Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[MX] Aliasing label "0" will be seen in Active-Active setup

0

0

Article ID: KB34973 KB Last Updated: 09 Jan 2020Version: 1.0
Summary:

This article describes a scenario where aliasing label value of 0 can be seen.

Solution:

In an EVPN multi-homing setup, configuring same RD (Route-Distinguisher) on the remote PE's can lead to '0' being installed as Aliasing label in the remote PE. This is an invalid configuration.  Distinct RD value must be configured on the multi-homing PE's.  This could lead to traffic being sent using MAC label instead of Aliasing label, which can lead to packet drop on the remote PE as it is expecting the traffic to being sent with Aliasing label.

Below is a sample EVPN setup with PE2 and PE3 in active-active multi-homing setup. PE1 is single homed. If the same RD value is misconfigured on both PE2 and PE3, it can lead to programming a aliasing label of '0' on PE1.

           +----------+                               +------------+
          |          |                               |            |
          |          |                               |   PE2      +--------+
          |          +-------------------------------+            |
          |          |                               |            |
          |          |                               +------|------+
          |  PE1     |
+---------+          |
          |          |
          |          |                               +-------------+
          |          |                               |             |
          |          |                               |    PE3      +--------+
          |          +-------------------------------+             |
          |          |                               |             |
          |          |                               +-------------+
          +----------+

Sample config and output:

PE2         
routing-instances {
     EVPN {
         instance-type virtual-switch;
         inactive: interface ge-5/0/0.0;
         interface ge-5/0/1.0;
         interface ge-5/1/9.0;
         route-distinguisher 1:2;
         vrf-target target:1:2;
         protocols {
             evpn {                  
                 traceoptions {
                     file EVPN.log size 10m;
                     flag all;
                 }
                 extended-vlan-list 1;
             }
         }
         bridge-domains {
             BD-1 {
                 domain-type bridge;
                 vlan-id 1;
                 routing-interface irb.0;
             }
             BD-2 {
                 domain-type bridge;
                 vlan-id 2;
             }
         }
     }
}
 
PE3
 
routing-instances {
    EVPN {
        instance-type evpn;
        vlan-id 1;
        inactive: interface ge-5/1/0.0;
        interface ge-5/1/1.0;
        interface ge-5/1/9.0;
        routing-interface irb.0;
        route-distinguisher 1:2;
        vrf-target target:1:2;
        protocols {
            evpn {
                traceoptions {
                    file evpn.log size 10m;
                    flag all;
                }
            }
        }
    }
    VRF {
        instance-type vrf;
        interface irb.0;
        route-distinguisher 1:5;
        vrf-target target:1:2;
    }
}
 
 
 
user@PE1> show evpn instance extensive
Instance: EVPN
  Route Distinguisher: 1:2
  VLAN ID: 1
  Per-instance MAC route label: 299776
  Per-instance multicast route label: 299792
  MAC database status                Local  Remote
    Total MAC addresses:                 0 4294967295
    Default gateway MAC addresses:       1       3
  Number of local interfaces: 2 (1 up)
    Interface name  ESI                            Mode             Status
    ge-5/1/1.0      01:02:03:04:05:06:07:08:09:00  all-active       Up   
    ge-5/1/9.0      00:00:00:00:00:00:00:00:00:00  single-homed     Down 
  Number of IRB interfaces: 1 (1 up)
    Interface name  Status  L3 context
    irb.0           Up      VRF                             
  Number of neighbors: 2
    10.255.32.32
      Received routes
        MAC address advertisement:              1
        MAC+IP address advertisement:           1
       Inclusive multicast:                    1
        Ethernet auto-discovery:                1
    10.255.32.59
      Received routes
        MAC address advertisement:              1
        MAC+IP address advertisement:           1
        Inclusive multicast:                    1
        Ethernet auto-discovery:                0
  Number of ethernet segments: 1
    ESI: 01:02:03:04:05:06:07:08:09:00
      Local interface: ge-5/1/1.0, Status: Up/Forwarding
      Number of remote PEs connected: 1
        Remote PE        MAC label  Aliasing label  Mode  <<< THIS IS WRONG
        10.255.32.32     0          0               all-active  
      Designated forwarder: 10.255.32.38
      Backup forwarder: 10.255.32.32
      Advertised MAC label: 299840
      Advertised aliasing label: 299840
      Advertised split horizon label: 299856
 
Instance: __default_evpn__
  Route Distinguisher: 10.255.32.38:0
  VLAN ID: 0
  Per-instance MAC route label: 299808
  Per-instance multicast route label: 299824
  MAC database status                Local  Remote
    Total MAC addresses:                 0       0
    Default gateway MAC addresses:       0       0
  Number of local interfaces: 0 (0 up)
  Number of IRB interfaces: 0 (0 up)
  Number of neighbors: 1
    10.255.32.32
      Received routes
        Ethernet auto-discovery:                0
        Ethernet Segment:                       1
  Number of ethernet segments: 0
Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search