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Small formatting updates

oej authored on 09/10/2009 20:33:11
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@@ -7,83 +7,86 @@
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 #
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9 9
 Overview
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+--------
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- The dns subsystem in ser can either directly use libresolv and a combination
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+ The dns subsystem in sip-router can either directly use libresolv and a combination
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   of the locally configured dns server, /etc/hosts and the local Network 
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   Information Service (NIS/YP a.s.o) or cache the query results (both positive
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   and negative) and look first in its internal cache.
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- When its internal dns cache is enabled, ser can also use dns failover: if
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-  one destination resolves to multiple addresses ser can try all of them until
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+ When its internal dns cache is enabled, sip-router can also use dns failover: if
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+  one destination resolves to multiple addresses sip-router can try all of them until
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   it finds one to which it can successfully send the packet or it exhausts all 
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-  of them. ser (tm to be more precise) uses the dns failover also when the
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-  destination host doesn't send any reply to a forwarded invite within the
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-  sip timeout interval (whose value can be configured using the tm fr_timer
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-   parameter).
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- When SRV based load balancing is enabled ser can even do DNS based load 
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- balancing (see RFC2782 and the dns_srv_lb option below).
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+  of them. sip-router (The tm module to be more precise) uses the DNS failover also 
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+  when the destination host doesn't send any reply to a forwarded invite within the
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+  SIP timeout interval (whose value can be configured using the tm fr_timer
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+  parameter).
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+  When SRV based load balancing is enabled sip-router can even do DNS based load 
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+  balancing (see RFC2782 and the dns_srv_lb option below).
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 DNS Cache and Failover Drawbacks
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+--------------------------------
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- Using the dns cache and the dns failover has also some drawbacks: 
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+ Using the DNS cache and the DNS failover has also some drawbacks: 
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-  1. only the locally configured dns server (usually in /etc/resolv.conf) is
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+  1. only the locally configured DNS server (usually in /etc/resolv.conf) is
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   used for the requests (/etc/hosts and the local Network Information Service
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   are ignored). 
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-     Workaround: disable the dns cache (use_dns_cache=off or
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-  compile without -DUSE_DNS_CACHE).
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+     Workaround: disable the dns cache (use_dns_cache=off or compile without -DUSE_DNS_CACHE).
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-  2. the dns cache uses extra memory
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-      Workaround: disable the dns cache.
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+  2. the DNS cache uses extra memory
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+      Workaround: disable the DNS cache.
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-  3. the dns failover introduces a very small performance penalty 
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-     Workaround: disable the dns failover (use_dns_failover=off).
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+  3. the DNS failover introduces a very small performance penalty 
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+     Workaround: disable the DNS failover (use_dns_failover=off).
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-  4. the dns failover increases the memory usage (the internal structures
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-  used to represent the transaction are bigger when the dns failover support is
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-  compiled).
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-     Workaround: compile without dns failover support (-DUSE_DNS_FAILOVER).
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-  Turning it off from the config file is not enough in this case (the extra
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-   memory will still be used).
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+  4. the DNS failover increases the memory usage (the internal structures
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+     used to represent the transaction are bigger when the DNS failover support is
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+     compiled).
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+     Workaround: compile without DNS failover support (-DUSE_DNS_FAILOVER).
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+     Turning it off from the config file is not enough in this case (the extra
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+     memory will still be used).
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- On the other hand using the dns cache saves lots of DNS queries and makes
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+ On the other hand using the DNS cache saves lots of DNS queries and makes
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  DNS based failover and DNS based load balancing possible. If the destination
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- blacklist is enabled, ser can do failover even if forwarding in stateless 
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+ blacklist is enabled, sip-router can do failover even if forwarding in stateless 
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  mode.
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- In the ideal case with dns cache enabled ser will do only one query for
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+ In the ideal case with the DNS cache enabled sip-router will do only one query for
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  a NAPTR (if enabled) or SRV lookup and then it will use the results for the
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  record's TTL (for example if all the resulting records have 1 minute TTL,
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-  ser won't make another query for this domain for 1 minute). Even negative
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+ the server won't make another query for this domain for 1 minute). Even negative
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  answers will be cached.
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- Without the dns cache, each NAPTR or SRV lookup will result in at least 2 
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+ Without the DNS cache, each NAPTR or SRV lookup will result in at least 2 
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  queries. These queries will happen every time, for each message (even if 
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  all of them go to the same domain).
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 DNS Resolver Options
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+--------------------
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- The DNS resolver options control how ser will interact with the external
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+ The DNS resolver options control how sip-router will interact with the external
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  DNS servers. These options (with the dns_try_ipv6 exception) are passed to
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  libresolv and are used each time a dns request is made.
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+
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  The default values are system specific and generally depend on the
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  /etc/resolv.conf content. For servers doing a lot of DNS requests it is
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- highly recommended to change the default values in the ser config file
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-  (even if using ser's internal dns cache).
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+ highly recommended to change the default values in the sip-router config file
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+  (even if using sip-router's internal dns cache).
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-   dns_try_ipv6 = on | off - if on and ser listens on at least one ipv6 socket,
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+   dns_try_ipv6 = on | off - if on and sip-router listens on at least one ipv6 socket,
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       ipv6 (AAAA) lookups will be performed if the ipv4 (A) lookups fail. 
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       If off only ipv4 (A) lookups will be used.
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-      Default: on if ser is compiled with ipv6 support.
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+      Default: on if sip-router is compiled with ipv6 support.
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-   dns_try_naptr = on | off - if on ser will first try a NAPTR lookup for
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+   dns_try_naptr = on | off - if on sip-router will first try a NAPTR lookup for
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       destinations that don't have the protocol or port specified and 
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       are not simple ip addresses (as described in RFC 3263). This will 
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       introduce a slight performance penalty and will probably cause extra
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       DNS lookups. For example a lookup for a non-existing domain will
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       produce one extra query: NAPTR(domain), SRV(_sip._udp.domain) 
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       and A/AAAA(domain).
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-      If the result of a query contains several NAPTR records, ser will select
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-      among them according to the RFC2915 and ser preference towards a
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+      If the result of a query contains several NAPTR records, sip-router will select
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+      among them according to the RFC2915 and sip-router preference towards a
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       specific protocol (see dns_udp_pref, dns_tcp_pref and dns_tls_pref 
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       below). For an RFC3263 compliant configuration (choose the remote side
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       preferred protocol if supported), set dns_udp_pref, dns_tcp_pref and
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@@ -166,6 +169,7 @@ DNS Resolver Options
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 DNS Resolver Compile Options
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+----------------------------
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    USE_NAPTR - if defined the naptr lookup support will be compiled in.
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       NAPTR support still has to be enabled from ser's config file (it's
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@@ -179,6 +183,7 @@ DNS Resolver Compile Options
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 DNS Cache and Failover Config Variables
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+---------------------------------------
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    use_dns_cache = on | off - if off the dns cache won't be used (all dns
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       lookups will result into a dns request).  When on all the dns request
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@@ -270,6 +275,7 @@ DNS Cache and Failover Config Variables
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       Default: on
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 DNS Cache Compile Options
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+-------------------------
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    USE_DNS_CACHE - if defined the dns cache support will be compiled in 
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       (default). If not needed/wanted the dns_cache can be disabled from the
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@@ -309,8 +315,8 @@ DNS Cache Compile Options
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    DNS_CACHE_DEBUG - if defined the dns cache will be very verbose (it will
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        log lots of messages at the L_DBG levell).
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- Note: To remove a compile options,  edit ser's Makefile.defs and remove it 
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-   form DEFS list. To add a compile options add it to the make command line,
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+ Note: To remove a compile options,  edit sip-router's Makefile.defs and remove it 
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+   from DEFS list. To add a compile options add it to the make command line,
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      e.g.: make proper; make all extra_defs=-DUSE_DNS_FAILOVER
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    or for a permanent solution, edit Makefile.defs and add it to DEFS 
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    (don't foget to prefix it with -D). Some options require editing