VOIP Switch Monitoring and Traffic Management-Final.ppt

VOIP Switch Monitoring and Traffic Management-Final.ppt
2 VOIP Switch Monitoring and Traffic Management Habib Madani Syed Khurram
3 3 3 3 Agenda • Overview of Softswitch • Voip Softswitch Call Processing Overview • Protocols • Call Flows • Softswitch Operations • Trend analysis • Summary
5 5 5 5 Overview of Softswitch • Network Overview • Network Configuration • Broadband Local Integrated Services Solutions
6 6 6 6 Network Overview • The BTS 10200 call agent offers telephony services over IP and ATM networks. • BTS 10200 provides call control intelligence for establishing, maintaining, routing, and terminating voice calls through the IP or ATM network via media gateways, while seamlessly operating with the PSTN • Supports Class 5 level services, such as 911 emergency, call forwarding and caller ID • Also provides support for messaging and announcements
7 7 7 7 IP Network Configuration ANNOUNCE- MENT SERVER AS5300 AS5300 PSTN CO 3660 ISDN PBX ISDN PBX AS5300 UBR CISCO 2600 CAS PSAP 911 Voice Mail SERVER SS7 STP SS7 STP D-Channel Backhaul MGCP SIP RUDP SS7 Links T1/Analog Lines BTS 10200 Another BTS 10200 or Call Agent
8 8 8 8 BLISS-T1 Signaling Interfaces ISDN Backhaul FCP CA Feature Servers Announcement Server Trunking Gateway PRI PBX Cisco SIP Voice Mail Server IMT CO Network Management & Operational Support Systems SNMP, CORBA, TELNET, FTP, CLI, HTTP IP Network CA SIP-T SS7 STP
10 10 10 10 VOIP Softwitch Call Processing Overview • ISUP trunking • Emergency Services • Trunking gateway for operator services • Voice mail services • Announcement services
11 11 11 11 SS7 Links IMTs MGX IAD C4/C5 BTS STP ISUP Trunking Gateway • Routes offnet calls to ILEC or IXC over Inter-machine Trunks (IMTs) • High port density • Interconnects SS7 links b/w IP Transfer Point (ITP) and C4/5 via STPs • BTS should be provisioned trunks of the same trunk group across multiple TGWs for redundancy • Sigtran used to backhaul ISUP to BTS CA for call control RTP MGCP MGCP V SCTP
12 12 12 12 MF/CAS Trunks IAD BTS RTP Primary PSAP E911 Tandem Trunking Gateway for 911 Services • Uses Feature Group D, Operator Service (OS) signaling protocol • TGW requires support of MGCP CAS “MO” package as described in “draft-foster-mgcp-cas-packages- 00.txt” • 2 types of 911s: enhanced 911 and basic 911 B911 has PSAP (Public Safety Answer Point) connect directly to TGW E911 has PSAP connect TGW via tandem switch • 911 requires “keep the circuit up even if the caller hangs up” • 911 trunks recommended connected to multiple TGWs for redundancy Selective Routing Database Alternate PSAP Automatic Location ID MGCP MGCP MGX V
13 13 13 13 MF/CAS Trunks IAD BTS RTP Operator Postions (OPs) Tandem Switch Trunking Gateway for Operator Services • Uses Feature Group D, Operator Service (OS) Signaling protocol • TGW requires support of MGCP CAS “MO” package as described in “draft-foster-mgcp-cas-packages- 00.txt” • BTS sends Preferred Carrier Info to tandem switch to determine appropriate operation position • OS does not have “keep the circuit up even if the caller hangs up” requirement as 911 • OS trunks recommended connected to multiple TGWs for redundancy MGCP MGCP MGX V
14 14 14 14 LDAP IMAP SMTP Directory Server Message Server SIP UC App. Server IAD BTS Application Services Backend Services RTP MGX Voice Mail Server Voice Mail Server • Provides voice messaging capabilities • Components UC Applications Server VM SW resides. Terminates calls, records and replays messages, and interacts with backend servers Directory Server Stores subscriber profiles and information about which greetings are active and where greetings are located Message Server Stores and retrieves personal greetings, subscriber messages, and distribution lists2 MGCP MGCP V
15 15 15 15 BTS IAD AS Announcement Server • Instructed by BTS with MGCP to play announcement RTP to ingress MG (MTA or MGX) • Audio files are stored in AS • MGCP package options for AS: Script (MG requires scripting language support such as TCL) Announcement Server • Deploy multiple AS for redundancy This # has been disconnected. Please check your # again. RTP MGX MGCP MGCP V
17 17 17 17 Protocols • SIP Methods • MGCP Implementation • MGCP Commands • MGCP Modes • ISDN • Channel Associated Signaling (CAS) • CAS - PSAP/911
18 18 18 18 SIP Methods •Consists of Requests and Responses •Requests (unless mentioned, each has a response) - REGISTER UA registers with Registration Server) - INVITE (request from a UA to initiate a call) - ACK (confirms receipt of a final response to INVITE) - BYE (sent by either side to end a call) - CANCEL (sent to end a call not yet connected) - OPTIONS (sent to query capabilities) •Messages contain SIP Headers and Body. Body might be SDP or an attachment or some other application **UA=User Agent (end device)**
19 19 19 19 MGCP Implementation • Communication between the BTS 10200 call agent and the media gateway (MGW) is done via MGCP • MGCP uses a sequence of commands and mandatory acknowledgements • Commands contain a requested verb (action to be performed by endpoint) and additional parameters
20 20 20 20 MGCP Commands • NotificationRequest-issued by CA instructing the MGW to watch for specific events, such as hook actions or DTMF tones on a specified endpoint (RQNT) • Notify-used by the MGW to inform the CA when the requested events occur (NTFY) • CreateConnection-used by the CA to create a connection that terminates at an endpoint inside the MGW (CRCX) • ModifyConnection - used by the CA to change parameters associated with a previously established connection (MDCX) • DeleteConnection - used by CA to delete an existing connection or by MGW when an existing connection can no longer be sustained (DLCX)
21 21 21 21 More MGCP Commands • AuditEndpoint - used by CA to audit the status of the endpoint (AUEP) • AuditConnection – used by CA to retrieve the parameters attached to a connection (AUCX) • RestartInProgress - used by MGW to notify the CA when the gateway or a group of endpoints on the gateway are taken out of service or being placed back in service (RSIP)
22 22 22 22 ISDN • Backhaul - Terminology for sending messages between CA - PBX through the AGW • ISDN-Q.931 - Normal application layer messages sent to the CA over IP • RUDP - Cisco proprietary protocol that makes UDP Reliable ISDN-Q.931 UDP IP Backhaul RUDP
23 23 23 23 ISDN Network Diagram RUDP – Signaling and Call Setup/Teardown on the D-Channel MGCP – Voice, data, or video on the B-Channels IP ISDN PBX ISDN PBX AS5300 D-Channel Backhaul MGCP BTS 10200
24 24 24 24 Channel Associated Signaling (CAS) • Inband signaling made up of tones carried on the same circuit as the call they are setting up • Implemented via MGCP to support PBX connectivity • Dual Tone Multi-frequency (DTMF) refers to the signaling (tones) generated when you touch a button on a push button pad • MGCP supports all the DTMF/MF (signaling types: DTMF loopstart, DTMF groupstart, DTMF imstart, DTMF winkstart, MF FGD, MF imstart, MF winkstart,) • CAS is required to: Support PBX interconnect and incoming CAS trunk interconnects Support Barge-In and Busy-Line Verification operator services (operator interrupt services) – Not supported release 1.0 Support PSAP/911 services
25 25 25 25 CAS - PSAP/911 • 911 services require support for MF signaling • PSAP operators must be able to hold the line even if caller goes on-hook
27 27 27 27 Call Flow • CA to CA Call Flow – SIP • RG to RG • TG - RG Using ISDN - MGCP Signaling • PBX/ISDN PRI to RG • Barge-In/Busy Line Verification • BLV/BLI Call Flow
28 28 28 28 CA to CA Call Flow - SIP CA-2 PSTN2 CA-1 PSTN1 1. IAM 2. Invite 3. IAM 4. 100 Trying 5. ACM 6. 183 Progress 7. ACM 8. ANM 9. 200 OK 10. ANM 12. Talking 13. REL 14. RELC 15. Bye 16. REL 17. RELC 18. 200 OK 19. ACK 11. ACK
29 29 29 29 BTS 10200 RG-o RG-t 1. Off-hook 5. digits 2. NTFY (O:hd) 200 OK 3. RQNT (R:hu (N)) 200 OK 4. RQNT (R:hu, hf, [0-9:#*T](D), S:dl) 200 OK 6. NTFY (O:9,1,6,3,4,2,1,2,1,2,T) 200 OK 7. RQNT (R:hu, hf) 200 OK 916-342-1206 916-342-1212 8. CRCX (M:recvonly) 200 OK orig. SDP Hey Call Agent, I’m going off hook Hey endpoint, let me know if your subscriber hangs up Hey endpoint, let me know if your subscriber hangs up, hook-flash or dials digits. Oh and signal dial tone to your subscriber Hey Call Agent, I am letting you know that I have collected digits Sure, but let me know if your subscriber hangs up or hook- flash I am going to create a backwards audio path to you in case some in-band info is played by an endpoint. Endpoint ACKs with his SDP info Onnet Call – RGW to RGW
30 30 30 30 Onnet Call – RGW to RGW BTS 10200 RG-o RG-t 200 OK with term. SDP 10. MDCX (M:recv only, term. SDP) 200 OK 916-342-1212 9. CRCX (M:sendrecv orig. SDP) 11. RQNT (R:hd S:rg) 200 OK 12. Ringing 14. Ring Back 15. Off-hook 16. NTFY (O:hd) 200 OK 17. RQNT (R:hu, hf) 200 OK 13. RQNT (R:hu S:rt) 200 OK Hey endpoint 2, you have a caller. Creating bi-directional path to you with orig. SDP info. Hey end endpoint 1, I am sending you the term. endpoint SDP information Hey, ring the phone. Hey, play a ring back tone, the termination is ringing too. Hey call agent, my subscriber answered the phone Ok, but let me know if he hangs up
31 31 31 31 Onnet Call – RGW to RGW BTS 10200 RG-o RG-t 18. MDCX (M:sendrecv) 200 OK 916-342-1212 19. RQNT (R:hu, hf) Bi-Directional Voice Path 200 OK 200 OK 20. On-hook 21. NTFY (O:hu) 23. DLCX 250 Connection Deleted 22. RQNT (R:hd) 200 OK I am making your connection bi-directional so you can talk to your buddy and hear him Hey endpoint, let me know if your subscriber hangs up or hook-flashes Hey call agent, my subscriber went on-hook. OK, but let me know if your subscriber goes back off-hook. Ok I am deleting the connection to you because the originating subscriber is now on-hook. Conversation: Aunt Pearl tells Sally about her new groovy hairstyle
32 32 32 32 Onnet Call – RGW to RGW BTS 10200 RG-o RG-t 916-342-1212 25. RQNT (R:hu) 24. DLCX 250 Connection Deleted 26. RQNT (R:hd) 200 OK 200 OK 28. NTFY (O:hu) 29. RQNT (R:hd) 200 OK 200 OK Deleting your connection because you went on-hook Let me know if your subscriber goes on-hook. Let me know if your subscriber goes off-hook 27. On-hook Hey my subscriber went on-hook Ok, but let me know if your subscriber goes off-hook.
33 33 33 33 TG - RG Using ISDN - MGCP Signaling endpoint/1@rg2.cisco.com IP endpoint/1@tg1.cisco.com ISDN Backhaul User 1 User 2 RG-2 PBX BTS 10200 TG-2
34 34 34 34 TG-3 EO/ User 2 PBX User 1 TG-1 RG-2 User 3 PBX/ISDN PRI to RG SETUP CRCX (M:recvonly) 14. Off-hook ACK (SDP1) CRCX (M:sendrecv, SDP1) ACK (SDP2) 13. Ring back tone Alert SETUP Backhaul CALL PROC MDCX (M:recvonly SDP2) ACK 12. Ringing RQNT (R:hd, S:rg, rbk(xxx)) 10. ACK BTS 10200 CALL PROC Aler t
35 35 35 35 BTS 10200 TG-3 User 3 EO/ User 2 PBX User 1 TG-1 RG-2 22. CONN ACK 19. MDCX (M:sendrecv) 20. ACK 16. OK 15. NTFY (O:hd) 21. CONN 18. ACK 17. RQNT (R:hu) 23. Bearer Connection Established PBX/ISDN PRI to RG (cont'd)
36 36 36 36 Barge-In/Busy Line Verification • Permits operators to establish a connection to a customers line to verify a busy condition • Operator access is provided over dedicated facilities • Facilities connect directly to a switchboard or via a switched network accessed by remote operator systems • The trunks may use reverse battery loop or E&M lead supervision with multi-frequency (MF) or dial pulse (DP) signaling
37 37 37 37 BTS 10200 BLV/BLI Call Flow Caller C B -TG/RG Operator A-RG TG Conversation seize NTFY (O:MS/sup) ACK wink-start RQNT (R:MS/inf,MS/rel) CRCX (M: inactive, SDPc) digits ACK(SDPc) NTFY(O:MS/inf(digits)) CRCX (M:recvonly) ACK ACK(I: BLV-2, SDPa) MDCX (M:reconly,S:MS/ans, SDPa) ACK answer MDCX (M: confrnce,I:BLV-1) ACK Operator reports line is busy MDCX (M: confrnce,I:BLV-2) MDCX(M:sendrec) ACK Conversationa 3-way call activeb
38 38 38 38 Agenda • Overview of Softswitch • Voip softswitch Call Processing Overview • Protocols • Call Flows • Softswitch Operations • Trend analysis • Summary
39 39 39 39 Softswitch Operations • Network management and Performance Counters • Network Performance- Voice Quality • Defining jitter, packet loss and latency • VOIP Switch Performance Counters • Performance Counters Flow • Types of Counter on CISCO BTS • Performance counter monitoring
40 40 40 40 Network management and Performance Counters • One of the key Network Management aspects is monitoring Performance counters or Performance Pegs. • Performance counter collection and reporting Typically in NMS/EMS and NE the Performance data is collected as reports. Performance counters are collected in various time buckets, these buckets keep historic and pseudo-real time data. The pseudo-real time buckets can be reset for immediate trouble shooting. These reports are also periodically dumped to disk as flat files. These files are then pulled off to a data store to perform Data mining. • Common Service Provider (SP) usage Preemptive trend analysis for capacity planning Service Level Agreements (SLA) Quality of service monitoring and network trouble shooting.
41 41 41 41 Network management and Performance Counters cont .. • How do we measure network performance? • VOIP network Key Measurements are based of Call Success Rate , Voice Quality and Voice Mail access % Ineffective Attempts Network issues: IP backbone partially down, DNS servers partially down, voicemail trunk congestion, HFC/Cable plant capacity. No Channels available for Off-net PSTN calls. % Dropped Calls OR IP backbone completely down, total outage Call Processing Failure at the PSTN, signalling link is down or the bearer trunks are down. • Thus all these factors are deterministic of VOIP network performance and they need to be effectively monitored.
42 42 42 42 Network Performance- Voice Quality • It is dictated by Mean Opinion Score or MOS in short. • How listeners perceive voice quality. • Key Factors affecting Voice Quality for VOIP network: Jitter Delay in packet loss Latency
43 43 43 43 Defining jitter, packet loss and latency • Delay is the time taken from point-to-point in a network. Delay can be measured in either one-way or round-trip delay. VoIP typically tolerates delays up to 150 ms before the quality of the call is unacceptable • Jitter is the variation in delay over time from point-to-point. If the delay of transmissions varies too widely in a VoIP call, the call quality is greatly degraded. VOIP Network compensates for this by having jitter buffers. • Packet loss is losing packets along the data path, which severely degrades the voice quality.
44 44 44 44 Performance Counters and VOIP Switch Vendors • Current Performance Counter Availability Currently Counters are available through private Interfaces which capture the VOIP call segments. ISUP counters for PSTN signaling, SIP counters , MGCP counters for trunk gateways, general Call processing counters and QOS counters. • Industry Standard for VOIP monitoring To Monitor VOIP Performance, Standard collection and polling mechanisms should available through SNMP/MIBS, CORBA/IDL, CMIP/Q3. • Alerting based of the Performance Counters The VOIP switch vendors need to implement configurable thresholds mechanisms, acting as a high/low/variable water marks. These watermarks would act as triggers for alarms and events, allowing real time monitoring of the System. • There is a lack of composite monitoring standard It would dictate guidelines for Performance counters, collection mechanism Alert trigger and generations.
45 45 45 45 Performance Counters Flow Provider Backbone HFC Plant LNP STP PSTN Signaling GW MG V CMS/ SoftSwitch MGC DOCSIS CMTS VM CONF SRV ANN SRV Media Servers CALEA NCS EMTA NCS EMTA CM NCS MTA Dqos Counters MGCP Counters SIP Counters ISUP Counters Dqos Counters
46 46 46 46 Case Study leveraging counters available on CISCO BTS • CISCO BTS offers a wide set of performance counters through its private interfaces SNMP MIB being one of them. • The following set of BTS counters capture system health across various VOIP call segments: ISDN User Part (SS7/PSTN) signaling protocol related information. MGCP signaling protocol related information. SIP Interface Adapter related information Call Processing specific information Trunk Group usage information Dynamic Quality of Service related information
47 47 47 47 Agenda • Overview of Softswitch • Voip softswitch Call Processing Overview • Protocols • Call Flows • Softswitch Operations • Trend analysis • Summary
48 48 48 48 Case Study for Trend Analysis • Trend Analysis and Visual Monitoring of Performance Counters • Architecture of DDRAW setup • DDRAW Dash Board in depth • Trend Analysis using Call Performance counters • Trend Analysis using MGCP Performance counters • Trend Analysis using ISUP Performance counters • Trend Analysis using Dynamic Qos Performance counters • Trend Analysis using SIP Performance counters • Trend Analysis for PSTN Bearer Trunks
50 50 50 50 Trend Analysis and Visual Monitoring of Performance Counters • BTS performance data collection BTS performance data was collected for a USA CABLE MSO. The reports were collected at 15 min. buckets for 24 hour, and dumped to flat files (CSV). 3 months worth of these data was collected. • Pull data The data was ftped over to a linux server which had Perl, Round Robin Database(RRD) and DRRAW(cgi) installed on them. • RRD update Perl was used to parse the CSV files and RRD was updated with 3 months of cable MSO performance data.
51 51 51 51 Trend Analysis and Visual Monitoring of Performance Counters (cont.) • DDRAW was customized to create a Dashboard for some of these counters. • RRD and DRRAW we have a pseudo real-time display of the performance stats. This Dashboard displays past 28 hours, 1 week, month and year of data. • It can be used to create a system wide view of the VOIP call flow, do capacity planning, and keep on top of SLA.
52 52 52 52 Architecture of DDRAW setup BTS 01 BTS 02 BTS 03 RRD Perl Script Parsing Parse Data Populate Data Client View HTTP Pull Data Pull PM Data Linux Server Client Client MGCP Callp ISUP DRRAW CGI DRRAW CGI Apache
54 54 54 54 Dash Board in depth • Call Stats Dash Board display, captures, the number of originating call attempts of all types, call attempts, call originating failures and call success on the reporting BTS. • DQOS Dash actually looks ok, which reflects the CMTS leg, it shows that the Gate SET attempts are equal to the Gate SET Successes. • MGCP Dash shows number of mgcp attempt success, fail or abandon
55 55 55 55 Dash Board in depth cont .. • ISUP Dash shows SS7 signaling pattern, which includes number IAM, ANM and REL message • SIP Dash shows number of SIP messages going thru the switch • Trunk Dash shows utilization of trunk and overflows- Which may help in capacity planning
56 56 56 56 Dash Board
57 57 57 57 Dash Board cont.
59 59 59 59 Trend Analysis using Call Performance Counters • It can easily be seen that there is a pattern. • Where the peaks represent the busy hour. Any deviations from these patterns represents anomalies that would need to be investigated by the Service Provider. • Also we see a clear gap between the Success and the Call originations, this gap indicates that we are losing calls. • It could be a result of hang-ups, busy dial, or network problems.
60 60 60 60 Trend Analysis using Call Stat counters – Example
61 61 61 61 Trend Analysis using Call Stat counters – Example cont.
63 63 63 63 Trend Analysis using MGCP Performance counters • It can help monitor any performance issues in the network just by reviewing ave mgcp attempts and failures. • Information can be segregated by gateway which could be related to trunking gateway or announcement server.
64 64 64 64 Trend Analysis using MGCP Performance counters – Example
65 65 65 65 Trend Analysis using MGCP Performance counters – Example cont.
67 67 67 67 Trend Analysis using ISUP Performance counters • It can identify issues related to PSTN signaling, or any ss7 link problems. • The Dashboard example is showing IAM,ANM,REL counters being monitored. • Any anomaly related to PSTN network/usage related to incoming/outgoing PSTN calls would be visible. As an example drop in IAM would clearly indicate the call originations are having issues.
68 68 68 68 Trend Analysis using ISUP Performance counters - Example
69 69 69 69 Trend Analysis using ISUP Performance counters – Example cont.
71 71 71 71 Trend Analysis using Dynamic Qos Performance counters • COPS protocol Gate Sets attempts, Success and Commits are tracked • Problem trend Network problem related to CMTS are visible through these Gate counters. A difference in Gate Set attempts and Gate Set Success would be a clear indication of CMTS resource allocation issue. A slight deviation from the norm could be an indication of a problem before SP starts experiencing it. • DQOS parameters of Jitter, Latency and Packet loss are also collected by the BTS and can be monitored in this way.
72 72 72 72 Trend Analysis using Dynamic QoS counters – Example
73 73 73 73 Trend Analysis using Dynamic QoS counters – Example cont.
75 75 75 75 Trend Analysis using SIP Performance counters • BTS uses SIP to interact with VOICEMAIL equipment and SIP trunks. • Dash Board SIP Counters SIP Outgoing messages, SIP Outgoing Success,5xx Errors • Problem trends An increase in retransmits or increase in 5xx errors is a visible indication that Voice mail server or SIP trunks is having issues.
76 76 76 76 Trend Analysis using SIP counters – Example
77 77 77 77 Trend Analysis using SIP counters – Example cont.
79 79 79 79 Trend Analysis using Trunk Usage Counters • Dash Board Trunk Counters Trunk total overflow, Incoming Trunk Busy, Outgoing trunk Busy, Total Trunk usage. • A pattern is seen we can see that most of the trunk seizers are for outgoing trunks. Incoming trunk seizures are low. Overflow of trunks is very low. • Problem indication Total Trunk Usage goes high, Overflow of trunks goes high are indications of capacity issue.
80 80 80 80 Trend Analysis using Trunk usage counters – Example
81 81 81 81 Trend Analysis using Trunk usage counters – Example cont.
82 82 82 82 Summary • VOIP switch technology is a new field. • Performance counter aspect of network management can be a key factor in monitoring the network for issues of equipment malfunction, degradation and capacity. • To provide seamless customer experience from traditional to softswitch, this will help us identifying issue proactively. • A monitoring strategy is to use RRD and Drraw, for monitoring the system through pseudo real time graphs at the NOCs.

VOIP Switch Monitoring and Traffic Management-Final.ppt

Check these out next

VOIP Switch Monitoring and Traffic Management-Final.ppt

Recomendados

Mais conteúdo relacionado

Similar a VOIP Switch Monitoring and Traffic Management-Final.ppt(20)

Último(20)

VOIP Switch Monitoring and Traffic Management-Final.ppt