Nortel Networks Passport Module 8672A - Manual (Page 25)

Chapter 1 About the Passport 8672ATM Module 25
Using the Passport 8672ATM Module
ATM ELANs, and Ethernet VLANs
The Passport 8672ATM Module supports ATM Forum Emulated LANs (ELANs).
An ELAN extends an Ethernet VLAN, which is a broadcast domain, over an ATM
network.
In general, there is a one-to-one mapping between an ATM ELAN and an Ethernet
VLAN. An ATM ELAN never spans more than one ATM port because the
software considers each ATM port completely separate.
The Passport 8672ATM Module participates in ELANs as RFC 1483 PVCs. Only
Ethernet ELANs are supported on this module.
If you delete a VLAN, you delete 1483 ELANs associated with the VLAN.
Virtual network router
Virtual network router (VNR) refers to the routing functions between two ATM
virtual/emulated networks. You can use the Passport 8672ATM Module as an IP-
and IPX-optimized VNR.
Traffic shaping
The Passport 8672ATM Module supports traffic shaping, which is enabled or
disabled on a port-by-port basis. Where it is enabled, a single traffic rate is
enforced for those ports. The maximum available rate for traffic shaping does not
exceed the maximum rate for the slowest interface on the module. Traffic shaping
is disabled by default. Traffic shaping is performed at the port level and not at the
PVC level.
The module provides support for unspecified bit rate (UBR) and variable bit rate
(VBR), both real-time and non-real-time; it does not support available bit rate
(ABR) or constant bit rate (CBR). Traffic shaping per port is supported on all
permanent virtual circuits (PVCs).