Documentation update,

When the routing table gets a route from a protocol, it recalculates

the selected route and broadcasts it to all protocols connected to

the table. The protocols typically send the update to other routers

in the network.

in the network. Note that although most protocols are interested 

in receiving just selected routes, some protocols (e.g. the <cf/Pipe/

protocol) receive and process all entries in routing tables (accepted

by filters).

<p><label id="dsc-sorted">Usually, a routing table just chooses a

selected route from a list of entries for one network. But if the

<cf/sorted/ option is activated, these lists of entries are kept

completely sorted (according to preference or some protocol-dependent

metric).

This is needed for some features of some protocols

(e.g. <cf/secondary/ option of BGP protocol, which allows to accept

not just a selected route, but the first route (in the sorted list)

that is accepted by filters), but it is incompatible with some other

features (e.g. <cf/deterministic med/ option of BGP protocol, which

activates a way of choosing selected route that cannot be described

using comparison and ordering). Minor advantage is that routes are

shown sorted in <cf/show route/, minor disadvantage is that it is

slightly more computationally expensive.

<chapt>Configuration

	defaults are here for a compatibility with older versions

	and might change in the future.

	<tag>table <m/name/</tag> Create a new routing table. The default

	routing table is created implicitly, other routing tables have

	to be added by this command.

	<tag>table <m/name/ [sorted]</tag>

	Create a new routing table. The default routing table is

	created implicitly, other routing tables have to be added by

	this command. Option <cf/sorted/ can be used to enable

	sorting of routes, see <ref id="dsc-sorted" name="sorted table">

	description for details.

	<tag>roa table [ { roa table options ... } ] <m/name/</tag>

	<tag>roa table <m/name/ [ { roa table options ... } ]</tag>

	Create a new ROA (Route Origin Authorization) table. ROA

	tables can be used to validate route origination of BGP

	routes. A ROA table contains ROA entries, each consist of a

	mode is the behavior specified by the BGP standard. Direct

	mode is simpler, does not require any routes in a routing

	table, and was used in older versions of BIRD, but does not

	handle well nontrivial iBGP setups and multihop. Default:

	<cf/direct/ for singlehop eBGP, <cf/recursive/ otherwise.

	handle well nontrivial iBGP setups and multihop.  Recursive

	mode is incompatible with <ref id="dsc-sorted" name="sorted

	tables">. Default: <cf/direct/ for singlehop eBGP,

	<cf/recursive/ otherwise.

	<tag>igp table <m/name/</tag> Specifies a table that is used

	as an IGP routing table. Default: the same as the table BGP is

	attributes to be transparent (for example does not prepend its AS number to

	AS PATH attribute and keeps MED attribute). Default: disabled.

	<tag>secondary <m/switch/</tag> Usually, if an import filter

	rejects a selected route, no other route is propagated for

	that network. This option allows to try the next route in

	order until one that is accepted is found or all routes for

	that network are rejected. This can be used for route servers

	that need to propagate different tables to each client but do

	not want to have these tables explicitly (to conserve memory).

	This option requires that the connected routing table is

	<ref id="dsc-sorted" name="sorted">. Default: off.

	<tag>enable route refresh <m/switch/</tag> When BGP speaker

	changes its import filter, it has to re-examine all routes

	received from its neighbor against the new filter. As these

	This option enables a different (and slower) algorithm

	implementing proper RFC 4271 route selection, which is

	deterministic. Alternative way how to get deterministic

	behavior is to use <cf/med metric/ option. Default: off.

	behavior is to use <cf/med metric/ option. This option is

	incompatible with <ref id="dsc-sorted" name="sorted tables">.

	Default: off.

	<tag>igp metric <m/switch/</tag> Enable comparison of internal

 	distances to boundary routers during best route selection. Default: on.