Справочник Пользователя для Avaya M770
Appendix E
Components in LANE Services
298
Avaya M770 ATM Switch User’s Guide
Communication on an Emulated LAN
It is the LEC in an ATM device that will perform most of the work of LAN
emulation. To do this it must join an ELAN.
emulation. To do this it must join an ELAN.
Discovering the ATM address of the LES
Before a LEC can join an ELAN, it typically gets the ATM address of the LES from
the LECS. The LECS decides which LES to direct a LEC to, on the basis of the
information that the LEC gives it. For example, the LEC may provide the name of
the ELAN it expects to join. Alternatively, the LECS may be configured to associate
a particular LEC with a specific ELAN.
the LECS. The LECS decides which LES to direct a LEC to, on the basis of the
information that the LEC gives it. For example, the LEC may provide the name of
the ELAN it expects to join. Alternatively, the LECS may be configured to associate
a particular LEC with a specific ELAN.
Discovering the ATM address of another LEC
Every LEC has one or more LAN addresses (for example, MAC address) and an
ATM address associated with it. When the network operating system passes a frame
to a LEC to transmit, the LEC checks whether it already has a connection set up to
that frame's LAN destination address. If there is no existing connection, the LEC
must discover the ATM address for that destination end-station, signal to the
network for a connection, and then transmit the data.
To discover an ATM address, the LEC consults its list of ATM stations that it has
communicated with. If the LEC cannot find the address it requires from its own list,
it will communicate with the LES for the required address.
When a LEC needs an ATM address, it sends a LANE ARP (Address Resolution
Protocol) request to the LES. If the LES knows the ATM address, it sends it to the
LEC. If it does not know the ATM address, the LES may forward the address
request to any LECs that are registered with it so that they can respond directly to
the LES. The LES will then forward the response to the LEC.
ATM address associated with it. When the network operating system passes a frame
to a LEC to transmit, the LEC checks whether it already has a connection set up to
that frame's LAN destination address. If there is no existing connection, the LEC
must discover the ATM address for that destination end-station, signal to the
network for a connection, and then transmit the data.
To discover an ATM address, the LEC consults its list of ATM stations that it has
communicated with. If the LEC cannot find the address it requires from its own list,
it will communicate with the LES for the required address.
When a LEC needs an ATM address, it sends a LANE ARP (Address Resolution
Protocol) request to the LES. If the LES knows the ATM address, it sends it to the
LEC. If it does not know the ATM address, the LES may forward the address
request to any LECs that are registered with it so that they can respond directly to
the LES. The LES will then forward the response to the LEC.
Setting up the connection
When the LEC has discovered the ATM address of the required LEC, it signals to
the ATM network for a Virtual Circuit Connection (VCC) to that LEC.
the ATM network for a Virtual Circuit Connection (VCC) to that LEC.
Transmitting the data
When the VCC is set up, the LEC transmits its data through the ATM network to the
destination LEC.
destination LEC.