qos and admission probability study for a sip-based central managed ip telephony system
DESCRIPTION
Jose Saldana, Jenifer Murillo, Julian Fernandez-Navajas, Jose Ruiz-Mas, Eduardo Viruete, Jose I. Aznar. "QoS and Admission Probability Study for a SIP-based Central Managed IP Telephony System". In Proc. New Technologies, Mobility and Security, NTMS 2011, 5th International Conference on, Paris. Feb. 2011. ISBN: 978-1-4244-8704-2TRANSCRIPT
Presentación
Jose Saldana
Jenifer Murillo
Julián Fernández Navajas
José Ruiz Mas
Eduardo Viruete Navarro
José I. Aznar
O M U N I C A C I O N E S
TRUPO DE
CECNOLOGÍAS
GDE LAS
CPS - University of Zaragoza, Spain
<>
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
4
Introduction
- VoIP is replacing traditional telephony systems.
- Software-based solutions allow a simple PC to assume the role of the PBX.
- This is interesting for SME that want to avoid the costs of proprietary systems.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
5
Introduction
- VoIP is a real-time service, but it uses a network designed for best effort services.
- Users demand a QoS similar to PSTN.
- Need of solutions to add quality to IP networks.
- Overprovisioning is not the best solution.
- Call Admission Control (CAC) can be used.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
6
Introduction
- The offices are grouped into countries and geographical zones.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
Country 1
Country 2
Country 3
Country 4
Country 5
Zone 1
Zone 2
Zone 3
IP network
PSTN
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
7
Introduction
- Central managed system: connection of different offices via IP, and sharing lines between offices. Cost savings by establishing calls from the GW of the destination country.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
PSTN
IP networkOffice 1 Office 2
GatewayGateway
IP call Local call
Country 1 Country 2
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
8
Introduction
- Control element: Local agent (SIP proxy)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
IP network
Data centre
PBX
Local
agent
Local
agentLocal
agent
Office 1 Office 2
Office i
Gateway
Gateway
Gateway
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
9
Introduction
- Control element: Local agent (SIP proxy)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
IP network
Data centre
PBX
Local
agent
Local
agentLocal
agent
Office 1 Office 2
Office i
Gateway
Gateway
Gateway
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
10
Introduction
- SIP proxy allows the CAC to be seamlessly integrated into the system.
- The PBX and the terminals do not have to be modified.
- SIP Redirect messages can be used to decrease blocking probability.
- A SIP proxy does not require a high processing capacity.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
11
Motivation of this work
Study the system in terms of
- QoS parameters
- OWD (One Way Delay)
- Packet Loss
- Jitter
- R-factor
- Establishment delay
- Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
12
R-factor - Defined by ITU G.107 (E-Model)
- Ranges from 0 (bad quality) to 100 (good)
- Acceptable for R > 70
- Dependence on delay and packet loss
- Widely accepted quality estimator for VoIP services
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
14
Signaling protocols
- H.323: Used by many proprietary solutions.
- SIP (Session Initiation Protocol): Becoming very popular. Many open-source PBX use it.
- SIP proxies: Used to add scalability, transferring workload from the network core to the borders.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
15
CAC systems
- Measurement-based: Use the state of the network to take admission decisions
- Parameter-based: Some measurements are carried out during system’s set up, and a maximum number of calls is set.
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
16
- «Rule of the thumb»: Bandwidth-delay product.
- «Stanford model»: Division by sqrt(N) (N:number of TCP flows).
- Other proposal: time-limited buffer. Interesting for this work. Limits OWD. But penalizes big packets.
Buffer size and buffer policies
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
18
- Offices in different countries
- Dial plan only at the PBX
- Internet used for VoIP traffic
- The system does not use any reservation protocol
- VoIP traffic is the only real-time one we are going to take care of in a special way
- A parameter-based CAC is used
IP Telephony system
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
19
- All signaling messages pass through it
- Counts the number of calls
- In charge of admission decissions
Local Agent
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 Trying
INVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
480 Temporarily
Unavailable
480 Temporarily
Unavailable
480 Temporarily
Unavailable
IP phone IP phoneLocal agent Local agent
Office 1 Office i
database
PBX
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
20
- All signaling messages pass through it
- Counts the number of calls
- In charge of admission decissions
Local Agent
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 Trying
INVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
480 Temporarily
Unavailable
480 Temporarily
Unavailable
480 Temporarily
Unavailable
IP phone IP phoneLocal agent Local agent
Office 1 Office i
database
PBX
There is no place for this call
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
21
Different call types
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
IP network
Office 1 Office 2
Gateway Gateway
Type 1
Type 2
Type 4 Type 6
Type 5
Type 3
User in a country
without office
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
22
- Calls to PSTN can be redirected if there are no available lines in a gateway
Redirected calls
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 TryingINVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
302 Moved
Temporarily
IP phone SIP proxy SIP proxy Gateway
INVITE
SIP proxy
database
Gateway
INVITE
100 Trying
100 Trying
Offic
e 1
PBX
Offic
e i
Offic
e j
database
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
23
- Calls to PSTN can be redirected if there are no available lines in a gateway
Redirected calls
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 TryingINVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
302 Moved
Temporarily
IP phone SIP proxy SIP proxy Gateway
INVITE
SIP proxy
database
Gateway
INVITE
100 Trying
100 Trying
Offic
e 1
PBX
Offic
e i
Offic
e j
database
There is no place for this call
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
24
- Calls to PSTN can be redirected if there are no available lines in a gateway
Redirected calls
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 TryingINVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
302 Moved
Temporarily
IP phone SIP proxy SIP proxy Gateway
INVITE
SIP proxy
database
Gateway
INVITE
100 Trying
100 Trying
Offic
e 1
PBX
Offic
e i
Offic
e j
database
Can it be established from another office?
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
25
- Calls to PSTN can be redirected if there are no available lines in a gateway
Redirected calls
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 TryingINVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
302 Moved
Temporarily
IP phone SIP proxy SIP proxy Gateway
INVITE
SIP proxy
database
Gateway
INVITE
100 Trying
100 Trying
Offic
e 1
PBX
Offic
e i
Offic
e j
database
Try Office j
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
26
- Calls to PSTN can be redirected if there are no available lines in a gateway
Redirected calls
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
100 TryingINVITE
100 Trying
183 Session
Progress
183 Session
Progress
INVITE
302 Moved
Temporarily
IP phone SIP proxy SIP proxy Gateway
INVITE
SIP proxy
database
Gateway
INVITE
100 Trying
100 Trying
Offic
e 1
PBX
Offic
e i
Offic
e j
database
Accept
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
28
- Xen Virtualization-based testbed
- Each computer is translated into a VM
- Bandwidth of office’s routers emulated with Linux tc (Traffic Control)
- Codec used: G.729a with 2 samples per packet
Testbed
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
Virtual network
Physical
machine
xenbr0
Public IP address
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
29
- Off-the-self tools:
- SIP Proxy: OpenSIPS 1.4
- PBX: Asterisk 1.6.0.1
- Softphone: PJSUA 1.0
- Gateways: Emulated with PJSUA 1.0
- Admission probability: We need a bigger scenario (Testbed has size limitations). Matlab simulations.
Software tools
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
pj
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
31
- Generator: D-ITG
- Network delays and dejitter buffer effect are added offline
QoS measurements
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
Traffic
Generation
RouterTraffic
Capture
Real Traffic in a testbed
Network
delays
+
Dejitter
buffer
Offline post-processing
Traffic
Trace
Final
Results
VoIP
Background
Buffer
policies
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
32
- Size distribution
- 50% 40 bytes
- 10% 576 bytes
- 40% 1500 bytes
- Only UDP, in order to avoid flow control: always the same background traffic.
- Different rates to saturate the access router
- Network does not loose packets
Background traffic
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
33
- Step-like graphs
- When the bandiwidht is not enough, QoS falls dramatically
High capacity buffer
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
70
75
80
400 450 500 550 600 650 700 750 800 850 900 950 1000
R-f
acto
r
background traffic (kbps)
R-factor
1 call
5 calls
10 calls
15 calls
20 calls
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
34
- The graphs present a slope
- Acceptable R values are obtained with more background traffic
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
60
65
70
75
80
85
400 450 500 550 600 650 700 750 800 850 900 950 1000
R-f
acto
r
background traffic (kbps)
R-factor 1 call
5 calls
10 calls
15 calls
20 calls
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
35
- Limits the maximum delay
- But increases packet loss for BG traffic
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
0
5
10
15
20
25
30
35
40
45
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
% p
acke
t lo
ss
Number of calls. Background traffic=800kbps
Packet loss of each trafficRTP
1500 bytes
572 bytes
40 bytes
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
36
- VoIP traffic is protected because of its small size
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
0
100
200
300
400
500
600
700
800
900
1000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Ban
dw
idth
(kb
ps
at e
th le
vel)
Number of calls. Background traffic=800kbps
Bandwidth of each trafficRTP1500 bytes572 bytes40 bytes
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
37
- OWD presents a limit
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
75
100
125
150
175
400 450 500 550 600 650 700 750 800 850 900 950 1000
OW
D (
ms)
background traffic (kbps)
One Way Delay1 call
5 calls
10 calls
15 calls
20 calls
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
38
- Packet loss grows indefinitely
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
0
1
2
3
4
5
6
400 450 500 550 600 650 700 750 800 850 900 950 1000
pe
rce
nta
ge o
f d
isca
rde
d p
acke
ts
background traffic (kbps)
Percentage of packet loss1 call
5 calls
10 calls
15 calls
20 calls
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
39
- Jitter (IPDV)
Time-limited buffer (60ms)
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
2
3
4
5
6
7
8
9
10
400 450 500 550 600 650 700 750 800 850 900 950 1000
IPD
V (
ms)
background traffic (kbps)
IPDV1 call
5 calls
10 calls
15 calls
20 calls
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
40
- Redirecting calls can increase this delay.
- Measured with simulation: From INVITE to arrival at the destination.
- Considered delays:
- Network delay at the LANs: Negligible
- Processing time: Proxy and PBX
- Queuing delay at the router
- Network delay at the WAN
Establishment delay
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
41
Establishment delay
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
INVITE
INVITE
302 Moved
IP phone SIP proxy SIP proxy
INVITE
INVITE
Offic
e 1
PBX
Offic
e i
Offic
e j
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
IP phone
Processing delays
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
42
Establishment delay
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
INVITE
INVITE
302 Moved
IP phone SIP proxy SIP proxy
INVITE
INVITE
Offic
e 1
PBX
Offic
e i
Offic
e j
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
IP phone
Queuing delays
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
43
Establishment delay
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
INVITE
INVITE
INVITE
302 Moved
IP phone SIP proxy SIP proxy
INVITE
INVITE
Offic
e 1
PBX
Offic
e i
Offic
e j
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
Queuing
Network
Proc. PBX
Network
Proc. Proxy
IP phone
WAN delays
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
44
- Different RTT values
- Independent of the number of offices
Establishment delay
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
50
100
150
200
250
300
350
25 50 75 100 125
Esta
blis
hm
en
t d
ela
y (m
s)
RTT (ms)
Establishment delay 2 offices
4 offices
6 offices
8 offices
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
45
- Matlab simulations
- Each office has 25 users
- Gateways have 6 lines
- CAC limit=6 (variable in some tests)
- Different values of and number of offices
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
... ...
IP network
M1 M2AI12AP1
AO1
AI21 AP2
AO2
N1 N2
PSTN PSTN
...
...
...
...
Office 1 Office 2
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
46
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
3 3,5 4 4,5 5
Pe
rce
nta
ge o
f ad
mit
ted
co
nfe
ren
ces
(%)
λ (conferences per hour per user)
Admission probability 3 offices
5 offices
7 offices
10 offices
15 offices
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
47
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
3 3,5 4 4,5 5
Pe
rce
nta
ge o
f ad
mit
ted
co
nfe
ren
ces
(%)
λ (conferences per hour per user)
Admission probability 3 offices
5 offices
7 offices
10 offices
15 offices
Increasing the number of offices is beneficial
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
48
- Influence of CAC limit
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
1 2 3 4 5 6 7 8 9 10 11 12 13
Ad
mis
sio
n p
rob
abili
ty (
%)
CAC limit
Admission probability2 offices and isolated mode
2 offices and sharing mode
4 offices and isolated mode
4 offices and sharing mode
6 offices and isolated mode
6 offices and sharing mode
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
49
- Influence of CAC limit
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
1 2 3 4 5 6 7 8 9 10 11 12 13
Ad
mis
sio
n p
rob
abili
ty (
%)
CAC limit
Admission probability2 offices and isolated mode
2 offices and sharing mode
4 offices and isolated mode
4 offices and sharing mode
6 offices and isolated mode
6 offices and sharing mode
Sharing mode is better than isolated mode
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
50
- Influence of CAC limit
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
1 2 3 4 5 6 7 8 9 10 11 12 13
Ad
mis
sio
n p
rob
abili
ty (
%)
CAC limit
Admission probability2 offices and isolated mode
2 offices and sharing mode
4 offices and isolated mode
4 offices and sharing mode
6 offices and isolated mode
6 offices and sharing mode
Increasing the number of offices is beneficial
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
51
- Influence of CAC limit
Admission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
80
85
90
95
100
1 2 3 4 5 6 7 8 9 10 11 12 13
Ad
mis
sio
n p
rob
abili
ty (
%)
CAC limit
Admission probability2 offices and isolated mode
2 offices and sharing mode
4 offices and isolated mode
4 offices and sharing mode
6 offices and isolated mode
6 offices and sharing mode
In Sharing mode, the increase of CAC limit improves the Asmission probability
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION TESTS AND RESULTS CONCLUSIONS
Index
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
53
- A SIP-based IP telephony system has been designed and tested.
- SIP proxies are used in order to implement a CAC.
- QoS measurements show the better performance of a time-limited buffer.
- Establishment delay does not depend on the number of offices.
- Sharing the gateways improves admission.
Conclusions
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
Presentación
Jose Saldana
Jenifer Murillo
Julián Fernández Navajas
José Ruiz Mas
Eduardo Viruete Navarro
José I. Aznar
O M U N I C A C I O N E S
TRUPO DE
CECNOLOGÍAS
GDE LAS
CPS - University of Zaragoza, Spain
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
55
Xen Virtualization
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS
NTMS February 7-10, 2011. Paris QoS and Admission Probability for a SIP-based Telephony System
56
PJSUA interface
INTRODUCTION RELATED WORKS SYSTEM ARCHITECTURE SYSTEM IMPLEMENTATION RESULTS CONCLUSIONS