Cabletron Systems BRIM-A6DP, User Manual

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VLAN Overview
BRIM-A6DP User’s Guide 3-25
3.10.1 Configuration Guidelines
This section provides guidelines for the operation of VLANs over ATM.
If the following guidelines are not followed, poor network performance
may result.
Maximum of 16 ELAN/VLAN Pairs
The maximum number of LAN Emulation Clients (LECs) that can be
created using Local Management or the ATM Forum’s LEC MIB is 16.
No Support for Spanning Tree Algorithm
This version of BRIM-A6DP firmware does not support the Spanning
Tree Algorithm. Ensure that no parallel network links to the ATM network
exist, otherwise data loops will occur and bring the network down.
ELAN to VLAN Mappings
It is not possible to map more than one ELAN to a single VLAN. Several
VLANs, however, can be mapped to a single ELAN.
LEC and PVC Mixture
A mixture of Permanent Virtual Channels (PVCs) and LAN Emulation
Clients (LECs) is not allowed in this version of BRIM-A6DP firmware. It
does allow, however, the mapping of Ethernet ports to LECs, or to other
Ethernet ports.
User Mobility
This version of BRIM-A6DP firmware allows the movement of Ethernet
users from one LEC to another, but a brief downtime will result. The ATM
Forum’s LAN Emulation 1.0 specification states that it may take up to
300 seconds for a LAN MAC address entry to be aged out of the old
LEC’s LE-ARP cache before it can communicate through a new LEC
instance.
Layer 3 Routing Requirement
Communication between ELANs requires the presence of an OSI Layer 3
routing protocol. Security may be achieved via access lists in the router.
Static Entry for Router MAC Address
If the router being used for inter-ELAN communication uses a single
MAC address for all LECs, this address must be entered in the Add
Router MAC screen. For information on how to complete this procedure
refer to Section 3.12.