Effective Deployment of IP-PBXs Date: Wed. October 15th Speaker: Tom Keating CTO/Executive Technology Editor, TMC Labs

1. Effective Deployment of IP-PBXs Date: Wed. October 15th Speaker: Tom Keating CTO/Executive Technology Editor, TMC Labs

2. BIO • B.S. Computer Engineering • With TMC for past 10 years • Executive Technology Editor & CTO • Head of TMC Labs • Background in technologies includes PDAs, telecom, call center & CRM technologies, CTI, wireless, VoIP

3. IP-PBX Advantages • Attractive ROI on long distance calling • Domestic calling can pay back the cost of the IP-PBX in less than a year • International calling can often pay back in just weeks. • Less expensive Than Traditional PBXs • Up to 40% less expensive than traditional PBX solutions • If you include advanced integrated features (web call-through, remote voice capabilities, no CTI links needed) IP-PBXs are even more cost advantageous • “One wire” to the desktop • One system to support multiple sites • Unified corporate-wide 3-4 digit extension dialing • Centralized voice mail • Consolidate toll and inbound 800 calling • Total Cost of Ownership (TCO) can be lowered • A single voice and data network (Administration – Training) • Centralized administration for multiple sites • Lower costs for (MACs) Moves, Adds, and Changes

4. What are the Issues That Face IP-PBX Implementation? • Quality of Service • Voice Quality • Class of Service • Standards • Interoperability • H.323 vs. SIP • Security • NAT firewall • VPN • Availability/survivability • Cost/Budget • Existing/legacy Infrastructure

5. Public/Private NETWORK VoIP Enabling your Legacy Solutions Legacy Key/PBX Branch/Remote Office Corporate Office w/ VoIP blade Legacy Phones VoIP Gateway with Legacy Phones IP Phone VoIP Adapter with Legacy Phone Remote IP Phone

6. Public/Private NETWORK 100% “All IP” Convergence Branch/Remote Office IP Phones Corporate Office IP-PBX Router IP Phones Teleworker IP Phone Road Warrior USB or IP Phone

7. So now you are Ready to Deploy, now what? • Do you plan to DIY? • Have professional installers? (VAR, interconnect, network reseller, etc.) • Combination of the two? (install it yourself and have professionals come if any problems crop up)

8. QoS Mechanisms • ToS – Type of Service • 802.1p – Layer 2 with 8 class levels • IntServ – Integrated Services • DiffServ – Differentiated Services • RSVP – Resource Reservation • CoS – Class of Service • CAR – Committed Access Rate • CIR – Committed Information Rate

9. IP Class of Service 32 Bits • Type of Service (TOS) • for CoS Marking • Now known as Differentiated Services Code Point (DSCP) • Usually set to 0, but may indicate particular Quality of Service needs from the network • The DSCP defines one of a set of class of service Ver/IHL TOS Total length Identifier Flags Offset TTL Protocol Checksum Source IP Address Destination IP Address Options and Padding IP Data

10. Choose a VoIP Codec… *Source: www.erlang.com

11. Bandwidth Calculations • Assumptions: • Each voice sample carries a IP/UDP/RTP header overhead of 320 bits. • 1 Voice Sample is defined as the number of packets required for 1 second of voice • Assume 1 packet contains or equals 20ms of voice samples • Therefore 50 packets=1s of voice samples (or 1 Voice Sample) • Q: What is Packet Frequency? • A: Defined as number of packets required to be sent for 1 second of voice sample. • Q: What is the Packet Frequency for 20ms of voice samples per packet? • A: 50 (it’s 50 packets/Voice Sample) (see Tip 1) • Q: What is the overhead in bits per one second of voice samples (assuming 20ms Voice Sample)? • A: 16000 (16kbps) overhead bits per 1 second of Voice Samples (See Tip 2) • Or 16,000 (16kbps) overhead bits/Voice Sample _________________________________________________________________________________ • Tip 1: The Packet Frequency is the inverse of the duration in seconds represented by the voice samples. (1/.02 = 50) • Tip 2: If each voice sample has 320 bits of overhead, then : • 50 packets/voice sample X 320bits of overhead bits/voice sample = 16,000 overhead bits/voice sample

12. The Weakest Link • VoIP is only as strong as its “weakest link” (bandwidth bottlenecks) • Leased line, frame relay, T1/E1 to branch offices. • However, you can’t focus on just the weak links, since even “strong” links (10/100BaseT networks) can have network issues

13. Troubleshooting VoIP network issues • Select a “generalized” network analyzer (i.e. Ethereal, Network Instruments) • Good for finding “top talkers” (bandwidth hogs), general network issues • Select a “specialized” network analyzer that specializes in VoIP analysis (e.g. Agilent, Empirix, Radcom, Qovia) • Good for pinpointing specific VoIP issues, measuring voice quality (MoS-Mean Opinion Score, PSQM-Perceptual Speech Quality Measurement scores), and graphically depicting VoIP ladder diagrams • Find VolP experts/consultants to troubleshoot your network • Psytechnics “swat team”

14. Security & SLA Challenges • For branch office IP-PBX deployment use Voice VPNs for added security (though adds some latency due to encryption) • How do I hold my service provider accountable for site-to-site Voice over IP-VPN performance? • How do I verify I am getting the IP Class of Service performance I am paying for?

15. “Unknown” traffic classification to identify mis-configured router Collected for 8 Classes Support TOS/DSCP bit ranges One Sample “SLA” Solution

16. Open, Flexible, Extensible • When choosing an IP-PBX you want to make sure it has an open architecture • Ability to utilize different vendors (Not locked into a vendor) for different telephony applications • Wireless (802.11) support • PDA Phone support • Useful applications (i.e. unified messaging, screenpop) • Call center applications (predictive dialer, skills-based routing, QM/call recording, etc.) • Support for branch offices/remote workers • Web application integration • IP Contact Centers – collaboration – • Instant Messaging - Video

17. Choosing the Right IP-Phones for each Individual • Single-line or multi-line phone? Not everyone needs a multi-line phone – Why waste the money? • Operators can use an Attendant Console (whether software or hardware-based) • Softphone with USB phone • Headset option

18. Multi-Line IP Phone Consideration: • Are there enough line appearances to fulfill the user’s call processing responsibilities? • Buy IP Phones with as many line appearances as possible to accommodate future expansion and ease of use. • Will additional IP devices be connected to the IP phone (PC, IP Phone, etc.)? • Buy compatible multi-line IP Phones with multiple Ethernet ports.

19. Sampling of IP-Phones… • Multi-line Phones: TelStrat (16 lines) Swissvoice (2 lines) Cisco (4 and 6 lines)Teledex (2 lines) Polycom (3 lines) Mitel • Single Phones: Pingtel Snom Cisco Swissvoice Teledex Mitel Symbol (*WiFi) IP Dialog

20. H.323 Or SIP? • Today it is still an H.323 world • Established protocol – lots of deployed solutions • Lots of vendors equipment interoperate • Telephony like signaling – complex • SIP is the “hot” new VoIP standard • Newer standard, Internet-based, easier/less complex • Simpler – Create “sessions” • Like HTTP – Wealth of available development resources • Integration with web based applications • Access via any SIP enabled technology – phone, video, IM • Make sure your IP-PBX is 100% compliant with relevant VoIP protocols so that 3rd party phones will work with it. • For the immediate future both will be around, but expect SIP to eventually dominate • There are transcoders for interoperability from H.323 to SIP and vice-versa

21. Network Characteristics Required for High Quality Voice • LANs provide good network characteristics – even better voice than the PSTN • Switched Ethernet to the desktop – lots of bandwidth • Estimate bandwidth requirements • LAN –G711 with 20 ms packetization • Assume worst case phone utilization - 1 of 4 phones • WAN characteristics are more challenging • Latency: Typical <100 ms Maximum < 200ms • Jitter: Typical < one sample Maximum < 40ms • Packet Loss: Typical – < 1% Maximum <5% • 85% maximum utilization at peak traffic Source:www.erlang.com

22. Minimize Bandwidth Requirements On The WAN • Minimize overhead, maximize bandwidth on your WAN links. But how? • First, you have to understand and minimize bandwidth requirements • Go with G.729/G.723. Is the voice quality acceptable? • Silence suppression • 35% savings • Header compression • 50% savings • RTP multiplexing • 50% savings

23. QoS Can Help Support Good Voice Quality • Support of VLAN and QoS capabilities • IP Phones support of VLAN tagging • Keep all the voice traffic on a layer 2 VLAN dedicated to voice and signaling traffic – 802.1q • Prioritization – 802.1p • VoIP devices support of TOS or Diff-Serv • Prioritize voice traffic through the routers and switches • Required at every point in the network

24. Supporting QoS Can be Challenging • QoS becomes more challenging the larger the network • Multiple methods of differentiating service classes • Requires compliance to the rules of the administrative domain • QoS must understand all methods of differentiation • QoS must be supported at every hop (internal & external) Or NO QoS • Any hop where QoS is not supported becomes a potential congestion point • QoS characteristics can be lost between domains • QoS is most needed where it is hard to support • WANs have the greatest latency. • Many remote sites use the Internet (as opposed to dedicate leased line)

25. Security At The Edge – Getting Around NAT • Tale of two data paths – signaling and voice • Call signaling provide the information to establish the call and is translated by the NAT • The signaling embeds the source and destination IP addressing for the media – unknown to the NAT • Various solutions • VoIP aware firewall – upgrades to existing some firewalls • VoIP to VoIP gateway – VoIP Call Relay • Site to Site VPNs • Adds bandwidth and latency due to the encryption

26. Security For The Media – Who Could Be Listening In? • There are steps that can improve the security of the media stream. • Protection behind the firewall • Support with some VoIP NAT capability • Put VoIP equipment on virtual LANs and enable the security features on the switches. • VPN routes between sites to support VoIP • Latency? QoS? • RTP encryption where possible

27. High Availability • Deliver power to the phones over the Ethernet • Find an IP-PBX that supports the 802.3af power-over-Ethernet standard • Ethernet switches that deliver the power on back-up power supplies • Remote office gateway may require one or more PSTN failover lines in case the connection to the IP-PBX is lost. • Real-time PSTN back-up trunks on the IP-PBX for off-net calling

28. Key Steps To Follow When Deploying IP Telephony • Planning and evaluating for VoIP deployment • Assessment of the existing infrastructure • Evaluation of VoIP requirements • Upgrade the IP network as required • Lay out the network, perform network trending • Run a pilot – Identify any issues, monitor traffic with a network analyzer • Perform Full implementation • Continue to perform monitoring with network analysis tools, VoIP quality of service tools, and voice quality measurement tools

29. Conclusion • With proper planning, an IP-PBX can successfully be deployed with voice quality at least as good at the PSTN • IP-PBXs offers both cost and application benefits • Many IP-PBXs provide a total end-to-end “converged” solution that covers every feature you can think of – UM, screenpop, predictive dialer, ACD, web call-through, chat, presence, and more. • There are a variety of solutions that allow you to begin small and grow your IP telephony network • Invest in VoIP monitoring utilities/analyzers • If you decide to DIY when deploying your IP-PBX, make sure you have the technical know-how to pinpoint network issues that can and will crop up. Don’t leave your most valuable business tool to chance!

30. Questions?