Each section of this document contains the system requirements to
implement Multilayer Switching (MLS) on the platforms described.
There are no specific requirements for this document.
This document is not restricted to specific software and hardware
For more information on document conventions, refer to the
Cisco Technical Tips
Cisco Catalyst 6000 series switches with Supervisor Engine I support
MLS with a Multilayer Switch Feature Card (MSFC1 or MSFC2) and a Policy Feature
Card (PFC). The MSFC2 with PFC2 perform Layer 3 (L3) switching using CEF. The
Supervisor Engine 720, PFC3, and MSFC3 perform L3 switching with CEF for the
PFC3. Refer to the document
CEF for PFC2 and PFC3 for more information.
Catalyst 6000 series switches support MLS for IP, IP multicast, and
Internetwork Packet Exchange (IPX) protocols. By default, IP and IPX MLS are
enabled, and IP multicast MLS is disabled.
Catalyst 6000 series switches do not support an external MLS route
processor (MLS-RP). The internal multilayer switching must be done by MSFC1,
MSFC 2, or MSFC3 with a PFC.
Catalyst 6000 series Supervisor Engine Catalyst OS (CatOS) software
version 5.1 CSX or later supports IP and IP multicast, and CatOS software
release 5.2(1) CSX or later supports IPX MLS.
The Multilayer Switch Module (MSM) is the equivalent of the Catalyst
8510 campus switch router (CSR) with four internal gigabit ports connecting it
to the Catalyst 6000 backplane. Since it is based on the Catalyst 8510 CSR, it
is already using the hardware CEF by default (for IP, IP multicast, and IPX, if
configured). There is no need to configure MLS for the MSM to do L3 hardware
Note: The MSM is an end of sale (EOS) product. (Refer to the
End of Sale
Announcement for Multilayer Switch Module (MSM) for Catalyst 6000 Family
Switches.) The MSM is effectively replaced by the MSFC.
Catalyst 5000 series switches support MLS in Supervisor Engine III
with Netflow Feature Card (NFFC) or NFFC II.
Catalyst 5000 also supports MLS using Route Switch Module (RSM),
Route Switch Feature Card (RSFC), or external Cisco
series routers. The MSM or MSFC on a Catalyst 6000 switch can also be used as
an external RP for Catalyst 5000.
Supervisor Engine CatOS software release 4.1(1) or later supports MLS
for IP, software release 5.1 or later supports MLS for IP multicasts, and
software release 5.2(1) or later supports IPX for Catalyst
Cisco IOS® Software Release 11.3(2)WA4(4) or later supports MLS on
RSM or Cisco 7500, 7200, 4700, and 4500 series routers, Cisco IOS Software
Release 12.0(2) or later on Cisco 3600 series routers, and Cisco IOS Software
Release 12.0(3c)W5(8a) or later on the RSFC.
When using an external router with the Catalyst 5500/5000, follow these
One directly attached external router per Catalyst 5000 series switch
is recommended to ensure that the MLS-Switching Engine (MLS-SE) caches the
appropriate flow of information from both sides of the routed
You can use Cisco high-end routers (Cisco 7500, 7200, 4500, 4700 and,
3600 series) for MLS when they are externally attached to the Catalyst 5000
series switch. You can make the attachment with multiple Ethernets (one per
subnet) by using FastEthernet with the Inter-Switch Link Protocol (ISL) or with
Fast EtherChannel (FEC).
You can connect end hosts through any media (Ethernet, FastEthernet,
ATM, and FDDI). However, the connection between the external router and the
Catalyst 5000 series switch must be through standard 10/100 Ethernet
interfaces, ISL, or FEC.