Cabletron Systems 04-0053-01 manual Single PVP connection between clients and Lane services

IP Over ATM and LANE Creating an Emulated LAN

Any Smar tSwitch

ATM Switch

	Single	Single
	Vir tual Por t	Vir tual Por t
LANE
Ser ver	Single	ATM WAN
(elan1)		Single
	PVP	PVP
SW2

SW1

Client

Join

Requests

Single	Single
Physical	Physical
Por t	Por t

Figure 2-1 Single PVP connection between clients and LANE services

Physical BUS multicasting implies that the BUS performs multicasting according to physical ports. With a single PVP, the BUS understands that all requests are coming from a particular port. Accordingly, the BUS replies over that port, and it is up to the switch at the other end of the PVP connection to sort out which reply belongs to which client (see Figure 2-2).

Another possible ATM WAN configuration involves multiple PVPs across the WAN, with each PVP terminated on its own virtual port, and all virtual ports residing on the same physical port. In this configuration, LANE join requests for the same ELAN may appear on different virtual ports of the same physical port of the switch running LANE services. Because these requests are appearing on multiple logical entities (multiple virtual ports), this requires the BUS to be capable of logical multicasting.

Must be

Smar tSwitch 6500

	Multiple	Multiple
	Vir tual Por ts	Vir tual Por ts	SW1
LANE			Client
Ser ver	ATM WAN		Join
(elan1)	Multiple	Multiple	Requests
SW2	PVPs	PVPs
Single		Single
Physical		Physical
	Por t	Por t

Figure 2-2 Multiple PVP connection between clients and LANE services

Logical BUS multicasting implies that the BUS of a particular ELAN can distinguish the difference between virtual ports on the same physical port. In essence, the BUS treats each virtual port as a physical entity, and keeps track of its point-to-multipoint connections to the clients through various PVPs.

SmartSwitch ATM User Guide 2-15