LAN Emulation
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The LECS implements the assignment of individual LE clients to different
emulated LANs. A LEC can either obtain the information from the LECS
using the configuration protocol, or from its own database. It assigns any
client which requests configuration information to a particular emulated LAN
service by giving the client the LES’s ATM address. This method supports
the ability to assign a client to an emulated LAN based on the client’s location
(ATM address).
It is optional for the LEC to obtain information from the LECS using the
configuration protocol. The LECS allows the LEC to configure automatically.
The LECS is also used to keep track of all the emulated LANs and the LECs
which belong to them. When a LEC is initialized, one of its first actions is to
set up a connection to the LECS. It then sends a request for its configuration,
including the ATM address of the LES it should contact to join an ELAN. The
database in the LECS would typically be initialized by the network
administrator and managed through SNMP management applications.
SNMP is defined by RFC-1157 and published by the Internet Engineering
Task Force. Full details of the ATM UNI MIB and of generic SNMP are
beyond the scope of this publication. The essential parameters are, however,
as follows:
❑
Physical layer type (SONET), medium (UTP, fiber, coaxial cable and
more), unique index number, status (normal or looped) and relevant
specifications.
❑
Number of ATM virtual paths and connections allowed. Numbers
active. How much of each address field is being used.
❑
ATM statistics: cells received, sent or dropped. Traffic descriptors and
the values that define the Sustainable Cell Rate, burst tolerance,
quality of service and more.
❑
MIB-II system group values that are required. This includes the
length of time since the last reset.
