Multilayer Switch

Multilayer switch is a switch with the ability to do the task of layer 3 routing and some task of the above layer.

Layer 3 switching means routing approximately at the speed of switching. High-end Cisco Layer 3 switches are now able to perform this second function, at the same speed as the Layer 2 switching function

most multilayer switch today doesn't have any visible router module. its ability is contained in its supervisor (CPU). but older chasis based switch can be a multilayer switch with a multi layer switch function card (MSFC) module. in this kind of multilayer switch you go to the router OS with the 'session slot-number' command where the slot-number is the number of the slot where the module is installed you can obtain this number by executing show module command.

with multilayer switch, routing inter vlan can be done by the swithc itself. this is done by creating an Switched Virtual Interface (SVI) for each vlan. with the command
interface vlan vlan-number

different series of cisco multilayer switch give different feature and flexibility. you must choose either a switch with limited routing capabilities, or a router with limited switching capabilities. 6500 switches has become the widley deployed in enterprise environment.

6500 switches come in different sizes from 3 slots up to 13 slots. 6500 has many modules that makes it very expandable Firewall Services Modul (FWSM - firewall and security), Content Switching Module (CSM - load balancing) and Network Analysis Modules (NAM - network monitoring) all in one chassis.

6500 switches is highly redundant. they support dual power supply and dual supervisor.
enhanced chasis type is recognized with the letter e in the end of the series number(6500e).
enhanced chasis use high-speed fans to cool these power-hungry modules.

Supervisor - over the years, different supervisor models have been introduced to offer greater speed and versatility. increased functionality has also been made available via a add-on daughter cards.

daughter card is an add-on for a module.
there are fabric-enabled module and nonfabric-enabled module
line cards (offers connectivity, such as copper or fiber ethernet) and service module (offers functionality such as FWSM, CSM)

Ethernet Module, provide connectivity for ethernet (RJ42, GBIC) available from 4 ports. 48 ports with speed up to 1000 mbps.and even 96 port RJ-21 connector module supporting 10/100 mbps.

*Firewall Services Module (FWSM), provide firewall services just like PIX.

*Content Switch Module (CSM).

Network Analysis Module, packet capturing, monitoring traffic. controlled through a web-browser which can be tedious when seeing a large scale of traffic.

*Intrusion Detection System Module (IDSM), act like an IDS appliance.

*FlexWAN Module, allow the connection of WAN links such as T1, DS3, OC3.

Communication Media Module (CMM), provide telephony integration (analog telephone, fax machines, modem)

3750 switches
3750 switches, successor of 3550 switches. have the ability of stacking (the ability to link together some switches, usually of the same type to form a single logical switch with a single management IP address. once you telnet or SSH to the IP address, you can control the stack as if it were a single device).

FlexLink support failover (a pair of link, where one is the primary link and the other is the backup link). flexlink is used on switches where you don't want to run STP.

Port Security. you can specify certain MAC addresses that you allow or deny the right to use the port.