maybe someone will find this one handy. it’s description + config file for bgp setup i’ve recently put on production using debian lenny + quagga.
\n
\nscenario:
\n two service providers – GTS\/AS8246 and CDP\/AS12968 providing full feed of internet routes.
\n i have interconnecting networks with both, my ip is 217.2.1.2\/30 and 85.128.0.2\/30 respectivly, isp’s routers have: 85.128.0.1 and 217.1.1.1.<\/p>\n
own AS number AS44444, own PI address range 91.0.0.0\/23 [ to protect innocent changed from original ]
\n slightly unequal link speed to both ISPs – with proportions 2:1 with GTS having bigger pipe.<\/p>\n
GTS’s BGP speaker 217.1.1.1 – is not directly reachable – it’s couple of hops away so i need static routing to it. i configure that in zebra.conf:<\/p>\n
\r\nhostname bulba\r\npassword bromba\r\nenable password bromba\r\nlog file \/var\/log\/quagga\/zebra.log\r\nlog syslog informational\r\n! eth0.3 goes to gts\r\ninterface eth0.3\r\n! eth0.4 goes to cdp\r\ninterface eth0.4\r\n! eth1 goes to end-users\r\ninterface eth1\r\ninterface lo\r\n! static route to gts BGP speaker. to protect innocent addres was slightly altered\r\nip route 217.1.1.0\/24 217.2.1.1\r\n<\/code>\r\n\r\nin bgpd.conf all the magic is happening:\r\n<code>\r\nhostname bulba\r\npassword bromba\r\nlog file \/var\/log\/quagga\/bgpd.log\r\nlog syslog warnings\r\n!\r\n! definition of my peers\r\nrouter bgp 44444\r\n bgp router-id 91.0.0.1\r\n network 91.0.0.0\/23\r\n ! configuration of neighbour CDP router - reachable directly on eth0.4\r\n ! 85.128.0.1 is address of CDP bgp speaker\r\n neighbor 85.128.0.1 remote-as 12968\r\n ! 85.128.0.2 is addres used by me on subnet where i have connection with CDP\r\n neighbor 85.128.0.1 update-source 85.128.0.2\r\n neighbor 85.128.0.1 soft-reconfiguration inbound\r\n neighbor 85.128.0.1 prefix-list my_announced out\r\n neighbor 85.128.0.1 route-map cdp_localpref in\r\n neighbor 85.128.0.1 route-map setcommunityCDP out\r\n !\r\n ! configuration of GTS neighbour. BGP speaker is at 217.1.1.1 but i cannot reach it directly - hence static routing in zebra.conf\r\n neighbor 217.1.1.1 remote-as 8246\r\n neighbor 217.1.1.1 ebgp-multihop 10\r\n ! 217.2.1.2 is my address on small interconnecting network with GTS router \r\n neighbor 217.1.1.1 update-source 217.2.1.2\r\n neighbor 217.1.1.1 soft-reconfiguration inbound\r\n neighbor 217.1.1.1 prefix-list my_announced out\r\n neighbor 217.1.1.1 route-map gts_localpref in\r\n neighbor 217.1.1.1 route-map setcommunityGTS out\r\n !\r\n ! some as-paths used to manipulate outgoing traffic\r\n ! matches anything that goes over cogent's network. we'll use it to make sure upload to cogent-connected hosts goes via GTS\r\n ip as-path access-list as_path_to_go_via_gts permit ^.*174.*$\r\n ! similarly but for TELIA-Sonera and all connected via it\r\n ip as-path access-list as_path_to_go_via_gts permit ^.*1299.*$\r\n ! all end-users of upc\/chello\r\n ip as-path access-list as_path_to_go_via_gts permit ^.*9141$\r\n !\r\n ! mci \/ verizone\r\n ip as-path access-list as_path_to_go_via_cdp permit ^.*701.*$\r\n ! qwest\r\n ip as-path access-list as_path_to_go_via_cdp permit ^.*209.*$\r\n ! all end-users of netia\r\n ip as-path access-list as_path_to_go_via_cdp permit ^.*12741$\r\n !\r\n ! in fact i have much more of those...\r\n !\r\n !\r\n ! and just for fun access lists for manipulating local prefs on subnet level\r\n ip prefix-list cdp_localpref seq 5 permit 193.110.228.0\/24\r\n !\r\n ip prefix-list gts_localpref seq 9 permit 89.64.0.0\/13\r\n !\r\n ip prefix-list any seq 5 permit any\r\n !\r\n ip prefix-list my_announced seq 1 permit 91.0.0.0\/23 \r\n !\r\n !\r\n ! apply higher local pref for selected routes \/ matching as-paths\r\n route-map cdp_localpref permit 10\r\n match ip address prefix-list cdp_localpref\r\n set local-preference 120\r\n route-map cdp_localpref permit 20\r\n match as-path as_path_to_go_via_cdp\r\n set local-preference 140\r\n !\r\n ! default - 100 - localpref for anythign else\r\n route-map cdp_localpref permit 100\r\n match ip address prefix-list any\r\n set local-preference 100\r\n !\r\n ! do the same for GTS\r\n route-map gts_localpref permit 10\r\n match ip address prefix-list gts_localpref\r\n set local-preference 120\r\n route-map gts_localpref permit 20\r\n match as-path as_path_to_go_via_gts\r\n set local-preference 130\r\n route-map gts_localpref permit 100\r\n match ip address prefix-list any\r\n set local-preference 100\r\n !\r\n !\r\n ! add communities to advertised routes - used to somehow control incomming traffic\r\n route-map setcommunityGTS permit 10\r\n match ip address prefix-list my_announced\r\n !\r\n route-map setcommunityGTS permit 20\r\n match ip address any\r\n !\r\n ! main objective - to shift some incoming traffic away from CDP to GTS. so - prepending + community from CDP that does even more prepending.\r\n route-map setcommunityCDP permit 10\r\n match ip address 2\r\n set as-path prepend 47884\r\n set community 12968:1011\r\n !\r\n route-map setcommunityCDP permit 20\r\n match ip address 2\r\n<\/pre>\nlist of GTS communities can be found in whois from their AS8246<\/a>.<\/p>\n