, and you
just wish to interconnect the different sites together with an end to
end Layer 2 support.

The most trivial solution would be to get a redundant point to point
Layer 2 service (2 layer 2 circuits) which would be used to connect the
6500 devices. As you are running VSS, the two links can be bundled into
a MEC (Multichassis EtherChannel), and then you can allow the specific
VLANs to be bridged across (and another VLAN for Layer 3 connectivity).

The disadvantage of this solution is that you carry the Spanning Tree
state across this link. If a link fails inside DC1, the TCN would be
carried to the other side as well, causing a MAC relearning event.
As you are on VSS, this is less critical, as you would most likely be
running MEC to the access layer switches as well.
You can also filter STP on the WAN link, but then you run into a
(slight) risk of a look due to some crazy failure scenario.

This option is described here:
http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/white_p
aper_c11_493718.html#wp9000207

Be aware that this design is strictly proposed for dual DC designs. If
you need to introduce a 3rd DC into the topology, you can't just connect
it to other pair using the same solution. This would create a layer 2
loop across the DCs.
We have other (slightly more complex) solutions for >2 DC designs.

Arie

-----Original Message-----
From: Arne Larsen / Region Nordjylland [mailto:arla at rn.dk] 
Sent: Sunday, January 17, 2010 09:41
To: cisco-nsp at puck.nether.net
Cc: Arie Vayner (avayner)
Subject: SV: [c-nsp] how to connect vss-setup via mpls core


 Hi Arie.

Sorry for not explaining the setup in detail. But anyway this is the
case.

layer2 sw  ---6500			6500 --- layer2 sw
 |        > vss1   - (MPLS-Core) -  vss2 < 
layer2 sw ----6500 			6500 --  layer2 sw


Each site has a full vss environment with it's own local layer 2
switches.
What I'll like to able to do is, setup a few Vlan's on both sites that
can host servers on the same broadcast domain. 
Further more I'll like to able to announce the layer3 connection on the
Vlan via bgp to our costumers. 
How is it possible to enable a layer3 interface on the Vlan in each
local site and run eompls or vpls between the 2 sites on layer2 .

Arne

-----Oprindelig meddelelse-----
Fra: Arie Vayner (avayner) [mailto:avayner at cisco.com] 
Sendt: 16. januar 2010 21:08
Til: Arne Larsen / Region Nordjylland; cisco-nsp at puck.nether.net
Emne: RE: [c-nsp] how to connect vss-setup via mpls core

Arne,

Why would you want to do that in such a way?
In order to get the real benefit of VSS you would need all the access
switches connected to both VSS nodes, which would require links from DC1
to DC2 per each access switch...
The same would apply to upstream Layer 3 connectivity...

If you do not plan to have this kind of a full mesh, then why would you
want to use VSS in the first place.

With regards to layer 2 interconnect between DCs, this is a very common
design nowadays, and MPLS is used in many solutions.
I suggest you take a look at this link:
http://www.cisco.com/en/US/netsol/ns975/index.html (take a look at the
whitepaper).

Also, there is a very good Cisco Press book about this whole subject:
http://www.ciscopress.com/bookstore/product.asp?isbn=9781587059926

In the coming Networkers event in Barcelona there would be a few
sessions about this, and a number of people in Meet the Engineer venue
which can help with this subject.

Arie
 

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Arne Larsen /
Region Nordjylland
Sent: Saturday, January 16, 2010 17:31
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] how to connect vss-setup via mpls core

Hi all.

I need an advice.
Is there a way to connect 2 vss-setup's with out using direct fibers on
layer 2 I would like the to sites to connect via our mpls cloud, so that
vlan's configured on the boxes can reach each other on layer2 and be
able top announce the layer3 network via bgp on both sites.
If vlan 200 is configured on both sites, is it possible to use eompls to
connect these 2, and make them active/stanby to each other on layer3
using vrrp or hsrp.
I been searching the cisco web for doc. But all I can find is only
useable on layer2.

/Arne

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