Juniper JUNOSE, Configuration Manual

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Related Topics
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Configuring HDLC Layer 2 Services on page 532
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 515 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 MPLS next hop. The attributes of the shim interface are used to
determine the encapsulation parameters. These MPLS packets are later forwarded
to the remote PE2 device. PE2 processes all the MPLS labels and determines that
CE-Side MPLS L2VPNs over LAG Overview
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Chapter 6: Layer 2 Services over MPLS Overview