Box to Box Redundancy in a C8200 Call Manager Express context

[bravo4019]

Good Day
I have a pair of C8200L  devices racked and online.
These will be running a redundant Call Manager Express install.
First I am told I must configure Box-to-Box redundancy.
I navigate here but find this document unusable:
Home > Support > Product Support > Routers > Cisco Catalyst 8300 Series Edge Platforms > Configuration Guides >
Cisco Catalyst 8300 and Catalyst 8200 Series Edge Platforms Software Configuration Guide >
Chapter: Configuring High Availability

That chapter refers to this guide which is not much better:
Home > Support
IP Addressing: NAT Configuration Guide, Cisco IOS XE Release 3S >
Chapter: Configuring Stateful Interchassis Redundancy
At least in the second guide there is in fact some instructions about how to actually configure the redundancy.
But still for example there is a step to set the protocol number:

Device(config-red-app)# protocol 4

But protocol 4? what is this?
I can discern from my box there are 8 available at least on this device

XXXX-02(config-red-app-grp)#control g0/0/0 protocol ?
  <1-8>  RG protocol instance

I can find no command reference whatsoever.
I infer form these very confusing documents that there are 2 configurable groups.
Are these groups like say HSRP has groups?
I have also see hints that the setup will monitor interfaces (using BFD) and failover according to default or specified criteria (Priority, timeouts etc, interfaces being tracked etc.)
I presume there is more to B2B redundancy that that?
Where is this documented?

Not even sure where to post this. Chose Application Networking as that is where I have seen other Box-2Box posts (Though quite old)
Much appreciate any reply.

[Jens Albrecht]

You may want to take a look at the following document that contains better explanations what e.g. protocol instances are used for and also includes a detailed step-by-step configuration guide on how to implement box-to-box redundancy for the CUBE functionality:

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/ios-xe/config/ios-xe-book/m-cube-ha-isr-g3.html

HTH!

[MammothIT]

Yes thank you @Jen I have seen that document
Similar questions.
That one instructs to configure protocol 1 (CF 4 above)
Not sure if this is just a locally significant number or if protocol 1 refers to a... umm specific protocol :)>
This command also was not available for me.

track 1 shutdown 

Very unclear
Appreciate your reply though..... 

[Jens Albrecht]

Regarding the "protocol <num>" command the number does not refer to any specific protocol but is just a number that is significant for the HA group you configure.

The "track 1 shutdown" command assumes that you already created the tracking object. In most cases the line-protocol of the corresponding interface is tracked so that e.g. the command "track 1 interface Gig0/0/0 line-protocol" needs to be entered beforehand. Otherwise you get an error message because the tracking object does not exist.

Have you seen the video posted by Cisco regarding this feature?

https://www.youtube.com/watch?v=Hm8AksllC6Q

It includes the prerequisites like configuring the tracking objects, shows the configuration of both routers including verification and hence serves as a better starting point.

HTH!

[bravo4019]

Is it accurate to say in the scenario above there are 2 redundancy groups
Lets say
RG1 = Pair of WAN interfaces redundant to each other (Red); and
RG2 = Pair of LAN interfaces redundant to each other (Green) ?

[bravo4019]

I cannot find anywhere which defines what in fact Box-2Box redundancy does.
Judging by the Youtube video and links mentioned above it seems to provide
A1. Interface redundancy (LAN/CUCM side) and (WAN/Service Provider side); AND
A2. CUBE function redundancy via the dedicated Control and Data interfaces.
Q06 - Is the above description of Box2Box redundancy accurate i.e. A1 and A2?

I have been tasked with implementing a Call Manager Express solution on a pair of C8200L devices.
As part of the setup I am to implement Box2Box redundancy on the C8200L pair.
This is of course topologically different from the CUCM/CUBE scheme mentioned above.
I cannot find any document which suggests to spells out that Box2Box redundancy can be integrated with such a solution
Q07 Can box2Box redundancy indeed be properly integrated with such a solution?