Конфигурация маршрутизатора Cisco:

   router bgp 5****
    no synchronization
    bgp log-neighbor-changes
    bgp deterministic-med
    network 9*.*.*.* mask 255.255.255.0
    neighbor 2*.*.*.* remote-as 3216
    neighbor 2*.*.*.* description #sov_PEER-2#
    neighbor 2*.*.*.* version 4
    neighbor 2*.*.*.* send-community
    neighbor 2*.*.*.* soft-reconfiguration inbound
    neighbor 2*.*.*.* route-map map-AS3216-in in
    neighbor 2*.*.*.* route-map map-AS3216-out out
    neighbor 3*.*.*.* remote-as 8615
    neighbor 3*.*.*.* description #cnt_PEER-1#
    neighbor 3*.*.*.* version 4
    neighbor 3*.*.*.* send-community
    neighbor 3*.*.*.* soft-reconfiguration inbound
    neighbor 3*.*.*.* route-map map-AS8615-in in
    neighbor 3*.*.*.* route-map map-AS8615-out out
    distance bgp 180 200 200
    no auto-summary
   !
   ip forward-protocol nd
   !
   ip bgp-community new-format
   ip as-path access-list 1 permit _6451[2-9]_
   ip as-path access-list 1 permit _645[2-9][0-9]_
   ip as-path access-list 1 permit _64[6-9][0-9][0-9]_
   ip as-path access-list 1 permit _65[0-9][0-9][0-9]_
   !         
   ip prefix-list bogons description #bogus nets#
   ip prefix-list bogons seq 15 permit 0.0.0.0/8 le 32
   ip prefix-list bogons seq 20 permit 127.0.0.0/8 le 32
   ip prefix-list bogons seq 25 permit 192.0.2.0/24 le 32
   ip prefix-list bogons seq 30 permit 10.0.0.0/8 le 32
   ip prefix-list bogons seq 35 permit 172.16.0.0/12 le 32
   ip prefix-list bogons seq 40 permit 192.168.0.0/16 le 32
   ip prefix-list bogons seq 45 permit 169.254.0.0/16 le 32
   ip prefix-list bogons seq 50 permit 192.42.172.0/24 le 32
   ip prefix-list bogons seq 55 permit 198.18.0.0/15 le 32
   ip prefix-list bogons seq 60 permit 192.88.99.0/24 le 32
   ip prefix-list bogons seq 65 permit 224.0.0.0/4 le 32
   ip prefix-list bogons seq 70 permit 240.0.0.0/4 le 32
   !
   ip prefix-list def_perfix description #deny def_net#
   ip prefix-list def_perfix seq 15 permit 0.0.0.0/0 le 32
   !
   ip prefix-list our_perfix description #our net#
   ip prefix-list our_perfix seq 15 permit 9*.*.*.0/24 le 32


   route-map map-AS3216-out permit 100
    match ip address prefix-list our_perfix
    set as-path prepend 5**** 5**** 5****
   !
   route-map map-AS3216-out deny 110
    match ip address prefix-list def_perfix
   !
   route-map map-AS8615-out permit 100
    match ip address prefix-list our_perfix
   !
   route-map map-AS8615-out deny 110
    match ip address prefix-list def_perfix
   !
   route-map map-AS8615-in deny 100
    description #filter private ASs#
    match as-path 1
   !
   route-map map-AS8615-in deny 110
    description #filter bogons#
    match ip address prefix-list bogons
   !
   route-map map-AS8615-in permit 200
    set local-preference 200
    set community 5****:8615
   !
   route-map map-AS3216-in deny 100
    description #filter private ASs#
    match as-path 1
   !
   route-map map-AS3216-in deny 110
    description #filter bogons#
    match ip address prefix-list bogons
   !         
   route-map map-AS3216-in permit 200
    set local-preference 100
    set community 5****:3216

1. Договариваемся с провайдерами на анонсирование в вашу AS 0/0

2. Манипулируем количеством повторов своего номера AS в "set as-path prepend
5**** 5**** 5****" для направления входящего трафика.

   route-map map-AS3216-out permit 100
    match ip address prefix-list our_perfix
    set as-path prepend 5**** 5**** 5****

3. Настраиваем маршрут назначения для исходящего трафика через "set
local-preference 100", чем больше цифра, тем больше шанс попасть маршруту в таблицу.

   route-map map-AS3216-in permit 200
    set local-preference 100
    set community 5****:3216

4. В итоге определили направления потоков информации, а точнее присутствие в
таблице 0/0 от другого провайдера.