How L2Pt Works; L2Pt Basics On Ex Series Switches - Juniper JUNOS OS 10.3 - SOFTWARE Manual

Complete Software Guide for Junos

How L2PT Works

L2PT Basics on EX Series Switches

Related
Documentation
1300
®
OS for EX Series Ethernet Switches, Release 10.3
NOTE: CDP and VTP cannot be configured on EX Series switches. L2PT does,
however, tunnel CDP and VTP PDUs.
L2PT works by encapsulating Layer 2 PDUs, tunneling them across a service provider
network, and decapsulating them for delivery to their destination switches. L2PT
encapsulates Layer 2 PDUs by enabling the ingress provider edge (PE) device to rewrite
the PDUs' destination media access control (MAC) addresses before forwarding them
onto the service provider network. The devices in the service provider network treat these
encapsulated PDUs as multicast Ethernet packets. Upon receipt of these PDUs, the
egress PE devices decapsulate them by replacing the destination MAC addresses with
the address of the Layer 2 protocol that is being tunneled before forwarding the PDUs
to their destination switches.
L2PT is enabled on a per-VLAN basis. When you enable L2PT on a VLAN, all access
interfaces are considered to be customer-facing interfaces, all trunk interfaces are
considered to be service provider network-facing interfaces, and the specified Layer 2
protocol is disabled on the access interfaces. L2PT only acts on logical interfaces of the
family ethernet-switching
NOTE: Access interfaces in an L2PT-enabled VLAN should not receive
L2PT-tunneled PDUs. If an access interface does receive L2PT-tunneled
PDUs, it might mean that there is a loop in the network. As a result, the
interface will be shut down.
L2PT is configured under the
meaning Q-in-Q tunneling is (and must be) enabled. If L2PT is not enabled, Layer 2 PDUs
are handled in the same way they were handled before L2PT was enabled.
NOTE: If the switch receives untagged or priority-tagged Layer 2 control PDUs
to be tunnelled, then you must configure the switch to map untagged and
priority-tagged packets to an L2PT-enabled VLAN. For more information on
assigning untagged and priority-tagged packets to VLANs, see "Understanding
Q-in-Q Tunneling on EX Series Switches" on page 1293 and "Configuring Q-in-Q
Tunneling (CLI Procedure)" on page 1386.
Example: Configuring Layer 2 Protocol Tunneling on EX Series Switches on page 1368
Example: Setting Up Q-in-Q Tunneling on EX Series Switches on page 1347
.
[edit vlans vlan-name dot1q-tunneling]
hierarchy level,
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