VoIP and IP IT Tralee

Transcription

1 VoIP and IP IT Tralee chris.bradshaw@staff.ittralee.ie Presentation outline: Basic overview of IP telephony and technology Detailed overview of IT Tralee deployment How IPT has benefited IT Tralee Future plans

2 What is VoIP? Voice packets transported using IP Traditional existing network infrastructure carries voice and data traffic Advantages: One physical layer/one cabling infrastructure Enhanced services (mobility, unified messaging, video) Simpler and cheaper moves/adds/changes Increased system redundancy (multiple handset power sources, distributed physical connectivity). Flexible addressing schemes (E.164, URI)

3 Basic elements of VoIP Typical VoIP traffic comprises multiple protocol streams: Signalling protocol (facilitates call setup/teardown, usually out of band (H.323, SIP, MGCP, Skinny)) Media protocol (carries digitized voice, usually RTP or crtp) Media control protocol (performance/diagnostic feedback in parallel with Media streams usually RTCP). Voice digitization via codecs (eg: G711a/u, GSM)

4 Basic elements of VoIP (cont d) Endpoints - IP phones (hardware or software based) Signalling server Registration server IP equivalent of a PBX Gateways to connect different network types (eg: VoIP PSTN, ISDN etc.) QoS aware switching network, perhaps/preferrably also providing PoE

5 History of IT Tralee Initial suggestion in 2000 while researching/designing network for new campus Historically, old campus Nortel Meridian PBX managed by Buildings/Estates Dept. (and Eircom) In early 2001 Computing Services took responsibility for telephony system in upcoming new campus. Sept 2001 new campus opens with Cisco IP Telephony system.

6 North Campus Logical Topology Wiring Closet Wiring Closet Gb fibre uplinks to core Wiring Closet Wiring Closet L3 backbone switch 100BaseTX to the desk 100BaseTX to the desk

7 ITT IP Telephony Components 2 node Cisco CallManager cluster 1 node Cisco Unity Voic Server ~300 IP handsets (Cisco 7910s, 7940s and 7960s) Phone power via 3524-PWR PoE switches. Cisco 6509 chassis with: 24 port FXS gateway for analog services 8 port E1 gateway for external PSTN connectivity Cisco VG200 H.323 E1 gateway to provide integration with south campus PBX system. (Our only gotcha.)

8 ITT Voice Network

9 WS-X6516A-GBIC WS-X6624-FXS PO RT FXS ANALOG ST ATION WS-X6608-T1 8 PORT VOICE T LIN K LIN K LIN K LIN K SYSTEM RPS STAT UTIL DUPLEX SPEED Analog device connectivity Comms Room Local Wiring Closet 25 pair Cat3 Copper to Comms Rm Cisco pair Cat3 uplinks from wiring closets UTP Patch Fibre to Comms Rm B A UTP Panels UTP Patch Analog device UTP Outlet Fibre GBIC Module FXS Module PoE Switch E1 Gateway 25 pair Cat3 FXS Patch Panel Central Copper Cabinet Wiring Closet CATALYST 3550

10 QoS Configuration CallManager, IP Phones set their own QoS values by default Gateways (E1, H.323, FXS) configured with same QoS settings QoS Trust Edge created at access layer Queue scheduling, access control and policing configured at core

11 QoS Configuration (cont d) QoS untrusted Wiring Closet Access layer trusts only IP phone CoS settings QoS Trust Edge Wiring Closet QoS untrusted Voice: CoS=5, DSCP=EF Sig: CoS=3, DSCP=AF31 Wiring Closet Wiring Closet QoS untrusted Core layer trusts CoS/DSCP settings from access layer and enforces queue access scheduling, prioritization policing etc. QoS untrusted Voice: CoS=5, DSCP=EF Sig: CoS=3, DSCP=AF31

12 WS-X6624-FXS PO RT FXS ANALOG ST ATION WS-X6608-T1 8 PORT VOICE T Traffic flow for Intra-campus call South Campus North Campus A IP Handset Digital Handset Analog FAX RTP Audio Streams SCCP signalling CallManager IP Handset Cisco 6509 SCCP signalling B Nortel PBX V H.323 E1 GW FXS Module E1 Gateway PSTN

13 WS-X6624-FXS PO RT FXS ANALOG ST ATION WS-X6608-T1 8 PORT VOICE T Traffic flow for Inter-Campus Call South Campus North Campus IP Handset A Digital Handset Analog FAX RTP Audio Streams C SCCP IP Handset Digital Audio Nortel Signalling CallManager Nortel PBX E1/Q.931 Signalling V H.323 Cisco 6509 Digital Audio H.323 E1 GW FXS Module E1 Gateway PSTN

14 WS-X6624-FXS PO RT FXS ANALOG ST ATION WS-X6608-T1 8 PORT VOICE T Traffic flow for External Call South Campus North Campus IP Handset Digital Handset Analog FAX IP Handset CallManager SCCP B Cisco 6509 Nortel PBX V MGCP H.323 E1 GW RTP Audio Streams FXS Module E1 Gateway D Analog audio and signalling PSTN E1/Q.931 Signalling Digital Audio

15 Benefits to IT Tralee Cheaper and simpler cabling infrastructure Flexibility Quick, easy and cheap system maintenance Enhanced services (personal web mgmt of ones own handset, corporate dir, address lists, phone services, ring sounds, call history) Learning/research opportunities (Asterisk, GSM/GPRS)

16 Enter *. Asterisk is a complete (open source) PBX in software Primarily runs on Linux but Windows version also available. Features include (short listing): Auto attendant, call forwarding and parking. ACD, IVR, CDR, Interactive Directory Listing. SMS messaging, text to speech, calling cards. Transcoding, trunking, voic , AGI (analagous to web CGI) TDMoE, H.323, SIP, MGCP, IAX, Skinny, wide range of codecs. Traditional telephony interfaces (analog: FXO, FXS; digital: E1, BRI)

17 WS-X6624-FXS PO RT FXS ANALOG ST ATION WS-X6608-T1 8 PORT VOICE T Asterisk in the ITT VoIP Network South Campus North Campus Skinny Handset/Client SIP Handset/Client H323 Handset/Client IAX Handset/Client Digital Handset H.323 E1 GW Asterisk Server E1 V H.323 E1 GSM/GPRS Node H.323 Cisco 6509 Nortel PBX Skinny Handset CallManager E1 FXS Module E1 Gateway PSTN E1

18 The future? Lower initial investment costs Convergence of telephony and internet/data services Public VoIP telephony services?? Migration to global IP Telephony Distributed delegation of dialplans: via DNS/ENUM and/or H.323/GDS Global communications mobility

19 Our (Possible) future? Migration of south campus to IPT Desktop video telephony (Cisco VT Advantage, Videophones) Wireless (non GSM or DECT) IP handsets Extend IPT to remote sites (possibly via Asterisk) Remote working

20 Resources Asterisk: and Terena IP Telephony Handbook: Cisco IP Telephony Design guide and other related Cisco resources:

21 Q&A Questions?.and thank you for your time.