Customer Training Center

1. Distribution ED01 English Code : STM230 IP Telephony Network Design Customer Training Center Samsung Electronics Co., Ltd.

2. Objectives • After successful completion of the course the trainees should be able to execute the following activities. • To understand basic network design for IP Telephony. • To suggest a optimized network design according to the VoIP system usage and its network status. • To trace down the VoIP quality problems occurred in VoIP system.

3. Contents Introduction to Network Design Basic Network Design Guidelines Case Study

4. Introduction to Network Design

5. Overview • Network Design for VoIP system is different from general network design in that it focuses more on efficient RTP packet transmission than Data packet. • Voice quality is significantly affected by how much network design is optimized to the VoIP system use and its network status. • Having a proper network design is a essential and prerequisite for a successful VoIP system.

6. Network Check Point Procedure Network Status Check using Ping Plotter (or other available s/w i.e., Chariot) Is Network Status Good? Yes Follow the basic network design guide No Is Delay more than 150ms? Yes Re-Configure Router settings and Diagnose physical network connection No Is Packet Loss more than 10 %? Yes No Review overall Network Design and Execute node to node diagnoses (Refer to Case Study) Check Point Procedure finished

7. Basic Network Design Guidelines

8. PSTN IP Network Basic Stand-Alone System • Basic Stand-Alone System with no Legacy • Hosts a small number of VoIP users. (20-50). • Suitable for Newly constructed VoIP system with which no legacy system is inter-operated. IP Phone Legacy Phone Soft Phone

9. PSTN IP Network Basic Stand-Alone System • Basic Stand-Alone System with Legacy • Hosts a small number of VoIP users. (20-50). • Suitable for VoIP system having legacy system inter-operated with. • IP Phone under local network uses Media Gateway to send/receive RTP packets. Router Firewall L2/L3 Switch IP Phone Legacy Phone Soft Phone

10. PSTN IP Network HQ-Branch Office System • VoIP system in HQ-Branch Office Configuration • Suggested for a middle sized or bigger VoIP system. • Hosts a large number of VoIP users. (50 or more). • VoIP and Data packets are transferred over WAN. Firewall Router L2/L3 Switch Branch Office A VPN Tunneling Header Quarter Office xDSL Modem Branch Office B Home Office Soft Phone

11. Case Study

12. Problem Types

13. IP Network Original Network Design Header Quarter Office Backbone OS500 Packet Loss being occurred by excessive network traffic Section 1 Firewall1 VoIP Dedicated IP band Switch ATM Cisco Router 98.24.251.1 Packet Delay happening by Dedicated ATM connection and router settings Dedicated for Data Network Dedicated for VoIP Network ATM Cisco Router 98.24.251.2 Section 2 Branch Office Network Status Check Ping test from HQ Office to Each Sub Section using VoIP Dedicated IP band Packet Send/Receive Test from HQ Office to target VoIP band IP in Branch Office. (Chariot) Firewall & Switch VoIP Dedicated IP band

14. Original Network Design • Ping Plotter Test Regular Packet Transmission Delay which lasts more than a second [From Test PC to Router in HQ Office] [From Test PC to Router in Branch Office]

15. Original Network Design • Chariot Test (Packet Loss) Successive Packet Loss Detected, each of which had over 10% packet loss and lasted about 10 seconds  Discontinuation of Sound [From HQ Office to Branch Office]

16. Original Network Design • Chariot Test (Oneway Delay) Over 1 second Delay happening consecutively [From HQ Office to Branch Office]

17. IP Network Network Design Change Phase #1 Header Quarter Office Change #3 Broadcast Equipment Backbone OS500 Change #2 Firewall2 Firewall1 Change List (1~5) Traffic load balancing by Firewall; New Path is marked in RED Loop traffic path change in Backbone Removing unnecessary traffic in broadcast equipment, and change its traffic path to ATM to relieve load in Firewall 1. Change queuing method in router Dedicated physical network line check VoIP Dedicated IP band Ping & Chariot test Switch Change #1 Change #4 ATM Cisco Router 98.24.251.1 Dedicated for Data Network Dedicated for VoIP Network Change #5 ATM Cisco Router 98.24.251.2 Branch Office Firewall & Switch VoIP Dedicated IP band

18. Network Design Change Phase #1 • Node-to-Node Packet Loss Test Assuming Traffic problem in Backbone switch Relatively low rate of packet loss between Routers [From Test PC to PC in Branch Office] [From Test PC to Router in HQ Office] [From Router in HQ to PC in Branch Office]

19. Network Design Change Phase #1 • Delay check when Packet Loss Decreased Happened in Backbone

20. IP Network Network Design Change Phase #2 Header Quarter Office Header Quarter Office Backbone OS500 BB-FW Node PC-BB Node FW-L4 Node Firewall1 Firewall2 L4-R Node VoIP Dedicated IP band Ping & Chariot test Switch Packet Loss not entirely removed since Network Design Change Phase #1 <Network Test after Phase #1> G729 packet test from PC to Branch Office In-between node packet captured using OmniPeek S/W installed in test Srv G729 packet’s sequence number analysis at the time of packet loss Traffic load analysis before and after the packet loss ATM Cisco Router 98.24.251.1 Dedicated for Data Network Dedicated for VoIP Network ATM Cisco Router 98.24.251.2 Branch Office Branch Office Firewall & Switch VoIP Dedicated IP band

21. Network Design Change Phase #2 • Packet Transmission interval of 40 ms • Packet Loss happed when going through Firewall • Switch maintains Packet Transmission interval

22. IP Network Network Design Final Phase Final Change As Firewall makes Packet Loss, network design changed so that packets from OS500 does not go through Backbone Issue: The Risk of Packet Loss still remains in Phones used in HQ Header Quarter Office Backbone Cisco 3550(Switch) OS500 Firewall1 Firewall2 L4 Switch ATM Cisco Router Dedicated for Data Network Dedicated for VoIP Network Branch Office #2 ATM Cisco Router 98.24.251.2 Branch Office #1 Firewall & Switch VoIP Dedicated IP band

23. Network Design Final Phase • Packet Loss Test Total 6 Packets were lost for 16 hours, and no loss happened during peak time i.e., 9 AM. Over 10% Packet Loss successively occurred within 2 minutes [Before Network re-Design] [After Network Design Final Phase]

24. Network Design Final Phase • One-way Delay More than a second delay happened, and sometimes even more than 4 seconds Stable Delay under tens of ms [Before Network re-Design] [After Network Design Final Phase]

25. Samsung Electronics Co., Ltd.