1. Real-Time IP Network Redundancy in Connection to Mobile Media Gateway
Sanna Santajärvi
S Tietoverkkotekniikan diplomityöseminaari

2. Basic Information Thesis written at Oy L M Ericsson Ab
Supervisor: Heikki Hämmäinen, Professor
Instructor: Juha Eloranta, M.Sc.

3. Contents Background Research Description Research Methods
Basic Concepts

4. Background
Heavy investments are being made by the Mobile Network Operators (MNO) to the mobile networks
Certain Service Level has to be maintained even in special situations (e.g. link failure, congestion)

5. Relationship between the Service Level and costs
Research Description
Around Media Gateway node
IP network redundancy
Redundant network possible but costly
Relationship between the Service Level and costs

6. Research Methods Literature Survey Interviews
Technical Specifications by 3GPP
Researches, studies, and white papers from different acedemic and comercial sources
Interviews
Assisting method
Ericsson experts in different fields

7. Basic Concepts (1) REDUNDANCY
Systems or elements of a system are backed up with secondary resources
Tradeoff between higher investments and costs caused by the system downtime

8. Basic Concepts (2) Fault Error Failure
FAULT – a physical defect in some component
ERROR – deviation from the required operation
FAILURE – system’s inability to perform its function

9. Basic Concepts (3)
RELIABILITY – probability that the system functions correctly over a period of a time
Mean time-to-failure (MTTF)
Mean time-to-repair (MTTR)
AVAILABILITY – probablity that the system is functioning correctly at a given time
= MTTF / (MTTF + MTTR)

10. The ’nines’ 1 nine 90.0% 36 days 12 hours 50 000 minutes
Availability
Downtime/year
Downtime/year
Examples
1 nine
90.0%
36 days 12 hours
 minutes
Personal Clients
2 nines
99.0%
87 hours 36 minutes
5000 minutes
Entry-level Businesses
3 nines
99.9%
8 hours 46 minutes
500 minutes
Internet Service Providers, Mainstream Businesses
4 nines
99.99%
52 minutes 33 s
50 minutes
Data centers
5 nines
99.999%
5 minutes 15 s
5 minutes
Carrier-grade Telco, Medical, Banking
6 nines %
31,5 s
0,5 minutes
Military Defense System, Carrier-grade Goal

11. Questions?
Thank you