The main purpose of this MIB is to define the statistics
information for Session Border Controller application. This MIB
categorizes the statistics information into following types:
1. RADIUS Messages Statistics - Represents statistics of
   various RADIUS messages for RADIUS servers with which the
   client (SBC) shares a secret.

2. Rf Billing Statistics- Represents Rf billing statistics 
   information which monitors the messages sent per-realm over
   IMS Rx interface by Rf billing manager(SBC).

3. SIP Statistics - Represents SIP requests and various SIP
   responses on a SIP adjacency in a given interval.

The Session Border Controller (SBC) enables direct IP-to-IP
interconnect between multiple administrative domains for
session-based services providing protocol inter-working,
security, and admission control and management. The SBC is a
voice over IP (VoIP) device that sits on the border of a 
network and controls call admission to that network. 

The primary purpose of an SBC is to protect the interior of the
network from excessive call load and malicious traffic.
Additional functions provided by the SBC include media bridging
and billing services. 

Periodic Statistics - Represents the SBC call statistics 
information for a particular time interval. E.g. you can 
specify that you want to retrieve statistics for a summary 
period of the current or previous 5 minutes, 15 minutes, hour, 
or day. The statistics for 5 minutes are divided into five 
minute intervals past the hour - that is, at 0 minutes, 5 
minutes, 10 minutes... past the hour.  When you retrieve 
statistics for the current five minute period, you will be 
given statistics from the start of the interval to the current
time. When you retrieve statistics for the previous five 
minutes, you will be given the statistics for the entirety of 
the previous interval. For example, if it is currently 12:43
-  the current 5 minute statistics cover 12:40 - 12:43

-  the previous 5 minute statistics cover 12:35 - 12:40

The other intervals work similarly.  15 minute statistics are 
divided into 15 minute intervals past the hour (0 minutes, 15 
minutes, 30 minutes, 45 minutes).  Hourly statistics are divided
into intervals on the hour. Daily statistics are divided into
intervals at 0:00 each day. Therefore, if you retrieve the 
statistics at 12:43 for each of these intervals, the periods
covered are as follows.  
-     current 15 minutes: 12:30 - 12:43

-     previous 15 minutes: 12:15 - 12:30

-     current hour: 12:00 - 12:43

-     last hour: 11:00 - 12:00

-     current day: 00:00 - 12:43

-     last day: 00:00 (the day before) - 00:00.


GLOSSARY
SBC: Session Border Controller

CSB: CISCO Session Border Controller

Adjacency: An adjacency contains the system information to be
transmitted to next HOP.

ACR: Accounting Request

ACA: Accounting Accept

AVP: Attribute-Value Pairs

REFERENCES
1. CISCO Session Border Controller Documents and FAQ
http://zed.cisco.com/confluence/display/SBC/SBC