# Практика

Поскольку мы имеем широковещательную L2 сеть на туннельных интерфейсах, указываем явно тип сети Broadcast на туннельных интерфейсах на всех узлах:

```
ip ospf network broadcast
```

Кроме того в такой сети должен выбираться DR. Логично, чтобы им стал хаб. Всем Spoke-маршрутизаторам запрещаем участие в выборах DR:

```
ip ospf priority 0
```

Ну и, естественно, определяем анонсируемые сети.

```
router ospf 1
network 172.16.0.0 0.0.255.255 area 0
```

Сети анонсируются:

> msk-arbat-gw1#sh ip route\
> \
> Gateway of last resort is 198.51.100.1 to network 0.0.0.0\
> \
> 172.16.0.0/16 is variably subnetted, 7 subnets, 3 masks\
> C 172.16.2.128/30 is directly connected, FastEthernet0/1.8\
> C 172.16.255.1/32 is directly connected, Loopback0\
> C 172.16.254.0/24 is directly connected, Tunnel0\
> C 172.16.2.32/30 is directly connected, FastEthernet0/1.7\
> C 172.16.2.16/30 is directly connected, FastEthernet0/1.5\
> C 172.16.2.0/30 is directly connected, FastEthernet0/1.4\
> O 172.16.255.128/32 \[110/11112] via 172.16.254.2, 00:05:14, Tunnel0\
> 198.51.100.0/28 is subnetted, 1 subnets\
> C 198.51.100.0 is directly connected, FastEthernet0/1.6\
> S\* 0.0.0.0/0 \[1/0] via 198.51.100.1

Пинг проходит

> msk-arbat-gw1#ping 172.16.255.128\
> \
> Type escape sequence to abort.\
> Sending 5, 100-byte ICMP Echos to 172.16.255.128, timeout is 2 seconds:\
> !!!\
> Success rate is 100 percent (5/5), round-trip min/avg/max = 60/70/80 ms

Вот так выглядят пакеты, передающиеся через сеть Интернет:

![](http://img-fotki.yandex.ru/get/4126/83739833.23/0_abbfe_750be85d_XXXL.jpg)\
\&#xNAN;*\* Дамп с nsk-obsea-gw1 fa0/0*

Проверяем, как у нас проходит пинг от одного филиала до другого:

> nsk-obsea-gw1#ping 172.16.255.132\
> \
> Type escape sequence to abort.\
> Sending 5, 100-byte ICMP Echos to 172.16.255.132, timeout is 2 seconds:\
> !!!\
> Success rate is 100 percent (5/5), round-trip min/avg/max = 132/231/492 ms\
> \
> nsk-obsea-gw1#traceroute 172.16.255.132\
> \
> Type escape sequence to abort.\
> Tracing the route to 172.16.255.132\
> \
> 1 172.16.254.3 240 msec \* 172 msec\
> \
> nsk-obsea-gw1#sh ip nhrp br\
> Target Via NBMA Mode Intfc Claimed\
> 172.16.254.1/32 172.16.254.1 198.51.100.2 static Tu0 < >\
> 172.16.254.3/32 172.16.254.3 198.51.102.2 dynamic Tu0 < >

Как видите пакеты не заходят на хаб, а идут напрямую сразу на маршрутизатор другого филиала через Интернет. Но действительность несколько сложнее.


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