====== JUNOS routing-instances ======
其概念有一點點類似大型 Router 的 logical-routers，不過 routing-instances 沒有像 logical-routers 可以切割的那麼完整，應付小型的分割其實是足夠的。

===== instance-type =====
  - forwarding
    * Forwarding instance
  - l2vpn
    * Layer 2 VPN routing instance 
  - mpls-internet-multicast
    * Internet Multicast over MPLS routing instance
  - no-forwarding
    * Nonforwarding instance
  - virtual-router
    * Virtual routing instance
  - vrf
    * Virtual routing forwarding instance

===== virtual-router =====
以下是將二個 vlan interface 獨立成一個 virtual-router instance，並為其建立自己的 routing table.
<code java>
interfaces {
    vlan {
        unit 3001 {
            family inet {
                address 10.1.1.2/24;
            }
            family inet6 {
                address 2001:288:1009:ffa1::2/64;
            }
        }
        unit 4001 {
            family inet {
                address 10.2.1.1/24;
            }
            family inet6 {
                address 2001:288:1009:ffb1::1/64;
            }
        }
    }
}
routing-instances {
    v3001_vr {
        instance-type virtual-router;
        interface vlan.3001;
        interface vlan.4001;
        routing-options {
            rib v3001_vr.inet6.0 { // 特別注意這邊 rib 的名稱，請一定要跟 routing-instances 的名稱相符！！
                static {
                    route 0::0/0 next-hop 2001:b030:2308:ffb1::2;
                    route 2001:b030:2308:38::/64 next-hop 2001:b030:2308:ffa1::1;
                }
            }
            static {
                route 0.0.0.0/0 next-hop 10.2.1.254;
                route 10.38.0.0/16 next-hop 10.1.1.1;
            }
        }
    }
}
</code>

===== forwarding =====
可用來處理類似 Policy Based Route，在 JUNOS 是使用 Firewall 這個 function 來處理判斷的條件，然後再由 routing-instances 中的 forwarding 來進行轉送動作。相關的設定範例請見[[juniper:junos:routing-policy|Routing Policy(AKA.Policy Based Route)]]