Juniper/Cisco Switch L2 Spanning-tree inter-op (config on Juniper side)

RSTP is standard and supported on every other vendors switch platforms and mostly be the default spanning-tree protocol.

However, Cisco from certain OS version can no longer config RSTP. Instead, its proprietary Rapid PVST became default and no way to go back to RSTP. It shows how evil Cisco is.

Cisco also send VLAN-1 traffic on the trunking (802.1q) interface to be untagged by default even there is no explicit native VLAN id been configured on the interface. It is again another stupid Cisco design.

Following is a configuration sample on Juniper EX switch to make it inter-op with Cisco switch. RSTP on Juniper side and rspid-PVST on Cisco side.

interfaces {
    ge-0/0/15 {
        description "## Cisco-SW g0/23 ##";
        ether-options {
            speed {
                1g;
            }
            802.3ad ae3;
        }
    }
    ge-1/0/15 {
        description "## Cisco-SW g0/24 ##";
        ether-options {
            speed {
                1g;
            }
            802.3ad ae3;
        }
    }
    ae3 {
        aggregated-ether-options {
            no-flow-control;
            minimum-links 1;
            link-speed 1g;
            lacp {
                active;
            }
        }
        unit 0 {
            family ethernet-switching {
                port-mode trunk;
                vlan {
                    members [ VLAN-10 VLAN-20 ];
                }
                native-vlan-id 1;
            }
        }
    }
protocols {
    rstp;
}
vlans {
    VLAN-1 {
        description "## Native VLAN for Spanning-Tree ##";
        vlan-id 1;
    }
    VLAN-10 {
        vlan-id 10;
        l3-interface vlan.10;
    }
    VLAN-20 {
        vlan-id 20;
        l3-interface vlan.20;
    }
}

All I can say is we should dump Cisco and go for other vendors.