High Availability: 4507R-E + 2 x 7206VXR

[NetInvKln]

Hi Experts,

I have a coreswitch (4507R-E) with dual Supervisor Engine (SupEngine 6-E) + 2 7206VXR Gateways.

1st Supervisor Uplink (media-type SFP) connects to 7206VXR (which is connecting to an ISP).

SupE6-E-1 <------> 7206VXR-1 <--------> ISP

2nd Supervisor Uplink (media-type SFP) connects to 2nd 7206VXR (which is connecting to SAME ISP).

SupE6-E-2 <--------> 7206VXR-2 <--------> SAME ISP

I've set the Supervisors to SSO mode, and used the coreswitch as gateway for internal vlans.

The coreswitch uplinks were configured as layer 3 port.

Then, I set GLBP on the 2 x 7206VXR and used its VIRTUAL IP as a gateway of the 4507R-E.

I believe that with my setup, if the active supervisor fails, the standby supervisor will take over, which is fine.

But the question is....assuming that ACTIVE connection is SupE6-E-1 <---------> 7206VXR-1 <---------> ISP

- How will SupEngine6-E-2 take over if the link between 7206VXR-1 <-------> ISP fails?

Can somebody advise what needs to be done, so that the supervisors will failover based the link/ route availability of the 2 routers to ISP.

Note: ISPs route back to my gateways have different metric.

Thanks in advance.

[Thotsaphon Lueangwattanaphong]

Hi,

   How do you run GLBP if 7206VXR-2 is connecting to standby supervisor engine?

Toshi

[NetInvKln]

Hi,

I just followed the instructions based on the forum (which has same scenario as mine).

https://supportforums.cisco.com/message/750645#750645

If wrong, what should I do sir.

Thanks

[manju.cisco]

Hi,

If link between 7206vxr-1 and ISP fails, the supe6-e-2 will not take over supe6-e-1.

Your standby supervisor takes over active supervisor only when active sup fails, and not when ISP link fails.

[NetInvKln]

What to do then sir, what should I do so that...if the corresponding supervisor connected to the router with active link/router will be the one active as well? Any suggestion?

[manju.cisco]

If you want failover to happen when ISP link fails, instead of connecting the two ISP links to SUP's, you may

connect both ISP links to any ports in SFP modules (slot 1, 2, 5, 6, or 7), enable L3 on that port, configure ip address, configure routing protocols(dynamic or static).

[manju.cisco]

NI KOLN wrote:
Ahh I see. Didn't thought of that 
What settings needed for the 2 x SFP ports (slots 1,2,5,6,7), should it be etherchannel or spanning tree?

NO NO, discard that......in a moment my mind mistook the actual scenario, i forgot your VXR's. and i made you confused....

try enabling some dynamic protocols between your VXR's and ISP and assign proper weightage on GLBP on the ISP links., that should work i believe.

[NetInvKln]

With your last reply which I just deleted (i hit the correct answer button) , I can't actually do the dynamic routing because of my ISP's capability.
I think your's suggestion above should work, having the SFP modules (which is in my slot 1).

I can use 2 ports connecting to inside interfaces of the 7206VXRs.

But what should I set on these 2 SFP ports, so that only of them is active?

[manju.cisco · Accepted solution]

If you cant use dynamic protocols, still there are many ways, but need to choose the best.

i am assuming, you are getting routes from ISP with best metric to VXR1 and second best metric to VXR2.

And also assuming, you just have a default route to ISP on both VXR's.

On VXR1, you can give a second default route to point to VXR2 when ISP link on VXR1 fails, so that the traffic which comes from 4507 to vxr1 will then go via vxr2.