2005-10-29 Paul Jakma <paul@dishone.st>

	* ospfd.texi: Document the new spf and max-metric commands, and
	  the additional form of dead-interval. Add documentation for
	  various other commands. Cleanup misc stuff, citations, etc.
	  Add some example configurations.
	* overview.texi: RFC3137 support added.
	* Makefile.am: Make quagga.pdf depend on the _TEXINFOS
	  variable, this still doesn't fix the dependency though,
	  sadly.

1 files changed, 238 insertions, 36 deletions

diff --git a/doc/ospfd.texi b/doc/ospfd.texi
index 789e9bf7..65d4e845 100644
--- a/doc/ospfd.texi
+++ b/doc/ospfd.texi
@@ -1,11 +1,13 @@
 @node OSPFv2
 @chapter OSPFv2
 
-  OSPF version 2 is a routing protocol which described in
-@asis{RFC2328} - @cite{OSPF Version 2}.  OSPF is IGP (Interior Gateway
-Protocols).  Compared with RIP, OSPF can provide scalable network
-support and faster convergence time.  OSPF is widely used in large
-networks such as ISP backbone and enterprise networks.
+@acronym{OSPF,Open Shortest Path First} version 2 is a routing protocol
+which is described in @cite{RFC2328, OSPF Version 2}.  OSPF is an
+@acronym{IGP,Interior Gateway Protocol}@..  Compared with @acronym{RIP},
+@acronym{OSPF} can provide scalable network support and faster
+convergence times.  OSPF is widely used in large networks such as
+@acronym{ISP,Internet Service Provider} backbone and enterprise
+networks.
 
 @menu
 * Configuring ospfd::           
@@ -15,18 +17,20 @@ networks such as ISP backbone and enterprise networks.
 * Redistribute routes to OSPF::  
 * Showing OSPF information::    
 * Debugging OSPF::              
+* OSPF Configuration Examples::
 @end menu
 
 @node Configuring ospfd
 @section Configuring ospfd
 
-There is no @command{ospfd} specific options.  Common options can be
+There are no @command{ospfd} specific options.  Common options can be
 specified (@pxref{Common Invocation Options}) to @command{ospfd}.
-@command{ospfd} needs interface information from @command{zebra}.  So
-please make it sure @command{zebra} is running before invoking
-@command{ospfd}.
+@command{ospfd} needs to acquire interface information from
+@command{zebra} in order to function. Therefore @command{zebra} must be
+running before invoking @command{ospfd}. Also, if @command{zebra} is
+restarted then @command{ospfd} must be too.
 
-Like other daemons, @command{ospfd} configuration is done in OSPF
+Like other daemons, @command{ospfd} configuration is done in @acronym{OSPF}
 specific configuration file @file{ospfd.conf}.
 
 @node OSPF router
@@ -44,15 +48,23 @@ number.
 
 @deffn {OSPF Command} {ospf router-id @var{a.b.c.d}} {}
 @deffnx {OSPF Command} {no ospf router-id} {}
+This sets the router-ID of the OSPF process. The router-ID may be an IP
+address of the router, but need not be - it can be any arbitrary 32bit
+number. However it MUST be unique within the entire OSPF domain to the
+OSPF speaker - bad things will happen if multiple OSPF speakers are
+configured with the same router-ID! If one is not specified then
+@command{ospfd} will obtain a router-ID automatically from @command{zebra}.
 @end deffn
 
 @deffn {OSPF Command} {ospf abr-type @var{type}} {}
 @deffnx {OSPF Command} {no ospf abr-type @var{type}} {}
-@var{type} can be cisco|ibm|shortcut|standard
+@var{type} can be cisco|ibm|shortcut|standard.
+
 More information regarding the behaviour controlled by this command can
-be found in draft-ietf-ospf-abr-alt-05.txt and 
-draft-ietf-ospf-shortcut-abr-02.txt
-Quote: "Though the definition of the Area Border Router (ABR)
+be found in @cite{RFC 3509, Alternative Implementations of OSPF Area
+Border Routers}, and @cite{draft-ietf-ospf-shortcut-abr-02.txt}.
+
+Quote: "Though the definition of the @acronym{ABR,Area Border Router}
 in the OSPF specification does not require a router with multiple
 attached areas to have a backbone connection, it is actually
 necessary to provide successful routing to the inter-area and
@@ -60,33 +72,122 @@ external destinations. If this requirement is not met, all traffic
 destined for the areas not connected to such an ABR or out of the
 OSPF domain, is dropped.  This document describes alternative ABR
 behaviors implemented in Cisco and IBM routers."
+
+The default ABR type is 'Cisco', allowing an ABR to consider summaries
+from non-backbone areas if, and only if, it has lost its link(s) to the
+backbone area.
 @end deffn
 
 @deffn {OSPF Command} {ospf rfc1583compatibility} {}
 @deffnx {OSPF Command} {no ospf rfc1583compatibility} {}
-This rfc2328, the sucessor to rfc1583, suggests according to section 
-G.2 (changes) in section 16.4 a change to the path preference
-algorithm that prevents possible routing loops that were possible in
-the old version of OSPFv2. More specifically it demands that inter-area
-paths and intra-area path are now of equal preference but still both
-preferred to external paths.
+This @cite{RFC2328}, the sucessor to @cite{RFC1583}, suggests according
+to section G.2 (changes) in section 16.4 a change to the path
+preference algorithm that prevents possible routing loops that were
+possible in the old version of OSPFv2. More specifically it demands
+that inter-area paths and intra-area path are now of equal preference
+but still both preferred to external paths.
+
+This command should NOT be set normally.
 @end deffn
 
 @deffn {OSPF Command} {passive interface @var{interface}} {}
 @deffnx {OSPF Command} {no passive interface @var{interface}} {}
-@end deffn
 
-@deffn {OSPF Command} {timers spf <0-4294967295> <0-4294967295>} {}
-@deffnx {OSPF Command} {no timers spf} {}
-@end deffn
+Do not speak OSPF interface on the given interface, but do advertise
+the interface as a stub link in the router-@acronym{LSA,Link State
+Advertisement} for this router. This allows one to advertise addresses
+on such connected interfaces without having to originate
+AS-External/Type-5 LSAs (which have global flooding scope) - as would
+occur if connected addresses were redistributed into OSPF,
+@xref{Redistribute routes to OSPF}.
+
+@end deffn
+
+@deffn {OSPF Command} {timers throttle spf @var{delay} @var{initial-holdtime} @var{max-holdtime}} {}
+@deffnx {OSPF Command} {no timers throttle spf} {}
+This command sets the initial @var{delay}, the @var{initial-holdtime}
+and the @var{maximum-holdtime} between when SPF is calculated and the
+event which triggered the calculation. The times are specified in
+milliseconds and must be in the range of 0 to 600000 milliseconds.
+
+The @var{delay} specifies the minimum amount of time to delay SPF
+calculation (hence it affects how long SPF calculation is delayed after
+an event which occurs outside of the holdtime of any previous SPF
+calculation, and also serves as a minimum holdtime).
+
+Consecutive SPF calculations will always be seperated by at least
+'hold-time' milliseconds. The hold-time is adaptive and initially is
+set to the @var{initial-holdtime} configured with the above command.
+Events which occur within the holdtime of the previous SPF calculation
+will cause the holdtime to be increased by @var{initial-holdtime}, bounded
+by the @var{maximum-holdtime} configured with this command. If the adaptive
+hold-time elapses without any SPF-triggering event occuring then 
+the current holdtime is reset to the @var{initial-holdtime}. The current
+holdtime can be viewed with @ref{show ip ospf}, where it is expressed as 
+a multiplier of the @var{initial-holdtime}.
 
-@deffn {OSPF Command} {refresh group-limit <0-10000>} {}
-@deffnx {OSPF Command} {refresh per-slice <0-10000>} {}
-@deffnx {OSPF Command} {refresh age-diff <0-10000>} {}
-@end deffn
+@example
+@group
+router ospf
+ timers throttle spf 200 400 10000
+@end group
+@end example
 
-@deffn {OSPF Command} {auto-cost refrence-bandwidth <1-4294967>} {}
-@deffnx {OSPF Command} {no auto-cost refrence-bandwidth} {}
+In this example, the @var{delay} is set to 200ms, the @var{initial
+holdtime} is set to 400ms and the @var{maximum holdtime} to 10s. Hence
+there will always be at least 200ms between an event which requires SPF
+calculation and the actual SPF calculation. Further consecutive SPF
+calculations will always be seperated by between 400ms to 10s, the
+hold-time increasing by 400ms each time an SPF-triggering event occurs
+within the hold-time of the previous SPF calculation.
+
+This command supercedes the @command{timers spf} command in previous Quagga
+releases.
+@end deffn
+
+@deffn {OSPF Command} {max-metric router-lsa [on-startup|on-shutdown] <5-86400>} {}
+@deffnx {OSPF Command} {max-metric router-lsa administrative} {}
+@deffnx {OSPF Command} {no max-metric router-lsa [on-startup|on-shutdown|administrative]} {}
+This enables @cite{RFC3137, OSPF Stub Router Advertisement} support,
+where the OSPF process describes its transit links in its router-LSA as
+having infinite distance so that other routers will avoid calculating
+transit paths through the router while still being able to reach
+networks through the router.
+
+This support may be enabled administratively (and indefinitely) or
+conditionally. Conditional enabling of max-metric router-lsas can be
+for a period of seconds after startup and/or for a period of seconds
+prior to shutdown. 
+
+Enabling this for a period after startup allows OSPF to converge fully
+first without affecting any existing routes used by other routers,
+while still allowing any connected stub links and/or redistributed
+routes to be reachable. Enabling this for a period of time in advance
+of shutdown allows the router to gracefully excuse itself from the OSPF
+domain. 
+
+Enabling this feature administratively allows for administrative
+intervention for whatever reason, for an indefinite period of time.
+Note that if the configuration is written to file, this administrative
+form of the stub-router command will also be written to file. If
+@command{ospfd} is restarted later, the command will then take effect
+until manually deconfigured.
+
+Configured state of this feature as well as current status, such as the
+number of second remaining till on-startup or on-shutdown ends, can be
+viewed with the @ref{show ip ospf} command.
+@end deffn
+
+@deffn {OSPF Command} {auto-cost reference-bandwidth <1-4294967>} {}
+@deffnx {OSPF Command} {no auto-cost reference-bandwidth} {}
+This sets the reference bandwidth for cost calculations, where this
+bandwidth is considered equivalent to an OSPF cost of 1, specified in
+Mbits/s. The default is 100Mbit/s (i.e. a link of bandwidth 100Mbit/s
+or higher will have a cost of 1. Cost of lower bandwidth links will be
+scaled with reference to this cost).
+
+This configuration setting MUST be consistent across all routers within the
+OSPF domain.
 @end deffn
 
 @deffn {OSPF Command} {network @var{a.b.c.d/m} area @var{a.b.c.d}} {}
@@ -97,12 +198,14 @@ This command specifies the OSPF enabled interface(s).  If the interface has
 an address from range 192.168.1.0/24 then the command below enables ospf
 on this interface so router can provide network information to the other
 ospf routers via this interface.
+
 @example
 @group
 router ospf
  network 192.168.1.0/24 area 0.0.0.0
 @end group
 @end example
+
 Prefix length in interface must be equal or bigger (ie. smaller network) than
 prefix length in network statement. For example statement above doesn't enable
 ospf on interface with address 192.168.1.1/23, but it does on interface with
@@ -121,6 +224,7 @@ announced to other areas. This command can be used only in ABR and ONLY
 router-LSAs (Type-1) and network-LSAs (Type-2) (ie. LSAs with scope area) can
 be summarized. Type-5 AS-external-LSAs can't be summarized - their scope is AS.
 Summarizing Type-7 AS-external-LSAs isn't supported yet by Quagga.
+
 @example
 @group
 router ospf
@@ -129,6 +233,7 @@ router ospf
  area 0.0.0.10 range 10.0.0.0/8
 @end group
 @end example
+
 With configuration above one Type-3 Summary-LSA with routing info 10.0.0.0/8 is
 announced into backbone area if area 0.0.0.10 contains at least one intra-area
 network (ie. described with router or network LSA) from this range.
@@ -144,6 +249,7 @@ This command makes sense in ABR only.
 @deffn {OSPF Command} {area @var{a.b.c.d} range IPV4_PREFIX substitute IPV4_PREFIX} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} range IPV4_PREFIX substitute IPV4_PREFIX} {}
 Substitute summarized prefix with another prefix.
+
 @example
 @group
 router ospf
@@ -152,6 +258,7 @@ router ospf
  area 0.0.0.10 range 10.0.0.0/8 substitute 11.0.0.0/8
 @end group
 @end example
+
 One Type-3 summary-LSA with routing info 11.0.0.0/8 is announced into backbone area if
 area 0.0.0.10 contains at least one intra-area network (ie. described with router-LSA or
 network-LSA) from range 10.0.0.0/8.
@@ -168,22 +275,33 @@ This command makes sense in ABR only.
 @deffnx {OSPF Command} {area <0-4294967295> shortcut} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} shortcut} {}
 @deffnx {OSPF Command} {no area <0-4294967295> shortcut} {}
+Configure th area as Shortcut capable. See @cite{RFC3509}. This requires
+that the 'abr-type' be set to 'shortcut'.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} stub} {}
 @deffnx {OSPF Command} {area <0-4294967295> stub} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} stub} {}
 @deffnx {OSPF Command} {no area <0-4294967295> stub} {}
+Configure the area to be a stub area. That is, an area where no router
+originates routes external to OSPF and hence an area where all external 
+routes are via the ABR(s). Hence, ABRs for such an area do not need
+to pass AS-External LSAs (type-5s) or ASBR-Summary LSAs (type-4) into the
+area. They need only pass Network-Summary (type-3) LSAs into such an area,
+just a default summary.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} stub no-summary} {}
 @deffnx {OSPF Command} {area <0-4294967295> stub no-summary} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} stub no-summary} {}
 @deffnx {OSPF Command} {no area <0-4294967295> stub no-summary} {}
+Prevents an @command{ospfd} ABR from injecting inter-area 
+summaries into the specified stub area.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} default-cost <0-16777215>} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} default-cost <0-16777215>} {}
+Set the cost of default-summary LSAs announced to stubby areas.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} export-list NAME} {}
@@ -192,6 +310,7 @@ This command makes sense in ABR only.
 @deffnx {OSPF Command} {no area <0-4294967295> export-list NAME} {}
 Filter Type-3 summary-LSAs announced to other areas originated from intra-
 area paths from specified area.
+
 @example
 @group
 router ospf
@@ -203,11 +322,14 @@ access-list foo permit 10.10.0.0/16
 access-list foo deny any
 @end group
 @end example
+
 With example above any intra-area paths from area 0.0.0.10 and from range
 10.10.0.0/16 (for example 10.10.1.0/24 and 10.10.2.128/30) are announced into
 other areas as Type-3 summary-LSA's, but any others (for example 10.11.0.0/16
 or 10.128.30.16/30) aren't.
-This command makes sense in ABR only.
+
+This command is only relevant if the router is an ABR for the specified
+area.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} import-list NAME} {}
@@ -234,16 +356,20 @@ makes sense in ABR only.
 @deffnx {OSPF Command} {area <0-4294967295> authentication} {}
 @deffnx {OSPF Command} {no area @var{a.b.c.d} authentication} {}
 @deffnx {OSPF Command} {no area <0-4294967295> authentication} {}
+Specify that simple password authentication should be used for the given
+area.
 @end deffn
 
 @deffn {OSPF Command} {area @var{a.b.c.d} authentication message-digest} {}
 @deffnx {OSPF Command} {area <0-4294967295> authentication message-digest} {}
+Specify that OSPF packets should be authenticated with MD5 HMACs for the given
+area.
 @end deffn
 
 @node OSPF interface
 @section OSPF interface
 
-@deffn {Interface Command} {ip ospf authentication-key AUTH_KEY} {}
+@deffn {Interface Command} {ip ospf authentication-key @var{AUTH_KEY}} {}
 @deffnx {Interface Command} {no ip ospf authentication-key} {}
 Set OSPF authentication key to a simple password.  After setting @var{AUTH_KEY},
 all OSPF packets are authenticated. @var{AUTH_KEY} has length up to 8 chars.
@@ -256,7 +382,7 @@ algorithm is MD5.  KEYID identifies secret key used to create the message
 digest.  KEY is the actual message digest key up to 16 chars. 
 
 Note that OSPF MD5 authentication requires that time never go backwards
-(correct time is not important, only that it never goes backwards), even
+(correct time is NOT important, only that it never goes backwards), even
 across resets, if ospfd is to be able to promptly reestabish adjacencies
 with its neighbours after restarts/reboots. The host should have system
 time be set at boot from an external source (eg battery backed clock, NTP,
@@ -271,11 +397,22 @@ Set link cost for the specified interface.  The cost value is set to router-LSA'
 metric field and used for SPF calculation.
 @end deffn
 
+@anchor{ip ospf dead-interval minimal}
 @deffn {Interface Command} {ip ospf dead-interval <1-65535>} {}
+@deffnx {Interface Command} {ip ospf dead-interval minimal hello-multiplier <2-20>} {}
 @deffnx {Interface Command} {no ip ospf dead-interval} {}
 Set number of seconds for RouterDeadInterval timer value used for Wait Timer
 and Inactivity Timer.  This value must be the same for all routers attached
 to a common network.  The default value is 40 seconds.
+
+If 'minimal' is specified instead, then the dead-interval is set to 1
+second and one must specify a hello-multiplier. The hello-multiplier
+specifies how many Hellos to send per second, from 2 (every 500ms) to
+20 (every 50ms). Thus one can have 1s convergence time for OSPF. If this form
+is specified, then the hello-interval advertised in Hello packets is set to
+0 and the hello-interval on received Hello packets is not checked, thus 
+the hello-multiplier need NOT be the same across multiple routers on a common
+link.
 @end deffn
 
 @deffn {Interface Command} {ip ospf hello-interval <1-65535>} {}
@@ -284,6 +421,9 @@ Set number of seconds for HelloInterval timer value.  Setting this value,
 Hello packet will be sent every timer value seconds on the specified interface.
 This value must be the same for all routers attached to a common network.
 The default value is 10 seconds.
+
+This command has no effect if @ref{ip ospf dead-interval minimal} is also 
+specified for the interface.
 @end deffn
 
 @deffn {Interface Command} {ip ospf network (broadcast|non-broadcast|point-to-multipoint|point-to-point)} {}
@@ -325,6 +465,9 @@ The default value is 1 seconds.
 @deffnx {OSPF Command} {redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) metric <0-16777214>} {}
 @deffnx {OSPF Command} {redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) metric <0-16777214> route-map @var{word}} {}
 @deffnx {OSPF Command} {no redistribute (kernel|connected|static|rip|bgp)} {}
+Redistribute routes of the specified protocol or kind into OSPF, with the
+metric type and metric set if specified, filtering the routes using the given
+route-map if specified.
 @end deffn
 
 @deffn {OSPF Command} {default-information originate} {}
@@ -336,6 +479,10 @@ The default value is 1 seconds.
 @deffnx {OSPF Command} {default-information originate always metric <0-16777214> metric-type (1|2)} {}
 @deffnx {OSPF Command} {default-information originate always metric <0-16777214> metric-type (1|2) route-map @var{word}} {}
 @deffnx {OSPF Command} {no default-information originate} {}
+Originate an AS-External (type-5) LSA describing a default route into
+all external-routing capable areas, of the specified metric and metric
+type. If the 'always' keyword is given then the default is always
+advertised, even when there is no default present in the routing table.
 @end deffn
 
 @deffn {OSPF Command} {distribute-list NAME out (kernel|connected|static|rip|ospf} {}
@@ -361,10 +508,15 @@ The default value is 1 seconds.
 @node Showing OSPF information
 @section Showing OSPF information
 
+@anchor{show ip ospf}
 @deffn {Command} {show ip ospf} {}
+Show information on a variety of general OSPF and area state and configuration
+information.
 @end deffn
 
 @deffn {Command} {show ip ospf interface [INTERFACE]} {}
+Show state and configuration of OSPF the specified interface, or all
+interfaces if no interface is given.
 @end deffn
 
 @deffn {Command} {show ip ospf neighbor} {}
@@ -390,10 +542,8 @@ The default value is 1 seconds.
 @deffn {Command} {show ip ospf database self-originate} {}
 @end deffn
 
-@deffn {Command} {show ip ospf refresher} {}
-@end deffn
-
 @deffn {Command} {show ip ospf route} {}
+Show the OSPF routing table, as determined by the most recent SPF calculation.
 @end deffn
 
 @node Debugging OSPF
@@ -430,3 +580,55 @@ The default value is 1 seconds.
 @deffn {Command} {show debugging ospf} {}
 @end deffn
 
+@node OSPF Configuration Examples
+@section OSPF Configuration Examples
+A simple example, with MD5 authentication enabled:
+
+@example
+@group
+!
+interface bge0
+ ip ospf authentication message-digest
+ ip ospf message-digest-key 1 md5 ABCDEFGHIJK
+!
+router ospf
+ network 192.168.0.0/16 area 0.0.0.1
+ area 0.0.0.1 authentication message-digest
+@end group
+@end example
+
+An @acronym{ABR} router, with MD5 authentication and performing summarisation
+of networks between the areas:
+
+@example
+@group
+!
+password ABCDEF
+log file /var/log/quagga/ospfd.log
+service advanced-vty
+!
+interface eth0
+ ip ospf authentication message-digest
+ ip ospf message-digest-key 1 md5 ABCDEFGHIJK
+!
+interface ppp0
+!
+interface br0
+ ip ospf authentication message-digest
+ ip ospf message-digest-key 2 md5 XYZ12345
+!
+router ospf
+ ospf router-id 192.168.0.1
+ redistribute connected
+ passive interface ppp0
+ network 192.168.0.0/24 area 0.0.0.0
+ network 10.0.0.0/16 area 0.0.0.0
+ network 192.168.1.0/24 area 0.0.0.1
+ area 0.0.0.0 authentication message-digest
+ area 0.0.0.0 range 10.0.0.0/16
+ area 0.0.0.0 range 192.168.0.0/24
+ area 0.0.0.1 authentication message-digest
+ area 0.0.0.1 range 10.2.0.0/16
+!
+@end group
+@end example