4-6. ATM LANE LANE provides an emulated IEEE 802.3 Ethernet or IEEE 802.5 Token Ring network over an ATM network. You can use LANE to transport traditional LANs over an ATM backbone or an ATM WAN cloud. LANE uses the concept of emulated LANs, or ELANs, to segment traffic into logical networks within the ATM domain. LANE consists of several logical components, each configured on a router, switch, or an ATM switch: - - LAN Emulation Configuration Server (LECS) The central administrative control point for all ELANs in a domain. The LECS keeps a database of ELANs and the ATM addresses of the LANE servers that control each ELAN. (Each administrative domain has only one LECS.)
- - LAN Emulation Server (LES) The central control point for all LANE Clients in an ELAN. The LES provides MAC to ATM Network Service Access Point (NSAP) address translation for each LANE Client. (Each ELAN has only one LES.)
- - Broadcast and Unknown Server (BUS) The BUS handles all broadcasts sent from a LANE host. The LANE Client must forward any broadcast or multicast from an end user to the BUS. The BUS is then able to replicate the broadcast to all other LANE Clients in the domain.
- - LAN Emulation Client (LEC) Provides the basic ELAN function at the edge of the ATM network. The LEC emulates an interface to a tradition LAN and provides data forwarding, address resolution, and MAC address registration with the other LANE components. A LEC is needed at any location where network layer addresses are used.
You can configure multiple LANE components in the network for redundancy. Simple Server Redundancy Protocol (SSRP) handles the communication between the active and standby components so that no single point of failure can exist within the components.
NOTE ATM addresses use the NSAP format, a 20-byte value. Typically, NSAP addresses are written out as groups of four hex digits separated by dots. The leftmost and rightmost two hex digits are usually grouped by themselves. The address is composed of the following parts: Prefix A 13-byte field that uniquely identifies every ATM switch in the network. Cisco ATM switches use a predefined 7-byte value of 47.0091.8100.0000 followed by the 6-byte MAC address of the switch. End-System Identifier (ESI) A 6-byte field that uniquely identifies every device attached to an ATM switch. Typically, this is the 6-byte MAC address of the device (an ATM router interface or LANE module, for example). Selector A 1-byte field that identifies a process running on an ATM device. Cisco devices usually use the ATM subinterface number as the selector value. Be sure to convert the ATM subinterface number from decimal to hex before configuring the selector byte on a Cisco switch.
The prefix value always comes from the ATM switch. The ESI value is determined from the ATM interface MAC address as follows: LEC (MAC address), LES (MAC address + 1), BUS (MAC address + 2), and LECS (MAC address + 3). The selector is the ATM subinterface number except for the LECS, which must always be configured on a major ATM interface (selector 00).
Configuration 1. | Access the ATM LANE module session:
COS | session module
| IOS | N/A |
A Telnet session is started with the LANE module in slot number module. To find the slot number, use the show module command. After the session has been opened, you communicate with the LANE module's IOS CLI. When you are finished and need to return to the COS switch, type exit.
| 2. | Define the control permanent virtual circuits (PVCs).
- a. Select the major ATM interface:
COS | N/A | IOS | (global) interface atm 0
|
- b. (Optional) Select the preferred PHY to use:
COS | N/A | IOS | (interface) atm preferred phy {A | B}
|
On a dual PHY ATM module, you can select either the A or B physical interface to be the preferred PHY.
- c. Define the ATM signaling PVC:
COS | N/A | IOS | (interface) atm pvc vcd 0 5 qsaal
|
The signaling PVC uses QSAAL and usually operates over VPI/VCI 0/5. The vcd is the virtual circuit descriptor, an arbitrary number (1 to 2047) used to uniquely identify the PVC.
- d. Define the ILMI PVC:
COS | N/A | IOS | (interface) atm pvc vcd 0 16 ilmi
|
Interim Local Management Interface (ILMI) is a protocol used between the LANE module and the ATM switch to communicate and set various ATM parameters. Specifically, ILMI can be used to pass the LECS address to any switch in the LANE cloud. ILMI is usually configured over VPI/VCI 0/16. The vcd field can be arbitrarily set to identify the PVC.
| 3. | Display the default LANE addresses on the ATM PHY interface:
COS | N/A | IOS | (exec) show lane default-atm-addresses
|
The default NSAP addresses for the LANE components are shown. If the LANE module has received the prefix portion of the address from an ATM switch, the entire NSAP address is shown. Otherwise, only the ESI or MAC address portion displays. These NSAP addresses are used in further LANE configuration steps. An example of the output from a LANE module follows:
(lane-module) show lane default-atm-addresses interface ATM0: LANE Client: 47.00918100000000E01E35A801.00503ED30C10.** LANE Server: 47.00918100000000E01E35A801.00503ED30C11.** LANE Bus: 47.00918100000000E01E35A801.00503ED30C12.** LANE Config Server: 47.00918100000000E01E35A801.00503ED30C13.00 note: ** is the subinterface number byte in hex
| 4. | (Optional) Define the LECS.
- a. Name the LECS database:
COS | N/A | IOS | (global) lane database database-name
|
The LECS database is named database-name (1- to 32-character string).
- b. Define an ELAN and its LES:
COS | N/A | IOS | [View full width] (lane-database) name elan-name server-atm-address  atm-address [restricted] [index index]
|
The ELAN named elan-name (1- to 32-character string) is bound to the LES at atm-address (20-byte NSAP address). The NSAP address can be obtained from the show lane default-atm-addresses command on the router or LANE module that will have the LES component. You can use the restricted keyword to restrict ELAN membership to only those clients explicitly listed in the database as shown in the bulleted steps that follow.
NOTE To use SSRP for redundancy, multiple LES components can be defined for a given ELAN. You must use the index keyword to assign a priority to each LES (0 is the highest priority). - (Unrestricted ELAN membership) Define a default ELAN name: COS | N/A | IOS | (lane-database) default-name elan-name
|
For an unrestricted membership ELAN, any client attempting to register itself with the LECS will be joined to the ELAN named elan-name (1- to 32-character string). - (Restricted ELAN membership) Define specific LECs and their ELAN: COS | N/A | IOS | [View full width] (lane-database) client-atm-address atm-address name elan-name
|
For a restricted membership ELAN, any client attempting to register itself with the LECS must be specifically identified by its atm-address (20-byte value, 40 hex digits; * can match any digit, … can match any number of digits). The matching client is joined to the ELAN named elan-name (1- to 32-character string).
- c. Enable the LECS.
- Select an ATM major interface: COS | N/A | IOS | (global) interface atm 0
|
- Use a specific LECS database COS | N/A | IOS | (interface) lane config database database-name
|
- Determine the LECS ATM address. NOTE To use redundant LECS components, you must configure each LECS ATM address in the ATM switch. As each LEC initializes, it contacts the ATM switch through ILMI and is provided a list of all the LECS addresses. If multiple ATM switches are used within the ELAN domain, all ATM switches must have an identical list of LECS addresses in the same order. In addition, each redundant LECS must have an identical database. You can choose from three different ATM addresses for the LECS. To use the automatic or predetermined address, use the following command: COS | N/A | IOS | (interface) lane config auto-config-atm-address
|
The LECS address is created from the value shown by the show lane default-atm-addresses command. To use the well-known LECS address, use the following command: COS | N/A | IOS | (interface) lane config fixed-config-atm-address
|
The LECS address is the well-known NSAP 47.007900000000000000000000.00A03E000001.00. To use a specific ATM address, use the following command: COS | N/A | IOS | [View full width] (interface) lane config config-atm-address nsap-address
|
The LECS receives the nsap-address (20-byte value, or 40 hex digits). The address can be given as a template, using * to match any single hex digit, or … to match any number of leading, middle, or trailing hex digits.
| 5. | (Optional) Define a LES/BUS pair.
- a. Select an ATM subinterface:
COS | N/A | IOS | (global) interface atm 0.subinterface
|
You can use an arbitrary subinterface number for the LES/BUS components. However, you can configure only one LES/BUS on a subinterface, serving only a single ELAN. In addition, only one LES/BUS pair is needed to support an ELAN.
- b. Enable the LES/BUS:
COS | N/A | IOS | (interface) lane server-bus ethernet elan-name
|
A LES and BUS are created for the ELAN named elan-name (1- to 32-character string). The emulated LAN acts as an Ethernet network.
| 6. | (Optional) Define a LEC.
- a. Select an ATM subinterface:
COS | N/A | IOS | (global) interface atm 0.subinterface
|
You can use an arbitrary subinterface number for the LEC component. You can configure a LEC on the same subinterface as the LES/BUS pair, although this is not required. However, you can create only one LEC on a single subinterface, serving a single ELAN.
- b. Enable the LEC:
COS | N/A | IOS | (interface) lane client ethernet vlan-id [elan-name]
|
The LEC is configured to emulate an Ethernet network. When the LEC joins the ELAN, the LECS will already have the ELAN name for the client in its database. The ELAN name, elan-name, can be given so that the LEC will present the ELAN name to the LECS for additional matching. The VLAN number vlan-id will be bridged to the ELAN.
|
ATM LANE Example A Catalyst LANE module is configured to participate in LANE in a hospital environment. After the signaling and ILMI PVCs have been configured, the LANE module is able to complete all of the parts for the default ATM addresses. The default addresses on the local LANE module are shown in the example, although the default addresses of other devices are also collected. A LECS database for the hospital is configured as hospital-db. An ELAN named radiology is configured with restricted membership. Two LES addresses are listed for redundancy: The local LANE module's LES as priority zero, and another device's LES as priority one. For simplicity, only one LEC is listed and able to join the radiology ELANthe LEC on the local LANE module. A second ELAN named surgery is also configured with unrestricted membership. By default, a LEC is joined to the surgery ELAN. The LECS is configured on interface atm 0, a LES/BUS for radiology on interface atm 0.1, and a LES/BUS for surgery on interface atm 0.2. Finally, a LEC in the radiology ELAN is configured on interface atm 0.3 to bridge to VLAN 10. Notice that the ATM addresses listed in the database have the correct LANE component value in the last ESI digit (0 = LEC, 1 = LES, 2 = BUS, 3 = LECS). The selector value also has the appropriate subinterface number used in the interface configuration:
Displaying Information About ATM LANE Table 4-5 lists some switch commands that you can use to display helpful information about ATM LANE. Table 4-5. Switch Commands to Display ATM LANE InformationDisplay Function | Switch OS | Command |
|---|
LECS status | COS | N/A | IOS | (exec) show lane config
| LECS database | COS | N/A | IOS | (exec) show lane database
| LES status | COS | N/A | IOS | (exec) show lane server
| BUS status | COS | N/A | IOS | (exec) show lane bus
| LEC status | COS | N/A | IOS | (exec) show lane client
| Default NSAP ATM addresses | COS | N/A | IOS | (exec) show lane default-atm-addresses
|
TIP If you are having trouble passing traffic over a LEC, use the show lane client command to see whether the LEC has been able to join the ELAN. The output for a successfully joined LEC is as follows: lane-module# show lane client LE Client ATM0.1 ELAN name: elan48 Admin: up State: operational Client ID: 1 LEC up for 7 days 18 hours 6 minutes 40 seconds Join Attempt: 3 HW Address: 00e0.1499.6410 Type: ethernet Max Frame Size: 1516 VLANID: 62 ATM Address: 47.00918100000000E01E35A901.00E014996410.01 VCD rxFrames txFrames Type ATM Address 0 0 0 configure 47.00918100000000E01E35A901.00E0FE1400C3.00 16 1 211337 direct 47.00918100000000E01E35A901.00E014996411.01 87 761437 0 distribute 47.00918100000000E01E35A901.00E014996411.01 90 0 916712 send 47.00918100000000E01E35A901.00E014996412.01 91 34484839 0 forward 47.00918100000000E01E35A901.00E014996412.01 198 13033702 11492132 data 47.00918100000000E01E35A901.00E0FE1400C0.01
|
