Cisco 3900 series, Cisco 2900 series, and Cisco 1900 series ISRs use a multi-gigabit fabric (MGF) for the new modules and interface cards to inter-communicate on the router. Legacy modules that support Cisco High-Speed Intrachassis Module Interconnect (HIMI) also support the MGF. Next generation module drivers integrate with the MGF to perform port configurations, configure packet flow, and control traffic buffering. On the router-side, there are no user-configurable features on the MGF. All configurations are performed from the module, which may or may not lead to changes on the MGF.
Modules and interface cards inter-communicate using the MGF on the router with or without CPU involvement. Modules and interface cards that communicate without CPU involvement reduce load and increase performance on the router. Modules and interface cards that do not utilize the MGF communicate with the CPU using the PCI Express (PCIe) link.
The following sections describe module and interface card communication through the MGF:
Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers support legacy interface cards and modules. Some modules will require an adapter. See your router’s hardware installation guide at Cisco.com for adapter installation information.
See the routers’s Product page at Cisco.com for a complete list of supported new and legacy modules.
Wireless LAN Module in the Cisco 1941W ISR
When configured as an autonomous access point, the wireless LAN (WLAN) device serves as the connection point between wireless and wired networks or as the center point of a stand-alone wireless network. In large installations, wireless users within radio range of a device can roam throughout a facility while maintaining seamless and uninterrupted access to the network.
Cisco 1941W supports ISM-to-EHWIC communication with an integrated switch communicating through the MGF. In this scenario traffic goes from the WLAN, through the Multi-Gigabit Fabric’s CPU port, and out through a port on the front panel.
Cisco Etherswitch Service Modules
The following Cisco EtherSwitch service modules provide Cisco modular access routers the ability to stack Cisco EtherSwitch service modules as Layer 2 switches using Cisco StackWise technology.
The Cisco EtherSwitch service modules are supported by either the IP base image (formerly known as standard multilayer image [SMI]) or the IP services image (formerly known as the enhanced multilayer image [EMI]).
The IP base image provides Layer 2+ features, including access control lists, quality of service (QoS), static routing, and the Routing Information Protocol (RIP). The IP services image provides a richer set of enterprise-class features, including Layer 2+ features and full Layer 3 routing (IP unicast routing, IP multicast routing, and fallback bridging). To distinguish it from the Layer 2+ static routing and RIP, the IP services image includes protocols such as the Enhanced Interior Gateway Routing Protocol (EIGRP) and the Open Shortest Path First (OSPF) Protocol.
Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers support the following Cisco EtherSwitch service modules for SM-to-SM or SM-to-ISM communication.
Cisco 3900 series and Cisco 2900 series routers use Cisco High-Speed Intrachassis Module Interconnect (HIMI) to support SM-to-SM or SM-to-ISM communication through the MGF.
Use the connect connection-name module Module1 Channel-id1 module Module2 Channel-id2 command to establish a maximum of two HIMI connections on the Cisco 3900 series ISR routers and one HIMI connection on Cisco 2900 series andCisco 1900 series ISRs. Module 1 and Module 2 are the slot/port of the two modules. The Channel-id1 and Channel-id2 variables must always have a value of 0.
When two modules are configured in a HIMI connection, the modules cannot send traffic to any other module except its HIMI-dedicated partner.
NoteSee the module documentation to validate HIMI support.
Using HIMI for VLAN Traffic Flows
For HIMI configurations, the port-level VLAN memberships are ignored on the Multi-Gigabit Fabric (MGF). Use the connect connection-name module module1 vlan-id module module2 command to redirect VLAN traffic flows from SM-to-SM or SM-to-ISM connections on the MGF.
The following two modules, as well as others, support VLAN traffic redirection:
Cisco Etherswitch service module
Cisco Services Ready Engine internal service module (ISM-SRE)
NoteSee the module documentation to validate HIMI support.
Viewing Platform Information
The following sections explain how to view VLAN, slot, module, interface card, and MGF statistics on the router.
Slots on the router are optionally assigned to VLANs. From privileged EXEC mode, enter the show platform mgf command, then press Enter to display VLAN and slot assignments on the router. An asterisk next to the slot indicates that the vlan is the slot's default VLAN. The following example displays output from a Cisco 3945 ISR.
Note VLAN1 is the default when no other VLAN are listed.
Multi-Gigabit Fabric’s CPU port statistics display details about the hardware status, data transmission rate, line type, protocols, and packets. The following example displays output for the show platform mgf statistics cpu command when entered on a Cisco 3945 ISR.
Router# show platform mgf statistics cpu
Backplane-GigabitEthernet0/3 is up, line protocol is up
Hardware is PQ3_TSEC, address is 001b.5428.d403 (bia 001b.5428.d403)
MTU 9600 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Full-duplex, 1000Mb/s, media type is internal
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles