@c -*-texinfo-*- @c This is part of the Quagga Manual. @c Copyright (C) 1999, 2000, 2001 2002 Kunihiro Ishiguro @c See file zebra.texi for copying conditions. @node BGP @comment node-name, next, previous, up @chapter BGP BGP stands for a Border Gateway Protocol. The lastest BGP version is 4. It is referred as BGP-4. BGP-4 is one of the Exterior Gateway Protocols and de-fact standard of Inter Domain routing protocol. BGP-4 is described in @code{RFC1771} - @cite{A Border Gateway Protocol 4 (BGP-4)}. Many extentions are added to @code{RFC1771}. @code{RFC2858} - @cite{Multiprotocol Extensions for BGP-4} provide multiprotocol support to BGP-4. @menu * Starting BGP:: * BGP router:: * BGP network:: * BGP Peer:: * BGP Peer Group:: * BGP Address Family:: * Autonomous System:: * BGP Communities Attribute:: * BGP Extended Communities Attribute:: * Displaying BGP routes:: * Capability Negotiation:: * Route Reflector:: * Route Server:: * How to set up a 6-Bone connection:: * Dump BGP packets and table:: @end menu @node Starting BGP, BGP router, BGP, BGP @comment node-name, next, previous, up @section Starting BGP Default configuration file of @command{bgpd} is @file{bgpd.conf}. @command{bgpd} searches the current directory first then @value{INSTALL_PREFIX_ETC}/bgpd.conf. All of bgpd's command must be configured in @file{bgpd.conf}. @command{bgpd} specific invocation options are described below. Common options may also be specified (@pxref{Common Invocation Options}). @table @samp @item -p @var{PORT} @itemx --bgp_port=@var{PORT} Set the bgp protocol's port number. @item -r @itemx --retain When program terminates, retain BGP routes added by zebra. @end table @node BGP router, BGP network, Starting BGP, BGP @comment node-name, next, previous, up @section BGP router First of all you must configure BGP router with @command{router bgp} command. To configure BGP router, you need AS number. AS number is an identification of autonomous system. BGP protocol uses the AS number for detecting whether the BGP connection is internal one or external one. @deffn Command {router bgp @var{asn}} {} Enable a BGP protocol process with the specified @var{asn}. After this statement you can input any @code{BGP Commands}. You can not create different BGP process under different @var{asn} without specifying @code{multiple-instance} (@pxref{Multiple instance}). @end deffn @deffn Command {no router bgp @var{asn}} {} Destroy a BGP protocol process with the specified @var{asn}. @end deffn @deffn {BGP} {bgp router-id @var{A.B.C.D}} {} This command specifies the router-ID. If @command{bgpd} connects to @command{zebra} it gets interface and address information. In that case default router ID value is selected as the largest IP Address of the interfaces. When @code{router zebra} is not enabled @command{bgpd} can't get interface information so @code{router-id} is set to 0.0.0.0. So please set router-id by hand. @end deffn @menu * BGP distance:: * BGP decision process:: @end menu @node BGP distance, BGP decision process, BGP router, BGP router @comment node-name, next, previous, up @subsection BGP distance @deffn {BGP} {distance bgp <1-255> <1-255> <1-255>} {} This command change distance value of BGP. Each argument is distance value for external routes, internal routes and local routes. @end deffn @deffn {BGP} {distance <1-255> @var{A.B.C.D/M}} {} @deffnx {BGP} {distance <1-255> @var{A.B.C.D/M} @var{word}} {} This command set distance value to @end deffn @node BGP decision process, , BGP distance, BGP router @comment node-name, next, previous, up @subsection BGP decision process @table @asis @item 1. Weight check @item 2. Local preference check. @item 3. Local route check. @item 4. AS path length check. @item 5. Origin check. @item 6. MED check. @end table @node BGP network, BGP Peer, BGP router, BGP @comment node-name, next, previous, up @section BGP network @menu * BGP route:: * Route Aggregation:: * Redistribute to BGP:: @end menu @node BGP route, Route Aggregation, BGP network, BGP network @comment node-name, next, previous, up @subsection BGP route @deffn {BGP} {network @var{A.B.C.D/M}} {} This command adds the announcement network. @example @group router bgp 1 network 10.0.0.0/8 @end group @end example This configuration example says that network 10.0.0.0/8 will be announced to all neighbors. Some vendors' routers don't advertise routes if they aren't present in their IGP routing tables; @code{bgp} doesn't care about IGP routes when announcing its routes. @end deffn @deffn {BGP} {no network @var{A.B.C.D/M}} {} @end deffn @node Route Aggregation, Redistribute to BGP, BGP route, BGP network @comment node-name, next, previous, up @subsection Route Aggregation @deffn {BGP} {aggregate-address @var{A.B.C.D/M}} {} This command specifies an aggregate address. @end deffn @deffn {BGP} {aggregate-address @var{A.B.C.D/M} as-set} {} This command specifies an aggregate address. Resulting routes inlucde AS set. @end deffn @deffn {BGP} {aggregate-address @var{A.B.C.D/M} summary-only} {} This command specifies an aggregate address. Aggreated routes will not be announce. @end deffn @deffn {BGP} {no aggregate-address @var{A.B.C.D/M}} {} @end deffn @node Redistribute to BGP, , Route Aggregation, BGP network @comment node-name, next, previous, up @subsection Redistribute to BGP @deffn {BGP} {redistribute kernel} {} Redistribute kernel route to BGP process. @end deffn @deffn {BGP} {redistribute static} {} Redistribute static route to BGP process. @end deffn @deffn {BGP} {redistribute connected} {} Redistribute connected route to BGP process. @end deffn @deffn {BGP} {redistribute rip} {} Redistribute RIP route to BGP process. @end deffn @deffn {BGP} {redistribute ospf} {} Redistribute OSPF route to BGP process. @end deffn @node BGP Peer, BGP Peer Group, BGP network, BGP @comment node-name, next, previous, up @section BGP Peer @menu * Defining Peer:: * BGP Peer commands:: * Peer filtering:: @end menu @node Defining Peer, BGP Peer commands, BGP Peer, BGP Peer @comment node-name, next, previous, up @subsection Defining Peer @deffn {BGP} {neighbor @var{peer} remote-as @var{asn}} {} Creates a new neighbor whose remote-as is @var{asn}. @var{peer} can be an IPv4 address or an IPv6 address. @example @group router bgp 1 neighbor 10.0.0.1 remote-as 2 @end group @end example In this case my router, in AS-1, is trying to peer with AS-2 at 10.0.0.1. This command must be the first command used when configuring a neighbor. If the remote-as is not specified, @command{bgpd} will complain like this: @example can't find neighbor 10.0.0.1 @end example @end deffn @node BGP Peer commands, Peer filtering, Defining Peer, BGP Peer @comment node-name, next, previous, up @subsection BGP Peer commands In a @code{router bgp} clause there are neighbor specific configurations required. @deffn {BGP} {neighbor @var{peer} shutdown} {} @deffnx {BGP} {no neighbor @var{peer} shutdown} {} Shutdown the peer. We can delete the neighbor's configuration by @code{no neighbor @var{peer} remote-as @var{as-number}} but all configuration of the neighbor will be deleted. When you want to preserve the configuration, but want to drop the BGP peer, use this syntax. @end deffn @deffn {BGP} {neighbor @var{peer} ebgp-multihop} {} @deffnx {BGP} {no neighbor @var{peer} ebgp-multihop} {} @end deffn @deffn {BGP} {neighbor @var{peer} description ...} {} @deffnx {BGP} {no neighbor @var{peer} description ...} {} Set description of the peer. @end deffn @deffn {BGP} {neighbor @var{peer} version @var{version}} {} Set up the neighbor's BGP version. @var{version} can be @var{4}, @var{4+} or @var{4-}. BGP version @var{4} is the default value used for BGP peering. BGP version @var{4+} means that the neighbor supports Multiprotocol Extensions for BGP-4. BGP version @var{4-} is similar but the neighbor speaks the old Internet-Draft revision 00's Multiprotocol Extensions for BGP-4. Some routing software is still using this version. @end deffn @deffn {BGP} {neighbor @var{peer} interface @var{ifname}} {} @deffnx {BGP} {no neighbor @var{peer} interface @var{ifname}} {} When you connect to a BGP peer over an IPv6 link-local address, you have to specify the @var{ifname} of the interface used for the connection. @end deffn @deffn {BGP} {neighbor @var{peer} next-hop-self} {} @deffnx {BGP} {no neighbor @var{peer} next-hop-self} {} This command specifies an announced route's nexthop as being equivalent to the address of the bgp router. @end deffn @deffn {BGP} {neighbor @var{peer} update-source} {} @deffnx {BGP} {no neighbor @var{peer} update-source} {} @end deffn @deffn {BGP} {neighbor @var{peer} default-originate} {} @deffnx {BGP} {no neighbor @var{peer} default-originate} {} @command{bgpd}'s default is to not announce the default route (0.0.0.0/0) even it is in routing table. When you want to announce default routes to the peer, use this command. @end deffn @deffn {BGP} {neighbor @var{peer} port @var{port}} {} @deffnx {BGP} {neighbor @var{peer} port @var{port}} {} @end deffn @deffn {BGP} {neighbor @var{peer} send-community} {} @deffnx {BGP} {neighbor @var{peer} send-community} {} @end deffn @deffn {BGP} {neighbor @var{peer} weight @var{weight}} {} @deffnx {BGP} {no neighbor @var{peer} weight @var{weight}} {} This command specifies a default @var{weight} value for the neighbor's routes. @end deffn @deffn {BGP} {neighbor @var{peer} maximum-prefix @var{number}} {} @deffnx {BGP} {no neighbor @var{peer} maximum-prefix @var{number}} {} @end deffn @node Peer filtering, , BGP Peer commands, BGP Peer @comment node-name, next, previous, up @subsection Peer filtering @deffn {BGP} {neighbor @var{peer} distribute-list @var{name} [in|out]} {} This command specifies a distribute-list for the peer. @var{direct} is @samp{in} or @samp{out}. @end deffn @deffn {BGP command} {neighbor @var{peer} prefix-list @var{name} [in|out]} {} @end deffn @deffn {BGP command} {neighbor @var{peer} filter-list @var{name} [in|out]} {} @end deffn @deffn {BGP} {neighbor @var{peer} route-map @var{name} [in|out]} {} Apply a route-map on the neighbor. @var{direct} must be @code{in} or @code{out}. @end deffn @c ----------------------------------------------------------------------- @node BGP Peer Group, BGP Address Family, BGP Peer, BGP @comment node-name, next, previous, up @section BGP Peer Group @deffn {BGP} {neighbor @var{word} peer-group} {} This command defines a new peer group. @end deffn @deffn {BGP} {neighbor @var{peer} peer-group @var{word}} {} This command bind specific peer to peer group @var{word}. @end deffn @node BGP Address Family, Autonomous System, BGP Peer Group, BGP @comment node-name, next, previous, up @section BGP Address Family @page @c ----------------------------------------------------------------------- @node Autonomous System, BGP Communities Attribute, BGP Address Family, BGP @comment node-name, next, previous, up @section Autonomous System AS (Autonomous System) is one of the essential element of BGP. BGP is a distance vector routing protocol. AS framework provides distance vector metric and loop detection to BGP. @code{RFC1930} - @cite{Guidelines for creation, selection, and registration of an Autonomous System (AS)} describes how to use AS. AS number is tow octet digita value. So the value range is from 1 to 65535. AS numbers 64512 through 65535 are defined as private AS numbers. Private AS numbers must not to be advertised in the global Internet. @menu * AS Path Regular Expression:: * Display BGP Routes by AS Path:: * AS Path Access List:: * Using AS Path in Route Map:: * Private AS Numbers:: @end menu @node AS Path Regular Expression, Display BGP Routes by AS Path, Autonomous System, Autonomous System @comment node-name, next, previous, up @subsection AS Path Regular Expression AS path regular expression can be used for displaying BGP routes and AS path access list. AS path regular expression is based on @code{POSIX 1003.2} regular expressions. Following description is just a subset of @code{POSIX} regular expression. User can use full @code{POSIX} regular expression. Adding to that special character '_' is added for AS path regular expression. @table @code @item . Matches any single character. @item * Matches 0 or more occurrences of pattern. @item + Matches 1 or more occurrences of pattern. @item ? Match 0 or 1 occurrences of pattern. @item ^ Matches the beginning of the line. @item $ Matches the end of the line. @item _ Character @code{_} has special meanings in AS path regular expression. It matches to space and comma , and AS set delimiter @{ and @} and AS confederation delimiter @code{(} and @code{)}. And it also matches to the beginning of the line and the end of the line. So @code{_} can be used for AS value boundaries match. @code{show ip bgp regexp _7675_} matches to all of BGP routes which as AS number include @var{7675}. @end table @node Display BGP Routes by AS Path, AS Path Access List, AS Path Regular Expression, Autonomous System @comment node-name, next, previous, up @subsection Display BGP Routes by AS Path To show BGP routes which has specific AS path information @code{show ip bgp} command can be used. @deffn Command {show ip bgp regexp @var{line}} {} This commands display BGP routes that matches AS path regular expression @var{line}. @end deffn @node AS Path Access List, Using AS Path in Route Map, Display BGP Routes by AS Path, Autonomous System @comment node-name, next, previous, up @subsection AS Path Access List AS path access list is user defined AS path. @deffn {Command} {ip as-path access-list @var{word} @{permit|deny@} @var{line}} {} This command defines a new AS path access list. @end deffn @deffn {Command} {no ip as-path access-list @var{word}} {} @deffnx {Command} {no ip as-path access-list @var{word} @{permit|deny@} @var{line}} {} @end deffn @node Using AS Path in Route Map, Private AS Numbers, AS Path Access List, Autonomous System @comment node-name, next, previous, up @subsection Using AS Path in Route Map @deffn {Route Map} {match as-path @var{word}} {} @end deffn @deffn {Route Map} {set as-path prepend @var{as-path}} {} @end deffn @node Private AS Numbers, , Using AS Path in Route Map, Autonomous System @comment node-name, next, previous, up @subsection Private AS Numbers @page @c ----------------------------------------------------------------------- @node BGP Communities Attribute, BGP Extended Communities Attribute, Autonomous System, BGP @comment node-name, next, previous, up @section BGP Communities Attribute BGP communities attribute is widely used for implementing policy routing. Network operators can manipulate BGP communities attribute based on their network policy. BGP communities attribute is defined in @code{RFC1997} - @cite{BGP Communities Attribute} and @code{RFC1998} - @cite{An Application of the BGP Community Attribute in Multi-home Routing}. It is an optional transitive attribute, therefore local policy can travel through different autonomous system. Communities attribute is a set of communities values. Each communities value is 4 octet long. The following format is used to define communities value. @table @code @item AS:VAL This format represents 4 octet communities value. @code{AS} is high order 2 octet in digit format. @code{VAL} is low order 2 octet in digit format. This format is useful to define AS oriented policy value. For example, @code{7675:80} can be used when AS 7675 wants to pass local policy value 80 to neighboring peer. @item internet @code{internet} represents well-known communities value 0. @item no-export @code{no-export} represents well-known communities value @code{NO_EXPORT}@* @r{(0xFFFFFF01)}. All routes carry this value must not be advertised to outside a BGP confederation boundary. If neighboring BGP peer is part of BGP confederation, the peer is considered as inside a BGP confederation boundary, so the route will be announced to the peer. @item no-advertise @code{no-advertise} represents well-known communities value @code{NO_ADVERTISE}@*@r{(0xFFFFFF02)}. All routes carry this value must not be advertise to other BGP peers. @item local-AS @code{local-AS} represents well-known communities value @code{NO_EXPORT_SUBCONFED} @r{(0xFFFFFF03)}. All routes carry this value must not be advertised to external BGP peers. Even if the neighboring router is part of confederation, it is considered as external BGP peer, so the route will not be announced to the peer. @end table When BGP communities attribute is received, duplicated communities value in the communities attribute is ignored and each communities values are sorted in numerical order. @menu * BGP Community Lists:: * Numbered BGP Community Lists:: * BGP Community in Route Map:: * Display BGP Routes by Community:: * Using BGP Communities Attribute:: @end menu @node BGP Community Lists, Numbered BGP Community Lists, BGP Communities Attribute, BGP Communities Attribute @comment node-name, next, previous, up @subsection BGP Community Lists BGP community list is a user defined BGP communites attribute list. BGP community list can be used for matching or manipulating BGP communities attribute in updates. There are two types of community list. One is standard community list and another is expanded community list. Standard community list defines communities attribute. Expanded community list defines communities attribute string with regular expression. Standard community list is compiled into binary format when user define it. Standard community list will be directly compared to BGP communities attribute in BGP updates. Therefore the comparison is faster than expanded community list. @deffn Command {ip community-list standard @var{name} @{permit|deny@} @var{community}} {} This command defines a new standard community list. @var{community} is communities value. The @var{community} is compiled into community structure. We can define multiple community list under same name. In that case match will happen user defined order. Once the community list matches to communities attribute in BGP updates it return permit or deny by the community list definition. When there is no matched entry, deny will be returned. When @var{community} is empty it matches to any routes. @end deffn @deffn Command {ip community-list expanded @var{name} @{permit|deny@} @var{line}} {} This command defines a new expanded community list. @var{line} is a string expression of communities attribute. @var{line} can include regular expression to match communities attribute in BGP updates. @end deffn @deffn Command {no ip community-list @var{name}} {} @deffnx Command {no ip community-list standard @var{name}} {} @deffnx Command {no ip community-list expanded @var{name}} {} These commands delete community lists specified by @var{name}. All of community lists shares a single name space. So community lists can be removed simpley specifying community lists name. @end deffn @deffn {Command} {show ip community-list} {} @deffnx {Command} {show ip community-list @var{name}} {} This command display current community list information. When @var{name} is specified the specified community list's information is shown. @example # show ip community-list Named Community standard list CLIST permit 7675:80 7675:100 no-export deny internet Named Community expanded list EXPAND permit : # show ip community-list CLIST Named Community standard list CLIST permit 7675:80 7675:100 no-export deny internet @end example @end deffn @node Numbered BGP Community Lists, BGP Community in Route Map, BGP Community Lists, BGP Communities Attribute @comment node-name, next, previous, up @subsection Numbered BGP Community Lists When number is used for BGP community list name, the number has special meanings. Community list number in the range from 1 and 99 is standard community list. Community list number in the range from 100 to 199 is expanded community list. These community lists are called as numbered community lists. On the other hand normal community lists is called as named community lists. @deffn Command {ip community-list <1-99> @{permit|deny@} @var{community}} {} This command defines a new community list. <1-99> is standard community list number. Community list name within this range defines standard community list. When @var{community} is empty it matches to any routes. @end deffn @deffn Command {ip community-list <100-199> @{permit|deny@} @var{community}} {} This command defines a new community list. <100-199> is expanded community list number. Community list name within this range defines expanded community list. @end deffn @deffn Command {ip community-list @var{name} @{permit|deny@} @var{community}} {} When community list type is not specifed, the community list type is automatically detected. If @var{community} can be compiled into communities attribute, the community list is defined as a standard community list. Otherwise it is defined as an expanded community list. This feature is left for backward compability. Use of this feature is not recommended. @end deffn @node BGP Community in Route Map, Display BGP Routes by Community, Numbered BGP Community Lists, BGP Communities Attribute @comment node-name, next, previous, up @subsection BGP Community in Route Map In Route Map (@pxref{Route Map}), we can match or set BGP communities attribute. Using this feature network operator can implement their network policy based on BGP communities attribute. Following commands can be used in Route Map. @deffn {Route Map} {match community @var{word}} {} @deffnx {Route Map} {match community @var{word} exact-match} {} This command perform match to BGP updates using community list @var{word}. When the one of BGP communities value match to the one of communities value in community list, it is match. When @code{exact-match} keyword is spcified, match happen only when BGP updates have completely same communities value specified in the community list. @end deffn @deffn {Route Map} {set community none} {} @deffnx {Route Map} {set community @var{community}} {} @deffnx {Route Map} {set community @var{community} additive} {} This command manipulate communities value in BGP updates. When @code{none} is specified as communities value, it removes entire communities attribute from BGP updates. When @var{community} is not @code{none}, specified communities value is set to BGP updates. If BGP updates already has BGP communities value, the existing BGP communities value is replaced with specified @var{community} value. When @code{additive} keyword is specified, @var{community} is appended to the existing communities value. @end deffn @deffn {Route Map} {set comm-list @var{word} delete} {} This command remove communities value from BGP communities attribute. The @var{word} is community list name. When BGP route's communities value matches to the community list @var{word}, the communities value is removed. When all of communities value is removed eventually, the BGP update's communities attribute is completely removed. @end deffn @node Display BGP Routes by Community, Using BGP Communities Attribute, BGP Community in Route Map, BGP Communities Attribute @comment node-name, next, previous, up @subsection Display BGP Routes by Community To show BGP routes which has specific BGP communities attribute, @code{show ip bgp} command can be used. The @var{community} value and community list can be used for @code{show ip bgp} command. @deffn Command {show ip bgp community} {} @deffnx Command {show ip bgp community @var{community}} {} @deffnx Command {show ip bgp community @var{community} exact-match} {} @code{show ip bgp community} displays BGP routes which has communities attribute. When @var{community} is specified, BGP routes that matches @var{community} value is displayed. For this command, @code{internet} keyword can't be used for @var{community} value. When @code{exact-match} is specified, it display only routes that have an exact match. @end deffn @deffn Command {show ip bgp community-list @var{word}} {} @deffnx Command {show ip bgp community-list @var{word} exact-match} {} This commands display BGP routes that matches community list @var{word}. When @code{exact-match} is specified, display only routes that have an exact match. @end deffn @node Using BGP Communities Attribute, , Display BGP Routes by Community, BGP Communities Attribute @comment node-name, next, previous, up @subsection Using BGP Communities Attribute Following configuration is the most typical usage of BGP communities attribute. AS 7675 provides upstream Internet connection to AS 100. When following configuration exists in AS 7675, AS 100 networks operator can set local preference in AS 7675 network by setting BGP communities attribute to the updates. @example router bgp 7675 neighbor 192.168.0.1 remote-as 100 neighbor 192.168.0.1 route-map RMAP in ! ip community-list 70 permit 7675:70 ip community-list 70 deny ip community-list 80 permit 7675:80 ip community-list 80 deny ip community-list 90 permit 7675:90 ip community-list 90 deny ! route-map RMAP permit 10 match community 70 set local-preference 70 ! route-map RMAP permit 20 match community 80 set local-preference 80 ! route-map RMAP permit 30 match community 90 set local-preference 90 @end example Following configuration announce 10.0.0.0/8 from AS 100 to AS 7675. The route has communities value 7675:80 so when above configuration exists in AS 7675, announced route's local preference will be set to value 80. @example router bgp 100 network 10.0.0.0/8 neighbor 192.168.0.2 remote-as 7675 neighbor 192.168.0.2 route-map RMAP out ! ip prefix-list PLIST permit 10.0.0.0/8 ! route-map RMAP permit 10 match ip address prefix-list PLIST set community 7675:80 @end example Following configuration is an example of BGP route filtering using communities attribute. This configuration only permit BGP routes which has BGP communities value 0:80 or 0:90. Network operator can put special internal communities value at BGP border router, then limit the BGP routes announcement into the internal network. @example router bgp 7675 neighbor 192.168.0.1 remote-as 100 neighbor 192.168.0.1 route-map RMAP in ! ip community-list 1 permit 0:80 0:90 ! route-map RMAP permit in match community 1 @end example Following exmaple filter BGP routes which has communities value 1:1. When there is no match community-list returns deny. To avoid filtering all of routes, we need to define permit any at last. @example router bgp 7675 neighbor 192.168.0.1 remote-as 100 neighbor 192.168.0.1 route-map RMAP in ! ip community-list standard FILTER deny 1:1 ip community-list standard FILTER permit ! route-map RMAP permit 10 match community FILTER @end example Communities value keyword @code{internet} has special meanings in standard community lists. In below example @code{internet} act as match any. It matches all of BGP routes even if the route does not have communities attribute at all. So community list @code{INTERNET} is same as above example's @code{FILTER}. @example ip community-list standard INTERNET deny 1:1 ip community-list standard INTERNET permit internet @end example Following configuration is an example of communities value deletion. With this configuration communities value 100:1 and 100:2 is removed from BGP updates. For communities value deletion, only @code{permit} community-list is used. @code{deny} community-list is ignored. @example router bgp 7675 neighbor 192.168.0.1 remote-as 100 neighbor 192.168.0.1 route-map RMAP in ! ip community-list standard DEL permit 100:1 100:2 ! route-map RMAP permit 10 set comm-list DEL delete @end example @c ----------------------------------------------------------------------- @node BGP Extended Communities Attribute, Displaying BGP routes, BGP Communities Attribute, BGP @comment node-name, next, previous, up @section BGP Extended Communities Attribute BGP extended communities attribute is introduced with MPLS VPN/BGP technology. MPLS VPN/BGP expands capability of network infrastructure to provide VPN functionality. At the same time it requires a new framework for policy routing. With BGP Extended Communities Attribute we can use Route Target or Site of Origin for implementing network policy for MPLS VPN/BGP. BGP Extended Communities Attribute is similar to BGP Communities Attribute. It is an optional transitive attribute. BGP Extended Communities Attribute can carry multiple Extended Community value. Each Extended Community value is eight octet length. BGP Extended Communities Attribute provides an extended range compared with BGP Communities Attribute. Adding to that there is a type field in each value to provides community space structure. There are two format to define Extended Community value. One is AS based format the other is IP address based format. @table @code @item AS:VAL This is a format to define AS based Extended Community value. @code{AS} part is 2 octets Global Administrator subfield in Extended Community value. @code{VAL} part is 4 octets Local Administrator subfield. @code{7675:100} represents AS 7675 policy value 100. @item IP-Address:VAL This is a format to define IP address based Extended Community value. @code{IP-Address} part is 4 octets Global Administrator subfield. @code{VAL} part is 2 octets Local Administrator subfield. @code{10.0.0.1:100} represents @end table @menu * BGP Extended Community Lists:: * BGP Extended Communities in Route Map:: @end menu @node BGP Extended Community Lists, BGP Extended Communities in Route Map, BGP Extended Communities Attribute, BGP Extended Communities Attribute @comment node-name, next, previous, up @subsection BGP Extended Community Lists Expanded Community Lists is a user defined BGP Expanded Community Lists. @deffn Command {ip extcommunity-list standard @var{name} @{permit|deny@} @var{extcommunity}} {} This command defines a new standard extcommunity-list. @var{extcommunity} is extended communities value. The @var{extcommunity} is compiled into extended community structure. We can define multiple extcommunity-list under same name. In that case match will happen user defined order. Once the extcommunity-list matches to extended communities attribute in BGP updates it return permit or deny based upon the extcommunity-list definition. When there is no matched entry, deny will be returned. When @var{extcommunity} is empty it matches to any routes. @end deffn @deffn Command {ip extcommunity-list expanded @var{name} @{permit|deny@} @var{line}} {} This command defines a new expanded extcommunity-list. @var{line} is a string expression of extended communities attribute. @var{line} can include regular expression to match extended communities attribute in BGP updates. @end deffn @deffn Command {no ip extcommunity-list @var{name}} {} @deffnx Command {no ip extcommunity-list standard @var{name}} {} @deffnx Command {no ip extcommunity-list expanded @var{name}} {} These commands delete extended community lists specified by @var{name}. All of extended community lists shares a single name space. So extended community lists can be removed simpley specifying the name. @end deffn @deffn {Command} {show ip extcommunity-list} {} @deffnx {Command} {show ip extcommunity-list @var{name}} {} This command display current extcommunity-list information. When @var{name} is specified the community list's information is shown. @example # show ip extcommunity-list @end example @end deffn @node BGP Extended Communities in Route Map, , BGP Extended Community Lists, BGP Extended Communities Attribute @comment node-name, next, previous, up @subsection BGP Extended Communities in Route Map @deffn {Route Map} {match extcommunity @var{word}} {} @end deffn @deffn {Route Map} {set extcommunity rt @var{extcommunity}} {} This command set Route Target value. @end deffn @deffn {Route Map} {set extcommunity soo @var{extcommunity}} {} This command set Site of Origin value. @end deffn @c ----------------------------------------------------------------------- @node Displaying BGP routes, Capability Negotiation, BGP Extended Communities Attribute, BGP @comment node-name, next, previous, up @section Displaying BGP Routes @menu * Show IP BGP:: * More Show IP BGP:: @end menu @node Show IP BGP, More Show IP BGP, Displaying BGP routes, Displaying BGP routes @comment node-name, next, previous, up @subsection Show IP BGP @deffn {Command} {show ip bgp} {} @deffnx {Command} {show ip bgp @var{A.B.C.D}} {} @deffnx {Command} {show ip bgp @var{X:X::X:X}} {} This command displays BGP routes. When no route is specified it display all of IPv4 BGP routes. @end deffn @example BGP table version is 0, local router ID is 10.1.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 0.0.0.0 0 32768 i Total number of prefixes 1 @end example @node More Show IP BGP, , Show IP BGP, Displaying BGP routes @comment node-name, next, previous, up @subsection More Show IP BGP @deffn {Command} {show ip bgp regexp @var{line}} {} This command display BGP routes using AS path regular expression (@pxref{Display BGP Routes by AS Path}). @end deffn @deffn Command {show ip bgp community @var{community}} {} @deffnx Command {show ip bgp community @var{community} exact-match} {} This command display BGP routes using @var{community} (@pxref{Display BGP Routes by Community}). @end deffn @deffn Command {show ip bgp community-list @var{word}} {} @deffnx Command {show ip bgp community-list @var{word} exact-match} {} This command display BGP routes using community list (@pxref{Display BGP Routes by Community}). @end deffn @deffn {Command} {show ip bgp summary} {} @end deffn @deffn {Command} {show ip bgp neighbor [@var{peer}]} {} @end deffn @deffn {Command} {clear ip bgp @var{peer}} {} Clear peers which have addresses of X.X.X.X @end deffn @deffn {Command} {clear ip bgp @var{peer} soft in} {} Clear peer using soft reconfiguration. @end deffn @deffn {Command} {show debug} {} @end deffn @deffn {Command} {debug event} {} @end deffn @deffn {Command} {debug update} {} @end deffn @deffn {Command} {debug keepalive} {} @end deffn @deffn {Command} {no debug event} {} @end deffn @deffn {Command} {no debug update} {} @end deffn @deffn {Command} {no debug keepalive} {} @end deffn @node Capability Negotiation, Route Reflector, Displaying BGP routes, BGP @comment node-name, next, previous, up @section Capability Negotiation When adding IPv6 routing information exchange feature to BGP. There were some proposals. @acronym{IETF} @acronym{IDR} working group finally take a proposal called Multiprotocol Extension for BGP. The specification is described in RFC2283. The protocol does not define new protocols. It defines new attributes to existing BGP. When it is used exchanging IPv6 routing information it is called BGP-4+. When it is used for exchanging multicast routing information it is called MBGP. @command{bgpd} supports Multiprotocol Extension for BGP. So if remote peer supports the protocol, @command{bgpd} can exchange IPv6 and/or multicast routing information. Traditional BGP does not have the feature to detect remote peer's capability whether it can handle other than IPv4 unicast routes. This is a big problem using Multiprotocol Extension for BGP to operational network. @cite{draft-ietf-idr-bgp4-cap-neg-04.txt} is proposing a feature called Capability Negotiation. @command{bgpd} use this Capability Negotiation to detect remote peer's capabilities. If the peer is only configured as IPv4 unicast neighbor, @command{bgpd} does not send these Capability Negotiation packets. By default, Quagga will bring up peering with minimal common capability for the both sides. For example, local router has unicast and multicast capabilitie and remote router has unicast capability. In this case, the local router will establish the connection with unicast only capability. When there are no common capabilities, Quagga sends Unsupported Capability error and then resets the connection. If you want to completely match capabilities with remote peer. Please use @command{strict-capability-match} command. @deffn {BGP} {neighbor @var{peer} strict-capability-match} {} @deffnx {BGP} {no neighbor @var{peer} strict-capability-match} {} Strictly compares remote capabilities and local capabilities. If capabilities are different, send Unsupported Capability error then reset connection. @end deffn You may want to disable sending Capability Negotiation OPEN message optional parameter to the peer when remote peer does not implement Capability Negotiation. Please use @command{dont-capability-negotiate} command to disable the feature. @deffn {BGP} {neighbor @var{peer} dont-capability-negotiate} {} @deffnx {BGP} {no neighbor @var{peer} dont-capability-negotiate} {} Suppress sending Capability Negotiation as OPEN message optional parameter to the peer. This command only affects the peer is configured other than IPv4 unicast configuration. @end deffn When remote peer does not have capability negotiation feature, remote peer will not send any capabilities at all. In that case, bgp configures the peer with configured capabilities. You may prefer locally configured capabilities more than the negotiated capabilities even though remote peer sends capabilities. If the peer is configured by @command{override-capability}, @command{bgpd} ignores received capabilities then override negotiated capabilities with configured values. @deffn {BGP} {neighbor @var{peer} override-capability} {} @deffnx {BGP} {no neighbor @var{peer} override-capability} {} Override the result of Capability Negotiation with local configuration. Ignore remote peer's capability value. @end deffn @node Route Reflector, Route Server, Capability Negotiation, BGP @comment node-name, next, previous, up @section Route Reflector @deffn {BGP} {bgp cluster-id @var{a.b.c.d}} {} @end deffn @deffn {BGP} {neighbor @var{peer} route-reflector-client} {} @deffnx {BGP} {no neighbor @var{peer} route-reflector-client} {} @end deffn @node Route Server, How to set up a 6-Bone connection, Route Reflector, BGP @comment node-name, next, previous, up @section Route Server At an Internet Exchange point, many ISPs are connected to each other by external BGP peering. Normally these external BGP connection are done by @code{full mesh} method. As with internal BGP full mesh formation, this method has a scaling problem. This scaling problem is well known. Route Server is a method to resolve the problem. Each ISP's BGP router only peers to Route Server. Route Server serves as BGP information exchange to other BGP routers. By applying this method, numbers of BGP connections is reduced from O(n*(n-1)/2) to O(n). Unlike normal BGP router, Route Server must have several routing tables for managing different routing policies for each BGP speaker. We call the routing tables as different @code{view}s. @command{bgpd} can work as normal BGP router or Route Server or both at the same time. @menu * Multiple instance:: * BGP instance and view:: * Routing policy:: * Viewing the view:: @end menu @node Multiple instance, BGP instance and view, Route Server, Route Server @comment node-name, next, previous, up @subsection Multiple instance To enable multiple view function of @code{bgpd}, you must turn on multiple instance feature beforehand. @deffn {Command} {bgp multiple-instance} {} Enable BGP multiple instance feature. After this feature is enabled, you can make multiple BGP instances or multiple BGP views. @end deffn @deffn {Command} {no bgp multiple-instance} {} Disable BGP multiple instance feature. You can not disable this feature when BGP multiple instances or views exist. @end deffn When you want to make configuration more Cisco like one, @deffn {Command} {bgp config-type cisco} {} Cisco compatible BGP configuration output. @end deffn When bgp config-type cisco is specified, ``no synchronization'' is displayed. ``no auto-summary'' is desplayed. ``network'' and ``aggregate-address'' argument is displayed as ``A.B.C.D M.M.M.M'' Quagga: network 10.0.0.0/8 Cisco: network 10.0.0.0 Quagga: aggregate-address 192.168.0.0/24 Cisco: aggregate-address 192.168.0.0 255.255.255.0 Community attribute handling is also different. If there is no configuration is specified community attribute and extended community attribute are sent to neighbor. When user manually disable the feature community attribute is not sent to the neighbor. In case of ``bgp config-type cisco'' is specified, community attribute is not sent to the neighbor by default. To send community attribute user has to specify ``neighbor A.B.C.D send-community'' command. ! router bgp 1 neighbor 10.0.0.1 remote-as 1 no neighbor 10.0.0.1 send-community ! ! router bgp 1 neighbor 10.0.0.1 remote-as 1 neighbor 10.0.0.1 send-community ! @deffn {Command} {bgp config-type zebra} {} Quagga style BGP configuration. This is default. @end deffn @node BGP instance and view, Routing policy, Multiple instance, Route Server @comment node-name, next, previous, up @subsection BGP instance and view BGP instance is a normal BGP process. The result of route selection goes to the kernel routing table. You can setup different AS at the same time when BGP multiple instance feature is enabled. @deffn {Command} {router bgp @var{as-number}} {} Make a new BGP instance. You can use arbitrary word for the @var{name}. @end deffn @example @group bgp multiple-instance ! router bgp 1 neighbor 10.0.0.1 remote-as 2 neighbor 10.0.0.2 remote-as 3 ! router bgp 2 neighbor 10.0.0.3 remote-as 4 neighbor 10.0.0.4 remote-as 5 @end group @end example BGP view is almost same as normal BGP process. The result of route selection does not go to the kernel routing table. BGP view is only for exchanging BGP routing information. @deffn {Command} {router bgp @var{as-number} view @var{name}} {} Make a new BGP view. You can use arbitrary word for the @var{name}. This view's route selection result does not go to the kernel routing table. @end deffn With this command, you can setup Route Server like below. @example @group bgp multiple-instance ! router bgp 1 view 1 neighbor 10.0.0.1 remote-as 2 neighbor 10.0.0.2 remote-as 3 ! router bgp 2 view 2 neighbor 10.0.0.3 remote-as 4 neighbor 10.0.0.4 remote-as 5 @end group @end example @node Routing policy, Viewing the view, BGP instance and view, Route Server @comment node-name, next, previous, up @subsection Routing policy You can set different routing policy for a peer. For example, you can set different filter for a peer. @example @group bgp multiple-instance ! router bgp 1 view 1 neighbor 10.0.0.1 remote-as 2 neighbor 10.0.0.1 distribute-list 1 in ! router bgp 1 view 2 neighbor 10.0.0.1 remote-as 2 neighbor 10.0.0.1 distribute-list 2 in @end group @end example This means BGP update from a peer 10.0.0.1 goes to both BGP view 1 and view 2. When the update is inserted into view 1, distribute-list 1 is applied. On the other hand, when the update is inserted into view 2, distribute-list 2 is applied. @node Viewing the view, , Routing policy, Route Server @comment node-name, next, previous, up @subsection Viewing the view To display routing table of BGP view, you must specify view name. @deffn {Command} {show ip bgp view @var{name}} {} Display routing table of BGP view @var{name}. @end deffn @node How to set up a 6-Bone connection, Dump BGP packets and table, Route Server, BGP @comment node-name, next, previous, up @section How to set up a 6-Bone connection @example @group zebra configuration =================== ! ! Actually there is no need to configure zebra ! bgpd configuration ================== ! ! This means that routes go through zebra and into the kernel. ! router zebra ! ! MP-BGP configuration ! router bgp 7675 bgp router-id 10.0.0.1 neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 remote-as @var{as-number} ! address-family ipv6 network 3ffe:506::/32 neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 activate neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 route-map set-nexthop out neighbor 3ffe:1cfa:0:2:2c0:4fff:fe68:a231 remote-as @var{as-number} neighbor 3ffe:1cfa:0:2:2c0:4fff:fe68:a231 route-map set-nexthop out exit-address-family ! ipv6 access-list all permit any ! ! Set output nexthop address. ! route-map set-nexthop permit 10 match ipv6 address all set ipv6 nexthop global 3ffe:1cfa:0:2:2c0:4fff:fe68:a225 set ipv6 nexthop local fe80::2c0:4fff:fe68:a225 ! ! logfile FILENAME is obsolete. Please use log file FILENAME log file bgpd.log ! @end group @end example @node Dump BGP packets and table, , How to set up a 6-Bone connection, BGP @comment node-name, next, previous, up @section Dump BGP packets and table @deffn Command {dump bgp all @var{path}} {} @deffnx Command {dump bgp all @var{path} @var{interval}} {} Dump all BGP packet and events to @var{path} file. @end deffn @deffn Command {dump bgp updates @var{path}} {} @deffnx Command {dump bgp updates @var{path} @var{interval}} {} Dump BGP updates to @var{path} file. @end deffn @deffn Command {dump bgp routes @var{path}} {} @deffnx Command {dump bgp routes @var{path}} {} Dump whole BGP routing table to @var{path}. This is heavy process. @end deffn