IBM SC30-3681-08 Sample Situations for Use of the Lecs Assignment Policies, ATM Address Policy

Overview of LAN Emulation

Sample Situations for Use of the LECS Assignment Policies

The following section offers examples of various LECS assignment policies.

ATM Address Policy

The LECS permits two types of ATM address policy values. The ®rst type is a variable length ATM address pre®x. For example, the policy value (3999999999999900000102, LES_A) means that all LE clients whose ATM address begins with 3999999999999900000102 should be assigned to LES_A.

The second type of ATM address policy value is an ESI and Selector of an ATM address. For example, the policy value (10002345003281, LES_A) means that the LE client with an ESI of 100023450032 and a selector of 81 should be assigned to LES A.

When given the ATM address of an LE client, the LECS searches ®rst for a matching ESI and selector. If no match is returned, the LECS searches for the ATM address pre®x policy value with the longest matching pre®x. Thus, for example, the above policy value (399999999999990000, LES_B).

ATM address ESI and selector policy values can be used to assign clients to LESs in a manner independent of the LE clients physical location (the ESI and selector is de®ned locally to the client). ATM address pre®xes are the only policy values which indicate any geographic information.

LAN Destination Policy

LE clients can be assigned to LESs based upon a MAC address or a route descriptor. Because a LAN destination uniquely identi®es an LE client in a manner that is independent of geographic location, this policy is useful in ensuring that the LE client is assigned to the correct ELAN regardless of its physical location, for example, retaining the ELAN memberships of a workstation when it is moved from one switch to another.

ELAN Name Policy

ELAN names are perhaps the most ¯exible of the assignment criteria. Some of the ways that ELAN name policy values can be used are:

vUse the actual name of the ELAN

If LES_A serves Elan 1, then create the policy value (Elan 1, LES_A). LE clients specifying Elan 1 in con®guration requests will then be assigned to LES_A.

vUse aliases for the ELAN

For example, all LE clients belonging to members of the Accounting Department could be con®gured to use the ELAN nameAccounting, while those belonging to the Engineering Department could use the ELAN name Engineering. Depending upon the number of LE clients on the ELANs, these names could be directed to the same ELAN by con®guring these policy values:

(Accounting, LES_A) (Engineering, LES_A)

or to different ELANs by con®guring these policy values:

(Accounting, LES_A) (Engineering, LES_B)

262MRS V3.2 Software User's Guide