Cisco Systems Network Router manual Closed User Group Overview, 3-14

Chapter 3 Address and Closed User Group Planning

Closed User Group Overview

•Confirm that each reconfigured node ID and node address are unique. The switch software does not detect configuration errors caused by duplicate ATM addresses.

•Use summary port prefixes wherever possible to reduce overhead.

Closed User Group Overview

The PNNI Closed User Group (CUG) feature allows network users to form a closed community within a PNNI network. Figure 3-7shows an example of closed user groups in a network.

Figure 3-7 Closed User Group Example

CPE A,

CUGs 1 & 2

Switch W

Switch Y

Switch Z

CPE C,

CUG 2CPE D, CUG 2

CPE B,

CUG 1

Switch X

CPE E

116412

A network user may be associated with one, multiple, or no CUGs. In Figure 3-7, CPE A is a CUG member of CUGs 1 and 2. CPE B, C, and D are members of either CUG 1 or CUG 2. Members of a specific CUG can communicate typically among themselves, but in general not with network users outside of the CUG. In the example, CPE A can communicate with CPE B, C, and D because it is a member of both CUGs. This section will also show how CPE A can be enabled for communications with CPE E.

Specific network users can have additional restrictions preventing them from originating calls to, or receiving calls from, network users of the same CUG. For example, CPE B can be configured so that it cannot originate calls to other CUG 1 members, but it can accept calls from other members.

Configuration options allow a network user to be further restricted when originating calls to, or receiving calls from, network users outside of any CUG membership defined for the network user. In Figure 3-7, CPE E is not a member of any CUG and the default configuration for CUG members will prevent communications between CPE E and the other CPE. Using configuration options, however, CPE1 can be allowed to originate calls to CPE E, and CPE D can be configured to accept calls from CPE E.

The user within a CUG is actually a UNI ATM End Station Address (AESA) or an ATM address prefix, and this address or address prefix can be assigned to more than one interface on a switch. When an ATM address is assigned to more than one CUG, the CPE that use that address must specify the CUG for a connection or accept a configured default CUG called the preferential CUG.

CUG membership is evaluated only when setting up connections. CUG membership is an independent feature and does not interoperate with the address filtering feature.

The CUG feature follows the ITU-T Q.2955.1 recommendation and supports point-to-point and point-to-multipoint connections.

CUGs are managed with the switch CLI. Cisco MGX switches and Cisco LS1010 switches can participate in CUGs. The Cisco WAN Manager (CWM) program does not currently support CUGs.

	Cisco PNNI Network Planning Guide for MGX and SES Products, Release 5
3-14	Part Number OL-3847-01 Rev. D0, April, 2004