Basics of Cisco Unified Border Element

Now a days SIP service are growing and the  service provider are providing SIP as  a service.These services can be terminated for a enterprise on a SBC/CUBE .
The CUBE has many benefit over traditional TDM circuit etc.

The benefit are

Interoperability : SIP is a protocol supported by many vendor  hence these can be deployed with different SIP solution

Demarcation Point : CUBE can be used as a demarcation point between PSTN and enterprise network

Encryption and security is also a part of  CUBE,you can use CUBE to hide the IP address of the CUCM 

To achieve the redundancy the SIP has more flexibility compared to Traditional Telephony.

CUBE can be deployed in two mode:

Media flow around : in case of media flow around  the CUBE doesn't comes into media path

Media flow through  : In case of media flow through the CUBE comes into media path

The command can be configured under dial-peer config using the command :

media flow-through|flow-around

CUBE can be used for media codec negotiation as well when the service provider link is terminated on the cube.
You can configure the media negotiation mode by configuring the below command under dial-peer
codec transparent

The above command define that the CUBE will not be part of any codec negotiation . if this command is not there then CUBE take part in codec negotiation

apart from then you need to configure allow-connection under voice service voip command

You can verify SIP calls in the CUBE using the command

show sip calls
show voice call status
show voip rtp connection
show call active voice

debug command used to debug dial peer

debug dialper voice inout