Content

| 5.1 |  | Multilayer Switching |
| 5.1.2 |  | MLS hardware and software requirements |

This information is presented only for reference.

The requirements for running MLS in the network are specific. Many technologies are widely available on Cisco products. For example, most Cisco router platforms have Cisco IOS Software releases that support IPX. However, with MLS, widespread support is not the case and options are limited.

MLS
Catalyst 5000 series switches comprise the majority of MLS deployments. For Catalyst 5000 switches, the MLS requirements are as follows:

- Supervisor Engine III with NetFlow Feature Card (NFFC) or NFFC II, a Supervisor Engine IIG, or a Supervisor Engine IIIG (the IIG and IIIG have integrated NFFCs). The only NFFCs still available for purchase are the NFFC-A and NFFC II-A. The other NFFCs were last sold on April 30, 2000.
- Catalyst 5000 Route Switch Module (RSM), Catalyst 5000 Route Switch Feature Card (RSFC), Catalyst 6000 MSFC, or Catalyst 6000 MSM.
- CatOS 4.1(1) or later.
- Cisco IOS Software Release 12.0(3c)W5(8a) or later on the RSFC.
- Cisco IOS Software Release 11.3(2)WA4(4) or later on the RSM.

Catalyst 2926G switches can also work in tandem with external Cisco routers to support MLS. 2926G switches are fixed-configuration switches. They were last sold in May 2000 and have been replaced by the 2948G switches.

The hardware and software guidelines for external routers are as follows:

- Cisco 3600, 4500, 4700, 7200, or 7500 router or Catalyst 8500 switch router externally attached to the Catalyst 5000 series switch.
- The connection between the external router and the Catalyst 5000 series switch must be a Fast or Gigabit Ethernet link, an ISL or IEEE 802.1Q trunk, or a Fast or Gigabit EtherChannel.
- Cisco IOS Software Release 11.3(2)WA4(4) or later on Cisco 4500, 4700, 7200, or 7500 routers. Cisco IOS Software Release 12.0 is the earliest release available on 8500 series switch routers.
- Cisco IOS Software Release 12.0(2) or later on Cisco 3600 series routers.
- Catalyst 6000 MSFC on a Supervisor Engine with CatOS 6.3.
- Catalyst 6000 MSM.

For Catalyst 6000 switches, the MLS hardware and software guidelines are as follows:

- Catalyst 6000 family switches do not support an external Multilayer Switching Route Processor (MLS-RP). The MLS-RP must be a Multilayer Switch Module (MSM) or Multilayer Switch Feature Card (MSFC). As of July 6, 2000, the MSM is no longer available for purchase and has been replaced by the MSFC.
- MSFC, Policy Feature Card (PFC), and CatOS 5.1CSX or later.
- MSM, CatOS 5.2(1)CSX or later, and Cisco MSM IOS Software Release 12.0(1a)WX5(6d) or later.

CEF
MLS, in the generic sense, is implemented with CEF in newer Catalyst 6000 products. In particular, Supervisor Engine 2, Policy Feature Card 2 (PFC2), and Multilayer Switch Feature Card 2 (MSFC2) comprise a standard configuration for newly purchased Catalyst 6000 switches. This configuration relies natively on CEF.

The Catalyst 4000 switch with the Layer 3 Services Module or the Supervisor Engine III also natively supports CEF.

With the hardware and software requirements clarified, it’s important to understand how MLS works. The following sections detail the concepts of MLS flow, MLS-SE, and MLS-RP.