Hi All

In my earlier post on VRRP https://networkzblogger.com/2017/04/15/vrrpv6-and-tracking-in-junos/ we looked at VRRPv6 and how VRRP tracking is working on receiving the Ipv6 default route. As that blog was mainly focusing on VRRP, so didn’t explained anything on Ebgp relationship over Ipv6 and IPV6 default route however in this post I will be mainly focusing on it.

Let’s start.

We will be using same Model as we used in earlier post, but in condensed form. Rather than looking at redundant configs, we will concentrate on one EBGP between 2 neighbors.

Below mentioned topology will be used where MX104 CE is connected to Juniper CE-1 ISP and we will have EBGP over IPV6 running between them and MX104 CE in turn receiving Ipv6 default route from ISP.

Lets look at Interface configs first on both sides.

MX104_CE> show configuration logical-systems LS1-Tower
interfaces {
    ge-0/0/4 {
        unit 600 {
            description "Connected to ISP-CE-1_ge-0/2/0.600";
            vlan-id 600;
            family inet6 {
                address 2a00:2380:3013:1000:0:0:0:3/127;
            }
        }
    }

ISP_CE-1> show configuration interfaces ge-0/2/0
description "Connected to MX104 CE_ge-0/0/4 ";
vlan-tagging;
mtu 1600;
hold-time up 0 down 1000;
link-mode full-duplex;
unit 600 {
    vlan-id 600;
    family inet6 {
        address 2a00:2380:3013:1000:0:0:0:2/127;
    }
}

Fairly straightforward configuration where we used statically configured IPV6 addresses. We could have also used 128-bit IPv6 addresses or we can use link local addresses but only requirement is that with link-local addressing we need to use statement “local-interface”. You can also use eui-64 address where we just need to know the /64 subnet and router auto calculates the ipv6 addresses by concatenating the subnet address with 48 bit mac-address and 16 bit 0xFFFE

Once this is done, let’s see the Ebgp config.

MX104_CE > show configuration logical-systems LS1-Tower protocols bgp group btnet6
type external;
authentication-algorithm md5;
authentication-key-chain IPv6-key-chain;
export [ Main_Subnets_IPV6 Backup_Subnets_IPV6 ];
local-as 65004;
neighbor 2a00:2380:3013:1000:0:0:0:2 {
    peer-as 2856;
}

ISP_CE-1> show configuration routing-instances Internet-600 protocols bgp group btnet6
type external;
authentication-algorithm md5;
authentication-key-chain IPv6-key-chain;
local-as 2856;
neighbor 2a00:2380:3013:1000:0:0:0:3 {
       peer-as 65004;
}

Again a straightforward configuration on the same lines as Ipv4 where we defined separate group btnet6 for IPV6 config and added the neighbor command with corresponding peer autonomous system.

Now let’s see the bgp status

MX104_CE > show bgp summary logical-system LS1-Tower
Groups: 2 Peers: 2 Down peers: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0
                       1          1          0          0          0          0
inet6.0
                       0          0          0          0          0          0
Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
2a00:2380:3013:1000::2  2856          3                      4       0       1           3 Establ
  inet6.0: 0/0/0/0

BGP is up on MX104 CE however it is not receiving anything so let’s advertise IPV6 default route from ISP CE.

We need to manually add the static route under routing-options with discard or reject option (one will send ICMP unreachable and other will silently reject). You can notice the difference from IPV4 static route where there was no need to define the rib.

ISP_CE-1> show configuration routing-instances Internet-600
instance-type vrf;
interface fe-0/1/2.0;
interface ge-0/2/0.600;
interface ge-0/2/0.602;
route-distinguisher 2856:1;
vrf-target target:2856:1;
routing-options {
    rib Internet-600.inet6.0 {
        static {
            route ::/0 discard;
        }
    }
}

Once this is done, configure this under policy-statement and reference that policy as export under neighbor statement.

ISP_CE-1> show configuration policy-options policy-statement default-export-ipv6
from {
    route-filter ::/0 exact;
}
then accept;

ISP_CE-1> show configuration routing-instances Internet-600 protocols bgp group btnet6
type external;
authentication-algorithm md5;
authentication-key-chain IGUK-IPv6-key-chain;
local-as 2856;
neighbor 2a00:2380:3013:1000:0:0:0:3 {
    export default-export-ipv6;
    peer-as 65004;
}

Now let’s check the default route on MX104:

Ok we see some activity now.

MX104_CE> show bgp summary logical-system LS1-Tower
Groups: 2 Peers: 2 Down peers: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0
                       1          1          0          0          0          0
inet6.0
                       1          1          0          0          0          0
Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
2a00:2380:3013:1000::2   2856                 7                       8       0       2             2:03              Establ
  inet6.0: 1/1/1/0

MX104_CE> show route logical-system LS1-Tower receive-protocol bgp 2a00:2380:3013:1000::2 extensive
inet6.0: 17 destinations, 17 routes (17 active, 0 holddown, 0 hidden)
* ::/0 (1 entry, 1 announced)
     Accepted
     Nexthop: 2a00:2380:3013:1000::2
     AS path: 2856 I

So we have this default route under MX104 and we used this to under VRRP tracking to track outgoing interface towards ISP.

So that’s all for this blog. If you have any queries, please let me know.

Regards

Mohit