Enterprise VoIP. Silvano Gai. ftp://ftpeng.cisco.com/sgai/t2000voip.pdf. Cisco Systems, USA Politecnico di Torino, IT

Transcription

1 Enterprise Vo Terena 2000 ftp://ftpeng.cisco.com/sgai/t2000voip.pdf Silvano Gai Cisco Systems, USA Politecnico di Torino, IT Terena

2 Compass Motivation for Vo Voice over in the Enterprise Standards Conclusions 2

3 Enterprise Telephony Goals CallManager Router CallManager Router PSTN Headquarters WAN Router Rest of World Branch Offices Telecommuter 3

4 Small/Branch Office Single Infrastructure for Data, Voice, and Video CallManager Ethernet Switch WAN Phones PSTN 4

5 VPN Telecommuter CallManager Cluster SoHo Router ISP Extension 1001 PSTN Extension

6 System Architecture Client Workstation CallManager Server TAPI/JTAPI Application CallManager Service TAPI/JTAPI Implementation 1) CTI Protocol 3) Signalling Protocol (TCP) 2) Enterprise Directory (LDAP) RTP Packet Bus Stations 6

7 Compass Motivation for Vo Voice over in the Enterprise Standards Conclusions 7

8 Enterprise Telephony Architectural Site Components Application Servers Hold Music Paging Voice Mail Call Manager PSTN A B V V V DSP Farm V Router/ Gateway WAN C 1. DSP Farm 2. Phone 3. Applications Servers 4. Gateways/Routers 5. Call Manager 8

9 Multi-site WAN Configuration Hold Voice Music Paging Mail Call Manager PSTN Call Manager Hold Voice Music Paging Mail A B V DSP Farm Router V Data Network V Router V DSP Farm C D G.711 within Campus DSP Farm Performs Transcoding of G.711 to G.729 DSP Terminates the Call Transparent to End Stations Still uses 3 limited Admission Control Mechanisms G.711 within Campus Compressed Voice in WAN Call Control/Signaling G.711 RTP Stream G.729/G.723 RTP Stream 9

10 Deployment Questions How do we deploy phones? Do the phones need their own address? If so, how do we preserve our existing Layer 2 and 3 topology? How can we make this deployment manageable? 10

11 VLAN Configuration Provides the benefits of VLAN technology for the phone Preserves existing address structure Uses standards-based 802.1Q technology between switch and phone Phone VLAN = 200 PC VLAN = 3 Phone: Subnet B Desktop PC: Subnet A 11

12 Deployment Questions How do we provide power for phones? Are phones plugged into the wall power? If not, how do we manage power distribution? 12

13 Inline Power Inline Power Ethernet Modules: Provides power over the same pairs as Ethernet (pairs 1 and 2) Inline power work-in-progress as IEEE 802.3af standard New cards or Power Patch Panels 48V DC Power 10/100 Ethernet without Inline Power 13

14 Reliable Power Distribution Switches available during power outages With inline power feature, switches provide power to phones which remain unaffected by outages UPS UPS UPS 14

15 Switch <-> Phone Interaction 1. Phone Discovery 2. Provide Power 3. Provide VLAN 4. DHCP (get addr) Step 4: Phone sends DHCP request on its own VLAN. After receiving address, it downloads configuration, e.g. from the TFTP server and registers with CallManager 15

16 Deployment Questions How do we ensure voice quality? What levels of QoS are needed? Where does QoS need to be applied? How can we make QoS manageable? 16

17 QoS Enabled Network telephony Two traffic types on campus network (data and voice) Sensitive to delay and jitter Requires preferential treatment across the entire network QoS Prioritizes traffic into different service levels Provides preferential forwarding to more important traffic IEEE 802.1D User Priority: 5 or 6 v4 Priority: 5 v4 and v6 DSCP: EF (Expedited Forwarding) 17

18 Deployment Questions How do we preserve our existing investment and infrastructure? What about analog (non-) end points? How do we provide scalable voice services? PSTN gateways Compression Conferencing 18

19 Analog End Stations FXS (Foreign exchange Station) port module : Provides analog connectivity for: fax machines speaker phones (Polycom) analog telephone sets 19

20 Voice T1/E1Modules Using the physical T1 or E1 ports: Provides connectivity to the PSTN or PBX Support for ISDN PRI Support for CAS/R2 Shared network resource PSTN PBX 20

21 Telephony Call Flow Outgoing Call to Local Gateway (Within Site) Phone A dials 9 for an outside line Call Manager directs Phone A Media stream to Local Gateway Application Servers Hold Music Paging Voice Mail Call Manager PSTN A B V V V DSP Farm (Media GW/Conf) V Router/ Gateway WAN C Call Control/Signaling (Skinny/MGCP) G.711 RTP Stream 21

22 Telephony Call Flow Conferencing (Within Site) Phone B Conferences Phone A with Phone C Call Manager directs Phone A, B + C media streams to DSP Farm and Bridges them Application Servers Hold Music Paging Voice Mail Call Manager PSTN A B V V V DSP Farm (Media GW/Conf) V Router/ Gateway WAN C Call Control/Signaling (Skinny/MGCP) G.711 RTP Stream 22

23 Multi-site WAN Configuration Phone to Phone Calls (Phone RSVP enabled) Hold Voice Music Paging Mail Call Manager C Calls A PSTN Call Manager Hold Voice Music Paging Mail A B V DSP Farm (Media GW/Conf) Router V Data Network V Router V DSP Farm (Media GW/Conf) C D Compressed Audio in WAN (G.723/G.729) Phones Utilize Low Bite Rate Codecs RSVP setup between Phones ( Phones must be RSVP enabled) RSVP Reservation between Phones Call Control/Signaling (Skinny/MGCP) G.711 RTP Stream G.729/G.723 RTP Stream 23

24 Compass Motivation for Vo Voice over in the Enterprise Standards Conclusions 24

25 Signaling Protocols Stimulus SCCP SGCP MGCP Megaco Peer to Peer H.323 S 25

26 Evolution of signaling protocols H.323 SCCP H.323v2 SGCP DC S MGCP MDCP H.323v3 Megaco/H

27 Compass Motivation for Vo Voice over in the Enterprise Standards Conclusions 27

28 Where are we now? Enterprise Toll Bypass Widely deployed for remote office to PBX Also some deployment for large PBX-PBX Carrier Toll Bypass Big business H.323 today moving to SGCP/MGCP and maybe Megaco down the road SS7 integration Little if any fancy applications Struggling to provide popular PSTN features Web and other Internet application integration really hasn t happened Some deployment of Internet Call Waiting 28

29 What s in store for Y2K Real Enterprise PBXes appear Phones become more than curiosities 3Com, PingTel, Cisco, more QoS under control for single sites; interesting challenges for multi-site DQOS subset appears to be a good alternative Where do the 600 PBX features come from? API-wars? Parlay, JTAPI, TAPI, what about CPL? Protocol wars? H.323, MGCP, Megaco, S 29

30 What s in store for Y2K Integration of Vo with Unified Messaging Finally, an all solution Interesting play to combine UM with Calendaring and Find-me-Follow me Nice conferencing control applications start to appear Both S and H.323-based with web interfaces that are actually usable Other possible developments: Finally get wideband coders adopted Multicast for hoot-n-holler applications Video gets over the Excedrine headache barrier 30

31 The End Thank You 31