Juniper JUNOSE 11.2.X BGP AND MPLS, Configuration Manual

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interfaces are directly cross-connected to each other. The cross-connected interfaces
can be different types and operate at different speeds; for example, you can cross-connect
a serial interface on a T1 circuit and a POS interface on an OC3 circuit.
Related Topics Configuring HDLC Layer 2 Services on page 538
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CE-Side MPLS L2VPNs over LAG Overview
MPLS L2VPNs over link aggregation groups (LAGs) uses the functionality of both layer
2 services over MPLS and LAG. MPLS L2VPNs (Martini circuits) over LAG enable MPLS
Martini circuits to use LAG in the network between the customer edge (CE) devices and
the provider edge (PE) routers to distribute traffic arriving from pseudowires across
multiple physical Ethernet interfaces. The criteria for distribution of packets that are
transmitted from the pseudowires across the LAG bundle are determined by the hashing
of VLAN and the source and destination MAC addresses. If a packet contains a VLAN
stack, all the VLAN identifiers of the received packet, the source MAC address, and the
destination MAC address are used in the hashing algorithm. If the packet does not contain
a VLAN stack, only the source and destination MAC addresses are used in the hashing
algorithm.
Using MPLS L2VPNs over the LAGs configured between CE and PE devices provides
redundancy and increased bandwidth on demand. The capability to use MPLS L2VPNs
over LAG is available on GE-HDE, GE-2, ES2 4G LM, and ES2 10G LMs.
Similarly, you can enable distribution of IP traffic from pseudowires across multiple
physical interfaces on the PE routers facing the CE-side devices. In this case, the source
and destination IP addresses are used in the hashing rule to determine the distribution
criteria for received packets. You must a different VLAN for IP packets from the one used
for MPLS L2VPN packets. However, you can use the same LAG bundle that you configured
for MPLS L2VPN traffic for IP traffic distribution.
Figure 118 on page 521 shows an example of an MPLS L2VPN or Martini tunnel over LAG
on the CE-side device. A set of Ethernet ports on a provider edge device, PE1, are configured
as member ports of LAG1. An MPLS L2VPN tunnel from PE1 to another provider edge
device, PE2, is configured over an interface, VLAN1, over LAG1. An MPLS shim interface
is stacked on the VLAN1 interface, when the MPLS L2VPN tunnel over VLAN1 over LAG1
is configured. The Martini tunnel from PE1 to PE2 can be configured either over Ethernet
or LAG. In this scenario, it is considered to be configured over LAG.
Figure 118: CE-Side MPLS L2VPN Tunnel over LAG
PE1 CE1 CE2 PE2
CE1
ports
CE2
ports
VLAN1 VLAN1
MPLS network
LAG1
PE1
ports
PE2
ports
VLAN2
IP traffic
g016505
Layer 2 frames arrive from CE1 to PE1 on the VLAN1 interface that resides below the MPLS
shim interface. These frames are encapsulated in an MPLS packet and forwarded to the
521 Copyright © 2010, Juniper Networks, Inc.
Chapter 8: Layer 2 Services over MPLS Overview