Cisco Presentation Guide

Transcript Cisco Presentation Guide

VOIP Switch Monitoring and Traffic Management

Habib Madani Syed Khurram

Agenda

• • • • • • •

Overview of Softswitch Voip Softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Agenda

• • • • • • •

Overview of Softswitch Voip Softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Overview of Softswitch

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Network Overview Network Configuration Broadband Local Integrated Services Solutions

Network Overview

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The BTS 10200 IP call agent offers and ATM networks.

telephony services over

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BTS 10200 provides establishing, maintaining, routing, and terminating voice calls through the IP call control intelligence or ATM network for via media gateways , while seamlessly operating with the PSTN

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Supports Class 5 level services, such as 911 emergency , call forwarding and caller ID

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Also provides support for messaging and announcements

Network Configuration

PSTN CO AS5300 SS7 STP SS7 STP AS5300 D-Channel Backhaul ISDN PBX ISDN PBX 3660 CAS PSAP 911 BTS Another BTS 10200 or Call Agent 10200

Voice Mail SERVER

MGCP SIP RUDP SS7 Links T1/Analog Lines

AS5300 ANNOUNCE MENT SERVER CISCO 2600 UBR

BLISS-T1 Signaling Interfaces

Network Management & Operational Support Systems SNMP, CORBA, TELNET, FTP, CLI, HTTP SIP-T Feature Servers CA SS7 FCP ISDN Backhaul SIP Voice Mail Server CA

STP

Cisco PBX PRI IP Network IMT Trunking Gateway CO Announcement Server

Agenda

• • • • • • •

Overview of Softswitch Voip Softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

VOIP Softwitch Call Processing Overview

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ISUP trunking Emergency Services Trunking gateway for operator services Voice mail services Announcement services

ISUP Trunking Gateway

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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 IAD Sigtran used to backhaul ISUP to BTS CA for call control BTS SCTP MGCP MGCP RTP V MGX SS7 Links STP IMTs C4/C5

Trunking Gateway for 911 Services

BTS

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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 IAD MGCP RTP Selective Routing Database MGCP MF/CAS Trunks E911 Tandem V MGX Primary PSAP Automatic Location ID Alternate PSAP

Trunking Gateway for Operator Services

BTS

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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 IAD MGCP MGCP MF/CAS Trunks Tandem Switch RTP V MGX Operator Postions (OPs)

Voice Mail Server

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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 IAD V MGX RTP MGCP MGCP UC App. Server Application Services LDAP Backend Services Directory Server SIP IMAP BTS SMTP Message Server Voice Mail Server

Announcement Server

BTS

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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) IAD Announcement Server

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Deploy multiple AS for redundancy MGX V MGCP RTP This # has been disconnected.

Please check your # again.

MGCP AS

Agenda

• • • • • • •

Overview of Softswitch Voip Softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Protocols

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SIP Methods MGCP Implementation MGCP Commands MGCP Modes ISDN Channel Associated Signaling (CAS) CAS - PSAP/911

SIP Methods

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Consists of Requests and Responses

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Requests (unless mentioned, each has a response) REGISTER UA registers with Registration Server) INVITE ACK BYE (request from a UA to initiate a call) (confirms receipt of a final response to INVITE) (sent by either side to end a call) CANCEL OPTIONS (sent to end a call not yet connected) (sent to query capabilities)

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Messages contain SIP Headers and Body. Body might be SDP or an attachment or some other application **UA=User Agent (end device)**

MGCP Implementation

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Communication between the BTS 10200 media gateway ( MGW ) is done via MGCP call agent and the

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MGCP uses a sequence acknowledgements of commands and mandatory

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Commands contain a requested verb (action to be performed by endpoint) and additional parameters

MGCP Commands

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NotificationRequest-issued specific events, such as endpoint ( RQNT ) by CA instructing the MGW to hook actions or DTMF tones watch for on a specified Notify-used by the MGW to inform occur ( NTFY ) the CA when the requested events 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 with a previously established connection ( MDCX ) associated DeleteConnection - used by CA to delete an existing MGW connection or when an existing connection can no longer be sustained ( by DLCX )

More MGCP Commands

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AuditEndpoint - used by CA to audit the status of the endpoint ( AUEP ) AuditConnection – used by CA to retrieve connection ( AUCX ) the parameters attached to a 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 )

ISDN

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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 Backhaul ISDN-Q.931 RUDP UDP IP

ISDN Network Diagram

AS5300 D-Channel Backhaul MGCP ISDN PBX ISDN PBX

RUDP – Signaling and Call Setup/Teardown on the D-Channel MGCP – Voice, data, or video on the B-Channels BTS 10200

Channel Associated Signaling (CAS)

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Inband signaling circuit as the call made up of tones carried on the same they are setting up

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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

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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

CAS - PSAP/911

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911 services require support for MF signaling PSAP operators must be able to hold the line even if caller goes on-hook

Agenda

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Overview of Softswitch Voip Softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Call Flow

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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

CA to CA Call Flow - SIP

PSTN1 1. IAM CA-1 2. Invite 4. 100 Trying CA-2 3. IAM 5. ACM 6. 183 Progress 7. ACM 8. ANM 9. 200 OK 10. ANM 11. ACK 12. Talking PSTN2 13. REL 14. RELC 15. Bye 16. REL 17. RELC 18. 200 OK 19. ACK

Onnet Call – RGW to RGW

916-342-1206 1. Off-hook RG-o Hey Call Agent, I’m going off hook BTS 10200 2. NTFY (O:hd) 200 OK 5. digits 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 8. CRCX (M:recvonly) 200 OK orig. SDP Hey endpoint, let me know if your subscriber hangs up RG-t 916-342-1212 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

RG-o Hey end endpoint 1, I am sending you the term. endpoint SDP information BTS Hey endpoint 2, you have a caller. Creating bi-directional path to you with orig. SDP info.

10200 9. CRCX (M:sendrecv orig. SDP) 200 OK with term. SDP RG-t Hey, ring the phone.

10. MDCX (M:recv only, term. SDP) 200 OK Hey, play a ring back tone, the termination is ringing too.

11. RQNT (R:hd S:rg) 200 OK 916-342-1212 12. Ringing 13. RQNT (R:hu S:rt) 200 OK Hey call agent, my subscriber answered the phone 14. Ring Back 15. Off-hook 16. NTFY (O:hd) Ok, but let me know if he hangs up 200 OK 17. RQNT (R:hu, hf) 200 OK

Onnet Call – RGW to RGW

RG-o I am making your connection bi-directional so you can talk to your buddy and hear him BTS 10200 18. MDCX (M:sendrecv) 200 OK Bi-Directional Voice Path 19. RQNT (R:hu, hf) 200 OK Hey endpoint, let me know if your subscriber hangs up or hook-flashes 916-342-1212 RG-t Conversation: Aunt Pearl tells Sally about her new groovy hairstyle Hey call agent, my subscriber went on-hook. 20. On-hook 21. NTFY (O:hu) 200 OK 22. RQNT (R:hd) 200 OK 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.

23. DLCX 250 Connection Deleted

Onnet Call – RGW to RGW

Deleting your connection because you went on-hook BTS RG-o 10200 24. DLCX 250 Connection Deleted Let me know if your subscriber goes off-hook 26. RQNT (R:hd) 200 OK Let me know if your subscriber goes on-hook.

25. RQNT (R:hu) 200 OK Hey my subscriber went on-hook RG-t 916-342-1212 27. On-hook Ok, but let me know if your subscriber goes off-hook.

28. NTFY (O:hu) 200 OK 29. RQNT (R:hd) 200 OK

TG - RG Using ISDN - MGCP Signaling

PBX BTS

ISDN Backhaul

10200 TG-2

endpoint/[email protected]

RG-2

endpoint/[email protected]

User 2 User 1

PBX/ISDN PRI to RG

PBX User 1 SETUP TG-1 CALL PROC User 3 TG-3 SETUP Backhaul CALL PROC CRCX (M:recvonly) ACK (SDP1) MDCX (M:recvonly SDP2) ACK BTS 10200 CRCX (M:sendrecv, SDP1) ACK (SDP2) RQNT (R:hd, S:rg, rbk(xxx)) 10. ACK Aler t Alert 13. Ring back tone RG-2 12. Ringing 14. Off-hook EO/ User 2

PBX/ISDN PRI to RG (cont'd)

PBX User 1 TG-1 User 3 TG-3 BTS 10200 15. NTFY (O:hd) 16. OK 17. RQNT (R:hu) 18. ACK RG-2 19. MDCX (M:sendrecv) 20. ACK 21. CONN 22. CONN ACK 23. Bearer Connection Established EO/ User 2

Barge-In/Busy Line Verification

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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

BLV/BLI Call Flow

BTS A-RG B -TG/RG Conversation a 10200 NTFY (O:MS/sup) TG RQNT (R:MS/inf,MS/rel) ACK seize wink-start digits NTFY(O:MS/inf(digits)) CRCX (M:recvonly) ACK(SDPc) CRCX (M: inactive, SDPc) ACK(I: BLV-2, SDPa) MDCX (M:reconly,S:MS/ans, SDPa) MDCX (M: confrnce,I:BLV-1) ACK answer ACK MDCX (M: confrnce,I:BLV-2) ACK MDCX(M:sendrec) Operator Caller C Conversation ACK 3-way call active b Operator reports line is busy

Agenda

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Overview of Softswitch Voip softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Softswitch Operations

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Network management and Performance Counters

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Network Performance- Voice Quality

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Defining jitter, packet loss and latency

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VOIP Switch Performance Counters

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Performance Counters Flow

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Types of Counter on CISCO BTS

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Performance counter monitoring

Network management and Performance Counters

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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.

Network management and Performance Counters cont ..

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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.

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Thus all these factors are deterministic of VOIP network performance and they need to be effectively monitored.

Network Performance Voice Quality

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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

Defining jitter, packet loss and latency

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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

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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.

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Packet loss is losing packets along the data path, which severely degrades the voice quality.

Performance Counters and VOIP Switch Vendors

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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.

Performance Counters Flow

MGC Signaling GW CM NCS MTA NCS EMTA DOCSIS

Dqos Counters

CMS/ SoftSwitch NCS EMTA

HFC Plant

CMTS

Provider Backbone

Dqos Counters MGCP Counters SIP Counters ISUP Counters

V MG CALEA ANN SRV CONF SRV

Media Servers

STP

LNP PSTN

Case Study leveraging counters available on CISCO BTS

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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

Agenda

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Overview of Softswitch Voip softswitch Call Processing Overview Protocols Call Flows Softswitch Operations Trend analysis Summary

Case Study for Trend Analysis

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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

Case Study for Trend Analysis

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Trend Analysis and Visual Monitoring of Performance Counters

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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.

Trend Analysis and Visual Monitoring of Performance Counters (cont.)

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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.

Architecture of DDRAW setup

Client HTTP Linux Server Apache DRRAW CGI Perl Script Parsing Client Pull PM Data

Pull Data Parse Data Populate Data DRRAW CGI Client View

RRD Callp ISUP MGCP BTS 01 BTS 02 BTS 03

Case Study for Trend Analysis

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Dash Board in depth

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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

Dash Board in depth cont ..

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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

Dash Board

Dash Board cont.

Case Study for Trend Analysis

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Trend Analysis using Call Performance Counters

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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.

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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.

Trend Analysis using Call Stat counters – Example

Trend Analysis using Call Stat counters – Example cont.

Case Study for Trend Analysis

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Trend Analysis using MGCP Performance counters

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It can help monitor any performance issues in the network just by reviewing ave mgcp attempts and failures.

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Information can be segregated by gateway which could be related to trunking gateway or announcement server.

Trend Analysis using MGCP Performance counters – Example

Trend Analysis using MGCP Performance counters – Example cont.

Case Study for Trend Analysis

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Trend Analysis using ISUP Performance counters

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It can identify issues related to PSTN signaling , or any ss7 link problems.

The Dashboard example is showing counters being monitored. IAM , ANM , REL

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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.

Trend Analysis using ISUP Performance counters - Example

Trend Analysis using ISUP Performance counters – Example cont.

Case Study for Trend Analysis

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Trend Analysis using Dynamic Qos Performance counters

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COPS protocol Gate Sets attempts, Success and Commits are tracked Problem trend Network problem related to CMTS are visible counters.

through these Gate 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.

Trend Analysis using Dynamic QoS counters – Example

Trend Analysis using Dynamic QoS counters – Example cont.

Case Study for Trend Analysis

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Trend Analysis using SIP Performance counters

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BTS uses SIP to interact with VOICEMAIL equipment and SIP trunks.

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Dash Board SIP Counters SIP Outgoing messages, SIP Outgoing Success,5xx Errors

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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.

Trend Analysis using SIP counters – Example

Trend Analysis using SIP counters – Example cont.

Case Study for Trend Analysis

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Trend Analysis using Trunk Usage Counters

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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.

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Problem indication Total Trunk Usage goes high, Overflow of trunks goes high are indications of capacity issue.

Trend Analysis using Trunk usage counters – Example

Trend Analysis using Trunk usage counters – Example cont.

Summary

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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.