Cabletron Systems MMAC-Plus SFCS-1000, Руководство по настройке

Страница: 78 / 404

3-6
Configuring an Emulated LAN
3.3.1 Initialization
Upon initialization, LEC1 obtains its own ATM address via address registra-
tion. LEC1 obtains the address of the LECS in one of three ways: via manual
configuration, via the “well-known” address defined by the ATM Forum’s
LANE standards (47.0079.00.000000.0000.0000.0000.00A03E000001.00), or via
PVC (0,17).
Once it knows the location of the LECS, LEC1 establishes a configuration-
direct connection
➊
to the LECS. When connected, the LECS provides LEC1
with the information necessary to connect to the ELAN it wishes to join. This
information includes such parameters as: the ATM address of the ELAN’s
LES, the type of LAN being emulated, the maximum packet size, and the
name of the ELAN (
engineering , for example). This configuration informa-
tion is contained in a configuration file that must be built and maintained by
the network administrator.
NOTE:
Detailed information about the LECS
configuration file may be found in Section
3.4.1.
3.3.2 Registration and Address Resolution
After obtaining the address of the LES, LEC1 establishes a control-direct con-
nection
➋
to the LES. The LES assigns LEC1 a unique identifier, and LEC1
registers its own MAC and ATM addresses with the LES. (The LES maintains
a table containing the MAC addresses and corresponding ATM addresses of
all members of the ELAN.) At this point, LEC1 has “joined” the ELAN.
The LES then establishes a control-distribute connection
➌
back to LEC1.
Connections
➋
and
➌
can now be used by LEC1 to send LAN Emulation
ARP (LE_ARP) requests to the LES, and receive replies.
LEC1 now sends an LE_ARP request to the LES to get the ATM address of the
BUS corresponding to the broadcast MAC address (FFFFFFFFFFFF). The LEC
then establishes a multicast-send connection
➍
to the BUS. The BUS responds
by setting up a multicast-forward connection
➎
to the LEC.
At this point, the LEC is ready to transfer data.