[MX] Ethertype implementation on MX Series devices

The Ethertype implementation on a Juniper MX Series device is used to determine the type of data or protocol being transmitted in an Ethernet frame. The Ethertype field in the frame header is used to indicate the protocol layer following the Ethernet header. Ethertype deployment on MX Series devices is used to support multiple protocols including IPv4, IPv6, VLAN tagging, MPLS and others. Deploying Ethertype on MX Series devices is an important feature for classifying and forwarding network traffic.

Describe

This article explains Ethertype implementation on Juniper MX Series routers.

Solutions

Juniper MX Series routers are capable of supporting different Ethertypes on one interface. Input packets are evaluated for Ethertype in the Ethernet header and should be configured in the system edit interfaces as follows:

lab# show interfaces ge-3/0/0

stacked-vlan-tagging;
gigether-options {
             ethernet-switch-profile {
                      tag-protocol-id [ 0x8a88 0x8100 ];
              }

}
unit 0 {
          vlan-tags outer 0x88a8.100 inner 0x8100.200;
          family inet {
                 address 10.1.1.1/24;
          }

}

However, if the main interface is configured to allow a specific TPID (tag protocol ID), even if that TPID is not allowed in the sub-unit, traffic will still pass through.

For example, see the following scenarios:

In MX, both TPID [0x8a88 and 0x8100] are allowed in the physical interface. In the logical interface vlan-tags 0x8a88.5 as outer and 0x8a88.100 as inner have been specified. In the Packet Generator, the vlan-tag is set to 0x8100.5 for outer and 0x8100.100 for inner. The stream has been processed.

In MX, both TPID [0x8a88 and 0x8100] are allowed in the physical interface. In the logical interface vlan-tags 0x8100.5 as outer and 0x8100.100 as inner have been specified. In the Packet Generator, the vlan-tag is set to 0x8a88.5 for outer and 0x8a88.100 for inner. The stream has been processed.

In MX, only TPID [0x8a88] is allowed in the physical interface. In the logical interface, specified vlan-tags 0x8a88.5 as outer and 0x8a88.100 as inner. In the Packet Generator, the vlan-tag is set to 0x8100.5 for outer and 0x8100.100 for inner. The traffic was not processed because the packet’s TPID was not specified in the physical interface.

Source: Juniper