Why is Kamailio so different? An introduction.
14 likes5,927 views
The document discusses the unique features of Kamailio, emphasizing that it is a SIP router rather than a traditional PBX system, allowing for more flexible SIP message handling. It highlights the need for coding in Kamailio's scripting language to manage SIP transactions and routing effectively. Additionally, it covers various modules and their interdependencies, as well as resources for learning and common mistakes to avoid during configuration.
Why is Kamailio so different? An introduction.
- 1. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Why is Kamailio so different? …than FreeSwitch, Asterisk and other PBXs oej@edvina.net | 2015-02-07 | v1.1
- 2. Ⓒ 2005-2014 Edvina AB, Sollentuna, Sweden All rights reserved. Because it’s not a PBX.
- 3. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. It’s a SIP router SIP Request SIP Response SIP The main decision you have to do when configuring Kamailio is whether to forward a SIP message, or respond to a request.
- 4. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Most PBX’s doesn't work like that SIP Call PBX In these systems, you route calls. The SIP messaging has been programmed by a developer. It’s not as flexible as Kamailio. Nor is it as dangerous…
- 5. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Most PBX’s handle media SIP Call PBX Kamailio by default does not handle media. We have 3rd party products for media NAT traversal assistance. RTP media
- 6. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. In Kamailio, we handle SIP messaging. REGISTER SIP PRACK INFO MESSAGE SUBSCRIBE NOTIFY ACK INVITE You need to understand all of SIP and do the right thing in every situation.
- 7. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. In Kamailio we handle SIP transactions SIP request SIP SIP request SIP request SIP request SIP response SIP response SIP response SIP response This is not a call - but a request and a response. Kamailio helps to find the right destination.
- 8. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Some transactions belong together SIP request SIP response SIP request SIP response SIP request SIP response This is what we in SIP call a dialog.Typically a call or a subscription. Kamailio by default does not bother with dialogs. In your script, you need to.
- 9. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Simplified routing script request_route() { xlog(“SIP request: $rm to $run”); ! if (has_to_tag()) { route(WITHINDIALOG); exit; } ! if ($fd == MYSELF) { route(AUTH); } ! if (!lookup()) { sl_send_reply(“404”, “Not found”); exit; } ! t_relay(); } The request_route starts with an incoming SIP request. Log what it is! Find out if it’s in a dialog. Find out if it’s a known user - authenticate - Find out if it’s to a known SIP address Forward the message
- 10. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. # record routing for dialog forming reque are routed) # - remove preloaded route headers remove_hf("Route"); if (is_method("INVITE|SUBSCRIBE")) record_route(); ! # account only INVITEs if (is_method("INVITE")) { setflag(FLT_ACC); # do accounting } ! # dispatch requests to foreign domains route(SIPOUT); ! ### requests for my local domains ! # handle registrations route(REGISTRAR); ! if ($rU==$null) { # request with no User sl_send_rep Yes, you write code. You configure Kamailio by writing programming logic. You write in Kamailio’s own script language Kamailio modules extend the language. The core alone is actually pretty stupid. But very powerful.
- 11. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Good to know Like in many script languages there are many ways to accomplish the same result. Many modules are overlapping. That’s fine.
- 12. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Where’s the CLI? Kamailio doesn’t have a command line interface where you can see what’s going on. We have utilities that communicate with a running server. In Kamailio 4.2 we got an event API module. We still don’t know what will happen with that. KAMCMD KAMCTL
- 13. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. A huge selection of modules Kamailio has over 100 modules. It’s hard to find the right set for your need. Start with the default configuration and build from there.
- 14. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Transaction handling. Some basic modules TM & TMX Stateless handling. SL Record Routing RR Authentication AUTH * Location database USRLOC SIP registration REGISTRAR Smart routing DIALPLAN In-memory hash tables HTABLE Pseudovariables PV Logging to syslog XLOG Denial-of-service attack prevention PIKE Accounting ACC APIs CTL, FIFO Signalling security TLS NAT traversal support NATHELPER
- 15. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Modules can depend on each other REGISTRAR USRLOC The REGISTRAR handles registrations of devices. The USRLOC module stores the registrations and handles lookups. Dependencies are well documented in each module’s documentation page.
- 16. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. The core MEMORY HANDLING CONFIGURATION MANAGEMENT NETWORK TRAFFIC PROCESS MANAGEMENT STATISTICS …much more The core starts Kamailio, loads modules and handles a lot of generic issues.
- 17. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Kamailio and databases DB A standardised data interface. Used by many modules. NDB For new databases, NoSQL. Not used by modules. db_mysql db_text db_pgsql ndb_redis ndb_cassandra db_oracle db_sqlite Please check the list of modules for all available database modules. ndb_mongodb
- 18. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. SIP authentication AUTH AUTH_DB Database-driven authentication Anything (using variables) Fetching over HTTP RADIUS or LDAP Your own application. SIP MD5 digest authentication can be done in multiple ways.
- 19. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Build your own data model, don’t just copy. Alias phone number Alias phone number Auth account desk phone Auth account soft phone Auth account cell phone Address of record, THE SIP address Don’t assume one SIP account, one phone number, one set of credentials
- 20. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Base your model on existing data Alias phone numbers Auth accounts The SIP server is just one server in your infrastructure. LDAP account Address of record, THE SIP address Name, address etc
- 21. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. What? No RELOAD? There’s no overall RELOAD command. Some modules have a reload command. Some modules only operate on database.
- 22. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Where to start. Learn SIP in detail. Read the core cookbook. Browse through the example configuration and make sure you understand it. 1. 2. 3. Now start building, add modules as you need them. 4.
- 23. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Getting help. Use the mailing list, the IRC channel or the G+ forum. Please do not mail developers directly. Use public channels. Consultants that can help you are available on the web site. Trainings are regularly held, both basic and advanced.
- 24. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Common mistakes: Call routing Carrierroute LCR The carrierroute module is not the only way to do carrier routing. It’s just one way, maybe it doesn’t fit your model. The LCR module is not the only module for least cost routing. Discover all the options and select the one that fits your business.
- 25. Ⓒ 2015 Edvina AB, Sollentuna, Sweden All rights reserved. Common mistakes: Call states Dialog The DIALOG module adds call states. Don’t add it by default, you may not need it. Having call states makes failover harder. You may have perfectly good call states in other servers in your network. Adding call states use memory and makes scalability not impossibly, but much harder.
- 26. Ⓒ 2005-2014 Edvina AB, Sollentuna, Sweden All rights reserved. Good luck, Kamailian! www.kamailio.org
- 27. EDVINATRAINING CLASSES • Kamailio from start • The SIP Protocol • RTP, RTCP and QoS • SIP Security • Scalability • Many Kamailio labs CUSTOM INHOUSE TRAININGS • SIP,Asterisk, Kamailio and much more • Done at your site, customized for your project • Cost effective when more than four students Find more details at http://edvina.net • Advanced Kamailio • SIP trunking • NAT handling • WebRTC/SIP • Testing, debugging • Scalability • Many Kamailio labs