Cisco Systems RJ-45-to-AUX manual Implementing Lane, Configuring ATM on the 5000 Switch, 175

Let’s step through the process. Suppose that you were working on an ELAN and you wanted to access a file stored on a server that was located on a physically separate LAN:

1.You send the file request. Your LEC determines if it knows the ATM address of its LES.

2.If your LEC does not know this address, the client queries the LECS and asks for the ATM address of the LES.

3.After your LEC receives the correct address, it queries the LES for the ATM address of the LES where the file is located. If the LES knows this address, it sends the address to your LEC.

4.If the LES does not know this address, it queries the LANE BUS. The LANE BUS, in turn, asks all the LECs on the ELAN for their ATM addresses. The LANE BUS returns the correct address to the LES, which returns the address to your LEC.

5.Your LEC establishes a virtual circuit to the server on which the file is stored. The LEC converts its Ethernet or Token Ring frames into cells and sends these cells over the virtual circuit to the server.

Implementing LANE

LANE is supported on many of the products offered by Cisco, including all Cisco switches from the Catalyst 1900 series through the 12000 series, the Cisco LightStream switches, and the 8000 series of WAN switches. Routers such as the Cisco 4000, 4500, 7000, and 7500 can support LANE, as well.

If you’re designing an ATM LANE network, you need to examine each switch’s level of performance and functionality. Doing so allows you to determine which switching product is needed at each point in the network. Cisco has created four product lines for specific network types. Each product provides a certain level of performance and functionality. Cisco provides ATM devices that fit well in all sizes of ATM implementations, from the smallest to the largest. These four product lines are as follows:

∙Workgroup switches—The smallest switches, typically found in the Access layer of the network. Workgroup switches begin with the 1900 series switches and includes the Cisco Catalyst 5000. Most workgroup switches are located in the wiring closet closest to the end user. These switches are usually Ethernet based for the local LAN environment and provide an ATM uplink to a campus switch.

∙Campus switches—Typically implemented to relieve the congested nature of the network and to eliminate bandwidth problems across the existing backbone. These switches include the LightStream family of ATM switches. Campus switches support a wide variety of interfaces, including those that have connections to backbone and to the WAN.

∙Enterprise switches—The next level of ATM switches. These switches allow multilevel campus ATM switches to be connected for enterprise installations. They also provide the internetworking processes necessary to route multi−protocol traffic in the network. These switches are not used in the Core layer or backbone; they are used in the enterprise or WAN to meet the needs of high−traffic enterprises or even public service providers. These are Cisco’s BPX and AXIS switches.

∙Multiservice access switches—Provide a multitude of services for the growing needs of networks. They can provide services to support MANs, WANs, and the campus network.

Configuring ATM on the 5000 Switch

The LANE module for the Catalyst 5000 and 5500 series is available with three different types of interfaces: multimode fiber (MMF), single−mode fiber (SMF), and unshielded twisted pair (UTP). On each module, two interfaces of each type are available—but only one may be used at any time. This arrangement provides redundancy in the event of a hardware failure or the loss of ILMI signaling.

Note When ILMI was first introduced, it was referred to as Interim Local Management Interface because the protocol was anticipated to have a short life span.

ILMI provides sufficient information for the ATM end−station to find a LECS. The ILMI also provides the ATM NSAP prefix information to the end−station. This prefix is configured on a local ATM switch. The prefix is 13 bytes long; it is then combined with the MAC address (6 bytes) of the end−node (end system identifier), and a 1−byte selector, to create a 20−byte ATM address.

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