Category Archives: IPv6

eBGP using IPv6 in Juniper JunOS

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.

eBGP_IPv6

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


		
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VRRPv6 and Tracking in Junos

In this blog, we will look at VRRP (Virtual Redundancy Routing Protocol) and specifically VRRPv6 which as you must have guessed works for IPv6 Protocol.

VRRP is standardized version of redundancy protocol in comparison to Cisco proprietary HSRP both of which provides redundant Default Gateway address for EU clients or devices. The VRRP routers share the IP address corresponding to the default gateway configured on the hosts. At any time, one of the VRRP routers is the master (active) and the others are backups. If the master fails, one of the backup routers becomes the new master router, thus always providing a virtual default router and allowing traffic on the LAN to be routed without relying on a single router.

We will look at 2 scenarios in this blog

1)      VRRPv6 configs and what additional things we need to take care

2)      VRRP Tracking

This can become lengthy blog so please bear with me till the end 🙂

Below topology will be used for these scenarios where we have 2 Juniper EX4550 switches connected to Juniper MX104 CE (Junos 13.3). Even though 2 MX104 CEs are shown we will using 2 Logical systems inside one MX104 to simulate 2 CEs. Clients are connected behind EX4500 (not shown in picture). MX104 is connected in-turn to ISP CEs over eBGP and receiving IPv6 Default route from ISP. Fairly straightforward setup as you can see.

VRRP

Below is the configuration for VRRPv6 on both logical-systems where we are configuring higher VRRP priority for CE1 in order for it to be Master and holds virtual mac-address and router replies with this mac-address when arp (or specifically neighbour solicitation message in case of IPv6) request comes from Client who wants to send packet to Virtual gateway address. Virtual MAC address is always in format 00:00:5e:00:02:XX where XX is Virtual Router-ID or group ID configured under VRRP configuration.

re1.MX104_CE1> show configuration logical-systems LS2-CLMB
 xe-2/0/3 {
 unit 601 {
 vlan-id 601;
 family inet6 {
 address 2001:db9::3/64 {
 vrrp-inet6-group 201 {
 virtual-inet6-address 2001:db9::1;
 virtual-link-local-address fe80:db9::1;
 priority 200;
 accept-data;
 }
 }
 address fe80:db9::3/64;
 }
 }
 }
}
protocols {
 router-advertisement {
 interface xe-2/0/3.601 {
 max-advertisement-interval 4;
 virtual-router-only;
 prefix fc80::/64;
 }
}

re1.MX104_CE2> show configuration logical-systems LS2-Tower
 xe-2/0/1 {
 unit 601 {
 vlan-id 601;
 family inet6 {
 address 2001:db9::2/64 {
 vrrp-inet6-group 201 {
 virtual-inet6-address 2001:db9::1;
 virtual-link-local-address fe80:db9::1;
 priority 100;
 accept-data;
 }
 }
 address fe80:db9::2/64;
 }
 }
 }
}
protocols {
 router-advertisement {
 interface xe-2/0/1.601 {
 max-advertisement-interval 4;
 virtual-router-only;
 prefix fc80::/64;
 }
}

VRRPv6 configuration is very similar to VRRP with some difference related to syntax which is understandable however there are 3 additional commands (highlighted in Red above) we need to know. First of them is virtual-link-local-address which according to Juniper must be explicitly defined in VRRP for IPv6 as this field is used as source IPv6 address when sending packet from this router. 2nd requirement is that link-local address and virtual-link-local-address must share netmask otherwise Junos won’t allow us to commit and this is where I have configured address fe80:db9::2/64.

3rd requirement which is very interesting one is usage of virtual-router-only command under router-advertisements. The master VRRP for an IPv6 router must respond to a router solicitation message with the virtual IP address of the router. However, when the interface statement is included at the [edit protocols router-advertisement] hierarchy level, the backup VRRP for an IPv6 router might send a response before the VRRP master responds, so that the default route of the client is not set to the master VRRP router’s virtual IP address. To avoid this situation, we need to include the virtual-router-only statement at the [edit protocols router-advertisement interface interface-name] hierarchy level. When this statement is included, router advertisements are sent only for VRRP IPv6 groups configured on the interface.

So with these configurations, let’s see how our VRRP is working

re1.MX104_CE1> show vrrp summary logical-system LS2-CLMB
Interface State Group VR state VR Mode Type Address
xe-2/0/3.601 up 201 master Active lcl 2001:db9::3
                                  vip fe80:db9::1
                                  vip 2001:db9::1

re1.MX104_CE2> show vrrp summary logical-system LS2-Tower
Interface State Group VR state VR Mode Type Address
xe-2/0/1.601 up 201 backup Active lcl 2001:db9::2
                                  vip fe80:db9::1
                                  vip 2001:db9::1

So as you can see, VRRP is working fine with CE1 acting as Master and CE2 acting as Backup.

Let’s see extract from extensive version of the command. Main thing to note here is Virtual mac which as I mentioned above is in format 00:00:5e:00:02:XX and XX in our case is c9 which is hex of Group ID 201.

re1.MX104_CE1> show vrrp extensive logical-system LS2-CLMB
.
.
Physical interface: xe-2/0/3, Unit: 601, Vlan-id: 601, Address: 2001:db9::3/64
 Index: 358, SNMP ifIndex: 611, VRRP-Traps: enabled, VRRP-Version: 2
 Interface state: up, Group: 201, State: master, VRRP Mode: Active
 Priority: 200, Advertisement interval: 1, Authentication type: none
 Advertisement threshold: 3, Computed send rate: 0
 Preempt: yes, Accept-data mode: yes, VIP count: 2, VIP: fe80:db9::1, 2001:db9::1
 Advertisement Timer: 0.698s, Master router: fe80:db9::3
 Virtual router uptime: 1d 20:59, Master router uptime: 1d 17:38
 Virtual Mac: 00:00:5e:00:02:c9
 
re1.MX104_CE2> show vrrp extensive logical-system LS2-Tower
.
.
Physical interface: xe-2/0/1, Unit: 601, Vlan-id: 601, Address: 2001:db9::2/64
 Index: 354, SNMP ifIndex: 607, VRRP-Traps: enabled, VRRP-Version: 2
 Interface state: up, Group: 201, State: backup, VRRP Mode: Active
 Priority: 100, Advertisement interval: 1, Authentication type: none
 Advertisement threshold: 3, Computed send rate: 0
 Preempt: yes, Accept-data mode: yes, VIP count: 2, VIP: fe80:db9::1, 2001:db9::1
 Dead timer: 3.002s, Master priority: 200, Master router: fe80:db9::3
 Virtual router uptime: 1d 21:01

Now as VRRP is working, we come to 2nd part of this blog where as per config VRRP will protect us against Default gateway failure on Master Router so that EU clients can always have access to remote Internet destinations. Now till this stage everything is fine however what will happen in case we lose link to ISP CE-1 from Master router?

In case of link failure, VRRP is still active on Master router and EU client are still getting access to default gateway however they are not able to reach the destinations because link to ISP is down. In these situations, VRRP tracking comes to rescue.

MX104 CEs routers are having Ebgp neighorship with ISP CEs and in turn receiving IPv6 default route only to reach all destinations in Internet.

re1.MX104_CE1> show route logical-system LS2-CLMB receive-protocol bgp 2001:db7:0:8:219:e202:5b5c:805d

inet6.0: 17 destinations, 17 routes (17 active, 0 holddown, 0 hidden)
 Prefix Nexthop                        MED Lclpref AS path
* ::/0 2001:db7:0:8:219:e202:5b5c:805d             2856 I

re1.MX104_CE2> show route logical-system LS2-Tower receive-protocol bgp 2001:db7:0:4:219:e202:595c:805d

inet6.0: 13 destinations, 13 routes (13 active, 0 holddown, 0 hidden)
 Prefix Nexthop                        MED Lclpref AS path
* ::/0 2001:db7:0:4:219:e202:595c:805d             2856 I

We will add the following command highlighted in Red on CE1 to track this default route under VRRP so that for any chance if link from Master router to ISP fails, it will drop the VRRP priority by 101 so that ultimately VRRP priority of Master router drops to 99 (200-101) and backup router takes over the role of Master.

family inet6 {
 address 2001:db9::3/64 {
 vrrp-inet6-group 201 {
 virtual-inet6-address 2001:db9::1;
 virtual-link-local-address fe80:db9::1;
 priority 200;
 accept-data;
 track {
 route ::/0 routing-instance default priority-cost 101;
 }
 }
 }
 address fe80:db9::3/64;
 }

Lets see this in action.

To simulate the failure, we will disable the CE1 outgoing interface towards ISP

[edit]
re1.MX104_CE1# set logical-systems LS2-CLMB interfaces ge-0/0/6.601 disable

[edit]
re1.MX104_CE1# commit
re1:
configuration check succeeds
re0:
commit complete
re1:
commit complete

Now you can see no default-route is being learned from the ebgp neighbour.

re1.MX104_CE1> show route logical-system LS2-CLMB receive-protocol bgp 2001:db7:0:8:219:e202:5b5c:805d

inet6.0: 10 destinations, 10 routes (10 active, 0 holddown, 0 hidden)

However default route is still available from other ebgp neighbour and it is good if Master ship is switched over!!!

re1.MX104_CE2> show route logical-system LS2-Tower receive-protocol bgp 2001:db7:0:4:219:e202:595c:805d

inet6.0: 17 destinations, 17 routes (17 active, 0 holddown, 0 hidden)
 Prefix Nexthop                          MED Lclpref AS path
* ::/0 2001:db7:0:4:219:e202:595c:805d              2856 I

And as we expected, you can see VRRP state has gone into Backup state on CE1 and Master on CE2.

re1.MX104_CE1> show vrrp summary logical-system LS2-CLMB
Interface State Group VR state VR Mode Type Address
xe-2/0/3.601 up 201 backup Active lcl 2001:db9::3
                                  vip fe80:db9::1
                                  vip 2001:db9::1

re1.MX104_CE2> show vrrp summary logical-system LS2-Tower
Interface State Group VR state VR Mode Type Address
xe-2/0/1.601 up 201 master Active lcl 2001:db9::2
                                  vip fe80:db9::1
                                  vip 2001:db9::1

re1.MX104_CE1> show vrrp track logical-system LS2-CLMB
Track route State Cost Interface    Group Cfg Run VR State
::/0        down  101  xe-2/0/3.601 201 200 99 backup

Lets see extensive command output as well:

re1.MX104_CE1> show vrrp extensive logical-system LS2-CLMB
.
.
Physical interface: xe-2/0/3, Unit: 601, Vlan-id: 601, Address: 2001:db9::3/64
 Index: 358, SNMP ifIndex: 611, VRRP-Traps: enabled, VRRP-Version: 2
 Interface state: up, Group: 201, State: backup, VRRP Mode: Active
 Priority: 99, Advertisement interval: 1, Authentication type: none
 Advertisement threshold: 3, Computed send rate: 0
 Preempt: yes, Accept-data mode: yes, VIP count: 2, VIP: fe80:db9::1, 2001:db9::1
 Dead timer: 2.907s, Master priority: 100, Master router: fe80:db9::2
 Virtual router uptime: 2d 03:45
 Tracking: enabled
 Current priority: 99, Configured priority: 200
 Priority hold time: disabled
 Interface tracking: disabled
 Route tracking: enabled, Route count: 1
 Route VRF name Route state Priority cost
 ::/0 default down 101
 
re1.MX104_CE2> show vrrp extensive logical-system LS2-Tower
.
.
Physical interface: xe-2/0/1, Unit: 601, Vlan-id: 601, Address: 2001:db9::2/64
 Index: 354, SNMP ifIndex: 607, VRRP-Traps: enabled, VRRP-Version: 2
 Interface state: up, Group: 201, State: master, VRRP Mode: Active
 Priority: 100, Advertisement interval: 1, Authentication type: none
 Advertisement threshold: 3, Computed send rate: 0
 Preempt: yes, Accept-data mode: yes, VIP count: 2, VIP: fe80:db9::1, 2001:db9::1
 Advertisement Timer: 0.931s, Master router: fe80:db9::2
 Virtual router uptime: 2d 03:45, Master router uptime: 00:01:19
 Virtual Mac: 00:00:5e:00:02:c9

So that’s all in this blog. I hope I was able to clearly define the problem and solution. If you have any comments/feedback on this or any of my previous blogs, do let me know.

Regards

Mohit

OSPFv3 for IPv6 alone or IPv4 as well?

We know that OSPFv2 is Link state routing protocol developed by IETF as a robust IP routing protocol suitable for large networks and to carry Ipv4 addresses. OSPF was first documented as a standard by John Moy in RFC 1131 and further Improvements were made in OSPF version 2. OSPF was then extensively modified by IETF to support IPv6 and called OSPFv3. But do you know OSPFv3 can be used to carry IPv4 addresses as well?

Before going into it, let’s review some differences between OSPFv2 and OSPFv3

  • OSPFv3 introduces new LSA types
  • OSPFv3 has different packet format
  • OSPFv3 adjacencies are formed over link-local IPv6 communications
  • OSPFv3 runs per-link rather than per-subnet
  • OSPFv3 supports multiple instances on a single link, Interfaces can have multiple IPv6 addresses
  • OSPFv3 uses multicast addresses FF02::5 (all OSPF routers), FF02::6 (all OSPF DRs)
  • OSPFv3 Neighbor Authentication done with IPsec (AH)
  • OSPFv2 Router ID (RID) must be manually configured, still a 32-bit number

Ok, now coming back to original question. If an organization wanted to use OSPF for both their IPv4 and IPv6 routing protocol, then they would likely use OSPFv2 for their IPv4 routing and OSPFv3 for their IPv6 routing. This would give the organization dual control planes for dual forwarding protocols. In this configuration, if there was a problem with either routing domain then it would not affect the other IP version. The same separation could also be achieved by running two completely different routing protocols. For instance, an organization could use OSPFv2 for IPv4 and IS-IS in single-protocol single-topology mode for IPv6. The IETF has continued to develop OSPFv3 so that it is now capable of working with multiple address families. In much the same way as Multi Protocol Border Gateway Protocol (MP-BGP) can function as an IPv4 and IPv6 routing protocol.

Once again, Cisco changed the IOS configuration commands required for OSPFv3 configuration. The new OSPFv3 configuration uses the “ospfv3” keyword instead of the earlier “ipv6 router ospf” routing process command and “ipv6 ospf” interface commands. OSPFv3 is still configured on the interfaces similarly to how the previous OSPFv3 commands were used. However, the biggest change is in the configuration of the routing process. This new syntax is more like multi-Address Family configuration of BGP and you have both an IPv4 and an IPv6 address family configuration section under “router ospfv3 “. New OSPFv3 syntax is used to configure a dual-protocol interface and for multi-address-family configuration under the OSPFv3 routing process is:

ipv6 unicast-routing
ipv6 cef
!
router ospfv3 <process-id>
router-id <router-id>
auto-cost reference-bandwidth 1000
address-family ipv6 unicast
area 0 range <range>
area 1 range <range>
address-family ipv4 unicast
area 0 range <Ipv4 range>
area 1 range <Ipv4 range>

So, OSPF is now evolved into a fully dual-protocol multi-AF routing protocol. Organizations now have multiple options for deploying OSPF. Organizations can stick with OSPFv2 for IPv4, and then use OSPFv3 for IPv6-only for a configuration that separates the control planes and the forwarding planes. Organizations can now combine the configuration of IPv4 and IPv6 into a single OSPFv3 process that can work equally well for both IP protocols.

 

Regards

Mohit Mittal