CUBE Active/Active Config with internal route link detection

[Hermanus Janse van Vuuren]

Hi,

I have 2 x Cisco cubes 4451 both linking to the same ITSP and they give us a 50/50 load of calls to the 2 different cubes in 2 different DC's.

My question here is, is the Cisco Cube capable if for some reason the external link to the ITSP is up so their SIP Ping options returns that the cube is up but the internal part for example is down (due to a firewall or switch) can the cubes be configured to re-route the calls between them with say a "direct" link between them when detected the internal interface is down?

This this at all possible to monitor the different loopback interfaces and should it be detected that one is down to a PABX to re-route the call via the other CUBE is can reach this PABX for example? 

 

[Mohammed al Baqari]

Hi,

This is not possible out of the box. You can use object tracking to detect
failures (for example ping failure to loop back or bgp route disappearing)
and accordingly shutdown interfaces on the active cube. This can trigger
box-to-box failover for the standby cube to start serving calls.

Having that said, box-to-box failover is supported for cubes in the same
DC. It can work on cubes in different DCs with L2 WAN such as OTV or VPLS
but not supported by Cisco.


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[Hermanus Janse van Vuuren]

Hi  Mohammed,

Thank you for the reply, this is actually very shocking that Cisco don't support such a feature on their CUBES, if I am not mistaken Oracle SBCs for example has the capability to detect links down and re-route traffic on a different interface to a different DC for example.

We have ping option configured but the ITSP sees the external interface that is up and return the ping options but now your internal interface linking to a FW or a switch is down, so the physical cube interface is not down but your route is down and one would have thought you could configure maybe a re-route traffic to a different interface on an SIP error 5XX or unavailable message from the internal side of the network.

An the ITSP won't re-route to the other DC as the error is not on the external leg of the call but the internal leg of the call so it will just keep on trying.

[Mohammed al Baqari]

I haven't used oracle SBC but I know that box-to-box is restricted to same
DC. See below.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book/voi-cube-high-availability-ISR4K.html

The option I proposed will force the ITSP to failover because your track
object will shutdown interfaces facing ITSP as a response to inside failure.

Here is an example

https://community.cisco.com/t5/network-management/shut-an-interface-if-no-ping-response-using-ip-sla-eem/td-p/1378421

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