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14  •  VoIP Protocol

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snom technology AG  •  15

The SIP 

Architecture

This paragraph is intended to serve only as a basic introduction to 

the SIP world. for more detailed information please refer to the available 

literature on this topic.  

User Agents

User  agents  play  a  central  role  in  SIP.    They  are  normally  the 

endpoints of the communication.  Typical examples for a user agent are 

telephones, gateway and media servers.

User agents typically fulfill the following tasks: 

•   they play and record audio,

•   they compress and uncompress the digital audio,

•   they do echo compensation if there is a need for this,

•   they compensate for packet jitter and packet loss, 

•   they look for the destination, 

•   they retrieve their configuration information,

•   they keep track of phones that offer a call pickup, 

•   they publish their state upon request,

•   they determine and publish the probability of finding somebody,

•   they terminate one or more identities, 

•   they redirect calls when nobody picks up,

•   they are part of a virtual LAN,

•   they search address books (LDAP),

•   they search internet addresses (DNS A, DNS SRV),

•   they usually include a web server,

•   they send an receive instant messaging information,

•   they publish network management information (SNMP),

•   they behave like normal computers on the network (DHCP, DNS).

2.

Summary of Contents for 4S Media Server

Page 1: ...Administrator s Manual snom 4S SIP Proxy Registrar Version 2 30 ...

Page 2: ...y commitment on the part of snom technology AG The software described in this document is furnished under a license agreement and may be used only in accordance with the terms of that license agreement It is against the law to copy or use this software except as specifically allowed in the license No part of this document may be reproduced republished or retransmitted in any form or by any means w...

Page 3: ...nd worked on remote management support If you set up a server farm you can create a robust solution that will continue operations even under adverse conditions This product is a proxy location server with built in registrar which means this software is also responsible for locating users Needless to say the proxy is stateful which means that is is capable of finding users on a priority based sched...

Page 4: ... This manual gives you a brief introduction to VoIP and SIP explains the installation process for Windows and Linux and shows how to run the SIP proxy For additional snom 4S information please visit our Web site at http snom com and if you have any comments and suggestions about snom 4S please contact us through snom technology AG s support link Web site We would appreciate your feedback And of co...

Page 5: ...2 What You Can Expect and What Not 13 The SIP Architecture 15 User Agents 15 Proxies 16 Location Server 16 Registrars 17 Media Server 17 Gateways 17 B2BUA 19 Installation 21 Update to 2 30 from Previous Versions 21 Windows Installation 23 Uninstalling in Windows 24 Linux Installation 24 Manual Starting 24 Automatic Starting 25 Licensing 27 Accessing the web server 27 Entering the license code 28 ...

Page 6: ...ture 34 Quotes 34 Case 35 Statements 35 if 35 foreach 36 return 37 Variables 37 Scope 37 Types 37 Operators 38 Functions 39 Definition 39 Calling 40 String Functions 40 Parsing Functions 42 SIP functions 44 Registration Related Functions 45 Proxy Related Functions 46 Other Functions 48 Callbacks 49 on_request 49 on_response 51 on_register 52 challenge 52 get_user 54 on_new_user 54 user_directory 5...

Page 7: ...the web interface 64 Uploading user accounts from file 64 Storing information 65 Registration 67 Registration Settings 67 Require Authorization 67 Min and Max registration time 68 Default Q 68 Reject Registrations Across NAT 68 Example Registrations 69 Snom 200 70 Microsoft Messenger 71 Routing 73 Protected Destinations 73 Max Forwards 74 Call Log File 74 Tel Domain 74 ENUM Suffix 74 NAT Gateway 7...

Page 8: ...ng ENUM 81 Error Information 82 Message Handling 85 Store Forward 85 Welcome Message 85 DNS 87 What is DNS 87 Setup DNS 87 Server Farm Operation 89 ENUM 90 Registering Phones 91 snom 100 Registration 91 Microsoft Messenger Registration 92 Maintenance 93 Registered Users 93 Call Logs 94 Condition for Logging a Call 94 Call Logs in the Web Interface 95 Pending Calls 96 Call Log File Format 96 SIP Me...

Page 9: ...herefore if you update the proxy we ask you to save old configuration information for later reference You can do this easily by storing the web content of the relevant configuration pages to a file The installation process has been inproved especially for the RedHat Linux edition and should now work smoothly on most systems That was especially on the 2 22 version one of the biggest problems for in...

Page 10: ...make check this document if the update is necessary or not Scripting This version introduces Scripting That means you may program your proxy to exactly meet your requirements However it is not a must The default script takes the settings from the web interface and allows the operation of the proxy that fits most small and medium business requirements So if you are not interested in scripting you m...

Page 11: ...tion Most network equipment can already fulfil this real time requirement Virtually all switches currently on sale support a VLAN with different priorities in the network and the vast majority of higher layer network equipment supports some means of transporting packets with different qualities DiffSrv The LAN usually supports a bandwidth of 100 MBit s which is more than enough to allow voice to f...

Page 12: ...y dynamic field of this new real time communication technology is resulting in evolutionary pressure to find the best common denominator RFC3261 can be seen as the core or a series of new RFC that define the rules of the new telephony industry just like DNS HTTP and other standards already did for the world wide web Most of the big players have jumped on the SIP train Microsoft Messenger 4 7 is ba...

Page 13: ...own from traditional telephony In addition to this telephones can now indicate their willingness to receive calls and the probability of finding a specific user You can call a PSTN number from a SIP phone just as you did ten years ago The network will usually be set up to terminate these calls on a gateway which translates the packet stream into a switched network signal You can also dial email li...

Page 14: ...14 VoIP Protocol S N O M 4 S P R O X Y R E G I S T R A R M A N U A L 1 ...

Page 15: ...o they do echo compensation if there is a need for this they compensate for packet jitter and packet loss they look for the destination they retrieve their configuration information they keep track of phones that offer a call pickup they publish their state upon request they determine and publish the probability of finding somebody they terminate one or more identities they redirect calls when nob...

Page 16: ...forward messages and serve as a hop on the path from a user agent client to a user agent server The rules for hopping may depend on all kinds of rules e g traversing NAT using a stateless proxy Stateful proxies keep a list of pending requests This way proxies can forward requests to different destinations at the same time When the responses come back from the destinations the proxy merges the resp...

Page 17: ...roxy redirects the call to the mailbox so that the caller may leave a message The owner of the mailbox calls the mailbox directly to listen to messages Implement music on hold Using a fat client all kinds of music tastes can be played with highest possible quality Implement call parking Calls can be parked on the media server until a user picks the call for processing In the meantime the caller ca...

Page 18: ...atrix Sonus and Vegastream The snom 4S gateway is a SIP NAT gateway software enabling Linux computers to be SIP aware B2BUA The back to back user agent B2BUA looks like a user agent but is a network component like a proxy Making a call though a B2BUA puts two user agents back to back This has several advantages One side can be SIP the other side can be anything including H 323 MGCP or SS 7 That so...

Page 19: ...introduces a domain concept which is not directly compatible to previous versions The configuration information is stored in a central directory along with all other configuration information The previous versions used a more distributed approach Figure 3 1 Installation Welcome Screen 3 ...

Page 20: ...eb interface which simplifies the sup port for the product across the Internet Although much of the interface remains the same the software update process cannot automatically convert the old configuration infor mation into the new format Therefore it is necessary to enter the con figuration information up again In case that you use an extensive dial plan we recommend tak ing a look at the scripti...

Page 21: ...3 1 Press Next to begin the installation At the beginning of the installation the setup program asks you to accept the license conditions see fig 3 2 Please read them carefully then select the accept button and press next to accept the conditions If you decline the installation will be aborted After accepting the license agreement the next screen asks you to enter your personal information Enter y...

Page 22: ... be useful to specify a different location for this e g a temporary directory It is important that the directory exists the proxy will not create this directory In the next step you can select the installation type We recommend using the Typical installation If you select Minimal the documentation is not installed Before the installation finishes you need to define on which ports the proxy will op...

Page 23: ...s expected This will be port 5060 in most cases and you should change this port only if you know exactly how the proxy can be addressed with a different port number After finishing the setup wizard check that the proxy is running If you do not want to reboot your system because it is running other critical applications you can also manually start the service in the services section of the Windows ...

Page 24: ...0 and so on It is important that you connect to the proxy to a web browser because that is the only way to control the proxy Uninstalling in Windows To uninstall the proxy first stop it in the services window Then go to the Software Window and click on remove for snom 4S proxy Server Linux Installation The software runs under SuSE 7 2 or 8 0 and Red Hat 8 0 Linux other Linux versions like mandrake...

Page 25: ...r the different proxy versions and for registrations It typically also contains the configuration information su cd usr local tar xvfz snom_sip_proxy i386 linux 2 30 tgz Go to the directory where you extracted the new version cd snom_sip_proxy i386 linux 2 30 The tarball includes a shell script with the name install sh which sets up the neccessary files and links for you install sh The file etc rc...

Page 26: ...ystem and check whether the sip proxy was started automatically after the reboot You can then continue with the installation using the web browser Stop and restart the proxy with the rcsip proxy command to check whether the configuration has been saved To update a version copy the latest tarball into the directory and run the install script of the new version It will automatically shut down the ol...

Page 27: ...y these ports in order to get access to the proxy In this case you should define the port number explicitly later in order to avoid future confusion You will then see the login page of the proxy The default user name and password are admin with no password Please enter this and push the login button You will see that the proxy opens the session for you The session identifier is always kept with al...

Page 28: ...demonstration license key When you buy the proxy from snom you will receive an unlimited license key This license key depends on the host names that you enter in the first field The Hostnames field has a function to uniquely identify this copy of the snom SIP proxy Therefore when requesting the license key from snom you should use the DNS names of the host which will run the proxy But examples are...

Page 29: ...he primary domain This is useful when a host can be found different ways for example by its DNS SRV name by its DNS A name or by its IP address In this case you would use the DNS as SRV name as a primary domain name and in the DNS A name and the IP address as alias In order to make the domain matching processing deterministic domain and alias names must be unique It is not allowed to use the same ...

Page 30: ...mains you should consider setting up the global settings context first The following chapters describe settings under the domain context However if present they can also be set up under the global context Creating a domain To create a domain you must log on with the administrative account of the proxy Go to the domain administration web page and enter the primary name of the domain If you wish to ...

Page 31: ...tom of the web page You can then edit the settings in the form However to change the primary remaining you need to remove that domain first and then enter the domain names again Going to a domain context To go to a domain context just click on the primary name in the domain list The proxy will then display all information in the domain context as if you logged on in the domain context However beca...

Page 32: ...ontrol for example with CVS and make sure that nobody overwrites them with some unproven settings The directory in which the domain settings are stored is set up during the installation process The domains of stored right in the main directory as directory and contains a file named domain xml However if you change the files in the filesystem you need to restart the proxy as it caches the informati...

Page 33: ...t the http server history we can learn that simple scripting languages like perl or PHP found a broad acceptance because of its simplicity flexibility stability and performance That was our motivation to integrate a PHP like scripting language even if it is not a powerful as PHP4 is today Apache offers handling of domains and URLs While the concept of domains has been adapted in the proxy it does ...

Page 34: ...ns The script does not respect line breaks like some BASIC implementations do That means you can insert line breaks and indentation as you like There are two exceptions to this rule The first are comments and the second are quoted text Comments As in most other programming languages you can se comments to make your code more readable Comments start with a hash symbol and go until the end of the li...

Page 35: ...ly The behaviour resembles the execution of C or PHP code if The if statement is used to execute code depending on conditions The syntax for the if statement is if condition1 body1 else if condition2 body2 else body3 If the value of the expression1 is true the proxy executes body1 and does not execute body2 or any other body of this if statement It also doe not evaluate and other condition stateme...

Page 36: ...e of looping is going through lists Lists always have a defined length and there is no danger that the proxy will end up in an endless loop The foreach command has the following syntax foreach variable list body The proxy will assign every element of the list to the provided variable and execute the body The scope of the variable of the current context that means the value of the variable after th...

Page 37: ...n different scopes This is necessary to separate domains from requests and allow function arguments When a domain is created it inherits to global variables of the proxy If a request within a domain is created the request object inherits the variables of the domain If a function is called either within a request context or within a domain context the arguments to the function are stored on a call ...

Page 38: ...opriate operation performs modulo All operations are done on integer numbers floating point is not supported Logical Operators Logical operators include and or and not The and operator evaluates the right hand side only if the left hand side evaluated to true The or operator evaluates the right hand side only if the left hand side evaluated not to true This is important when the expression has a s...

Page 39: ...ctions in the domain script as you wish Function names are similar to variables with the difference that function names do not contain the leading dollar sign Function names are like most of the proxy functionality non case sensitive The built in functions are described later in this document Definition Functions are defines on the top level of a script That means it s not possible to define neste...

Page 40: ...hich looks like a procedure call To avoid endless looping when a function calls itself directly or indirectly through recursion the number of nested function calls is limited The default value for this limit is 50 If that limit has been reached every function just returns an empty string so that the processing of the current proxy action stops In such a case the proxy will write a log message This...

Page 41: ...nction extracts a field from a string It takes three arguments The first argument contains the string from which the field should be extracted The second argument indicates the field number starting at 0 The third argument is optional and indicates the field seperator characters which default to whitespace Examples get_field a b c 1 returns b get_field a b c d 1 returns c d match match is used for...

Page 42: ...n URL or contact parameters must be checked Example parameter_name bla 123 returns bla parameter_ value bla 123 returns 123 get_time get_date get_day These functions return the current time the current date or the current day All date related information are relative to GMT The get_time function returns a string in HH MM format for example 14 54 The get_date function returns the current date in M ...

Page 43: ...amples parse_name Fred F Feuerstein sip ff stoneage org returns Fred F Feuerstein parse_cparm parse_uparm This function extracts the contact parameters parse_cparm or the URL parameters parse_uparm of a string The contact parameters are not part of the URL and are only present if the url is protected by the and symbols If these symbols are not present the parameters are assumed to be part of the U...

Page 44: ...on always creates a sip URL Example create_url 123 domain com 5062 transport udp line 1 returns sip 123 domain com 5062 transport udp line 1 get_header get_field retrieves a SIP message header of the request of the current open request This function is helpful when the script needs information directly from the SIP request Examples include User Agent or proprietary information The function takes o...

Page 45: ...solvable_contact does not take any parameters It checks if the contact in the current request can be resolved from the proxy point of view If the proxy has a NAT address this function will always return true Otherwise the proxy will check if the request contains a Path header and if that is the case it is assumed that the contact is resolvable If this is also not the case the proxy will return fal...

Page 46: ...he registration probability so that users with a probability will receive the request immediately users with a probability of zero will receive the request after the delay Users having a probability between these extremes will receive the request with a delay that scales linear between the extremes sequential forking If no user is registered with this account this function sends a 404 response to ...

Page 47: ... the number of branches open on the current request This is helpful in situations when the proxy needs to know if a request is pending to a request For example when you try different low cost gateways to terminate a call you want to redirect the call to a expensive gateway only if all of the low cost gateways did not pick up the call exec_dialplan The exec_dialplan function exists to simplify the ...

Page 48: ... can be left blank in most cases as it will be overwritten by the sending procedure store_message To put a message into the store and forward buffer of an account you may use the store_message function It takes as arguments the account and the message string which is typically generated by the create_message function create_user The proxy does not create a user by default it needs an explicit call...

Page 49: ...ment is evaluated to the log level The other arguments are concatenated and printed to the log file if the log level is high enough Example log 5 This is a log n Callbacks The proxy scripting is primary determined by overriding the default implementation of callbacks on_request Condition for Calling Whenever the proxy receives a new request it sets up an object representing that request and the as...

Page 50: ...me is not a tel URL the proxy checks if the request is a messag to a user which is offline In this case it stores the message in the user account for later delivery Otherwise it determines the user which is being called by looking at the request_uri If that user is registered with the proxy it forks the request to that user using the sequential forking delay Otherwise it calls the exec_dialplan fu...

Page 51: ...n error code or one of the call legs returned a success code The return code indicates weather the proxy should consider the response as an answer to the original request Default Implementation The default implementation takes care about the redirection codes 300 399 The proxy initiates the sending of a 181 provisional response and then forks a new request for each of the contacts given in the red...

Page 52: ...ion The default implementation checks if the contact can be resolved or if that feature has been turned off If the contact is accepted but the user account does not exist the user account is created which may trigger the on_new_user function Otherwise if the contact is not accepted the request is rejected with a message that the contact is not ok on_register user if resolvable_contact if known use...

Page 53: ... it generates a new nonce and rejects the request with the code 407 Proxy Authorization Required If the user agent has the matching password it will send another request which matches the generated response and then the request will be processed Default Implementation The default implementation differentiates between REGISTER and other methods just like the web interface does it For REGISTER reque...

Page 54: ...ase the user agent may decide which account it uses to answer the question Default Implementation The default implementation retrieves the user part of the URL in the From header get_user return parse_user from on_new_user Condition for Calling When a new user is created via the web interface or through explicit command in the scripting interface the proxy calls a function on_new_user The function...

Page 55: ...t message into the store and forward offer of the respective account on_new_user user if welcome_file welcome_event welcome_method MESSAGE welcome_type store_message user create_message create_url From create_url user To welcome_method method welcome_event event welcome_type type welcome_file file user_directory Condition for Calling For a large number of registered users it is important to have a...

Page 56: ...e first character of the user name This gives the proxy at least a minimum level of hierachy user_directory user return leftstr user 1 require_billing Condition for Calling Before the proxy starts billing a request with RADIUS it calls a the require_billing function This is necessary because RADIUS assumes that before a call can start the RADIUS server from its access If the function returns the v...

Page 57: ...to bypass the proxy at all Default Implementation The default implementation merely checks if the request is an INVITE request and if this is the case returns true All other requests are assumed not to require billing require_billing return method INVITE on_denial Condition for Calling When the RADIUS admission request has been denied the proxy calls the on_denial function This function will usual...

Page 58: ...tion for Calling When a SIP URL cannot be resolved via DNS the proxy calls this callback This includes DNS NAPTR DNS SRV DNS A and ENUM searches Default Implementation The default implementation merely returns in an error code 404 Not Found on_unroutable reject_request 404 Not Found 6 ...

Page 59: ... Settings There are a number of general settings that you should set up in the beginning To do this go to the Administration Settings menu item SIP Port The SIP port defines where the proxy expects SIP traffic Typically this will be port 5060 7 ...

Page 60: ...to use only UDP you can enter a large number here e g 1000000 if you want the proxy to use only TCP enter a 1 here The recommended value for this field is 1300 Using this value a UDP packet can be sent within one Ethernet frame without fragmentation Log Level The log level defines how many messages get to the log If you are only interested in the most important messages you can set this to 0 If yo...

Page 61: ...fter this change You need to re enter the port in the web browser HTTP User and Password To protect the access to the web server you can set up a user name and a password for the web server Remember that this provides only basic security as the content of the web page is transmitted without encryption over the network and the passwords can easily monitored by network specialists However it avoids ...

Page 62: ...62 General Setup S N O M 4 S P R O X Y R E G I S T R A R M A N U A L box at the bottom of the web page This way you can also easily distribute configuration files over several redundant proxies 7 ...

Page 63: ...t and sip bm company net Users may register more than one time with the proxy When a user agents registers with the proxy it also says all probable that registration is when the proxy is trying to find that account it will send out the request to all registered users one after another if it is an invite request For more details see below on sequential forking Sometimes that this behavior is undesi...

Page 64: ...t button You will see your new account occur in the list of known accounts for this domain Just like with the administration the names for the account must be unique Of course it does not make sense to use an alias name as primary account name somewhere else To delete an account just click on the delete button next to the account And to edit an account click on the edit button Please remember that...

Page 65: ...g the upload button Storing information The proxy creates a file for every user account This file is located in the directory named after the primary name of the user account Alias also create files which point to the primary account All account related files are in XML format and you can edit it with a plain text editor You can also put under revision control and make backups like you do with all...

Page 66: ...004c4165c8 7tbzmqd51asz 192 168 0 11 User Agent snom100 1 11g CSeq 10 REGISTER Route sip 192 168 0 1 lr Contact sip test 192 168 0 11 5060 line 1 q 0 7 Expires 86400 Content Length 0 Received from 192 168 0 1 5060 at Wed 31 Dec 1969 21 25 22 614 GMT SIP 2 0 200 OK Via SIP 2 0 UDP 192 168 0 11 5060 branch z9hG4bK 9jodhbwsu13y From Theo Test sip test snomag de To Theo Test sip test snomag de Call ID...

Page 67: ...ed the registration policy You can specify the registration policy both in domain and administration mode Registration Settings Require Authorization If the flag is set to on all registration requests for the proxy are challenged for authentication This means that unknown users can not register on the proxy If the flag is set to off only known users are challenged that means the proxy is open for ...

Page 68: ... register with the proxy with a low probability a softphone would reregister with a lower probability value when the screen saver goes on In this field you can define which value should be taken if no such value has been specified The value must be in the range between 0 0 and 1 0 A good value is 0 5 or 1 0 Reject Registrations Across NAT When a user agent registers it provides a contact and a pat...

Page 69: ...ut you need to fill out the user name and password fields and then push the save button After this you can fill out the account in host name information address this IP lines web page If the phone displays a NR symbol in the display something went wrong during the registration Otherwise if everything went fine the phone will not complain You can also check on the proxy is the registration succeede...

Page 70: ... a good way of making voice over IP phone calls without any further investments Depending on your sophistication level you can use the built in speaker of you laptop of desktop PC or a dedicated headset for making phone calls However the standard version of the Messenger does not support transferring calls which might be a major usability problem for you if you intend to use it in your company env...

Page 71: ...ger go to the Extras menu and select Options Go to Accounts and select the Communication Services account If you push at the Advanced button you should see a dialogue where you can select the transport layer Because the proxy does not support TLS you should select either UDP or TCP however normally that is being done automatically You don t have to fill in the server address Close the window and f...

Page 72: ...2 Registration S N O M 4 S P R O X Y R E G I S T R A R M A N U A L Then you can check the registration on the proxy in the same way that you check the registration with the snom 200 voice over IP phone 9 ...

Page 73: ...tinations If one of the destinations match the requested URL the proxy first challenges the client for authentication The protected destinations are seperated by space and contain a pattern according to the rules described in the Dial Plan see below Typically you want to protect access to the PSTN because this requires payment For example if your PSTN gateways are located at 192 168 0 248 and 192 ...

Page 74: ...o route a call with a tel URL as destination it needs a domain context to do this The name of the domain which is úsed for this is stored in this setting This name must be the primary name of the domain not an alias name ENUM Suffix When converting a tel URL into a URL the proxy needs a suffix for the translated telephone number By default this is e164 apra However in many environments you want to...

Page 75: ...ain circumstances For this reason loose routing a new and better way of routing messages was developed For more information see the SIP standard RFC3261 or the literature available on this topic The snom 4S supports both routing methods Although loose routing is mandatory for new SIP equipment and is compatible with the old routing method strict routing some equipment can still cause headaches You...

Page 76: ...irected contacts may have an even lower probability If the 3xx response for the only pending request the proxy passes the response through to the request client The client itself then takes care of the redirection This is important in cases where a call from a PSTN gateway comes in and should be redirected to a PSTN number The gateway then does not have to pass the call through the proxy it can im...

Page 77: ...d user If you have a standard problem using the dial plan via the web interface can easily solve your problem if you want to do something advances you better use the scripting interface instead The algorithm for checking the dial plan is simple Determine the source user group by looking at the From header of the request take only a look at the URL provided there Determine the destination by lookin...

Page 78: ...rison process includes the sip identifier at the beginning of the URL The action can be one of the following Allow tells the proxy to use this number as is Deny tells the proxy to forbid this number error code 403 Forbidden Incomplete tells the proxy to signal that more digits are expected Use Gateway directs the call to the provided URL pattern typically a PSTN gateway Not Found triggers the prox...

Page 79: ...to a PSTN gateway The proxy checks all rules of the dial plan This has the effect that the last matching rule will be executed not the first one Example 1 Setting up overlap dialling In this example the proxy should try to use the PSTN gateway when more than three digits have been dialled Otherwise the number should be marked as incomplete Rule Mode User Group Pattern Destination 1 Use Gateway sip...

Page 80: ...s all emergency calls to the gateway number one which could be connected a local analog line Rule 3 redirects local calls 7 digits not starting with 0 to the second gateway rule 4 does this for national calls a prefix of 0 indicates a national call International calls start with two 0s and get redirected in any case to the gateway this works only if the gateway is able to generate incomplete respo...

Page 81: ...nvert a number entered by a user into a globally resolvable telephone number This example shows how this could be done in Dallas USA 972 prefix The example assumes that by default the proxy signalls that more numbers are needed to make a decision The second entry converts the emergency number 911 into a number that resolves to the local fire department This is important in order to reach the right...

Page 82: ...t it may also be a SIP URL While most VoIP phones can not display http content they can place a call to an announcement server that reads out the error message This means that the system is much smarter than traditional telephone systems You can even customize the announcements according to your special requirements You can simply set up the error information redirection by selecting the approriat...

Page 83: ... AG 83 S N O M 4 S P R O X Y R E G I S T R A R M A N U A L For the available error messages please refer to RFC3261 and the extensions that apply The proxy includes a list of the most frequenly used error messages 10 ...

Page 84: ...84 Routing S N O M 4 S P R O X Y R E G I S T R A R M A N U A L 10 ...

Page 85: ...e The message typically becomes deliverable when a user agent signs in on an account that had no contact registered If a message is deliverable the proxy tries to deliver that message Should this delivery fail the proxy does not store the message and sends the error code back to the user agent client that initiated the message delivery There is no limitation on the number of messages that canbe st...

Page 86: ... used for sending media attachments message is the instant message notification style which is compatible with most popular equipment While notify requires a event type message usually does not require an event type The content type indicates the type of the attachment The attachment file points to the location of the file what should be sent to the users 11 ...

Page 87: ...n One of the key features of SIP is that your email can be the same as your telephone number your marketing department and your friends will love it Setup DNS Using DNS has two sides Finding someone with DNS and being found with DNS Finding somebody with the proxy is easy All you need to do is set up the DNS on your computer correctly and the proxy will talk to the DNS server directly to find addr...

Page 88: ... 10 mail anycom de _sip _tcp anycom de IN SRV 0 5 5060 sip server anycom de IN SRV 0 1 5060 test anycom de IN SRV 1 5 5060 www anycom de _sip _udp anycom de IN SRV 0 5 5060 sip server anycom de IN SRV 0 1 5060 test anycom de IN SRV 1 5 5060 www anycom de localhost IN A 127 0 0 1 ns IN A 232 145 142 95 anycom de IN A 232 145 142 95 test IN A 232 145 142 95 www IN A 232 145 142 96 sip server IN A 23...

Page 89: ...ate the system with an excellent availability For example if your hardware if up only 99 of the time and you place two servers in independent locations using these two servers will increase the availability to 99 99 Using three servers the uptime would be already 99 9999 which is an excellent value for stablity This way you can set up an extremly robust system for less than 3000 USD hardware cost ...

Page 90: ...that you keep the same setup information on all proxies that replicate registration information Otherwise you will have strange effects depending on the destination where the request was send by the user agent Future releases will address the automatic replication of setup information ENUM ENUM is a machanism built on top of DNS ENUM bridges the old telephone numbering system with the new features...

Page 91: ...he following meaning Name The name of the user as given in the registration User The account that is used as identification in the proxy This corresponds to the telephone number of the user within the proxy realm Registrar The registrar the user registered on This is one of the names listed in the hostnames Contact This field has two components One is the path used to route requests to the destina...

Page 92: ... otherwise you would have to wait until it expired Call Logs Condition for Logging a Call A call is logged when the following conditions are met 1 The proxy received an INVITE and forwarded the request successfully 2 Then the proxy received a 2xx class code on this INVITE This defines the start time of the call 3 The proxy receives a 2xx code on a BYE for this call This defines the end time of the...

Page 93: ...ou can go to the call log page The call log has the following fields Date Time The date and time when the call started in GMT Duration The duration of the call in hours minutes and seconds From The originator of the call If you click on the originator you see all SIP packets that were involved in this call To The call s destination The call log stores only the last 100 calls and discards older cal...

Page 94: ...hed calls If you want to see the packet history associated with the calls just click on the link shown in the web interface Call Log File Format A line in the call log file has the following format Start time Seconds Duration From To The start time is separated by a colon from the rest so that it is easier to parse the log file automatically The date itself has the format Weekday Month Date Time Y...

Page 95: ...e list has the following elements Time The time when the packet was sent or received Type The type indicates whether the packet was received R or transmitted T By clicking on the symbol you get a list of all packets that have the same call ID as the packet Source Destination Here you can see which transport layer UDP or TCP was used the IP address of the source or destination and the port that was...

Page 96: ...96 Maintenance S N O M 4 S P R O X Y R E G I S T R A R M A N U A L By clicking on the header line you get the whole packet 13 ...

Page 97: ...n a specific packet and the proxy does not know when the old packets are no longer needed If you have a lot of packets flowing through the proxy it might be that older packets are no longer available However the packets are kept in the call flow analysis log and on the registration page Logging If you want to see the log file just go to the Log file menu item To clear the log go to the bottom and ...

Page 98: ...98 Maintenance S N O M 4 S P R O X Y R E G I S T R A R M A N U A L 13 ...

Page 99: ... 13 17 Configuration 11 33 Contact 59 D Delay 7 Delete 60 DHCP 11 Dial Plan 45 Dial plan 15 DiffSrv 7 DNS 11 52 DNS SRV 28 DSL 16 DTMF 13 E Echo Compensation 11 Email 7 Error Information 17 49 ETSI 8 Expires 60 F Failure recovery 15 Find Me 9 Firewall 16 Force authorization 37 G Gateway 9 Gateways 13 General Concepts 27 General Settings 34 H H 323 7 HTTP 7 42 I Installation 19 Installation Directo...

Page 100: ...rts 21 PPPoE 16 Private IP Address 31 Private Networks 16 Probability 9 30 59 Proxies 12 Proxy realm 36 PSTN 9 13 PSTN Gateway 41 Public IP Address 31 Public Networks 16 Q Quality 9 R Realm 28 Rebooting 23 Record Route 42 Redirect 11 Registered Users 59 Registering 55 Registrar 12 59 Registration Time 39 Release Notes 67 Reliabilty 28 Replace International Prefix 41 Route 42 Routing 32 RTP Port Ra...

Page 101: ...R E G I S T R A R M A N U A L Stateless Proxy 16 Supplementary Services 8 Switched Network 7 T TCP threshold 39 Transfer 9 Transport Layer 16 29 U UAC 32 UAS 32 Uninstalling 23 User 59 User Agent 11 59 V VLAN 7 VoIP 7 W Web Access 16 Wildcards 46 ...

Page 102: ...rmany Phone 49 30 39833 0 mailto info snom de http www snom com sip info snom com 2003 snom technology AG All rights reserved snom USA Representation ABP International Inc Crestside Dr Coppell Texas 75019 USA Phone 1 972 831 0280 sip usa snom com mailto usa snom de ...

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