Trunk Disaster Recovery site

Unanswered Question

Hello,


I'm quite new in the cisco world, i need your lights.


Application team request to have same vlan over a MAN (4Gb dark fiber connection) between our data center and the disaster recovery site in order to speed the process to recover the virtual machines if the data center is down.


To summarize, we have a network design like this :


2 cata 6509 in the datacenter connected to a wan link and a internet link

1 cata 3750 at the dr site, with wan link and probably a internet link in the future


I want to trunk the cata 6509 to the 3750 in the DR site to have the same vlans and use the 2Gb line for traffic

Till that, i think it's ok, but now, how i do fail over when the fiber between the 2 sites are down.

Can i use the IP SLA thing to do that ? to enable other routes when the 2Gb line is down ?

Can we have like a "stand by" routing table for that ?


Let me know if you need anything else regarding the configuration.


Thank you in advance

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Jon Marshall Mon, 01/18/2010 - 09:39
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Hello,


I'm quite new in the cisco world, i need your lights.


Application team request to have same vlan over a MAN (4Gb dark fiber connection) between our data center and the disaster recovery site in order to speed the process to recover the virtual machines if the data center is down.


To summarize, we have a network design like this :


2 cata 6509 in the datacenter connected to a wan link and a internet link

1 cata 3750 at the dr site, with wan link and probably a internet link in the future


I want to trunk the cata 6509 to the 3750 in the DR site to have the same vlans and use the 2Gb line for traffic

Till that, i think it's ok, but now, how i do fail over when the fiber between the 2 sites are down.

Can i use the IP SLA thing to do that ? to enable other routes when the 2Gb line is down ?

Can we have like a "stand by" routing table for that ?


Let me know if you need anything else regarding the configuration.


Thank you in advance


Michael


When you say failover, failover to where ?


Could you clarify ie. you have a WAN link between the 2 sites + internet at main site. Do you also have a separate fibre connection between the 2 sites and you want to failover from the L2 fibre connection to the WAN link ?


If so is the WAN link routed between the 2 sites ?


Jon

scenario is like this :


if fiber is up between the 2 site (consider as a lan link), all traffic should pass by the trunk i'll create.

when the fiber goes down,it should route traffic through the wan and internet line for webaccess.

Is it clear ?

WAN is a specific link between all our site we have in the world.

With the same vlans of course

Jon Marshall Mon, 01/18/2010 - 10:30
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scenario is like this :


if fiber is up between the 2 site (consider as a lan link), all traffic should pass by the trunk i'll create.

when the fiber goes down,it should route traffic through the wan and internet line for webaccess.

Is it clear ?

WAN is a specific link between all our site we have in the world.

With the same vlans of course


Michael


Sorry to keep asking questions but still need some clarification -


when the fiber goes down,it should route traffic through the wan and internet line for webaccess.


so you want traffic between your 2 sites to go via the WAN link and the internet or just the WAN link. Unless you are encrypting the traffic i would not have thought you want internal traffic going out across the internet ?


You also say the WAN link has the same vlans. Is the WAN link a L2 WAN or do you route across the WAN. Because if you route then you have problems ie.


with your fiber link it is a L2 trunk so you have the same vlan in both sites. Note this is not just the same vlan number it is actually the same vlan so a host at main site talking to a host in backup site simply L2 switches traffic.


If your WAN is L3 then you cannot route between the same vlan at both sites. You would need to look into something like L2TPv3 or EoMPLS if you have an MPLS WAN.


Does this make sense ?


Jon

on the datacenter, we host many esx servers with several VM's on it.

We want to restore them as fast as we can on the dr site, that's why we want the same vlans on both side. And as we have a very good bandwidth, we will use this link as well in production, as it was in the same site.

We have a big wan link in the datacenter, on the dr site, the link will be slow as we will only use it only if the datacenter is down.

I'm not sure if you understand cleary what i wanted to achieve, maybe we can discuss on a live chat or so, you can contact me by mail if you prefer.


So the scenario is :


When fiber link between the 2 sites is up, all traffic should pass by the fiber.

When the fiber is down (datacenter down) all requests for servers hosted in the datacenter (we will restore servers in the dr site) should pass by the dr site WAN link.


That's why i tought to use ip sla with let say 5 minutes response time to switch all wan routers to the dr site route.

At the moment, there is only 1 static route on each wan router, pointing to the datacenter WAN.


As i don't have experience in such things, i'll appreciate any recommendation.


Regards,


Mike

Jon Marshall Mon, 01/18/2010 - 11:48
User Badges:
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on the datacenter, we host many esx servers with several VM's on it.

We want to restore them as fast as we can on the dr site, that's why we want the same vlans on both side. And as we have a very good bandwidth, we will use this link as well in production, as it was in the same site.

We have a big wan link in the datacenter, on the dr site, the link will be slow as we will only use it only if the datacenter is down.

I'm not sure if you understand cleary what i wanted to achieve, maybe we can discuss on a live chat or so, you can contact me by mail if you prefer.


So the scenario is :


When fiber link between the 2 sites is up, all traffic should pass by the fiber.

When the fiber is down (datacenter down) all requests for servers hosted in the datacenter (we will restore servers in the dr site) should pass by the dr site WAN link.


That's why i tought to use ip sla with let say 5 minutes response time to switch all wan routers to the dr site route.

At the moment, there is only 1 static route on each wan router, pointing to the datacenter WAN.


As i don't have experience in such things, i'll appreciate any recommendation.


Regards,


Mike


Mike


You seem to be talking about 2 different things or i am not following which is just as likely .


You have a DC and DR site. You have a WAN.


When fiber link between the 2 sites is up, all traffic should pass by the fiber


what traffic ? Are you talking about server to server traffic or client to server traffic. If client to server where are the clients based ie. across the WAN ?


When the link goes down you want to use the WAN but for which traffic ie. server to server or client to server.


Can you follow where i am getting confused ie.


you have a DC that has servers in use. Your clients get routed to the DC but surely not via the fibre link ??

If the DC goes down you want to send your clients to the DR site ?


if the above is true how does this relate to the fibre link between the DC and the DR ?


And it still matters how the WAN is set up ie.


1) what type of WAN eg frame-relay, point to point, MPLS

2) routed or L2 switch WAN

3) What routing protocol is in use both internally in the DC/DR and on the WAN


Sorry to ask so many questions but it is still not clear what you are trying to do.


Edit - if any other NetPros reading this understand what is needed please jump in.


Jon

You seem to be talking about 2 different things or i am not following which is just as likely

.


You have a DC and DR site. You have a WAN.


When fiber link between the 2 sites is up, all traffic should pass by the fiber


what traffic ? Are you talking about server to server traffic or client to server traffic. If client to server where are the clients based ie. across the WAN ?

          Fiber will be only use for servers traffic, or client-server traffic coming through the wan link in the DC to server at the DR


When the link goes down you want to use the WAN but for which traffic ie. server to server or client to server.

          When the fiber goes down (data center down), we want to restore VM servers on the DR site and send traffic through small wan link we have at the DR site


Can you follow where i am getting confused ie.


you have a DC that has servers in use. Your clients get routed to the DC but surely not via the fibre link ??

     They are routed through WAN link on each site to the wan link at the DC

   

If the DC goes down you want to send your clients to the DR site ?

     Yes


if the above is true how does this relate to the fibre link between the DC and the DR ?

     Fiber link should be like "lan extension"

    


And it still matters how the WAN is set up ie.


1) what type of WAN eg frame-relay, point to point, MPLS -> MPLS

2) routed or L2 switch WAN -> L3

3) What routing protocol is in use both internally in the DC/DR and on the WAN -> static routes


Sorry to ask so many questions but it is still not clear what you are trying to do.


Edit - if any other NetPros reading this understand what is needed please jump in.


Jon

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