Presentation done at AstriCon 2014, Las Vegas, USA - how relevant can be SIP signaling traffic in a Real Time Communications platform and where pure SIP signaling servers such as Kamailio can be used.

1. kam ailio
sip servers everywhere
Daniel-Constantin Mierla
@miconda
www.asipto.com
www.kamailio.org
AstriCon 2014 - Las Vegas, USA

2. WHOIS KAMAILIO
2
Let's Speak SIP = E Kama'ilio SIP
Sep 2001 2002 Jun 2005 Jul 2008 Aug 2008 Nov 2008
Sep 2011
SIP Express Router (SER)
OpenSER Kamailio
Other Forks...
Oct 2009 Jan 2010
Same application:
Kamailio - SER
v3.0.0
Integration
Completed
v1.5.0
First
Line
Of
Code
Open
Source !
GPL
FhG
Fokus
Institute
rename
Awarded
Best Open
Source
Networking
Software
2009
By InfoWorld
Oct 2014
………. v4.2.0
10
Years
Jun 2012
ITSPA
UK
Award
v3.3.0
Mar 2013
v4.0.0
Dec 2013
Kamailio
v4.1.0

3. credits to @voicegal - theivrvoice.com
3

4. !
SIP signalling routing
• fast
• reliable
• flexible
4
GROUND ZERO
In other words
• not initiating calls
• not answering calls
• no audio-video processing

5. DON’T PANIC
!
5
Real Time Communications
multimedia notifications
telephony
video conferences
file transfer
desktop sharing
gaming
instant messaging
presence
alerts
monitoring
mobility

6. INTER-NET-WORKING
!
6
Real Time Communications
multimedia notifications
telephony
video conferences
file transfer
desktop sharing
gaming
instant messaging
presence
alerts
monitoring
mobility
Internet of Humans Internet of (Every)Things

7. THE INVISIBLE SIGNALLING
!
7
Real Time Communications
you get on the net
telephony
video conferences
file transfer
desktop sharing
gaming
• Registrations
• Authentication challenges
• NAT keepalives
• Servers monitoring
• Gateway hunting
• Re-routing
• Session updates

8. !
8
THE IMPACT OF SIGNALLING
typical day for a person
morning
at
home
work
not at
home
evening
at
home
going out with friends is work duty

9. !
9
THE IMPACT OF SIGNALLING
typical home phone activity
morning
3-5
calls
work
0-2
calls
evening
3-5
calls
no football game last evening

10. 10
SIP CALL SIGNALLING
INVITE
100
180
183
INVITE
INVITE
ACK
BYE
200 OK
200 OK
200 OK
200 OK
INVITE
407

11. 11
SIP REGISTRATION SIGNALLING
REGISTER
REGISTER
OPTIONS
401
200 OK
200 OK
OPTIONS
200 OK
REGISTER
NAT
keepalive
!
every 20 sec
every 3600 sec

12. THE IMPACT OF SIGNALLING
!
12
a day on the wire
user actions device actions
12 msg x 10 (calls) 4 msg x 24 (regs)
6 msg x 60 x 24 (ka)
120 8736
8856

13. 13
SIP SIGNALLING
taking over facebook subscriber base
msgs/day
1 000 x 9 000 = 9 000 000
…
1 000 000 x 9 000 = 9 000 000 000

14. 14
SIP SIGNALLING
taking over facebook subscriber base
estimated bandwidth / day
1000 phones: 9 000 000 x 1kB = ~ 9GB
…
1000000 phones: 9 000 000 000 x 1kB = ~9TB

15. FORGETTING ANYONE?
15

16. 16
SIP SIGNALLING
your friendly scanners
extra traffic
100 requests/seconds => 200 messages/second
200 x 60 x 60 x 24 = 17 280 000 msgs/day
17GB/day

17. 17
SIGNALLING REMARKS
can be a significant source of processing
(both network and application layer)
!
can be a lot even with small subscriber base
(your online friends don’t let you rest)
!
numbers estimated for very basic usage model
(imagine instant messaging, presence, mwi, blf, …)

18. SIP SERVERS EVERYWHERE
18

19. TWO BASIC ARCHITECTURES
!
19
main signalling server edge signalling server

20. !
dispatcher module
• list of balancing nodes from file or database
• monitoring of nodes (activate/inactivate
automatically)
• re-route in case of failure
• various algorithms: hashing, weight distribution, round
robin, call load distribution, priority routing
• reload list of nodes without restart
20
LOAD BALANCER
# Dispatch requests
route[DISPATCH] {
# round robin dispatching on gateways group '1'
if(!ds_select_dst("1", “4")) {
send_reply("404", "No destination");
exit;
}
xdbg("--- SCRIPT: going to <$ru> via <$du>n");
t_on_failure("RTF_DISPATCH");
route(RELAY);
exit;
}
# Re-route in case of failure
failure_route[RTF_DISPATCH] {
if (t_is_canceled()) {
exit;
}
# next node - only for 500 or local timeout
if (t_check_status(“500") || (t_branch_timeout() && !t_branch_replied())) {
if(ds_next_dst()) {
t_on_failure("RTF_DISPATCH");
route(RELAY);
exit;
}
}
}

21. !
LEAST COST OR DID ROUTING
plenty of options
• lcr module
• carrierroute module
• prefix_route module
• drouting module
• combinations: mtree + dispatcher
21
route[LCR] {
if (!load_gws("1")) {
send_reply("503", "Error loading gateways");
exit;
}
if (!next_gw()) {
send_reply("503", "No available gateways");
exit;
}
t_on_failure(“RTF_LCR");
route(RELAY);
exit;
}
# Re-route in case of failure
failure_route[RTF_LCR] {
if (t_is_canceled()) {
exit;
}
# next node - only for 500 or local timeout
if (t_check_status(“500") || (t_branch_timeout() && !t_branch_replied())) {
if(next_gw()) {
t_on_failure("RTF_LCR");
route(RELAY);
exit;
}
}
}
pstn
provider
pstn
provider
pstn
provider
lcr DID
routing

22. !
block DOS or dictionary attacks
part of default kamailio.cfg
• htable module
• pike module
• detect high volume of traffic from same source and
block it for a specific interval of itme
22
SIP FIREWALL
# ip ban htable with autoexpire after 5 minutes
modparam("htable", "htable", “ipban=>size=8;autoexpire=300;")
…
route[SAFEGUARD] {
# flood detection from same IP and traffic ban for a specific interval
# be sure you exclude checking trusted peers, such as pstn gateways
# - local host excluded (e.g., loop to self)
if(src_ip!=myself) {
if($sht(ipban=>$si)!=$null) {
# ip is already blocked
xdbg("request from blocked IP - $rm from $fu (IP:$si:$sp)n");
exit;
}
if (!pike_check_req()) {
xlog("ALERT: pike blocking $rm from $fu (IP:$si:$sp)n");
$sht(ipban=>$si) = 1;
exit;
}
}
if($ua =~ "friendly-scanner") {
sl_send_reply("200", "OK");
exit;
}
}

23. core and tm module
• set transport in R-URI or outbound proxy address
• force transport via dedicated function
!
23
TRANSPORT LAYER GATEWAY
# Force UDP
route[TOUDP] {
# round robin dispatching on gateways group '1'
record_route();
$du = “sip:nexthop.com:5060;transport=udp”;
force_send_socket(“udp:10.1.1.10:5080”);
route(RELAY);
exit;
}
tls
web socket
udp
udp udp
IPv6
bridging networks
• public to private networks and back
• IPv4 to IPv6 and back
• any transport layer to another one and back

24. !
edge proxy
• authentication
• nat traversal
• parallel forking
• serial forking
• call forwarding
• call blocking
• white/black listing
• DNS handling
24
OFFLOAD SIGNALLING PROCESSING

25. 25
DESIGNED FOR SCALABILITY
forking
replication

26. TICTACTOE
TURNRIGHT PUBLISH
!
plenty at signalling layer
• instant messaging
• presence
• gaming
• notifications
26
EXTRA FEATURES
additional functions
• embedded XCAP server
• embedded MSRP relay
• IMS
extensibility
• define your new request types
• flexibility in handling unknown requests, headers, etc.
INVITE
NOTIFY
MESSAGE

27. TO CONCLUDE
27

28. SUITABLE FOR
28
lot of subscribers
!
lot of traffic (good or bad)
!
innovation
!
personal usage

29. 29
FEATURES
IPv4
IPv6 (since 2002!)
UDP/TCP/TLS/SCTP
SCTP
multi-homing
multi-streaming, statistics
UDP Raw Sockets
DNS NAPTR & SRV
Plug-in Module Interface
(about 200)
!
Scripting Config Language
!
Embedded Interpreters
Lua, Perl
Mono (C# and the rest)
Python, Java
Load Balancing
Least Cost Routing
DID - Prefix
Routing
Aliases
Ring Groups
Speed Dial
ENUM Routing
Presence Services
Instant Messaging
Embedded XCAP Sever
Embedded HTTP Client & Server
Embedded MSRP Relay
Asynchronous Processing
TCP - TLS
SIP Request Processing
Config Route Block Execution
Suspend-Resume Transactions
NoSQL Backends
Memcached
Redis
Cassandra
MongoDB
SQL Backends
MySQL
PostgreSQL
SQLite
UNIXODBC
ORACLE
Text Files
WebSocket
(WebRTC)
!
IMS
OMA
Control API
!
XMLRPC
JSONRPC
Event API
Focus
!
Stability
High Performances
Strong Security
Innovation

30. 30
2014 HIGHLIGHTS
db_mongodb evapi
ndb_mongodb nosip
core
tm
dispatcher
uac
rtpengine
dialog
enhancements
tsilo
kazoo
jsonrpc-s
debugger
(per module debug)
(log pv assignment)
usrloc - dmq - ims
uuid
V4.2.0 released on Oct 16, 2014
http://www.kamailio.org/wiki/features/new-in-4.2.x

31. SIREMIS WEB INTERFACE
31

32. OUT OF THE BOX
• sip:provider CE
• Elastix 3.0
• Kazoo
• Plivo
32
open source options

33. www.kamailioworld.com
33

34. Thank You!
!
Questions?
Daniel-Constantin Mierla
@miconda
www.asipto.com
www.kamailio.org
34