Understanding Eompls; Atom Load Balancing; Eompls Guidelines And Restrictions - Cisco 7604 Configuration Manual

Any Transport over MPLS
For information on requirements for Supervisor Engine 2-based EoMPLS, see this publication:
http://www.cisco.com/en/US/docs/routers/7600/install_config/12.2SX_OSM_config/mpls.html#Super
visor_Engine_2-Based_EoMPLS
For information on other AToM implementations (ATM AAL5 over MPLS, ATM Cell Relay over MPLS,
Frame Relay over MPLS), see this publication:
http://www.cisco.com/en/US/docs/routers/7600/install_config/12.2SX_OSM_config/mpls.html#Any_
Transport_over_MPLS
These sections describe AToM:
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AToM Load Balancing

PFC3BXL or PFC3B mode EoMPLS does not support load balancing at the tunnel ingress; only one
Interior Gateway Protocol (IGP) path is selected even if multiple IGP paths are available, but load
balancing is available at the MPLS core.

Understanding EoMPLS

EoMPLS is one of the AToM transport types. AToM transports Layer 2 packets over a MPLS backbone
using a directed LDP session between edge routers for setting up and maintaining connections.
Forwarding occurs through the use of two level labels that provide switching between the edge routers.
The external label (tunnel label) routes the packet over the MPLS backbone to the egress PE at the
ingress PE. The VC label is a demuxing label that determines the connection at the tunnel endpoint (the
particular egress interface on the egress PE as well as the VLAN identifier for an Ethernet frame).
EoMPLS works by encapsulating Ethernet PDUs in MPLS packets and forwarding them across the
MPLS network. Each PDU is transported as a single packet.
Note Use OSM-based EoMPLS when you want local Layer 2 switching and EoMPLS on the same VLAN.
You need to configure EoMPLS on the SVI; the core-facing card must be an OSM. When local Layer 2
switching is not required, use PFC-based EoMPLS configured on the subinterface or physical interface.

EoMPLS Guidelines and Restrictions

When configuring EoMPLS, follow these guidelines and restrictions:
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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
24-14
AToM Load Balancing, page 24-14
Understanding EoMPLS, page 24-14
EoMPLS Guidelines and Restrictions, page 24-14
Configuring EoMPLS, page 24-16
Ensure that the maximum transmission unit (MTU) of all intermediate links between endpoints is
sufficient to carry the largest Layer 2 packet received.
EoMPLS supports VLAN packets that conform to the IEEE 802.1Q standard. The 802.1Q
specification establishes a standard method for inserting VLAN membership information into
Ethernet frames.
Chapter 24 Configuring PFC3BXL and PFC3B Mode Multiprotocol Label Switching
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