Static Routes

Ze supports static routes with ECMP, weighted load balancing, BFD-tracked failover, blackhole, and reject. Routes are programmed directly to the kernel via netlink (or VPP when available). Routes are grouped under named tables for policy-based routing support.

Configuration

All routes live under a named table. Use default for the main routing table:

static {
    table default {
        route 0.0.0.0/0 {
            next { hop 10.0.0.1 { } }
        }
    }
}

Named routing tables

Define named tables via the routing-table config block, then reference them in static:

routing-table {
    table lns {
        id 100
    }
}

static {
    table lns {
        route 0.0.0.0/0 {
            next { interface tun100 { } }
        }
    }
}

The same prefix can appear in different tables independently. Routes in non-default tables are not redistributed into BGP.

Reserved table IDs (0, 253-255) are rejected.

Interface-only next-hops

For point-to-point links (PPPoE, GRE tunnels) where the next-hop is the interface itself:

static {
    table default {
        route 0.0.0.0/0 {
            next { interface pppoe0 { } }
        }
    }
}

Interface-only next-hops do not support BFD profiles (BFD requires a peer address). Weight is supported for ECMP:

static {
    table default {
        route 0.0.0.0/0 {
            next {
                interface pppoe0 { weight 3; }
                interface pppoe1 { weight 1; }
            }
        }
    }
}

Mixed ECMP

Gateway and interface-only next-hops can coexist in the same route:

static {
    table default {
        route 0.0.0.0/0 {
            next {
                hop 10.0.0.1 { weight 3; }
                interface pppoe0 { weight 1; }
            }
        }
    }
}

Multiple next-hops (ECMP)

All next-hops are installed simultaneously as a multipath route:

static {
    table default {
        route 10.0.0.0/8 {
            next {
                hop 192.168.1.1 { }
                hop 192.168.1.2 { }
                hop 192.168.1.3 { }
            }
        }
    }
}

Weighted ECMP

The weight field controls traffic distribution. Higher weight means more traffic. Default is 1 (equal distribution).

static {
    table default {
        route 0.0.0.0/0 {
            next {
                hop 10.0.0.1 {
                    weight 3
                }
                hop 10.0.0.2 {
                    weight 1
                }
            }
        }
    }
}

This sends 75% of traffic via 10.0.0.1 and 25% via 10.0.0.2.

BFD failover

Reference a BFD profile on each next-hop. When the BFD session goes down, that next-hop is removed from the ECMP group and the route is reprogrammed with the remaining active next-hops. When the session recovers, the next-hop is re-added.

bfd {
    profile wan-fast {
        detect-multiplier 3
        desired-min-tx-us 100000
        required-min-rx-us 100000
    }
}

static {
    table default {
        route 0.0.0.0/0 {
            next {
                hop 10.0.0.1 {
                    weight 3
                    bfd-profile wan-fast
                }
                hop 10.0.0.2 {
                    weight 1
                    bfd-profile wan-fast
                }
            }
        }
    }
}

If all BFD-tracked next-hops go down, the route is withdrawn entirely.

Blackhole and reject

Blackhole silently discards matching packets. Reject discards and sends an ICMP unreachable reply.

static {
    table default {
        route 192.0.2.0/24 {
            blackhole { }
        }
        route 198.51.100.0/24 {
            reject { }
        }
    }
}

IPv6

IPv6 routes work the same way. For link-local next-hops, specify the outgoing interface:

static {
    table default {
        route 2001:db8::/32 {
            next { hop 2001:db8::1 { } }
        }
        route 2001:db8:1::/48 {
            next {
                hop fe80::1 {
                    interface eth0
                }
            }
        }
    }
}

Route attributes

static {
    table default {
        route 172.16.0.0/12 {
            description "internal networks"
            metric 100
            tag 42
            next { hop 10.0.0.1 { } }
        }
    }
}

• description: operator note (not programmed to kernel)
• metric: kernel route priority (lower is preferred)
• tag: opaque value for route policy matching in redistribute

CLI

ze> show static

Shows all configured static routes with their prefixes, next-hops, weights, and BFD status in JSON format.

Route programming

Static routes are programmed with RTPROT_ZE (protocol 251), a Ze-specific identifier distinct from the FIB kernel plugin (protocol 250). On config reload, the plugin computes the diff between old and new routes and applies only the changes.

Kernel ECMP uses RTA_MULTIPATH with per-next-hop weight mapped from the weight field (kernel weight = weight - 1).

Redistribute

Static routes register as protocol "static" in the redistribute framework. BGP redistribute can import static routes:

redistribute {
    destination bgp {
        import static
    }
}